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steering - Central States Bus Sales, Inc.

1. The adjusting screw remains in this position and acts as the contact point for the lower poppet until poppets need to be reset again Je 5 APPENDIX om STEERING Self Test 1 Poppets reduce system pressure A After full turn B When axle stop contact is made C Just before full turn 2 Reducing pressure lessens A Temperature in the hydraulic system B Stress on the linkage C Both 3 Agood reason to reset poppets would be A Wheelcut has been reduced B Loose Steering C Wheel kick 4 Always set axle stops before setting poppets A True B False 5 If the sector shaft timing mark points toward the upper poppet you should set the lower poppet A True B False 2 APPENDIX BLUE BIRD SERVICE MANUAL Glossary of Terms Gear Families TAS Family TAS40 TAS55 TAS65 TAS85 RCS cylinders are TAS gears without worm and valve HFB Family HFB52 HFB64 HFB70 RCB cylinders are HFB gears without worm and valve HF Family HF54 HF64 Linear Cylinder A cylinder with a piston rod that provides in out thrust Lower End End of cylinder bore farthest from the input shaft Master Gear Main steering gear located on driver s side of vehicle
2. 5 F F SERVICE MANUAL Test 7 Measured Internal Leakage 1 Install temperature gauge in reservoir Figure 7 1 Install PSSA in pressure line with shut off valve fully open Figure 7 2 Nie THIS TEST CAN BE DANGEROUS IF NOT PER FORMED CORRECTLY KEEP YOUR FINGERS CLEAR OF THE AXLE STOPS AND SPACER BLOCK DURING THIS TEST MAKE SURE THAT THE SPACER BLOCK CONTACTS THE AXLE STOP SQUARELY CONTACT THAT IS NOT SQUARE COULD BREAK THE AXLE STOPS OR DANGER OUSLY THROW OR EJ ECT THE SPACER BLOCK 2 To test the steering gear for internal leakage you must first prevent operation of the gear s internal unloading poppet valves or relief valve or both in some gears This will allow full pump relief pressure to develop To prevent operation of the poppets place an unhardened steel spacer block about one inch thick and long enough to keep your fingers clear between the axle stop at one wheel Figures 7 3 7 4 To prevent operation of the relief valve remove the relief valve cap o ring and two piece relief valve if equipped from valve housing Install the relief valve plug Special tool number J 37130 in its place NOTE Be sure you reinstall the relief valve and valve cap with new o ring back onto the gear after leakage test ee ii When running this test do not hold the steering wheel in the full tum position for longer than 5 to 10 seconds at a time to avoid damaging the pump yas KEEP YOUR FINGERS CLEAR OF THE AXLE
3. Seal Part No Serration Size Major Serration Dia 478044 13 16 x 36 0 807 0 799 478060 7 8 x 36 0 866 0 857 478050 x36 0 987 0 977 478050 1 x 79 1 008 1 000 STEERING Sector Shaft Adjustment This adjustment can only be completed on the vehicle if the adjusting screw jam nut is accessible This nut is located on the side cover Tools Required Materials Required Screwdriver 34 Socket 3 Photos in this section were taken on a mock frame rail for 3 Open end wrench clarity Center the sector 1 With the engine on rotate the steering wheel input shaft shaft until the timing mark on the sector shaft lines up with the mark on the housing The line on the sector shaft should be at a 90 angle from the input shaft The sector shaft is now on its center of travel Turn the vehicle off Remove the drag 2 Remove the drag link from the pitman arm link N EAT Eg To avoid resetting the poppets do not rotate the input shaft more than 11 turns from the center of travel position while the drag link is disconnected Check for sector 3 From the center of travel position grasp the shaft lash pitman arm and gently try to rotate it back and forth If looseness or lash is felt at this point the sector shaft is out of adjustment Loosen jam nut 4 Loosen the jam nut If the gear is removed from the vehicle to adjust the lash e Leave the pitman arm connected to the gear e Best optio
4. end of timing mark toward adjusting screw until axle stop contact Is made c Hold the steering wheel in this position with 40 los rim pull for 10 seconds then release Repeat this hold and release process as many times as necessary while completing steps 11 and 12 first on the master gear then on the rotary cylinder 29 3 BLUE BIRD APPENDIX B3 FE SERVICE MANUAL 11 a With steering wheel held at full turn loosen the jam nut on the master gear and hold it in place with a wrench b Turn the adjusting screw in clockwise using finger pressure only don t use a ratchet until the Allen wrench comes to a stop Do not attempt to turn it in farther Pause the turning in process each time the driver releases the steering wheel Continue turning only while the wheel is held at full turn c Back off the adjusting screw 31 turns and tighten the sealing nut Torque nut to 33 37 ftelb 45 50 Nem 12 a With steering wheel held at full turn loosen the jam nut on the rotary cylinder and hold it in place with a wrench b Turn the adjusting screw in clockwise using finger pressure only don t use a ratchet until the Allen wrench comes to a stop Do not attempt to turn it in farther Pause the turning in process each time the driver releases the steering wheel Continue turning only while the wheel is held at full turn c Back off the adjusting screw 31 turns and tighten the sealing nut Torque nu
5. leakage or if preload adjustment Is required go to Valve Housing Worm Screw Disassembly procedures on page 53 If not proceed to step 27 Remove dirt seal 27 Remove and discard the dirt and water seal 40 Screwdriver Remove pressure 28 Insert a screwdriver through the trunnion opening seal and carefully push the seal 40 out without damaging the sealing area of the bore Discard the seal A special hook groove has been machined into the bore to hold the seal in position Clean out rubber from groove prior to installing new seal Inspect roller 29 Inspect the roller bearing 39 for brinelling or bearing spalling If replacement is required go to Roller Bearing Replacement on page 60 If not proceed to step 30 40 3 BLUE BIRD APPENDIX STEERING Inspect housing 30 Inspect the following for damage screws and plugs ePoppet fixed stop screw 38 ePoppet adjusting screw 38A and sealing nut 38B eAuto bleed plug 37 eManual bleed screw Not shown eAuxiliary port plugs 7 and o rings 6 If any are damaged go to Replace Housing Port Plugs and Screws on page 61 If not proceed to the Inspection Section 41 3 APPENDIX BLUE BIRD B3 FE SERVICE MANUAL Inspection Make sure all sealing surfaces and seal cavities are free from nicks and corrosion Any nicked or corroded surface requires part replacement to ensure proper sealing Wash all parts in clean
6. 15 Lash in Steering System Two people are needed for this test One person will slowly tum the steering wheel back and forth one quarter tum each way from center with the engine idling The other person should check for looseness at each of the following areas from steering wheel to road wheels Figures 15 1 15 5 Steering wheel to steering column U joints or slip joint and or miter boxes Steering column to steering gear input shaft Steering gear input shaft to steering gear output shaft Pitman arm to output shaft Drag link to pitman arm connection Drag link ends Sockets and adjustable areas Axle arm to drag link connection King pin axle connections bushings Tie rod arms to tie rod connection Tie rod ends sockets and adjustable areas Steering spindle Wheel bearings Lug nuts Spring pin connectors Front axle u bolts Spring hanger brackets rear shackles Cracked or broken components can cause symptoms Similar to loose components but may be more difficult to find Be sure to check rear drive axles for any looseness and inspect tires for signs of abnormal wear Test 16 Steering Gear Adjustment Check and adjust according to the appropriate service manual for your steering gear if necessary 30 4 APPENDIX STEERING Test 17 U J oint Phasing and Lubrication 1 Make sure u joints are properly lubricated 2 Steering column assemblies with more than o
7. 24 5 Nem is achieved N CAUTION Ball cap seal is greased to hold seal in groove while assembling Be sure not to trap the seal outside of the groove during reassembly Rotate the input shaft from one end of travel to the other without contacting the poppet stem to the valve housing and without moving the valve hous ing face more than 212 69 1 mm from input end upper end of rack piston If you cannot rotate the input shaft remove the balls and reassemble them N AV eg If you install a gear on a vehicle with the worm shaft unable to rotate the gear will not function correctly Steering and gear failure may result Apply clean oil to Teflon seal ring 23 on rack piston Make sure there is a space of V2 10 0 13 0 mm between valve housing 5 and poppet stem to prevent poppet contact at either end Remove the All Threads and push the rack piston assembly into the housing with the rack piston teeth toward the sector shaft cavity Line up the valve housing cylinder feed hole with the gear housing feed hole Make sure both o rings in the valve housing remain IN position Do not damage the seal ring 23 while installing the rack piston N CAUTION into housing The poppet seat and sleeve assemblies 27 must not bottom against the internal poppet stops in the steering gear until the gear is installed on the vehicle and the poppet adjustment procedures are performed N CAUTION Lubricate a
8. BLUE BIRD introduction This THP PCF Service Manual applies to all TRW THP45 PCF45 THP60 and PCF60 steering gears This service manual reflects TRW s commitment to provide easily usable material and highly recognizable hazard notices Some of the updates are e Caution and warning definitions e Torque force pressure and flow notations that provide metric equivalents e Service manual divided into sections for easier reference e Uninterrupted resealing instructions Reference to damage section allows you to repair or replace damaged parts and return to the resealing procedures easily The three column format used in the service manual will also help make it easy for you to service a steering gear Column 1 illustrates the procedure with photographs column 2 gives a brief key as well as tools to be used for each procedure and column 3 explains in detail the procedure you should follow Pay special attention to the notes cautions and warnings Item numbers on the exploded view correspond with item numbers in that are used throughout the service manual As you gain experience in servicing THP PCF series steering gears you may find that some information in this service manual could be clearer and more complete If so let us know about it Don t try to second guess the service manual if you do not understand a procedure or are stuck contact our Field Service Department at 317 423 5377 Servicing THP PCF series steering gears sho
9. Ball Return Guide Cap Torx Screw 2 Housing Dirt and Water Seal Trunnion Grease Fitting Plug Auto Bleed Fixed Stop Screw Poppet Poppet Adjusting Screw Nut Poppet Adjusting Screw Bearing Roller Seal 2 Output Sector Shaft Assembly Sector Shaft Adjusting Screw Washer Bearing Roller Side Cover O ring Side Cover Assembly Jam Nut Vent Plug Side Cover Bolts Side Cover 6 These items are included in complete seal kits along with 045422 lubricant and a service bulletin 8 BLUE BIRD 3 APPENDIX THP PCF Service Parts List Common Parts Item Description 1 Bolts 4 Valve Housing 2 Dirt and Water Seal 13 16 Serr 2B Dirt and Water Seal 7 8 Serr 2C Dirt and Water Seal 1 Ser 3 Retaining Ring 4 Seal Input Shaft 6 O ring 2 Aux Port Plug 7 Auxiliary Port Plug 2 9 O ring Relief Valve 10 Cap Relief Valve 11 Seal Ring 12 Ball Bearing Assy 13 Seal Ring Valve Housing 14 Seal Ring Valve Housing 16 Thrust Bearing 17 Thrust Washer 18 Seal Ring 19 O ring 20 Bearing Adjuster 21 Adjuster Locknut 24 Push Tube 25 Poppet Spring 26 Poppet 2 27 Poppet Seat and Sleeve Assy 2 29 Balls 31 Cap Seal 32 Ball Return Guide Cap 33 Torx Screws 2 36 Grease Fitting 37 Plug Auto Bleed 37A Screw Manual Bleed 38 Screw Fixed Stop 38A Screw Poppet Adjusting 38B Nut Poppet Adjusting Screw 44 O ring Sidecover 46 Nut Jam 47 Plug Vent Side Cover 48 Bolts Side Co
10. Park the vehicle with the wheels turned all the way to the axle stop in either direction Turn the vehicle off Lower Poppet Upper Poppets 2 Look at the output shaft timing mark nearest the Lower Poppet housing piston bore on the master gear Is this EE EWE mark pointing toward the poppet screw or away from it Poppet Screw 3 Now check the same timing mark on the rotary cylinder Does it point toward the poppet screw or away from it If they point to opposite ends of the gears you have a mirror image system see pg 27 If they both point toward the poppet screws or both point toward the end opposite the poppet screws you have a reversed image system see pg 29 26 H 3 BLUE BIRD APPENDIX STEERING Poppet Readjustment Dual Gears Mirror Image Tools Required TAP PCF45 6mm Allen wrench 19mm Open end wrench 3 Open end wrench Socket Open end wrench ftelb Torque wrench 18mm Open end wrench Materials Required THP PCF60 Hydraulic fluid 72 Allen wrench Jack 19mm Socket 1 Set the axle stops to vehicle manufacturer s wheelcut or clearance specifications Start the engine and allow the vehicle to idle for 5 10 minutes to warm the hydraulic fluid Shut off the engine 2 If new poppet adjusting screws and nuts will be used turn each screw into the non sealing end of the jam nut until the drive end of sc
11. Pressed Fit The fitting of two components that allows a controlled movement between them but will not allow them to move during normal operational actions Pump Relief Pressure Maximum pressure of the power steering pump Rim Pull Force used to turn the steering wheel measured in pounds at the rim of the steering wheel Slave Gear Auxiliary gear on passenger side of vehicle Has no worm screw ball nut mechanism or control valve Steering System Includes mechanical and hydraulic components steering wheel column u joints slip joints miter box steering gear pump reservoir hoses and connections pitman arm drag link and sockets axle arm king pin bushings tie rod arms and ends steering spindle wheel bearings springs and spring pin connectors spring hanger brackets front axle u bolts Steering Wheel Travel Number of times the steering wheel can rotate between full turns Thread Engagement The amount of contact between threads on screw and nut Timing Marks Use the output shaft timing mark nearest the cylinder bore to judge which poppet to set Upper End End of cylinder bore nearest the input shaft Ee 5 BLUE BIRD APPENDIX STEERING y Answers to the Self Test AA BWN mm Ur ON TAS Poppet Workbook MEE a MS TRW Commercial Steering Systems AAN di 800 Heath Street Lafayette IN 47904 Phone 765 423 5377 Fax 765 423 4453 TRW1102 Electronic Version February 2001
12. Retain the guides for reassembly Remove steel balls 22 Remove the steel balls 29 from the rack piston 28 by rotating the input shaft valve worm assembly until the balls fall out Place the balls and return guides in a cup or other container Count the balls and make sure all have been removed N PA VEG The steel balls are a matched set If any are lost the set must be replaced by service balls Number of factory balls installed THP PCF45 29 balls THP PCF60 31 balls Separate rack 23 Remove the input worm and valve housing subas piston from worm sembly from the rack piston 8 17 subassembly Remove seal ring 24 Cut and remove the Teflon seal ring 23 and o ring and o ring 22 from the rack piston Pocket knife 39 3 APPENDIX BLUE BIRD SERVICE MANUAL Inspect poppet 25 Push poppet stems they should spring back Push assemblies poppet seat it should not move by hand If compo nents are bent or broken poppet stems don t spring back or poppet seat moves by hand go to Poppet Component Replacement section on page 51 Other wise proceed to step 26 TRW recommends the poppet adjuster seat and sleeve assem blies 27 not be removed unless replacement of poppet components is required Inspect valve 26 Inspect valve housing worm screw subassembly for housing and worm heat damage or bearing roughness If these condi screw tions are present or if there was excessive internal
13. Yes oos Vehicle Alignment TEST 21 i Oo Yes ore Steer Axle Wheel Bearing Adjustment TEST 22 Yes ore No Check Caster and toe on the front axle Yes oos No Power Steering Pump TEST 5 COMMENT Yes oos Flow Control Response TEST 6 Oo Pump Reference Chart Flow settings according to pump part numbers END BINDING DARTING amp OVERSTEER 11 4 APPENDIX BLUE BIRD SERVICE MANUAL Directional Pull Does vehicle pull while braking or accelerating Unequal Braking Force TEST 25 Accelerating COMMENT F Preliminary checklist 1 Vehicle pre alignment TEST 21 2 Wheel bearing adjustment TEST 22 3 Air suspension adjustment TEST 23 4 Steer tires a Swap tires b Belt tread mismatched 5 Vehicle loading Overloaded Unbalanced Gear TEST 24 Power Steering Pump TEST 5 Call technical service Yes Yes END DIRECTONAL PULL 12 4 BLUE BIRD APPENDIX STEERING oad Wander Loose Steering Wheel Bearing Adjustment TEST 22 Torque Steer COMMENT E Preliminary checklist 1 Vehicle pre alignment TEST 21 2 Steer tires a Swap tires b Belt tread mismatched 3 Fifth wheel properly greased TEST 2 Yes re No Torque steering gear mounting bolts to OEM specifications Yes ore No Mechanical Looseness TEST 15 TEST 16 TEST 20 N
14. fluid STEERING Poppet Readjustment Single Gears This resetting procedure will work in most cases with at Tools Required least 13 hand wheel turns from each side of center If THP PCF45 ya Open end wrench you re making a large reduction in wheelcut and this 6mm Allen wrench Ya Socket procedure does not work you may have to replace or 19mm Open end wrench Open end wrench internally reset the poppets using the procedure de 19mm Socket ftelb Torque wrench scribed in the Poppet Component section of this Service 18mm Open end wrench Materials Required manual THP PCF60 Hydraulic fluid 7 32 Allen wrench Jack Set axle stops 1 Set the axle stops to vehicle manufacturer s warm up system wheelcut or clearance specifications Start the engine and allow the vehicle to idle for 5 10 minutes to warm the hydraulic fluid Shut off the engine Assemble adjust 2 Ifa new poppet adjusting screw and nut are being ing screw into nut used turn the screw into the non sealing end of the jam nut until the drive end of screw is flush with the nut Your steering gear will have either a fixed stop bolt or an adjusting screw If the adjusting screw is already part of the steering gear back the nut off of the adjusting screw until it is flush with the end of the adjusting screw Remove poppet 3 Make sure the engine is off and the road wheels are stop bolt in straight ahead position Remove and discard the popp
15. 1 Look for Tire damage Uneven or extreme tread wear mis matched tires or other wear indicators that would cause the problem Figure 1 1 2 Check tire pressures on steer axle tires Figure 1 2 Test 2 Fifth W heel and Trailer Plate 1 Look for dry fifth wheel or trailer plate Figure 2 1 2 Look for damage to fifth wheel or trailer plate Figure 2 2 3 Inspect fifth wheel for looseness Test 3 Steer Axle and Linkage Binding 1 With vehicle steer tires on radius plates turntables or equivalent disconnect the drag link or pitman arm from the steering gear and linkage from assist cylinder if there is one on the vehicle Figure 3 1 EHNE Do not steer the gear with linkage removed as misadjustment of automatic poppets may result 2 By hand pull the tire to one axle stop and release engine off The tire should self retum to near straight ahead Figure 3 2 3 Repeat the test in the opposite direction 4 If tire does not self retum to near straight ahead a problem is likely in steer axle king pin bushings bearings or linkage Figure 3 2 20 4 BLUE BIRD APPENDIX STEERING Test 4 Steering Gear Mounting 1 Look for anything between the steering gear and frame that could cause a binding problem For example hoses or brackets that have been routed or are interfering between the steering gear and frame frame flanges or spring mounting points Figure 4 1 Mounting pads lower than steeri
16. Figure 21 1 Test 24 Gear Imbalance 1 Install alow pressure gauge 200 300 psi 14 21 bar maximum with approximately 10 psi 70 bar per division in the pressure line from pump to gear Figure 24 1 Neeme Do not allow system pressure to exceed the rating of the gauge in the following procedure or damage to the gauge will result 2 At engine idle slightly tum the steering wheel one direction until a pressure rise is observed at the gauge Figure 24 2 3 Stop steering and gently allow the steering wheel to recenter 4 Next slightly turn the steering wheel the opposite direction while observing the gauge and determine if pressure initially rises or falls with initiation of a tum 5 Repeat test a few times in each direction 6 If aconsistent fall in pressure is associated with the initiation of a tum in one direction the steering gear s control valve is unbal anced and needs to be replaced Test 25 Unequal Brake Force Visually inspect brake assemblies for oil grease on braking sur faces and overall condition of brake surfaces Adjust or replace brakes if necessary 32 4 BLUE BIRD APPENDIX STEERING Test 26 Tire Balance Runout Have wheel assemblies balanced and checked for lateral and radial run out per manufacturer s specifications Preferred method for checking balance is with wheels still on the vehicle Balance includes total rotating assembly TEST 27 Steering Column Noise
17. If column does not include a clockspring remove steering wheel and add dielectric grease to the hom contact The grease TRW uses IS Model No K 5 X Semifluid CA product code 134613 from Century Lubricants If noise continues check steering wheel and Shroud not applicable to columns with clockspring TEST 28 Steering Column Bearing Check upper bearing gaskets Gaskets should cover bearing TEST 29 Intermediate Column Lash Check intermediate column I Shaft for torsional lash in U J oints of slip section Replace intermediate column if necessary 4 APPENDIX 33 BLUE BIRD SERVICE MANUAL This page intentionally left blank 34 BLUE BIRD APPENDIX STEERING y Section 4 Comments C mMeEnt A M EO EO OE AE EE EE EE Re 36 EM ENKE 37 35 BLUE BIRD APPENDIX ES gt F F SERVICE MANUAL BLUE BIRD Comment A Some power steering pumps have a temporary state during which the pumping element vanes do not extend Usually increasing engine speed briefly will correct the problem Comment B The maximum speed of steer with power assist for a power steering gear is limited by the pump flow and internal leakage Example Recommended minimum flow for a new TAS65 steering gear is 3 0 gpm 11 4 Ipm and is based on a maximum steering speed capability of 1 5 steering wheel tums per second Comment C Vehicle linkages are designed to minimize the affect at the steering gear
18. Materials Required Hammer inelb Torque Small probe or ftelb Torque wrench pick wrench J37464 Sockets Punch center J37070 12 point sockets Punch roll pin 137073 Screwdriver Place valve 1 With worm vertical place the valve housing 5 housing and valve input shaft valve worm assembly 15 in a vise assembly in vise Unstake adjuster 2 Unstake the valve housing 5 where it was upset locknut into the adjuster locknut 21 slot Also unstake adjuster nut from adjuster 20 Roll pin punch Hammer Remove bearing 3 Turn bearing adjuster locknut 21 out of the valve adjuster locknut housing J37464 Remove bearing 4 Turn bearing adjuster 20 out of the valve housing adjuster J37070 53 3 APPENDIX BLUE BIRD SERVICE MANUAL Remove seal ring 5 Remove and discard seal ring 18 and o ring 19 and o ring from bearing adjuster Small probe or pick Remove input shaft 6 Remove the input shaft valve worm assembly 15 from the valve housing 5 Remove thin 7 Remove thin thrust washer 17 and thrust bearing washer and 16 from input shaft 15 bearing AN dil E Input shaft valve worm assembly must not be disassembled further The components were a select fit at assembly and are available only as part of this subassembly If disas sembled further the subassembly must be replaced Remove ball 8 Remove bearing 12 from valve housing bearing iN PPU egg Do not remo
19. STOPS AND SPACER BLOCK DURING THIS TEST MAKE SURE THAT THE SPACER BLOCK CONTACTS THE AXLE STOP SQUARELY CONTACT THAT IS NOT SQUARE COULD BREAK THE AXLE STOPS OR DANGEROUSLY THROW OR EJ ECT THE SPACER BLOCK 3 With the fluid temperature between 125 135 F 52 57 C tum the steering wheel until the axle stop bolt contacts the spacer block 4 Apply 20 pounds of force to the rim of the steering wheel during this test to be sure that the steering gear control valve is fully closed Figure 7 5 The pressure gauge should now read pump relief pressure aS noted during the Flow Control Response Test Test 6 You can now read steering gear internal leakage on the flow meter 5 Repeat this test for the opposite direction of tum 6 If intemal leakage is greater than 1 gpm 3 8 Ipm and there is no auxiliary hydraulic linear or rotary cylinder in the system repair or replace the gear If the internal leakage is greater than 2 gpm 7 6 lpm and there is an auxiliary hydraulic linear or rotary cylinder in the system controlled by the gear isolate the auxiliary cylinder from the system by disconnecting the auxiliary cylinder hydraulic 26 Figure 7 5 4 BLUE BIRD APPENDIX lines at the gear auxiliary ports Plug the steering gear ports with Suitable steel or high pressure plugs or caps In the event that a rotary cylinder is used in the system connect the disconnected lines together with a suitable union fitting In
20. Valve Hydraulic Steering Pump FLOW mud Steering Schematics BLUE BIRD 0000432 3c Flushing the Steering System Appendix 1 Flushing the Steering System The steering system must be flushed every time a gear pump or reservoir gets replaced regardless if the components are new or are remanufactured 1 2 10 11 12 13 14 15 Set parking brake on vehicle and block rear wheels Raise the front end off the ground Take vehicle out of gear and put into neutral position Raise hood and wipe down area around the steering gear and the hydrau lic lines related to the steering system Place a drip pan under the steering gear to catch the oil Remove both the pressure and return lines Figure 1 from the steering gear and allow the oil to drain into the empty container Remove filter Figure 2 from the power steering fluid reservoir and discard Disconnect the supply line from the reservoir Rinse and clean the inside of the reservoir with an approved solvent then air dry Do not use a shop rag to wipe the inside of the reservoir and make sure that none of the solvent enters the rest of the steering system If the reservoir is made from plastic inspect for cracks and damage Replace if necessary Turn steering wheel from full left to full right 3 4 times Collect the drained oil in the same container as in Step 6 This will purge the oil from the steering gear Reconnect pressure and r
21. caution when you remove lift carry or fix in a bench vise Remove the steering gear from the vehicle and take it to a clean work surface Clean and dry the gear before you start to disassemble it As you disassemble the gear clean all parts in clean OSHA approved solvent and air blow dry them only AME NA Because they are flammable be extremely careful when using any solvents Even a small explosion or fire could cause injury or death NETTIE Wear eye protection and be sure to comply with OSHA or other maximum air pressure requirements N dT Never steam clean or high pressure wash hydraulic steering components Do not force or abuse closely fitted parts Use care that bearing and sealing surfaces are not damaged by the assembly and disassembly procedures Keep each part separate to avoid nicks and burrs Discard all seals o rings and gaskets removed from the gear Replace them with new parts only The steering gear should be identified to the vehicle from which it was removed The poppet adjuster seat and sleeve assemblies are set for that particular vehicle only 34 3 BLUE BIRD APPENDIX Disassembly Tools Required STEERING Materials Required Screwdriver Sockets eStandard eTorx Vise Allen wrenches Pocket knife Ratchet Rolling head pry bar Rubber mallet Position gear in vise Unplug ports Appropriate size socket or open end wrench Position sector sh
22. contact with the poppet stem Insert two 14 mm x 2 0 mm All Threads through valve housing bolt holes and tighten into housing to support the worm 14mm X 2 0mm i Men screw Line up rack piston ball guide holes with the worm ball track grooves by rotating the input shaft 45 3 APPENDIX BLUE BIRD SERVICE MANUAL Assemble ball 7 Assemble the ball return guide 30 into the rack return guide piston until seated rotate the input shaft slightly if halves necessary AN MEINA Do not seat guides with a hammer Damage to guides can result in subsequent lockup or loss of steering iN CAUTION If a new rack piston 28 or a new input shaft valve worm subassem bly 15 is being assembled the balls 29 removed from the unit must be discarded and a service ball kit utilized The balls in a service ball kit are sized to function in the ball track guide path as altered by component replacement N CAUTION When using the service ball kit use the correct guantity of service balls THP PCF45 29 balls THP PCF60 31 balls Assemble balls 8 Hold the ball return guide 30 firmly in place during this entire procedure Insert as many of the steel balls as you can through the hole in the top of the ball return guides Rotate the input shaft to pull the balls down and around the ball track guide path Continue until the correct number of balls are in the ball track guide path N TITEL TER Hold down the ball
23. full left turn to full out from bleed right turn several times Stop steering and loosen screw the manual bleed screw about one turn Allow air and aerated fluid to bleed out until only clear fluid is seen Close the bleed screw refill the reservoir if required Manual Bleed Screw inelb Torque wrench 6 Socket Repeat step 4 three to four times until all the air is discharged Torque manual bleed screw to 45 inelb iN dT EA Do not turn steering wheel with bleed screw loosened 3 BLUE BIRD APPENDIX STEERING Input Shaft Seal Replacement This procedure uses the vehicle s power steering pump Tools Required Materials Required to force out the input shaft seal To use this procedure the power steering pump should have a minimum of 1 500 psi available Hammer Clean cloth J37073 Seal Driver Drip pan Screwdriver High pressure fitting Hydraulic fluid Plug Shop towel Disconnect return 1 Disconnect return line from the steering gear and line plug the line Also cap the return port of the gear with a high pressure fitting High pressure fitting Plug Disconnect 2 Remove the steering column from the gear input column shaft Remove dirt amp 3 Remove the dirt and water seal from the steering water seal gear Save this seal to match the new seal to the correct size Remove retaining 4 Wipe out the grease and then remove the spiral ring retaining ring Us
24. gear You may start the shaft and cover assembly removal by tapping the end of the shaft lightly with a soft mallet or wooden hammer handle Remove and discard the side cover o ring 44 STEERING Remove vent plug 10 Remove and discard the vent plug 47 Remove sector 11 Turn sector shaft adjusting screw 41A clockwise shaft from cover through the side cover and pull the sector shaft out of the side cover Remove side cover 12 N e TT Don t damage the bore or bearing seal and washer when removing the seal 3 Drive socket Rolling head pry Clamp the side cover in a vise Place a standard 56 or 116 drive socket in the center of the side cover Pry the seal 40 out with a rolling head pry bar using the socket for support Discard the seal and remove the socket Remove washer 42 bar Inspect adjusting 13 Inspect the sector shaft assembly for damaged screw and retainer adjusting screw threads The retainer 41B not 8 15 shown must be securely staked in place The adjusting screw must rotate by hand with no perceptible end play lash Remove relief 14 If equipped remove relief valve cap 10 o ring 9 valve components and two piece relief valve 8 from the valve hous ing Discard the o ring 37 3 0 APPENDIX BLUE BIRD SERVICE MANUAL Remove dirt amp 15 Remove and discard the dirt amp water seal 2 2B or water seal 2C from the input shaft worm and valve assembly S
25. gear driven The configuration of hydraulic lines from the pump to the steering gear is dependent on whether the bus has a hydraulic brake or air brake system On All Americans equipped with air brakes the power steering fluid flows from the reservoir to the pump then to the steering gear and returns directly to the res ervoir On All Americans equipped with hydraulic brakes the power steering fluid flows from the reservoir to the pump to the power steering gear and then to the hydraulic brake power assist booster From there the fluid returns to the reservoir er Le The power steering fluid and the brake fluid are not the same They must be kept separate Use DOT 3 for the brake system and use Dexron III for the power steering fluid TRW POPPET TRW STEERING TRW THP TRW SYSTEM TRW SYSTEM ADJUSTMENT DIAGNOSTICS STEERING GEAR AIR BLEEDING FLUSHING APPENDIX APPENDIX APPENDIX APPENDIX APPENDIX BLUE BIRD 0 SERVICE MANUAL There are a number of acceptable hydraulic fluids approved for use in the power steering system the system must be drained and flushed to use a different type of fluid See Appendix 3 THP Steering Gear Service Manual for approved hydraulic fluids Do not mix oils or fluids if you change the fluid The steering reservoir on an All American Forward Engine can be accessed by opening the drivers side front access panel The hydraulic brake reservoir is located in the same area GLTNINIS The hydraulic fluid f
26. in the Chassis Electrical section of this manual STEERING Steering Wheel Removal 1 Remove the screws retaining the steering wheel cover 2 Lift the cover and disconnect any electrical circuits 3 Check the alignment marks on the steering shaft and steer ing wheel flange make new alignment marks if necessary and remove the steering wheel nut 4 Remove the steering wheel The steering shaft and the mat ing flange on the steering wheel has splines but are not ta pered A rubber hammer may be required to provide enough force to loosen the connection Steering Wheel Reinstallation To replace the steering wheel assembly reverse the procedure above Making sure the steering wheel is aligned with the steering shaft Torque the steering wheel nut to 40 to 50 ft Ibs Steering Wheel Installation Stems Not Illustrated BLUE BIRD BLUE BIRD SERVICE MANUAL Steering Gear The THP 60 is an integral hydraulic power steering unit The steering gear contains a manual steering mechanism a hydraulic control valve and a hydraulic power cylin der The control valve senses steering requirement from the driver and directs oil flow to the appropriate cylinder cavity at the proper flow rate thus providing a smooth power assist steering The speed at which the driver can turn the steering wheel with power assist is dependent upon the rate of flow provided by the hydraulic pump Normal flow rate is 3 6 to 6 3 gpm
27. leaks and correct if necessary 18 Bleed air from the system if required Refer to your steering gear service manual for recommended air bleeding procedures 19 Remove drip pan and lower vehicle Remove blocks from wheels and release vehicle for normal service 887 Comment K Identifying Bumt Oil Sometimes the power steering reservoir oil Supply will become hotter than the normal operating temperature and overheat This condition may result in an intermittent loss of power assist and alSo cause deterioration of the power steering hoses and component seals TRW recommends that the power steering hoses be examined for deterioration due to overheated oil which can be identified by wet hoses and determine the condition of the reservoir fluid by looking for signs of burt oil 37 4 APPENDIX BLUE BIRD BLUE BIRD SERVICE MANUAL This page intentionally left blank APPENDIX 38 STEERING y Section 5 Test Results Test 5 Power Steering Pump Test sees ss ee ee EE 40 Test 5 1 40 Minute Power Steering Pump Test 40 Test 6 Flow Control Response Test ccccccssseeeeeeeeeeees 41 Test 6 1 40 Minute Flow Control Response Test 41 Test 10 Restricted Hydraulic Line Test iis sesse sesse 42 Steering Gear Flow Requirements cccccssssseeeeeseeeees 43 Pump Part Number Reference Guide ese ee 44 39 4 APPENDIX BLUE BIRD AD F F SERVICE
28. on vehicle and block rear wheels Raise the front end off the ground Take vehicle out of gear and put into neutral position Raise hood and place a drip pan under the steering gear Remove both the pressure and retum lines from the steering gear Remove filter from the power steering fluid reservoir and discard Or RE iS IMPORTANT Discard only the filter other components may be required to hold filter element in place inside the reservoir 7 Clean the inside of the reservoir 8 Turn steering wheel from full left to full right 3 4 times This will purge the oil from the steering gear 9 Reconnect pressure and retum lines to the steering gear and tighten 10 Install new filter element into the reservoir 11 Clean reservoir filler cap with an approved solvent Inspect gasket and replace if necessary 12 Fill reservoir with approved replacement fluid and reinstall the filler cap 13 Start engine for 10 seconds stop and check reservoir fluid level and top off if necessary You may need to repeat this procedure 3 or 4 times 14 Upon completion of filling the reservoir start the engine and let it idle At engine idle steer full right and full left once and retum to straight ahead Stop engine and check power steering reservoir level and top off if required 15 Restart engine and steer full turns each direction 3 or 4 times 16 Stop engine and recheck reservoir fluid level and adjust to correct level if needed 17 Inspect system for
29. return guides until cap is reinstalled Failure to hold the guides will result in a trapped ball or balls which could cause a vehicle accident If the ball guide becomes unseated raises at any time repeat the procedure starting at step 7 ANETTE The correct number of balls are required for proper gear operation Count the balls and insert each carefully as in step 7 Number required THP PCF45 29 balls THP PCF60 31 balls AN CAUTION Do not allow valve housing to contact the poppet stem or move more than 212 inches 69 1 mm from upper end of rack piston during these procedures This could incorrectly reset the poppet or back out worm beyond closed ball loop trapping balls AN ei eg Remove any fluid present in the two screw holes Fluid in these holes could cause improper clamp load when torquing the cap 46 e gt 3 BLUE BIRD APPENDIX Assemble ball 9 return guide cap T 30 Torx socket inelb Torque wrench Grease Rotate input shaft 10 to check for proper installation of balls Install rack piston 11 worm valve assembly Install valve 12 housing bolts E 18 Torx socket ftelb Torque wrench STEERING Place a new ball return guide cap seal 31 in the seal groove of the cap 32 Make sure the seal makes full contact with the rack piston surface Install two new Torx head screws 33 and torque each screw alternately until a final torque of 18 ftelb
30. side cover design that reduces weight package size more robust seal and a roller bearing to reduce friction and wear e Material and design changes made to operate at the higher pressure ear I doll pa z i s 1 z 3 7 a z 1 a i i r j D ed del n r j lal Le i x i mm La F F r z ed id a A a i a i T 1 y P j p i E 1 T F a 7 p 5 d n a ml e P E a ph Ba af ar VER ON m Mid F p T 1 TN l 1 5 F w mr I af a 1 sr Ka mii af 3 APPENDIX BLUE BIRD B3 FE SERVICE MANUAL Contents Section 1 Section 2 Section 3 Section 4 Section 5 General Information roae HOM RR OR ER Oe OE EE N EE 2 eo ICS T de SE N EE EE OR OE 3 EE EG SION PE ER EN 4 EEG RE GE ese Re EG ee EE De 5 Approved Hydraulic FIWIGS ei eie RE N EE ae EE De Ed 6 ae ele see is RE OE N N N EE 6 Gear Specification Numbers ee ee ee ee ee ee ee ee ee ee 6 ie el 0 ga EEE 7 Exploded iN 8 obve Parta SE De OE een ee eo ke ee ii tease 9 Initial Installation Tr sje 1 og AA ei RO orion lt 8 AA OE EE aver 13 Fv N ER N ie 13 MST 14 On Vehicle Service Filling and Air Bleeding the System ee ee ee ee ee ee ee ees 16 Input Shaft Seal Replacement ee ee ee ee ee ee ee ee ee ee ee 17 Sector Shaft AAUSUTIERE steke ese OE ge ORE Ge Ee Ek DE ER 21 Poppet Readjustment Sale GE EEE 23 BEE EEE EE 26 Mirror ante ee
31. steering gear to a inspect the steering gear for abnormal wear and damage b choose a repair procedure which will not endanger his her safety the safety of others the vehicle or the safe operation of the vehicle and c fully inspect and test the THP PCF steering gear and the vehicle steering system to ensure that the repair or service of the steering gear has been properly performed and that the steering gear and system will function properly Patents TRW Commercial Steering Systems THP PCF power steering gears are covered by several United States and foreign patents either issued or pending TRW Inc 2001 aa 3 BLUE BIRD APPENDIX LE Design Features 1 Size Reduced package size for increased wheelcut 2 Weight Reduced weight for improved vehicle efficiency 3 Improved Steering Performance e Faster steering ratio for improved handling and lower lock to lock turns e Low internal friction for better return to center 4 High Pressure Capability Provides for the smallest and lightest package 5 Positive Center Feel Optional e Provides steering precision through improved straight ahead torque feedback more stiffness and improved position feedback control less hysterisis e Allows separation of parking efforts from on highway efforts e Premium performance steering gear designed for line haul vehicles 6 Design THP PLF gear is based on the TAS model s proven steering gear technology plus e mproved
32. the lip with the garter spring is toward the shoulder of the tool Working from 137705 the side cover side of the housing pilot the seal tool THP PCFA5 into the washer and bearing and press with a force 137071 of 100 800 Ib 445 3 560 N until the seal is seated THP PCF60 firmly Install dirt amp water 6 Install the dirt amp water seal 35 with the bearing and seal seal tool long end making sure it is not cocked Press the seal only until it seats against the bearing don t push it in farther Press Liberally pack the roller bearing and new seals with clean high temperature industrial grease Exxon Polyrex EP P N 045422 44 BLUE BIRD APPENDIX STEERING Assemble seal 3 Lightly oil new seal ring 11 and assemble in valve rings housing mounting face groove Then oil new seal ring 10 and assemble in valve housing 5 mounting face groove Install rack piston 4 Install anew backup o ring 22 and then a new o ring and seal Teflon seal ring 23 on rack piston 19 Do not ring over stretch these rings as you install them Do not allow the Teflon seal ring to be twisted Position rack 5 Apply clean oil to housing cylinder bore Place the piston in housing rack piston 28 in the housing piston bore with ball return guide holes up Insert worm and 6 Insert the worm screw into the rack piston close to valve assembly maximum depth without the valve housing making 823 into rack piston
33. the pump relief setting shown in the example below See illustration on where to find the pump part number If the values that you have recorded are within 100 psi 7 bar your pump is functioning properly If the values recorded are below the negative tolerance your pump is malfunctioning and should be replaced For TRW power steering pumps the relief setting will be the 5th and 6th numbers in the pump part number EV 1812 15 R 10100 Family designation EE 5 PS PS Pump EV EV Pump Displacement per revolution 18 18 cc 1 10 cir 22 22 cc 1 34 cir 25 25 cc 1 53 cir 28 28 cc 1 71 cir Flow control 12 12 Ipm 3 17 gpm 14 14 Ipm 3 70 gpm 16 16 Ipm 4 23 gpm 20 20 Ipm 5 28 gpm 24 24 Ipm 6 34 gpm Relief setting 09 90 bar 1305 psi 10 100 bar 1450 psi 12 120 bar 1740 psi 14 140 bar 2030 psi 15 150 bar 2175 psi 16 160 bar 2320 psi 17 170 bar 2465 psi 18 185 bar 2683 psi Direction of rotation R clockwise rotation L counterclockwise rotation Shaft type 1 11 tooth 16 32 spline 2 625 dia woodruf key Housing Varies between PS and EV Series pump Customer version 00 Standard 44 4 APPENDIX STEERING BLUE BIRD APPENDIX gt FE SERVICE MANUAL BLUE BIRD AAN did 4 APPENDIX TRW Automotive Commercial Steering Systems 800 Heath Street Lafayette IN 47904 Tel 765 423 5377 Fax 76
34. to the tool turn one adjuster adjuster seat seat and sleeve assembly out of the rack piston If 829 the ratchet does not turn easily strike the adjuster removal tool again with a hammer If the engaging J36452 A eo bo tangs won t stay in place while torquing it might be necessary to hold in place with an arbor press while applying loosening torque Discard poppet seat and sleeve assembly Remove poppet 4 Remove the two poppets 26 spring 25 and push components tube 24 Poppet Components ns YY Xn WN WY Poppet f Poppet N 4 C gt Poppet Seat and Push Tube Sleeve Assembly 51 3 APPENDIX BLUE BIRD BLUE BIRD 52 SERVICE MANUAL 3 APPENDIX Remove other seat amp sleeve if necessary Reset remaining poppet seat and sleeve assembly Press 3 X 6 Drill rod Apply Locquic T primer and Loctite RC680 Locquic T primer Loctite RC680 Install one poppet seat and sleeve assembly Soft jawed vise Install remaining poppet compo nents J36452 A ftelb Torque wrench 5 Remove and discard remaining poppet seat and sleeve assembly only if reguired It is possible to reset one poppet adjuster seat and sleeve assembly for automatic poppet adjustment while it is in the rack piston if one adjuster seat and sleeve assembly and the poppets spring spacer rod and push tube a
35. turned the con trol valve spool mounted on the torsion shaft the torsion shaft connects the input shaft to the worm shaft shifts and redirects oil flow to either side of the rack piston A relief valve mounted on the valve housing limits maximum pressure to protect the power steering system This is the primary pressure relief valve for the steering system A secondary pressure relief valve is located in the hydraulic pump assembly on All American Forward Engine units Objectionable kickback is prevented due to the geometry of the steering gear If the wheels receive a shock load from hitting rough areas in the road it is transmitted back through the sector shaft rack piston and worm gears This load is neutralized by the control valve which sends oil flow to the correct side of the rack piston to resist the shock forces By absorbing the shock forces hydraulically the steering gear prevents objectionable kickback at the steering wheel and driver The steering gear is equipped with two poppet valves one on each end of the rack piston The poppet valves are set specifically to the turning radius of each bus after the axle stop adjustment has been made When the steering wheels are turned and approach the axle stop one poppet valve depending on the direction of turn BLUE BIRD STEERING trips The tripped poppet valve opens allowing oil flow to bypass the piston which reduces pressure in the gear and helps reduce heat buil
36. 2 APPENDIX BLUE BIRD
37. 4 8 bar respec tively The line reservoir pressure drop for a flow of 3 4 5 or 6 gpm 11 15 19 or 23 lpm should not be greater than 20 20 25 or 25 psi 1 4 1 4 1 7 1 7 bar respectively 4 APPENDIX STEERING Test 11 Axle Stop Setting Put vehicle steer tires on radius plates turntables Check to make sure axle stops are set to manufacturer s specifications Figure 11 1 Test 12 Pitman Arm and Output Shaft Alignment Look to make sure the output shaft timing mark is lined up with the pitman arm timing mark Some pitman arms have more than one mark so make sure the right one is used Figure 12 1 Test 13 M isadjusted Drag Link The length of the drag link must be correct for the steering system Check the length after you make sure the pitman arm Shaft timing marks are aligned the gear is at its center position and the road wheels are straight ahead Figure 13 1 Test 14 Poppet Setting Procedure 1 If you are working on a newly installed TAS steering gear refer to the service manual to correctly set the poppets If you are working on a steering gear other than a TAS series refer to the OEM s service manual for correct poppet setting instructions 2 To set poppets on a TAS series gear using the adjustable service kit refer to your steering gear service manual Figure 13 1 29 4 APPENDIX BLUE BIRD 880 0 BLUE BIRD SERVICE MANUAL Test
38. 5 429 1868 http www trucksteering com http trucksteering trw com TRW Inc 2002 TRW 1250 Rev 4 02 TAS Poppets Appendix 5 STEERING y AAN di TRW Automotive CommercialSteering Systems TAS Poppets A Workbook and Self Test to be used with the TRW TAS Poppet SettingVideo Follow all precautions and warnings in Service Manual when setting or resetting poppets BLUE BIRD APPENDIX SERVICE MANUAL What Poppets Are Poppets reduce pressure in full right and left turns e Reduces hydraulic system heat e Reduces force on linkage components Pressure and heat build up in the steering system during turning maneuvers High temperatures can deteriorate the hydraulic system over time High pressure could put a lot of stress on linkage components over time How Poppets Work Rotating input shaft causes rack piston to move Lower poppet in rack piston contacts fixed stop bolt or adjusting screw Upper poppet in rack piston contacts valve housing Contact of poppet and screw or valve housing pushes poppet away from it s seat Gap between poppet and seat allows fluid to pass through the rack piston reducing pressure Poppet should contact screw or valve housing just before axle contacts axle stop Ee 5 BLUE BIRD APPENDIX STEERING TAS Poppet Components e Two Poppet Seat and Sleeve Assemblies e Two Poppets Spring Nylon Spacer Rod e Push Tube Spacer Rod Poppet
39. 7 071035 021426 021407 025119 3 APPENDIX BLUE BIRD B3 FE SERVICE MANUAL Section 2 Initial Installation sae TS Eee OE AE NE RE 13 Initial Poppet Setting eo SE ee N N ee 13 Maintenance THOS ONE EE EE ER EE 14 2 7 9 D j o BLUE BIRD APPENDIX Initial THP PCF Installation STEERING e Bolt steering gear to frame torque bolts to vehicle manufacturer s recommendation e Connect return line to THP PCF gear return port e Connect hydraulic line from pump to pressure port on THP PCF unit e Connect steering column to input shaft torque pinch bolt to vehicle manufacturer s recommendation e Install pitman arm on output shaft torque bolt to vehicle manufacturer s recommenda tion Initial Poppet Setting For this procedure to work correctly you must have A new gear received from TRW or your vehicle manufacturer s aftermarket system or a used gear on which poppet seats have been replaced or reset during gear disassembly procedures ALSO A fixed stop screw installed in the housing or a poppet adjusting screw installed so that it dupli cates the fixed stop screw length Full turn in one direction Full turn in other direction P AN dT Vg The axle stops and all steering linkage must be set according to vehicle manufacturer s specifications and the pitman arm must be correctly aligned on the sector shaft for poppets to be set correctly With the engine at id
40. F Can 990625C2 Union 15W 40 Ford Spec M2C138CJ Unocal Guardol 15W 40 Motor Oil Mack EO K2 Engine Oil The steering system should be kept filled with one of the above fluids N WAY eg Completely flush the steering system with one of the recommended fluids above only Do not mix oil types Any mixture or any unapproved oil could lead to seal deterioration and leaks A leak could ultimately cause the loss of fluid which could result in a loss of power steering assist Approved Grease Exxon Polyrex EP2 P N 045422 Gear Specification Numbers The steering gear specification number and date code are stamped ona machined surface opposite the input shaft of every THP PCF gear An example date code would be 29001 this means THPxxxxx the gear was built on the 29001500B00 290th day of 2001 Serial Number A letter suffix at the end of the specification number indicates a design level for the gear Trademark of Exxon Oil Corporation 3 BLUE BIRD APPENDIX Torque Chart STEERING _ Torque Range Dry Torque Range Lubricated Valve housing bolts Auxiliary port plug Relief valve cap Bearing adjuster Locknut Poppet sleeve assembly Torx screw Plug auto bleed Poppet fixed stop screw Sector shaft adjusting screw jam nut Side cover bolts Poppet sealing nut service Manual bleed screw 118 138 ftelb 160 187 Nem 25 35 ftelb 34 48 Nem 25 35 Ttelb 34 48 N
41. G y NET A warning describes hazards or unsafe practices which could result in severe personal injury or death Pei A caution describes hazards or unsafe practices which could result in personal injury or product or property damage NOTE A note gives key information to make following a procedure easier or quicker Notice This guide was prepared for the purpose of providing general advice concerning the diagnosis and correction of commercial vehicle steering related problems This guide is intended for the use of properly trained professional mechanics NOT Do it Yourselfers Also this guide should be used in conjunction with service manuals provided by both the vehicle and component manufacturers Diagnosis and correction of commercial vehicle steering related problems should only be handled by properly trained professional mechanics who have the proper equipment tools instructions and know how to perform the work properly and safely Power Steering System Analyzer PSSA Gauge Some of the tests in this manual require the use of aPSSA This device is a combination flow meter shut off valve and pressure gauge This tool will allow you to measure flow and pressure and provide a load on the pump through the hydraulic lines of the steering system This tool is required to correctly analyze a steering system TRW recom mends that you DO NOT BEGIN TROUBLESHOOTING A STEERING SYSTEM WITHOUT THE USE OF A PSSA If 847 you are not sure ho
42. HP PCF60 Press Press in housing roller bearing 2 If roller bearing 39 in housing needs to be replaced place the bearing removal end long end of the bearing and seal tool against the trunnion end of the bearing and press it out of the side cover end of the bearing bore Discard bearing Press the new roller bearing 39 into the housing from the side cover end of the bearing bore until it is seated against the step bore Be sure the housing is square with the press base and the bearing is not cocked AMA NU TE Use the bearing installation end of the tool short end If the bearing removal end of the bearing amp seal tool is used to press in bearing the cage on the new bearing may be damaged If the unmachined trunnion face is not square use shims to square it before pressing in the bearing Return to step 29 page 40 Replace Housing Port Plugs Screws and Fittings Tools Required Materials Required STEERING Allen wrench Torx sockets SAE Metric sockets Open end wrench inelb Torque wrench ftelb Torque wrench Replace poppet 1 fixed stop screw THP PCF45 18mm Socket THP PCF60 5 Socket ftelb Torque wrench Replace poppet 2 adjusting screw TAP PEF45 6mm Allen wrench 18mm Socket 19mm Wrench THP PCF60 7 32 Allen wrench Socket 3 Wrench ftelb Torque wrench Replace automatic 3 bleed screw and aux port plugs E 14 Torx socket ftelb Torque
43. MANUAL Test 5 0 Power Steering Pump Test Relief Pressure PSI BAR Engine RPM 1000P SI Table 5 0 Test 5 1 40 Minute Pow er Steering Pump Test Relief Pressure PSI BAR Engine RPM 1000PS Table 5 1 40 4 APPENDIX BLUE BIRD STEERING Test 6 0 Pump Flow Control Response Test Unit of Measure PSI or BAR Unit of Measure PSI or BAR Pump Relief 1 1500 RPM Pump Relief 2 1500 RPM Pump Relief 1 Idle Pump Relief 2 Idle Pump Relief 3 Idle Pump Relief 3 1500 RPM Table 6 0 Test 6 1 40 Minute Pump Flow Control Response Test 40 M inutes Unit of Measure F or C Unit of Measure PSI or BAR Unit of Measure PSI or BAR Pump Relief 1 Idle Pump Relief 1 1500 RPM Pump Relief 2 Idle Pump Relief 2 1500 RPM pt Pump Relief 3 Idle Pump Relief 43 1500 RPM Table 6 1 41 4 APPENDIX BLUE BIRD SERVICE MANUAL With PSSA 125 135 F 52 57 C RPM GPM or LPM With pressure gauge at pressure line to steering gear at pump end RPM GPM or LPM Remove pressure and return lines and measure pressure with gauge at pump outlet RPM PSI or BAR Table 10 0 42 4 BLUE BIRD APPENDIX Steering Gear Flow Requirements Single Gear STEERING 4 APPENDIX 43 BLUE BIRD BLUE BIRD SERVICE MANUAL Pump Part Number Reference Guide Check the part number on your TRW power steering pump and note
44. Minimum flow rate is 2 9 gpm As the driver turns the steering wheel faster or slower more or less oil flow is required by the gear The pressure of the hydraulic fluid is used to overcome the resistance in the system The higher the pressure the more work it can perform Maximum operating pressure is 2 682 psi The steering wheel is connected to the steering gear input shaft The input shaft is connected to a worm shaft When the driver turns the steering wheel the input shaft and worm shaft rotate The worm shaft is in turn connected to a rack piston through the recirculating ball mechanism This rotational movement moves the rack piston axially in the gear housing cylinder bore The rack piston turns the sector shaft which is connected by linkage to the wheels on the front axle As resistance is encountered in the steering effort pressure in the steering hy draulic system will increase proportionally to assist the movement of the rack pis ton thus reducing the effort needed to steer the bus As the input shaft is turned the control valve spool mounted on the torsion shaft the torsion shaft connects the input shaft to the worm shaft shifts and redirects oil flow to either side of the rack piston A relief valve mounted on the valve housing limits maximum supply pres sure to protect the power steering system This is the primary pressure protection for the steering system A secondary pressure relief valve is located in the hydraulic pum
45. OSHA approved solvent Air blow them dry only N MAPIA Because they are flammable be extremely careful when using any solvents Even a small explosion or fire could cause injury or death NT TT TH Wear eye protection and be sure to comply with OSHA or other maximum air pressure requirements N WARNING Condition Brinelling Cracks or Breaks Twisted serrations Any of the following conditions present in the steering gear indicates impact damage Area e Ball track grooves of rack piston e Ball track grooves of worm screw e Bearing area of sector shaft e Thrust washer and bearing in valve housing e Ball cup and bearing in valve housing e Bearing area of sector shaft e Sector shaft teeth e Rack piston teeth e Housing e Thrust washer and bearing in valve housing e Worm screw e Ball cup and bearing in valve housing e Output shaft serrations If one of these conditions is found in one component be sure to inspect all components carefully for signs of impact damage Replace components noted in individual inspection steps below if you suspect impact damage Failure to replace all damaged components could result in a serious vehicle accident teeth 42 3 APPENDIX BLUE BIRD Inspect rack piston 1 Inspect rack piston 2 and worm ball track grooves Inspect the rack piston 28 teeth for cracks or obvious damage If teeth are damaged replace the rack piston sector shaft 41 and set of ba
46. PENDIX STEERING Adjust adjusting 4 Adjust sector shaft adjusting screw 41A clockwise screw to increase maximum torque noted in step 3 by 7 inelb 8 Nem Tighten jam nut 47 firmly against side cover while holding the adjusting screw in Ja Socket oa Wan Seker position Finally torque jam nut to 43 ftelb 58 Nem p and check input shaft valve worm assembly torque ftelb Torque S N again Readjust if input shaft torque exceeds wrench i l 40 inelb 4 5 Nem inelb Torque wrench 63 3 BLUE BIRD APPENDIX B3 FE SERVICE MANUAL Section 5 Reinstallation Es Eee EE ie ee EE EE GE he EG 65 Poppet Resetting ee ee ee ee ee ee ee ee ee ee ee ee ee 65 UN 66 LA T amh D BLUE BIRD APPENDIX STEERING Reinstallation e Verify that axle stops are set to manufacturer s wheelcut or clearance specifications e Bolt gear to frame torque to vehicle manufacturer s recommendation e Connect return line to reservoir in THP PCF return port e Connect hydraulic line from pump to pressure port in THP PCF unit e Connect steering column to input shaft torque pinch bolt to vehicle manufacturer s recommendation e Install pitman arm on output shaft with timing marks aligned Torque bolt to vehicle manufacturer s recommendation e Connect drag link to pitman arm Poppet Resetting IF Poppets remain unchanged from when gear was After installation check to make
47. PSSA in pressure line with shut off valve fully open Figure 5 2 Run the engine at 1000 rpm JYT TE When closing the PSSA shut off valve do so slowly and keep an eye on the pressure gauge Do not allow the system to exceed 3000 psi 207 bar for safety of personnel and to prevent damage to the vehicle JYT TE Do not keep the load valve closed for more than 5 seconds at a time because damage to the system may result from excessive heat build up Measure and record the following flow and pressure readings See chart by adjusting the load valve while listening for any unusual noises as the valve is being opened and closed Figures 5 3 5 7 Now with the load valve fully open increase the engine speed to governed RPM and measure and record the following flow and pressure readings by adjusting the load valve while listening for any unusual noises as the valve is being opened and closed Determine the recommended flow range and maximum allowable system pressure for the steering system being used by referring to your service manual Compare the minimum and maximum flows and the relief pressure you measured to gear and pump specifications If the minimum measured pump flow is less than the minimum recommended flow for the steering gear used See Steering Gear Flow Requirements chart the pump may not be putting out enough flow for an adequate steering speed If the maximum system pressure is lower than that specified for the pum
48. STEERING Overview This section will address those parts of the steering system related to the e Steering wheel e Steering column e Power steering fluid requirements Steering gear THP 60 e Hydraulic steering pump Appendixes In This Chapter Appendix 1 TRW Flushing the Steering System This two page exerpt from TRW s Steering System Maintenance Guidelines includes full details and instructions on flushing the steering system Appendix 2 TRW Air Bleeding the Steering System This two page exerpt from TRW s Steering System Maintenance Guidelines includes full details and instructions on bleeding air from the steering system Appendix 3 THP Steering Gear Service Manual This TRW Service Manual includes design features fluid information an exploded parts diagram torque specifications general information and on vehicle service for the THP steering gear Appendix 4 TRW Steering Maintenance This TRW publication entitled Chart Your Way To Easy Steering provides a solid overview of potential steering problems their diagnosis and correction Appendix 5 Poppet Adjustment This TRW publication explains what poppets are how they work and readjustment procedures TLTIMITA Hydraulic fluid must be handled stored and disposed of in a manner consistent with all the applicable local state and federal guidelines concerning hazardous materials The hydraulic pump for the power steering assist is flange mounted to the engine and
49. Seat Poppet Seat and Push Tube Sleeve Assembly Sleeve Setting poppets means pushing the poppet seat into the poppet sleeve This backs off the poppet so it will contact the screw or valve housing just before axle contacts axle stop TAS Factory Setting or New Aftermarket Gear e Set axle stops e Raise front axle e Turn full right engine on e Turn full left engine on 2 APPENDIX BLUE BIRD SERVICE MANUAL New steering gear poppet components look like this before setting At this point they are ready for automatic adjustment The amount of gear travel is determined on each vehicle by the axle stop settings End of gear travel is marked in these diagrams by dotted lines The rack piston will stop when it reaches these points because the axle stops will not allow the road wheels to travel further On the first full turn after installation on a vehicle the poppet seat will make contact internally and be pushed into the sleeve Since the rack piston has travelled to its farthest point for the vehicle the poppet seat in its new set position has also reached its farthest point of travel of In the second full turn the remaining poppet seat will be pushed in the amount required for that vehicle Since t
50. adjusted Draglink on gear TEST 13 Draglink Diagram Figure 13 1 Poppet Setting TEST 14 END REDUCED WHEELCUT 4 APPENDIX BLUE BIRD SERVICE MANUAL Steering Wheel Kick Air in System con TEST 9 COMMENT H Looseness in Mechanical System TEST 15 TEST 16 ae Yes Verify if looseness in the system has been eliminated No Gear Adjustment Procedures HFB Valve TAS HFB HF Sector Shaft Shock Absorbers Worn or missing shocks Reference TMC document RP643 Section 1 Shock Absorbers Linkage Geometry COMMENT C Power Steering Pump TEST 5 Flow Control Response TEST 6 Are any numbers input on chart below specifications Yes Call technical service No END STEERING WHEEL KICK 10 4 BLUE BIRD APPENDIX STEERING Binding Darting and Oversteer Occuring once per revolution Cyclic binding Yes Column Friction Eccentric es oos at steering Condition Interference wheel TEST 18 More than one U joint U joint Lube or ES Improperly Phased TEST 17 TEST 19 No Excessive U joint Angle COMMENT D Check for these Conditions 1 Binding at input side of gear a U joint rubbing TEST 17 b Intermediate shaft binding TEST 19 2 Firewall boot interference cab mount drop TEST 18 3 Gear to frame interfernce TEST 4 4 Binding at king pins steer axle linkage TEST 3
51. aft Clean sector shaft Fine grade emery cloth Emery cloth Masking tape G 4 Put the steering gear in a vise clamping firmly against the housing mounting flange or boss Input shaft should be horizontal side cover and valve housing are accessible for disassembly Do not clamp against body of housing If mounting boss or flange N CAUTION is not accessible fabricate and attach a mounting plate to the housing mounting bosses Prepare for fluid drainage and unplug hydraulic ports Rotate the input shaft until the timing mark on the end of the sector shaft is in line with the timing mark on the end of the housing This will position the sector shaft for removal Remove any paint or corrosion from the exposed area of the sector shaft 41 35 3 BLUE BIRD APPENDIX SERVICE MANUAL Masking tape bolts Soft mallet 36 3 BLUE BIRD APPENDIX Tape sector shaft 5 Remove jam nut 6 Remove side cover 7 Remove side cover 8 Discard O ring 9 Tape the serrations and bolt groove of the sector shaft with one layer of masking tape The tape should not extend onto the sector shaft bearing diameter Remove the sector shaft adjusting screw jam nut 46 Be prepared for more fluid drainage and remove the six bolts 48 from the side cover 45 Be prepared for more fluid drainage and remove the side cover and sector shaft assembly from the
52. allows up and down movement of the steering wheel for tilt control and in and out movement of the steering column for telescopic control When the control lever is actuated a set of lock paws in the tilt locking mecha nism is released allowing the steering wheel and upper steering column to be posi tion up or down in one of 9 detents positions When the control lever arm is re leased the lock paws reengages the detent providing a positive lock in the position selected At the same time the tilt lock paw is released the telescoping lock pad is released allowing the upper steering column to slide in and out of the lower steering column support This function provides an almost infinite height control within its range of travel of the steering wheel and upper column When the tilt telescoping control is released a friction pad mounted on the lower stationary support column makes contact with the upper column providing a non incremental positive lock of the telescoping mechanism The steering column and its control mechanism is a self contained unit Although the it provides tilt and telescoping adjustment of the steering wheel and column there are no adjustments to steering column control mechanism The steering col umn requires no lubrication and is considered a non serviceable component Some components attached to the steering column are serviceable i e turn sig nal switch cruise control ignition switch and the horn brush contact See details
53. alve observing the flow meter The flow rate must instantly return to the reading you noted above 674 3 With the load valve open run the engine to govemed speed and note the flow rate Fully close the load valve until the flow drops to zero Ouickly open the load valve observing the flow meter The flow rate must instantly retum to the reading noted above 4 Conduct this pump response test three times at idle and three times at 1500 RPM If the flow rate does not return immediately the pump is malfunctioning which can result in momentary loss of power assist When hydraulic tests are completed and fluid lines are reconnected check fluid level and bleed the air from the hydraulic system 24 4 BLUE BIRD APPENDIX STEERING Test 6 1 40 Minute Pump Flow Control Response Read the following instructions below before completing Table 6 1 in the Test Results section 1 Install temperature gauge in reservoir Figure 6 1 Install PSSA in pressure line with shut off valve fully open Figure 6 2 Park the vehicle outside Record ambient temperature Run the engine at governed RPM for 40 minutes to bring the fluid up to an elevated testing temperature Measure and record the fluid temperature at the start and at 10 20 30 and 40 minutes Do not allow the temperature to exceed 250 121 C If the temperature goes over 250 F 121 C or 150 F 66 C above the surrounding temperature ambient at any ti
54. and brittle and not pliable like the new seal it is probably heat damaged Determine and fix the cause of excessive heat in the vehicle Put clean grease 045422 on the inside dia of the new input shaft seal and place it over the input shaft With the small dia of tool J37073 against the seal tap the tool until the tool shoulder is square against the valve housing Remove any seal mate rial that may have sheared off in the seal bore or retaining ring groove N H V il EN Do not use a socket to install this seal because you will not be able to control seal installation depth possibly causing a leak Insert new retaining ring into the groove Pack the end of the valve housing bore around the input shaft with grease 045422 Choose the correct size dirt amp water seal by comparing the choices to the old seal or by measuring the major diameter of the input shaft serrations See chart next page Apply more grease 045422 to the new dirt amp water seal and install it over the input shaft Seat it in the groove behind the serrations and against the valve housing 19 3 APPENDIX BLUE BIRD BLUE BIRD 20 3 APPENDIX Reconnectcolumn 15 Reconnect the steering column to the input shaft and tighten the pinch bolt to torque level specitied Reconnect return 16 Reconnect the return line to the steering gear return line port Air bleed system 17 Air bleed the system using the procedure on pg 16
55. and steering wheel during normal steered axle suspension movements Be sure that linkage used is as specified by vehicle manufacturer Comment D A single u joint operating at an angle will cause a cyclic torque variation at the steering wheel The amount of torque variation increases with the amount of operating angle A secondary couple that side loads the input shaft also in creases with increased u joint angles U joint operating angles of 15 degrees or less will minimize the torque variation felt at the steering wheel Comment E Deflections in the suspension and linkage front and rear due to high engine generated torque levels can cause a steering effect This most often occurs at lower vehicle speeds while accelerating Comment F The location of the axle arm ball center is important during spring wind up conditions such as severe braking A steering arm different from that specified by the manufacturer could cause a steering effect while braking Comment G Soft or loosely supported rear suspensions may allow the rear driving axles to become non square with the centerline of the chassis during load shifting or trailer roll which will tend to produce a steering effect Comment H Power steering pump cavitation Pump cavitation is defined as a wining or noisy power steering pump Usually pump cavitation is most noticed during engine start up at low temperature extremes However other conditions can cause the power steering pump to c
56. anual NAP PELSER Hydraulic fluid 72 Allen wrench Jack 1 Set the axle stops to vehicle manufacturer s 7 a Start the engine and let it run at idle speed wheelcut or clearance specifications Start the engine and allow the vehicle to idle for 5 10 minutes to warm the hydraulic fluid Shut off the engine 2 If new poppet adjusting screws and nuts are being used turn the screws into the non sealing end of the jam nuts until the drive end of screw is flush with the nut Your steering gear and rotary cylinder will have either fixed stop bolts or adjusting screws If the adjusting screw is already part of the steering gear or cylinder back the nut off of the adjusting screw 8 until it is flush with the end of the adjusting screw 3 Make sure the engine is off and the road wheels are in straight ahead position Remove and discard the poppet fixed stop bolts if equipped and washers if equipped from the lower end of housing on both the master gear and the rotary cylinder If the unit has poppet adjusting screws and sealing nuts that need to be replaced remove and discard 9 them 4 Turn the adjusting screws and sealing nut assem blies without rotating the nut on the screw into the housing until the nut is firmly against the housing on both the master gear and the rotary cylinder using a6mm THP PCF45 or 742 THP PCF60 allen wrench Tighten the sealing nut against the housing 5 Refill system reservoir with appr
57. ave this seal for comparison with the new seal Clean input shaft 16 Clean any paint or corrosion from the exposed area of the input shaft Fine grade emery cloth Remove valve 17 Remove the four torx head valve housing bolts 1 housing bolts E 18 Torx socket Remove valve 18 Be prepared for more fluid drainage and remove the housing worm and rack piston subassembly Place the assembly on a rack subassembly clean cloth AN EAT eg The set position of poppet seat and sleeve assemblies 27 must not be disturbed if the poppets are not going to be replaced or reset during disassembly Remove seals 19 Remove and discard the valve housing seal rings 118 13 AN eV ate Do not remove the input shaft valve worm assembly or balls from the rack piston until the ball return guides are removed as damage to the ball guides will occur 38 BLUE BIRD APPENDIX STEERING Remove ball return 20 Remove and discard the two special sealing screws guide cap 33 Remove the ball return cap 32 and seal 31 discard the seal T 30 Torx wrench Remove ball return 21 Make sure the rack piston is on a cloth so the steel guides balls that fall out won t roll very far Remove ball return guide 30 by carefully inserting a screwdriver between the rack piston and guides Left hand ball return guide halves are plated with copper or zinc chromate for identification Right hand guides are not plated
58. complaint 2 Run the engine at idle speed NG mim When closing the PSSA shut off valve do so slowly and keep an eye on the pressure gage Do not allow the system to exceed 3000 psi 207 BAR for safety of personnel and to prevent damage to the vehicle VATE Do not keep the load valve closed for more than 5 seconds at a time because damage to the system may result from excessive heat build up 3 Measure and record the following flow and pressure readings See chart by adjusting the load valve while listening for any unusual noises as the valve is being opened and closed Figures 5 3 5 7 4 Now with the load valve fully open increase the engine speed to governed RPM and measure and record the following flow and pressure readings by adjusting the load valve while listening for any unusual noises as the valve is being opened and closed 5 Determine the recommended flow range and maximum allowable system pressure for the steering system being used by referring to your service manual 6 Compare the minimum and maximum flows and the relief pressure you measured to gear and pump specifications 7 If the minimum measured pump flow is less than the minimum recommended flow for the steering gear used See Steering Gear Flow Requirements chart the pump may not be putting out enough flow for an adequate steering speed If the maximum STEERING Figure 5 7 23 4 APPENDIX BLUE BIRD F SERVICE MANUAL system pr
59. d hold it in place with a wrench b Turn the adjusting screw in clockwise using finger pressure only don t use a ratchet until the Allen wrench comes to a stop Do not attempt to turn it in farther Pause the turning in process each time the driver releases the steering wheel Continue turning only while the wheel is held at full turn c Back off the adjusting screw 31 turns and tighten the sealing nut Torque the sealing nut to 33 37 ftelb 45 50 Nem d Release the steering wheel and shut off the engine 3 APPENDIX The poppets have now been completely reset Lower the vehicle Check the reservoir and fill if required NETTIE The length of the adjusting screw beyond the nut must be no more than 1146 for proper thread engagement The length of adjusting screw beyond the sealing nut may be different for each vehicle STEERING Poppet Readjustment Dual Gears Reversed Image This resetting procedure will work in most cases with at least 13 hand wheel turns from each side of center It you re making a large reduction in wheelcut and this procedure does not work you may have to replace or internally reset the poppets using the procedure de scribed in the Poppet Component section of this Service Tools Required THP PCF45 6mm Allen wrench 19mm Open end wrench 3 Open end wrench Jya Socket Open end wrench 19mm Socket ftelb Torque wrench 18mm Open end wrench Materials Required M
60. dged in the pitman arm boss If you cannot remove the pitman arm from the shaft with a chisel and your hands remove the chisel from the arm boss and use a puller only to remove pitman arm N CAUTION Do not use a hammer on the pitman arm to remove it from sector shaft as internal damage to steering gear could result Be sure there is no spreading wedge left in the pitman arm boss before tightening pitman arm clamp bolt after assembly on sector shaft Do not pound the universal joint or input shaft coupling on or off the input shaft as internal damage to the steering gear can result N d VI il EN Unless the poppet adjuster seat and sleeve assemblies 27 are to be removed and replaced or reset for automatic poppet adjustment or a manual adjustment with a service poppet adjuster screw 38A and nut 38B is anticipated do not allow the input shaft on a steering gear with the automatic poppet adjustment feature to rotate more than 1 5 input shaft revolutions from straight ahead posi tion when the output shaft is disconnected from the vehicle steering linkage this could disrupt the poppet setting achieved at initial installation The steering gear is in the straight ahead position when the timing marks on the end of the housing trunnion and sector shaft are aligned Remove the supply and return lines from the gear and immediately plug all port holes and fluid lines ANETT TT THP PCF steering gears can weigh up to 70 pounds dry Exercise
61. dup in the hydraulic system At the same time the valves also reduce forces on the steering linkage Careful preliminary checks should be done to identify a steering problem and its symptoms before deciding the steering gear has failed In most cases the steering gear should be the last component suspected as cause of a steering problem Refer to the Appendixes in this chapter for detailed step by step troubleshooting procedures Steering System Maintenance Before attempting to work on the steering gear or any portion of the steering sys tem you must stabilize the vehicle Read and understand the Warnings and Cautions in the General Maintenance chapter of this manual Regularly check the fluid level in the power steering reservoir Change the fluid and replace the filter at the intervals specified in the Specs amp Maintenance chapter Clean around the reservoir filler cap before removing it Dirt and other foreign matter can damage the hydraulic system Do not bend or straighten any steering component or linkage Never attempt to weld any broken steering component Do not use a torch to remove any steering component Use only original equipment replacement parts Never use high pressure or steam to clean the power steering gear Doing so can force contaminants inside the gear and lead to malfunction Proper alignment of the steering column is important to assure smooth steering Correct the cause of any free play rattle or shimmy immedia
62. e a screwdriver inserted into the notch formed in the end of the ring Be careful not to scratch the bore with the screwdriver Clean cloth Screwdriver 17 3 APPENDIX BLUE BIRD N oO ML SERVICE MANUAL D3FE Replace column 5 Slip the steering column back onto the input shaft with the pinch bolt installed but not tightened Wrap exposed 6 Tie or wrap a shop towel around the input shaft area area and place a drip pan under the vehicle to catch the oil Drip pan Shop towel Fill reservoir 7 Add fluid as necessary to the full line on the dip stick Do not mix fluid types Hydraulic fluid ANACI Any mixture of fluid types or use of any unapproved fluid could lead to seal deterioration and leaks A leak could ultimately cause the loss of fluid which could result in a loss of power steering assist Force out the seal 8 With the vehicle in neutral momentarily turn the starter quickly turn off the engine if it starts Remove input shaft 9 Remove the shop towel Disconnect the steering seal column and remove the input shaft seal BLUE BIRD APPENDIX Inspect seal area 10 Inspect old seal 11 Install new seal 12 J37073 Seal Driver Install retaining 13 ring Install dirt amp water 14 seal STEERING Check the seal area of the valve housing for any seal fragments Remove any that are found Check the seal for heat damage If the seal is stiff
63. e damaged steering components THP PCF Gear Do not attempt to weld any broken steering component Replace the component with original equipment only Do not cold straighten hot straighten or bend any steering system component Always clean off around the reservoir filler cap before you remove it Prevent dirt or other foreign matter from entering the hydraulic system Investigate and correct any external leaks no matter how minor Replace reservoir filters according to requirements If you feel the vehicle is developing excessively high hydraulic fluid temperatures consult with your vehicle manufacturer for recommendations Maintain grease pack behind the output shaft dirt and water seal as a general maintenance procedure at least twice a year in the Spring and Fall Grease fitting is provided in housing trunnion Use Exxon Polyrex EP2 P N 045422 or NLGI grade 2 or 3 multipurpose chassis lube and use only a hand operated grease gun on fitting Add grease until it begins to extrude past the sector shaft dirt and water seal Corrosion Inhibiting Grease Barrier Water Seal 3 APPENDIX a PG Vi GEEET ZY VIG la Dirt and High Pressure Output Seal Section 3 STEERING On Vehicle Service Filling and Air Bleeding the System ee ee ee ee ee ee 16 Input Shaft Seal Replacement oaeee 17 Sector Shaft AdjustMent ss EE RS EE De EE ER Ge 21 Poppet Readjustment Single Gear ee cece ee e
64. e into the bearing adjuster seal groove in bearing adjuster 20 Oil and work a new seal ring 18 into the same groove and smooth it out Be sure the valve housing adjuster locknut and bearing adjuster threads are clean and free of any staking burrs that would impede the locknut from turning freely on adjuster or the adjuster turning freely in valve housing 56 3 BLUE BIRD APPENDIX Assemble bearing adjuster J37070 ftelb Torque wrench Assemble new locknut J37464 Adjust to required input torque 3a or 1 46 12 point socket inelb Torque wrench Torque locknut J37070 J37464 ftelb Torque wrench Check input shaft torque 20 21 22 23 24 TR Lightly oil and assemble bearing adjuster 20 over worm and into valve housing Torque adjuster to 13 ftelb 18 Nem indicated torque using a torque wrench inserted in adjuster tool 4J37070 This will seat the components Back off adjuster Va to 1 2 of a turn Lightly oil and assemble new locknut 21 onto bearing adjuster 20 with radius slightly rounded side down Tighten slightly to keep the bearing adjuster in place Reverse assembly in vise so the worm end is down With an inch pound torque wrench on the input shaft note torque required to rotate the input shaft 360 in each direction Tighten the bearing adjuster to increase the maximum torque at the input shaft 5 10 inelb 5 1 0 Nem over tha
65. edure does not work you may have to replace or internally reset the poppets using the procedure de scribed in the Poppet Component section of this Service Manual 7 a Start the engine and let it run at idle speed b Turn the steering wheel in the direction that makes the timing mark on the master gear move toward the adjusting screw just installed Turn in this direction until axle stop contact is made c Pull hard on the steering wheel put 40 Ibs rim pull on a 20 dia steering wheel after the axle stop is contacted 8 a Turn the steering wheel in the opposite direction end of timing mark on the master gear away from adjusting screw until the other axle stop is contacted b Pull hard on the steering wheel put 40 Ibs rim pull on a 20 dia steering wheel c Release the steering wheel and shut off the engine 9 Loosen the sealing nut and back out the adjusting screw on the master gear until 1 is past the nut Tighten the sealing nut against the housing Do not hold the steering wheel at full turn for more than 10 seconds N CAUTION at a time the heat build up at pump relief pressure may damage components 10 a Start the engine and let it idle b Turn the steering wheel in the original direction end of timing mark on the gears toward adjusting screw until axle stop contact is made c Hold the steering wheel in this position with 40 los rim pull for 10 seconds then release Repeat th
66. el Turn off engine e Back out adjusting screw until 1 is past the nut e Start engine e Turn steering wheel in original direction pull hard when axle stop contact is made e Screw in adjusting screw until it stops e Back out adjusting screw 3 1 4 turns e Torque jam nut Turn off engine lower vehicle 2 APPENDIX BLUE BIRD ICE MANUAL MANUAL DORRE Introduction to Internal Components Housing Cylinder Bore Lower Poppet Upper Poppet Seat Lower Poppet Seat Upper Poppet Sleeve Valve Housing Fixed Stop Bolt Lower Poppet Sleeve Upper Poppet Rack Piston VO Lower End Steel Balls of Gear Upper End of Gear Housing Pitman Arm 5 BLUE BIRD APPENDIX Axle stops have been reset in this diagram They have been moved in indicating that wheel cut has been reduced STEERING An adjusting screw is installed in the gear for the resetting process so the poppet components can be forced together to push on one another Once the poppet components are pushed together they will stay that way The adjusting screw will also remain as part of the gear Do not try to reuse the fixed stop screw after resetting poppets is O Turning in a direction that makes the rack piston move toward the lower end o
67. em 11 15 ftelb 15 20 Nem 101 122 Ttelb 137 165 Nem 16 20 ftelb 22 27 Nem 14 22 Ttelb 19 29 Nem 38 58 Ttelb 52 79 Nem 38 42 ftelb 52 57 Nem 40 45 ftelb 54 61 Nem 180 220 Ttelb 244 298 Nem 33 37 ftelb 45 50 Nem 40 50 inelb 3 1 3 7 Nem Item numbers referenced are shown on the exploded Special tools can be purchased through view located on page 8 SPX Corporation Kent Moore Tool Group After tightening to this torque value the adjuster must 28635 Mound Road be backed off Va to 1 2 of a turn as described in step 20 Warren MI 48092 on page 57 1 800 328 6657 Torque value indicated is using recommended tools 3 APPENDIX BLUE BIRD SFE SERVICE MANUAL THP PCF Exploded View Item 1 2 2B 2C 3 4 5 6 8 9 10 11 12 13 14 15 16 9 10 Description Valve Housing Bolts 4 Dirt and Water Seal 13 16 Serr Dirt and Water Seal 7 8 Serr Dirt and Water Seal 1 Serr Retaining Ring Seal Input Shaft Valve Housing Assembly Auxilliary Port O ring 2 Auxilliary Port Plugs 2 Relief Valve 2 Piece O ring Relief Valve Cap O ring Valve Housing Bearing Assembly O ring Seal Ring Worm and Valve Assembly Thrust Bearing 38 34 Thrust Washer Seal Ring O ring Bearing Adjuster Lock Nut O ring Seal Ring Push Tube Poppet Spring Poppet 2 Poppet Seat amp Sleeve Assy 2 Rack Piston Balls Ball Return Guide Seal Cap
68. es Installation is accomplished in the reverse order of the removal instructions Always install a new hydraulic pump gasket Also install a new split ring lock washer and torque the mounting capscrews to 53 58 ft Ibs 71 86 78 64 Nm After filling the reservoir start and run the engine at idle for 10 seconds then switch the ignition off refill the reservoir start the engine and run for another 20 seconds repeat this process until the reservoir maintains a full oil level With the front wheels off the floor refer to Jacking Procedures in the Specs amp Maintenance sec tion of this manual lifting by the axle not the wheels start the engine and turn the steering wheel one direction and then the other direction a couple of times then stop the engine and refill the reservoir Perform this cycle until the reservoir main tains a full oil level Supply Hose sy Pressure Line BLUE BIRD SERVICE MANUAL Test drive the bus and let the power steering fluid warm to operating tempera ture then check the fluid level again Check for leaks in the system Steering Pump Removal All American With Hydraulic Brakes 1 Drain the system of fluid in a manner consistent with all local state and fed eral laws Wear protective gear when working with hydraulic fluids including eye protection 2 Remove the supply hose 3 Remove the pressure line from the fitting at the output port of the pump 4 Secure the pressure line sa
69. essure is lower than that specified for the pump refer to your OEM service manual it may not be developing enough pressure to steer If either case exists the pump needs to be repaired or replaced When hydraulic tests are completed and fluid lines are reconnected check fluid level and bleed the air from the hydraulic system Test 6 Pump Flow Control Response IMPORTANT Read the following instructions below before completing Table 6 in the Test Results section 1 Install temperature gauge in reservoir Figure 6 1 Install PSSA in pressure line with shut off valve fully open Figure 6 2 If the temperature goes over 250 F 121 C or 150 F 66 C above the surrounding temperature ambient at any time during the test stop the test This temperature level is considered extreme and steering system performance and life will be seriously affected Damage to hoses seals and other compo nents may result if operated at extreme temperature If the steering system is operating above the recom mended temperatures the heat problem may be the root cause of the complaint Figure 6 2 Nemi Do not keep the load valve closed for more than 5 seconds at a time because damage to the system may result from excessive heat build up Do not allow the pressure to exceed 3000 psi 207 bar 2 With the engine at idle note the flow rate Fully close the load valve until the flow drops to zero Quickly open the load v
70. et fixed stop bolt if equipped and washer if THP PCF45 equipped from the lower end of the housing edie a ke If the unit has a poppet adjusting screw and sealing THP PCF60 nut that need to be replaced remove and discard 58 Open end en wrench Turn adjusting 4 Turn the adjusting screw and sealing nut assembly screw assembly without rotating the nut on the screw into the into housing housing until the nut is firmly against the housing using a 6mm THP PCF45 or 22 THP PCF60 Allen THP PCF45 wrench Tighten the sealing nut against the housing 6mm Allen wrench 19mm Wrench N dril Ifthe drive end of the screw is THP PCF6O below the face of the nut the 72 Allen wrench 34 Wrench poppet seat flange will break during step 7d 25 3 APPENDIX BLUE BIRD BLUE BIRD 24 SERVICE MANUAL APPENDIX Refill reservoir Hydraulic fluid Jack up vehicle Push upper poppet out to prepare it for setting Set upper poppet Back out adjusting screw TEPIPEFAS 6mm Allen wrench 19mm Wrench THP PCF60 732 Allen wrench 3 Wrench 5 op Refill the system reservoir with approved hydraulic fluid N TUNEL gi Do not mix fluid types Mixing of transmission fluid motor oil or other hydraulic fluids will cause seals to deteriorate faster Place a jack under the center of the front axle and jack up the front end of the vehicle so the steer axle tires are off t
71. eturn lines to the steering gear Connect the supply line to the reservoir and then tighten all fittings Install new filter element into the reservoir Clean reservoir filler cap with an approved solvent Inspect gasket and replace if necessary Inspect all hydraulic hoses Figure 3 for cracks soft or sweat spots and signs of local collapse remove all covers corrugated tubing from hoses to do this and replace any that are found to be defective Check any banjo fittings and connectors for blockage Clear any blockages using an appropriate method Filter contaminated oil through a coffee filter and examine for metal and foreign particles Fine metal particles are evidence of normal wear and tear velde STEERING Figure 1 Figure 2 Figure 3 1 APPENDIX BLUE BIRD SERVICE MANUAL e Metal chips signify that the power steering pump needs to be replaced If black rubber particles are present the inner lining of the pressure return or suction lines may be disintegrating Replace all three hoses 16 Fill reservoir with approved replacement fluid and reinstall the filler cap Figure 5 17 Start engine for 10 seconds stop and check reservoir fluid level and top off if necessary You may need to repeat this procedure 3 or 4 times 18 Upon completion of filling the reservoir start the engine and let it idle At engine idle steer full right and full left Figure 6 once and return to straig
72. f the steering gear will force the lower poppet seat against the adjusting screw The lower poppet seat then contacts the push tube and forces it against the upper poppet seat This will force the upper poppet seat out so it can be set automatically on the next turn This turn sets the upper poppet seat in just the same way as it was set when the gear was new Notice that since the poppet components are still forced together the upper poppet seat is now forcing the push tube against the lower poppet seat to push it out m EA 2 APPENDIX BLUE BIRD Ww a b a a R f BLUE BIRD gt FE SERVICE MANUAL The adjusting screw is backed out of the way so the poppet seat will not contact it on the next turn Holding the wheel at full turn places the poppet seat in the proper position for setting The adjusting screw is then turned in to meet the lower poppet seat and backed out 3 1 4 turns NETO
73. fely out of the way 5 Remove two capscrews from the hydraulic pump mounting flange 6 Remove and discard the o ring Steering Pump Reinstallation All American With Hydraulic Brakes Install the pump in the reverse order of the removal Ensure that a new o ring is in Stalled Install a new split ring lock washer and torque the mounting capscrews to 53 58 ft Ibs 33 32 44 74 Nm BLUE BIRD Torque Chart 18 Nut 270 300 lb ft Driver Control Module Steering Wheel 24 Nut 36 43 b ft DCM 14 Nut 200 250 Ib ft 15 Nut 120 170 Ib ft 16 Nut 50 60 Ib ft Steering Column 47 Nut 29 33 b ft 41 Nut 185 190 Ib ft 60 Bolt 53 58 Ib ft Hydraulic Reservoir Steering Pump mounted at 0000432 3c STEERING Hydraulic Booster With Air Brakes or Air Suspension Only With Hydraulic Brakes Only D A 24 Intermediate Columns Steering Components 0 BLUE BIRD SERVICE MANUAL Steering Hydraulics with Hydraulic Brakes Hydraulic Brake Booster Flow Switch Hydraulic Steering Reservoir Pressure Relief Valve Pressure Relief amp Flow Control Valve FLOW iin Steering Hydraulics with Air Brakes Hydraulic Steering Reservoir Steering Gear Pressure Relief amp Flow Control Valve Pressure Relief
74. forces to steering gear components during accidents or other similar events which exceed the hydraulic capacity of the steering gear Internal Leakage Fluid leaking inside the gear Lash Free play Manual Bleed Systems Gears are mounted in such a way that an air pocket could form in one end of the steering gear The bleed screw Is positioned so trapped air can be forced out when loosened OSHA Occupational Safety and Health Administration PCF Positive Center Feel option available on THP series steering gears Poppets Unloading valves reduce pressure in full turns Relief Valve Limits maximum supply pressure Return Line Line that connects steering gear to reservoir to recirculate hydraulic fluid Rotary Control Valve Controls flow in internal cavities Scoring Scratch Shock Load Shake or jar Spalling Flaking or chipping Subassembly An assembled unit that fits into a larger unit Supply Line Line that connects pump to steering gear Twisted Serrations Output shaft serrations damaged by impact overload Serrations can be twisted at the area between the large diameter of the shaft and the end of the serrations Steering Diagnostics Appendix 4 STEERING 4 VIRSTL RW Automoti Commercial Steering ten Steering Diagnostics Service M anual CHART YOUR WAY TO EASY STEERING BLUE BIRD SERVICE MANUAL BLUE BIRD APPENDIX STEERIN
75. he end of housing trunnion Socket or box AN CAUTION Do not rotate the input shaft more than 1 5 revolutions from center position until the steering gear is installed during poppet setting procedure Doing so could make the automatic poppets inoperative which would require disassembly of steering gear to reposition poppet seat and sleeve assemblies end wrench Initial poppet contact will occur at less than one input shaft rotation in one direction from steering gear center position if new or reset poppet adjuster seat and sleeve assemblies are assembled in the unit Worm preload adjustment was set when input shaft valve and worm were assembled into valve housing Tighten adjusting 2 VVith adjusting screw jam nut 46 loose turn sector screw shaft adjusting screw 41A clockwise to provide 45 50 inelb 5 5 5 Nem of torque required to rotate the input shaft valve worm assembly 15 through one half turn 180 each side of center inelb Torque wrench Screwdriver 116 or 3 4 Socket This procedure will properly mesh and seat the rack piston and sector shaft teeth for final adjustments Loosen adjusting 3 Turn sector shaft adjusting screw 41A counter screw and note clockwise one half turn and note maximum torque torque required to rotate the input shaft valve worm assembly through one half turn 180 each side of inelb Torque CESI wrench Screwdriver 116 Socket 0 BLUE BIRD AP
76. he ground a Start the engine and let it run at idle speed b Note which output shaft timing mark is nearest the housing piston bore c Turn the steering wheel in the direction that makes this timing mark move toward the adjust ing screw just installed Turn in this direction until axle stop contact is made d Pull hard on the steering wheel put up to 40 Ib rim pull on a 20 dia steering wheel after the axle stop is contacted a Turn the steering wheel in the opposite direction end of timing mark away from adjusting screw until the other axle stop is contacted b Pull hard on the steering wheel put up to 40 Ib rim pull on a 20 dia steering wheel c Release the steering wheel and shut off the engine Loosen the sealing nut and back out the adjusting screw until 1 is past the nut Tighten the sealing nut against the housing N dT Do not hold the steering wheel at full turn for more than 10 seconds at a time the heat build up at pump relief pressure may damage components Set lower poppet 10 Position adjusting 11 screw THP PCF45 6mm Allen wrench 19mm Wrench 19mm Socket THP PCF60 72 Allen wrench 34 Wrench Socket ftelb Torque wrench The procedure is IZ complete STEERING a Start the engine and let it idle b Turn the steering wheel in the original direction end of timing mark toward adjusting screw until axle stop contact is made c Hold the steering w
77. he poppet seat and sleeve assemblies are a pressed fit both poppet seats will now remain in this set position until they are reset using the procedure that follows Notice that the poppets were adjusted along with the poppet seat In all subsequent turns the poppet will be pushed off the seat to reduce pressure and the poppet seat should never again make contact with the housing or the fixed stop screw When the poppet makes contact pressure is reduced which also reduces the power assist felt at the steering wheel Axle to axle stop contact can still be achieved but with manual steering only 5 BLUE BIRD APPENDIX STEERING Reasons for Resetting Poppets e Changing to larger tires e Reducing wheelcut for any reason If the steer axle u bolts were bent or broken e If the pitman arm was mistimed Axle stop bolts were damaged e Steering gear is mounted on a different vehicle TAS Resetting e Set axle stops e Install adjusting screw e Raise Front Axle e Start Engine e Turn in the direction that moves the inner output shaft timing mark toward adjusting screw e Pull hard on the steering wheel e Turn in opposite direction pull hard on the steering whe
78. heel in this position with up to 40 Ib rim pull for 10 seconds then release Repeat this hold and release process as many times as necessary while completing step 11 a With steering wheel held tightly at full turn loosen the jam nut and hold it in place with a wrench b Turn the adjusting screw in clockwise using finger pressure only don t use a ratchet until the Allen wrench stops Do not attempt to turn it in further Pause the turning in process each time the driver releases the steering wheel continue turning only while the wheel is held at full turn c Back off the adjusting screw 3 turns and tighten the sealing nut Torque sealing nut to 35 ftelb 48 Nem The poppets have now been completely reset Lower the vehicle Check the reservoir and fill if required N PAEIT The length of the adjusting screw beyond the nut must be no more than 1145 for proper thread engagement The length of adjusting screw beyond the sealing nut may be different for each vehicle 25 3 APPENDIX 0 BLUE BIRD B3 FE SERVICE MANUAL Poppet Readjustment Dual Gears Mirror Image Systems and Reversed Image Systems Before setting poppets on a dual gear system you must determine whether the system has mirror image gears or reversed image gears The procedures are slightly Poppet Screw S N different for each type of system SSS iw 1
79. ht ahead Stop engine and check power steering reservoir level and top off if required Do not hold steering wheel at full turn for longer than 10 seconds as this will cause system to overheat 19 Restart engine and steer full turns each direction 3 or 4 times Figure 6 20 Stop engine and recheck reservoir fluid level and adjust to correct level if needed 21 Inspect system for leaks and correct if necessary 22 Bleed air from the system if required 23 Remove drip pan and lower vehicle Remove blocks from wheels and return vehicle for normal service TRW Automotive Commercial Steering Systems P O Box 60 Lafayette Indiana 47902 Tel 765 423 5377 Fax 765 429 1868 http trucksteering trw com http www trucksteering com TRW Automotive Inc 2003 TRW800 3A Rev 9 03 velde 1 BLUE BIRD APPENDIX Air Bleeding the Steering System Appendix 2 Air Bleeding the Steering System Visual Identification When you air bleed a steering system you are simply allowing air trapped in the cavities of the steering gear to escape As a general rule if your steering gear is a standard mount you should use the Automatic Bleed method If your gear is an inverted mount you will need to use the Manual Bleed method to purge the trapped air from the gear Standard Gear Mounting Configurations Automatic Bleed Gears 1 Fill the reservoir 2 Start the engine let it run for 10 seconds without stee
80. increase may not be noticeable depending on the size of the pocket Bleed the steering gear if there is a manual bleed screw at the top of the gear With system at normal operating temperature and engine at proper idle speed and running open the bleed screw and wait until clean clear oil begins to flow from the gear Close the bleed screw and steer the vehicle completely from stop to stop Repeat the bleeding operation three times and recheck oil level in reservoir to make sure there is enough oil for the system to operate properly STEERING Figure 9 1 4 APPENDIX BLUE BIRD Test 10 Restricted Hydraulic Line BLUE BIRD SERVICE MANUAL Read the following instructions below before completing Table 10 in the Test Results section Look at the supply line that goes to the pump to check for kinking or any other obstructions or irregularities on the inside of the hose Figure 10 1 Install PSSA with load valve fully open Figures 10 2 10 3 Insert temperature gauge into reservoir With oil between 125 135 F 52 57 C determine a test engine speed RPM that causes pump to deliver 3 4 5 or 6 gpm 11 15 19 or 23 Ipm which ever is easier and note this speed Remove the PSSA and install a low pressure gauge 200 300 psi 14 21 bar maximum with approximately 10 psi 70 bar per division in the pressure line to the steering gear at the pump end Install a temperature gauge in the power steer
81. ing on the direction of turn will trip as the steered wheels approach the axle stops which must be set according to manufacturer s specification The tripped valve reduces pressure in the gear and helps to reduce heat generated by the pump At the same time the valves also reduce forces on the steering linkage These valves are automatically set to axle stops after installation in vehicle at first full right and left turn Relief Valve Some THP PCF gears with or without poppets are supplied with a relief valve The relief valve limits maxi mum supply pressure to protect the power steering gear but it does not reduce pressure as the steered wheels approach the axle stops Bleed Systems Some THP PCF gears which are mounted with the output shaft above the rack piston bore are equipped with either an automatic bleed system or a manual bleed screw The procedure for air bleeding the system is on page 16 of this manual Replacement of damaged automatic bleed plugs and manual bleed screws is described on page 61 3 BLUE BIRD APPENDIX B3 FE SERVICE MANUAL Approved Hydraulic Fluids Automatic Transmission Fluid Dexron II Mobil ATF 210 Automatic Transmission Fluid Type E or F Mobil Super 10W 40 Motor Oil Chevron 10W 40 Premium Blue 2000 SAE 15W 40 Chevron Custom 10W 40 Motor Oil Texaco 10W 40 Chevron Torque 5 Fluid Texaco TL 1833 Power Steering Fluid Exxon Nuto H32 Hydraulic Fluid Union 10W 40 Fleetrite PS
82. ing reservoir Nei N Do not allow system pressure to exceed the rating of the gauge during the following procedure or damage to the gauge will result Extremely high restrictions may be indicated with the PSSA gauge as installed with load valve fully open Be sure that the steering gear input shaft is not being restrained from recentering because this will cause a false steering gear pressure drop If there is any question conduct this test with the steering column removed Bring the power steering fluid temperature to 125 135 F 52 57 C at engine idle with no steering force applied to the steering wheel Figure 10 4 At the test engine speed selected from step 2 above measure and record the gauge reading and shut off the engine This measures total system pressure Remove the pressure and retum lines from the steering gear and connect them together with a fitting that will not restrict the flow Figure 10 5 Start the engine and run at the RPM identified in step 2 with the fluid temperature between 125 135 F 52 57 C Measure and record gauge reading and shut off engine This is hydraulic line reservoir pressure The difference between the total system pressure gauge reading and the hydraulic line reservoir pressure gauge reading is the steering gear pressure drop For a TRW steering gear at a flow of 3 4 5 or 6 gpm 11 15 19 or 23 lpm the drop should not be greater than 30 40 55 or 70 psi 2 0 2 8 3 8
83. ir Refill if required 6 Start the engine again Steer the vehicle from full left to full right several times 7 Again check the fluid level in the reservoir 8 With the engine idling steer from full left turn to full right turn several times Stop steering with the wheels pointed straight ahead and loosen the manual bleed screw 2 3 turns 9 Allow air and aerated fluid to bleed out until fluid appears without bubbles 10 Close the bleed screw refill the reservoir if required 11 Repeat this process three or four times until all the air is discharged Torque manual bleed screw to 45 inelb Figure 1 Do not turn steering wheel with bleed screw loosened 5 16 Hexagon Screw Manual Bleed Screw Style TRW Automotive Commercial Steering Systems P O Box 60 Lafayette Indiana 47902 Tel 765 423 5377 Fax 765 429 1868 http trucksteering trw com http www trucksteering com TRW Automotive Inc 2003 TRW800 3B Rev 9 03 velde 2 BLUE BIRD APPENDIX THP PCF Steering Gear Appendix 3 STEERING tw RW Automotive Commercial Steering Systems THP PCF Steering Gear Service M anual THP PCF 45 AND 60 SERIES BLUE BIRD B3 FE SERVICE MANUAL Hazard Warning Definitions N TT em A warning describes hazards or unsafe practices which could result in severe personal injury or death N AE A caution describes hazards or unsafe practices which could result in
84. is hold and release process as many times as necessary while completing steps 11 amp 12 27 3 APPENDIX BLUE BIRD DSFE a With steering wheel held at full turn loosen the 15 BLUE BIRD 28 SERVICE MANUAL jam nut on the master gear and hold it in place with a wrench b Turn the adjusting screw in clockwise using finger pressure only don t use a ratchet until the Allen wrench comes to a stop Do not attempt to turn it in farther Pause the turning in process each time the driver releases the steering wheel Continue turning only while the wheel is held at full turn c Back off the adjusting screw 31 turns and tighten the sealing nut Torque the sealing nut to 33 37 ftelb 45 50 Nem d Release the steering wheel and shut off the engine Loosen the sealing nut and back out the adjusting screw on the rotary cylinder until 1 is past the nut Tighten the sealing nut against the housing a Start the engine and let it idle b Turn the steering wheel in the opposite direction end of timing mark on master gear away from adjusting screw until axle stop contact is made c Hold the steering wheel in this position put up to 40 Ib rim pull on a 20 dia steering wheel for 10 seconds then release Repeat this hold and release process as many times as necessary while completing step 14 a With steering wheel held at full turn loosen the Jam nut on the rotary cylinder an
85. le is moving Yes No Occurs Yes Rubbing or Yes only when squeaking steering sound No Check if wheel moves side to side relative to column See NOTE Is a rattle sound present Check if shaft is moving Yes in the bearing Location of Shaft in Column TEST 28 Check for loose steering wheel and or column mounting Tighten if necessary Is the related noise originating from under hood or within the cab No Is noise due to pump relief valve belt squeal Yes No Cab gt Call technical service Restricted Line Torque steering gear TEST 10 mounting bolts to OEM specifications at Yes No Low fluid level or loose inlet line ar Yes No Plugged reservoir vent or debris in reservoir Clean and Flush Steering System COMMENT J O Yes No Improperly installed filter in reservoir O Yes No Call technical service END NOISE 4 APPENDIX Lash in System TEST 15 Is steering wheel touching the column Yes Correct the source of the problem No Lubricate Horn Contact TEST 27 No Check I Shaft TEST 29 No Yes Call technical service Some noises are normal Inspect to make sure a more Call technical service serious condition does not exist me Call technical service STEERING Externa Yes Correct the problem causing the leak and verify it has been fixed Occur
86. le and the vehicle unloaded turn the steering wheel to full travel in one direction until axle stop contact is made Maximum input torque to be applied during this procedure is 40 Ib rim pull 178 N on a 20 in 508mm diameter steering wheel If you encounter excess rim pull effort allow the vehicle to roll forward or jack up the vehicle at the front axle Follow the same procedure while turning the steering wheel in the other direction The poppets are now positioned to trip and reduce pressure as the steered wheels approach the axle stops in either direction 3 APPENDIX 793 0 BLUE BIRD DSFE BLUE BIRD SERVICE MANUAL Maintenance Tips Never high pressure wash or steam clean a power steering gear while on or off the vehicle Doing so could force contami nants inside the gear and cause it to malfunction Make sure vehicle wheel cut or clearances meet manufacturer s specifications and make sure pitman arm timing marks are aligned properly to prevent internal bottoming of the steering gear Regularly check the fluid and the fluid level in the power steering reservoir Keep tires inflated to correct pressure Never use a torch to remove pitman arm Investigate and immediately correct the cause of any play rattle or shimmy in any part of the steering system Make sure the steering column is aligned properly Encourage drivers to report any malfunctions or accidents that could hav
87. ling areas and sector teeth contact surfaces for brinelling spalling or cracks Run your fingernail edge across these areas to detect steps Remove masking tape from the shaft and inspect for twisted or otherwise damaged serrations If any of these conditions exist replace the sector shaft A service sector shaft will come assembled with the adjusting screw 41A and retainer Not shown 3 APPENDIX BLUE BIRD B3 FE SERVICE MANUAL Assembly Preparation Wash all parts in clean OSHA approved solvent Air blow dry them only AMA EN TT TA Because they are flammable be extremely careful when using any solvents Even a small explosion or fire could cause injury or death N WAPAA Wear eye protection and be sure to comply with OSHA or other maximum air pressure requirements Replace all seals seal rings and gaskets with new ones each time you disassemble the gear TRW Commercial Steering Division makes complete seal kits available These parts can be purchased through most OEM parts distributors Contact your local dealer for availability Assembly Tools Required Materials Required Hammer Screwdriver ATF oil Seal kit THP450001 J37705 THP PCF45 Sockets Grease Exxon THP600001 J37071 THP PCF60 Torx sockets Polyrex EP2 Press Vise Masking tape Punch Torque wrench 14mm X 2 0mm Ratchet All Thread Press seal into 4 All gears Assemble new seal 40 onto bearing and housing seal tool short end so
88. lips of the new input shaft seal 4 and assemble it garter spring side first over the input shaft Align seal in the valve housing seal bore Place seal installer tool J37073 small diameter end first over the input shaft and against the seal Tap the seal installer tool until the tool shoulder is squarely against the valve housing This will cor rectly position the seal in the housing bore just beyond the retaining ring groove AN CAUTION Remove any seal material that may have sheared off and is in seal bore and retaining ring groove iN VUE EA The input shaft seal must be square in the seal bore and installed to the correct depth Insert new retaining ring 3 into its groove in valve housing 5 Install dirt amp water seal Grease 29 STEERING Pack the end of the valve housing bore around the input shaft with clean high temperature industrial grease Exxon Polyrex EP2 P N 045422 Apply more of the grease to the inside of a new dirt and water seal 2 2B or 2C and install it over the input shaft Seat the seal in the groove behind the serrations and against the valve housing Return to step 26 page 40 3 APPENDIX 59 BLUE BIRD DSFE Roller Bearing Replacement BLUE BIRD Tools Required SERVICE MANUAL Materials Required Press J37705 THP PCF45 J37071 A THP PCF60 60 3 APPENDIX Remove roller bearing if required T
89. lls 29 Inspect the rack piston 28 ball track grooves for brinelling or spalling If either condition exists replace the input shaft valve worm assembly 15 valve housing 5 rack piston subassembly 28 and balls 29 Inspect input shaft valve worm assembly sealing areas Inspect housing cylinder bore Inspect valve housing surface Inspect side cover bearing Inspect sector shaft assembly 3 6 ve STEERING Inspect the sealing area of input shaft and valve 15 for nicks and damage Inspect for discoloration trom excess heat Inspect input shaft ball track grooves for brinelling or spalling If any of these conditions exist replace the input shaft valve worm assembly valve housing and balls Also replace rack piston if brinelling or spalling is found Inspect the housing 34 cylinder bore some scoring marks are normal If there was internal leakage greater than 1 2 gom 4 5 Ipm make sure there are no damaged seals before replacing the housing Inspect the valve housing mating surface for nicks that would prevent proper sealing Replace the gear housing if these nicks are present and cannot be easily removed with a fine tooth flat file without changing the dimensional characteristics Inspect roller bearing in side cover assembly 45 for brinelling or spalling If either condition exists 821 replace the side cover and bearing assembly Inspect the sector shaft 41 bearing and sea
90. me during the test stop the test This temperature level is considered extreme and steering system performance and life will be seriously affected Damage to hoses seals and other compo nents may result if operated at extreme temperature If the steering system is operating above the recom mended temperatures the heat problem may be the root cause of the complaint Figure 6 2 ei Do not keep the load valve closed for more than 5 seconds at a time because damage to the system may result from excessive heat build up Do not allow the pressure to exceed 3000 psi 207 bar 2 With the engine at idle note the flow rate Fully close the load valve until the flow drops to zero Quickly open the load valve observing the flow meter The flow rate must instantly return to the reading you noted above 3 With the load valve open run the engine to governed speed and note the flow rate Fully close the load valve until the flow drops to zero Quickly open the load valve observing the flow meter The flow rate must instantly retum to the reading noted above 4 Conduct this pump response test three times at idle and three times at 1500 RPM If the flow rate does not return immediately the pump is malfunctioning which can result in momentary loss of power assist When hydraulic tests are completed and fluid lines are reconnected check fluid level and bleed the air from the hydraulic system 25 4 APPENDIX BLUE BIRD
91. n is to follow the Final Adjustment procedure on page 62 e Alternate option is to continue with step 5 of this procedure 21 3 APPENDIX BLUE BIRD BLUE BIRD 22 SERVICE MANUAL 3 APPENDIX Position adjusting screw Screwdriver Adjust shaft Screwdriver y4 Open end wrench Recheck for lash si Connect drag link 5 8 If no lash was detected in step 3 turn the shaft adjusting screw counterclockwise until you feel lash at the output shaft Slowly turn the shaft adjusting screw clockwise until you feel no lash at the output shaft without using more than 10 ftelb 14 Nem of torque From this position turn the screw clockwise to 3e of a turn more Hold the adjusting screw in place and tighten the jam nut Final jam nut torque 43 ftelb 58 Nem Turn the steering wheel turn each side of center then back to center and recheck the pitman arm for lash You should feel no lash if there is lash repeat steps 4 6 and 7 Reconnect the drag link to the pitman arm according to manufacturer s specifications AN CAUTION Maintain grease in the sector shaft bearing through the grease fitting in the housing using only a hand operated grease gun Add grease until it begins to extrude past the dirt and water seal Do not use a power grease gun because it will supply grease too fast this could adversely affect the high pressure seal and contaminate the hydraulic
92. nd install the four valve housing bolts 1 into the housing Torque the bolts to 118 138 ftelb 160 187 Nem 47 3 APPENDIX BLUE BIRD BLUE BIRD 48 SERVICE MANUAL 3 APPENDIX Install relief valve parts Ve Socket ftelb Torque wrench Lubricate side cover bearing Press seal in side cover J37705 THP PCF45 J37071 THP PCF60 Press Lubricate sector shaft Install sector shaft into side cover Screwdriver 18 14 15 16 17 If the gear is equipped with a relief valve assemble a new o ring 9 on relief valve cap 10 Assemble the small end of tapered spring onto the pin on the relief valve cartridge and insert the assembly 8 large end of tapered spring end first into the relief valve cap cavity Turn the relief valve cap as as sembled into the valve housing and torque to 30 ftelb 41 Nem Apply a generous amount of Exxon Polyrex EP2 TRW P N 045422 do not substitute another type of grease to the caged bearing assembly inside the side cover Next install washer 42 on top of bearing before inserting the seal 40 AN EAT Eg This bearing is sealed and will receive no lubrication from the hydraulic fluid in the gear Failure to use the proper grease could result in premature bearing wear Grease and assemble new seal 40 onto installation tool so the side with the garter spring is against the shoulder of the tool Pilot
93. ne universal joint cardan type can cause a cyclic binding feel or torque variation at the steering wheel if the u joints are not in phase with each other Figure 17 1 17 2 If a steering column assembly with multiple u joints is taken apart it must be reinstalled with the timing marks for slip mechanisms aligned This is true for both the cross type and the splined type two piece intermediate shaft Test 18 Steering Column Interference Position steering wheel at the location where steering wheel interference is noticed and look for something interfering or rubbing on the rotating column assembly such as brackets bolts floorboard boot etc Test 19 Intermediate Column Interference 1 Check the slip column by looking to make sure there is proper travel allowance when in use Figure 19 1 2 Look for wear or galling Figure 19 2 3 Check slip column for too much slip force Figure 19 2 31 4 APPENDIX BLUE BIRD 0 5 F F SERVICE MANUAL Test 20 Miter Box Misadjusted if equipped Check and adjust per manufacturer s instructions Figure 20 1 Test 21 Vehicle Alignment Check alignment of steered axle and rear drive axles and trailer axles if problem only exists with trailer Figure 21 1 Test 22 Wheel Bearing Adjustment Verify that adjustment is made according to manufacturer s Specification Figure 22 1 Test 23 Air Suspension Adjustment Check and set to manufacturer s specifications
94. next step These boxes are arranged in order of likelihood of being the cause of the driver s complaint It is important to complete the tests in order and follow the flow of the chart Locate correct test number in the TEST PROCEDURES section and follow the test procedure When you are done with the test note the results and correct the root cause If condition still exists keep going through the chart if necessary to correct the problem The results of some tests will need to be recorded Use the TEST RESULTS section to record these values If you identify a problem through a test procedure it is important that you retest the vehicle to make sure the condition has been corrected Warranty If you have identified that a steering component on your vehicle needs to be replaced this does not always mean it is warrantable Please read your manufacturer s warranty carefully before submitting a steering component for warranty consideration 4 APPENDIX BLUE BIRD TA FE SERVICE MANUAL Definitions 1 Hard Steering Hard Steering is when steering effort at the steering wheel is more than 200 inch pounds typically 18 22 Ibs at the rim of the steering wheel Steering is still possible but there is not enough power assist Common phrases used e Won t tum e Hangs up e Locks up e No assist e Shuts down e Won t tum unless moving e Tums hard 2 Reduced Wheelcut Common phrases used Too great of tuming radius requi
95. ng gear housing lack of clearance between frame and steering gear valve housing adapter sector Shaft adjusting screw and nut contact with access adjustment hole in frame If interference is found correct the problem 2 If the steering gear has been mounted to the frame in a way that causes the gear to distort not be flat it may cause a steering problem Figure 4 2 Checking to see if distortion is present on the vehicle may require the following test 3 With vehicle parked and engine running steer the wheel slowly checking for a binding type of feel at the steering wheel When binding is felt stop engine loosen one mounting bolt restart engine and steer the vehicle again Continue to loosen one mounting bolt at a time shutting off engine each time and check for improvement in the binding condition If improvement is made by loosening the bolts determine by inspection the condition causing the gear to distort and correct the problem Distortion of 030 80 mm or less is acceptable If greater than 030 80 mm surface flatness condition must be corrected Figure 4 2 21 4 APPENDIX BLUE BIRD TY BLUE BIRD gt E F SERVICE MANUAL Test 5 Power Steering Pump Test IMPORTANT Read the following instructions below before completing Table 5 located in the TEST RESULTS section Verify Engine Idle speed per your OEM specifications Install temperature gauge in reservoir Figure 5 1 Install
96. nt Steering systems for heavy duty trucks are made up of many components from the steering wheel to the road wheel The purpose of the steering system is to give the driver directional control of the vehicle When a driver feels the steering control over his her vehicle is not like it should be it is up to you to determine if there is a problem and if so figure out what is causing it It is always easier to fix something if you really understand the complaint Some ways you could do this are e Talk to the driver and ask a lot of questions like what when where and how e Make sure you can feel or see the problem Have the driver show you exactly what he she means e Walk around the truck looking for anything that may be an obvious cause of the problem To make your job easier and faster this manual has both the flow charts and test procedures comments each in their own section Once you have a good understanding of what the complaint is choose the flow chart that best matches the symptoms described to you Because there are different ways to say the same thing we have provided our definitions of the 10 most common complaints in this book Use these to determine which section of the manual would be helpful to begin diagnosing the steering system Reading the flow charts Start the chart at the BEGIN box Follow the lines to the next box answer the question or perform the test to verify the cause of the complaint then proceed to the
97. o Rear Steer Condition COMMENT G No Call technical service END ROAD WANDER 13 4 APPENDIX BLUE BIRD SERVICE MANUAL Non Recovery Preliminary Checklist 1 Tire pressure values Entire vehicle TEST 1 2 Fifth wheel properly greased TEST 2 3 Vehicle pre alignment TEST 21 4 Verify caster angle Binding in Steer Axle Linkage or King Pins TEST 3 Gear Column Binding TEST 8 Binding isolated to gear or column Ye Steering Gear Gear to Frame Interference TEST 4 Column Checks TEST 18 Driveline Slip Joint Travel and U joint Seizure TEST 17 reer i 9 Power Steering Pump TEST 5 COMMENT Steering too Tight TEST 16 Miter Box TEST 20 Firewall Boot Interference Restricted Line TEST 10 Call technical service END NON RECOVERY 14 4 BLUE BIRD APPENDIX STEERING Shimmy Mechanical Looseness TEST 15 TEST 22 Tire Wheel Balance and Runout COMMENT G Air in System TEST 9 COMMENT H Call technical service END SHIMMY 15 4 APPENDIX BLUE BIRD BLUE BIRD 16 SERVICE MANUAL NOTE Less than 25 in 6 35 mm at 18 in 647 mm Yes at steering wheel rim is normal Is noise associated with the steering column Is noise mechanical in nature Occurs only when vehicle is stationary Yes Yes No Occurs when vehic
98. olts and torque bolts to 180 220 ftelb 244 298 Nem Remove tape trom the sector shaft 41 Pack the end of the valve housing bore around the input shaft with clean high temperature industrial grease Exxon Polyrex EP2 P N 045422 Apply more of the grease to the inside of a new dirt and water seal 2 2B or 2C and install it over the input shaft Seat the seal in the groove behind the serrations and against the valve housing This step may have already been completed if you disassembled the valve housing and worm screw for repair Proceed to Final Adjustments on page 62 STEERING Poppet Component Replacement Tools Required Materials Required 2 Ib Sledge Ratchet Locquic T primer ftelb Torque Soft jawed vise Loctite RC680 wrench J36452 A Press 3 x 6 drill rod Place rack piston 1 If the poppet assemblies are to be removed for in vise replacement place rack piston in a soft jawed vise Soft jawed vise Loosen poppet 2 Slide special tool J36452 A over the seat of poppet adjuster seat adjuster seat and sleeve assembly 27 and engage tool in the slots in the threaded sleeve Hit the end of the tool firmly four or five times with a 2 lb sledge J36452 A hammer to loosen Loctite 2 Lb Sledge AN CAUTION Poppet adjuster seat and sleeve assemblies 27 are retained by Loctite applied to the threads which makes the assem blies difficult to remove Remove poppet 3 With a ratchet applied
99. ontinually cavitate and cause intemal pump damage and ultimately failure These conditions are 1 Twisted loose or cracked inlet line 2 Inlet line blockage due to a Contamination dirt and foreign material b Damaged filters c Reservoir components d Inner hose liner separation 3 Displaced improper or improperly installed filters 4 Reservoir cap vent plugged 36 4 APPENDIX STEERING Comment I Excessive Flow TRW steering gears are rated for 8 gpm maximum power steering pump flow Although the gears have the capability to handle this maximum flow it is not always a system need or requirement When using combinations of dual gears or a single gear with a hydraulic linear cylinder supply flows for both components should be considered See Steering Gear Flow Requirements Single gear applications have a recommended flow at engine idle For acceptable steering Speed performance again refer to the Steering Gear Flow Requirements Increasing the engine idle flow by more than 50 of the recommended flow can cause power steering system overheating vehicle directional control prob lems Darting and steer axle retumability Non recovery If you measure idle flows above the 50 limit consult your OEM for guidance and recommendations Comment Flushing and Air Bleeding the System IMPORTANT Clean the area around the reservoir steering gear and pump thoroughly before beginning this procedure Set parking brake
100. or the steering system and the brake fluid used in the brake master cylinder are not compatible and could result in a loss of steering or a loss of braking if incorrect fluids are used in either system Steering System Operation The speed at which the driver can turn the steering wheel with power assist is dependent upon the rate of flow provided by the hydraulic pump Normal flow rate is 3 6 6 3 gpm Minimum flow rate is 2 9 gpm As the driver turns the steering wheel faster or slower more or less oil flow is required by the gear The pressure of the hydraulic fluid is used to overcome the resistance in the system The higher the pres sure the more work it can perform Maximum operating pressure is 2 682 psi The steering wheel is connected to the steering column shaft The steering col umn shaft is connected to the steering gear input shaft When the driver turns the steering wheel the input shaft and worm shaft rotate The worm shaft is in turn con nected to a rack piston through the recirculating ball mechanism This rotational movement moves the rack piston axially in the gear housing cylinder bore The rack piston turns the sector shaft which is connected by linkage to the wheels on the front axle As resistance is encountered in the steering effort pressure in the steering hy draulic system will increase proportionally to assist the movement of the rack piston thus reducing the effort needed to steer the bus As the input shaft is
101. orce from the steering wheel to the steering gear input shaft A torsion bar pinned at its one end to the input shaft and at its other end to the worm shaft turns with the input shaft and exerts a rotational force on the worm shaft In response to this rotational force the worm shaft acting through the recirculating ball mechanism tries to move the rack piston axially through the gear housing cylinder bore The rack piston s axial movement is resisted by its engagement to the sector shaft which is connected by linkage to the steered wheels Because of this resis tance the torsion bar is twisted by the input shaft thereby actuating the control valve Pressurized fluid directed by the control valve assists in moving the rack piston axially through the cylinder bore The rack piston then turns the sector shaft to steer the vehicle Shock Loads to the Gear If the steered wheels receive a shock load the shock forces are transmitted through the sector shaft to the rack piston and on to the worm shaft The internal geometry of the steering gear causes the control valve to send high pressure fluid to the correct cylinder cavity to resist the shock forces By absorbing the shock forces hydraulically the steering gear prevents objectionable kickback at the steering wheel STEERING Unloading Poppet Valves Most THP PCF gears are equipped with two unloading valves one at each end of the rack piston One valve or the other depend
102. oved hydraulic fluid 10 Do not mix fluid types Mixing of transmission fluid motor oil or CAUTION other hydraulic fluids will cause seals to deteriorate faster 6 Place a jack under the center of the front axle and jack up the front end of the vehicle so the steer axle tires are off the ground b Note which output shaft timing mark is nearest the housing piston bore c Turn the steering wheel in the direction that makes this timing mark move toward the adjusting screws just installed on both the gear and the cylinder Turn in this direction until axle stop contact is made d Pull hard on the steering wheel put 40 Ibs rim pull on a 20 dia steering wheel after the axle stop is contacted a Turn the steering wheel in the opposite direction end of timing mark away from adjusting screw until the other axle stop is contacted b Pull hard on the steering wheel put 40 Ibs rim pull on a 20 dia steering wheel c Release the steering wheel and shut off the engine 809 Loosen the sealing nut and back out the adjusting screw until 1 is past the nut on both the master gear and the rotary cylinder Tighten the sealing nuts against both housings Do not hold the steering wheel at full turn for more than 10 seconds at a time the heat build up at pump relief pressure may damage components CAUTION a Start the engine and let it idle b Turn the steering wheel in the original direction
103. p check your manual it may not be developing enough pressure to steer If either case exists the pump needs to be repaired or replaced When hydraulic tests are completed and fluid lines are reconnected check fluid level and bleed the air from the hydraulic system 4 APPENDIX Figure 5 5 Test 45 1 40 Minute Pow er Steering Pump Test IMPORTANT Read the following instructions below before completing Table 5 1 in the Test Results section Verify Engine Idle speed per your OEM specifications 1 Install temperature gauge in reservoir Figure 5 1 Install PSSA in pressure line with shut off valve fully open Figure 5 2 Park the vehicle outside Record ambient temperature Run the engine at governed RPM for 40 minutes to bring the fluid up to an elevated testing temperature Measure and record the fluid temperature at the start and at 10 20 30 and 40 minutes Do not allow the temperature to exceed 250 F 121 C If the temperature goes over 250 F 121 C or 150 F 66 C above the surrounding temperature ambient at any time during the test stop the test This temperature level is considered extreme and steering system performance and life will be seriously affected Damage to hoses seals and other compo nents may result if operated at extreme temperature If the steering system is operating above the recom mended temperatures the heat problem may be the root cause of the
104. p assembly Objectionable kickback is prevented due to the geometry of the steering gear If the wheels receive a shock load it is transmitted back through the sector shaft rack piston and worm gears This load is neutralized by the control valve which sends oil flow to the correct side of the rack piston to resist the shock forces By absorbing the shock forces hydraulically the steering gear prevents objectionable kickback at the steering wheel and driver The steering gear is equipped with two poppet valves one on each end of the rack piston The poppet valves are set specifically to the turning radius of each bus after the axle stop adjustment has been made When the steering wheels are turned and approach the axle stop one poppet valve depending on the direction of turn trips The tripped poppet valve opens allowing oil flow to bypass the piston which reduces pressure in the gear and helps reduce heat buildup in the hydraulic system At the same time the valves also reduce forces on the steering linkage Careful preliminary checks should be done to identify a steering problem and its symptoms before deciding to tear down the steering gear In most cases the steer ing gear should be the last component suspected as cause of a steering problem Refer to Appendix 3 4 and 5 in this chapter for detailed step by step trouble shooting procedures STEERING Steering Pump The hydraulic steering pump on the Blue Bird All American Forwa
105. personal injury or product or property damage NOTE A note gives key information to make following a procedure easier or quicker Disclaimer This Service Manual has been prepared by TRW Commercial Steering Systems for reference and use by mechanics who have been trained to repair and service steering components and systems on heavy commercial vehicles TRVV Commercial Steering Systems has exercised reasonable care and diligence to present accurate clear and complete information and instructions regarding the TRW Commercial Steering THP PCF Series Integral Power Steering Gears Since this is a general service manual the photographs and illustrations may not look exactly like the steering gear being ser viced The procedures therefore must be carefully read and understood before servicing If inspection or testing reveals evidence of abnormal wear or damage to the THP PCF steering gear or if you encounter circum stances not covered in the Manual STOP Consult the vehicle manufacturer s Service Manual and warranty Do not try to repair or service a THP PCF steering gear which has been damaged or includes any part that shows excessive wear unless the damaged and worn parts are replaced with original TRW replacement and service parts and the unit is restored to TRW s specifications for the THP PCF steering gear It is the responsibility of the mechanic performing the maintenance repairs or service on a particular THP PCF
106. power assist is dependent upon the pump flow measured in gallons per minute or liters per minute Maximum internal leakage for all THP PCF gears is 1 2 directed to a cylinder cavity The control valve controls gpm 4 5 lpm flow through the steering gear The pressure measured in pounds per square inch or bar required for the gear to steer the vehicle is created by the power steering pump to overcome resistance at the steered wheels The control valve senses these requirements and directs fluid to the appropriate cylinder cavity in the steering gear and in the auxiliary cylinder if it is a dual steering system at the proper flow rate and pressure Pressure Means Work Flow Means Speed The higher pressure a steering gear can withstand the more work it can perform The maximum operating pressure for all THP PCF gears is 2685 psi 185 bar maximum flow rate for all THP PCF gears is 6 gpm 22 7 lom The THP PCF series gears can steer a vehicle within its front end weight rating through a turn at low speed and engine idle As the driver turns the steering wheel faster or slower more or less fluid will be required by the gear THP PCF series vehicle front end weight ratings are as follows Gear Front Axle Rating THP PCF45 9 000 Ib 4 100 kg THP PCF60 14 300 Ib 6 500 kg 3 BLUE BIRD APPENDIX General Operation What Happens During a Steering Maneuver When the driver turns the steering wheel he transmits f
107. racks Replace any part with these conditions Place valve housing 5 firmly in a vise so the input shaft valve worm assembly 15 can be assembled vertically with the worm end up Do not clamp against threaded port hole or relief valve hole sealing faces when placing valve housing in vise N CAUTION 55 3 0 APPENDIX BLUE BIRD SERVICE MANUAL Assemble seal ring 15 Lightly oil and assemble new seal ring 14 into the large diameter seal ring groove in valve housing bending and working it in and smoothing it out as necessary The seal ring must be smoothed out or it may be damaged when the worm is installed Install ball bearing 16 Install ball bearing 12 into valve housing 5 into valve housing Incorrect installation mnanaa Correct installation l l l EONA IE GT Assemble input 17 Dip the input end of the input shaft valve worm shaft valve worm assembly 15 into oil up to the worm lead As semble the input shaft end of the assembly into the valve housing 5 until it is firmly seated Assemble bearing 18 Apply oil and assemble the other thrust bearing 16 and thrust washer then the thin thrust washer 17 over the ball groove end of worm and seat them against the shoulder of input shaft valve worm assembly 15 Assemble sealsin 19 Lightly oil a new o ring 19 and assembl
108. rd Engine is a posi tive displacement pump with an integrated pressure relief valve and a flow regulator valve When troubleshooting it is important to remember to always do the simple steps first Look for obvious signs of leaking component wear or damage and hose problems before removing the power steering pump Special attention should be given to the supply hose for signs of clasping or routing issues creating kinks in the hose that could restrict oil flow to the pump Using a flow meter determine whether the pump is providing the necessary flow for proper steering The steering pump should provide a flow of approximately 4 minimum 2 9 gallons per minute GPM It is recommended that you use a Power Steering System Analyzer PSSA to assist in the diagnosis of steering system prob lems For details on troubleshooting the steering system see Appendix 4 TRW Steer ing Maintenance in this chapter Steering Pump Removal All American With Air Brakes 1 Drain the system of fluid in a manner consistent with all local state and fed eral laws Wear protective gear when working with hydraulic fluids including eye protection 2 Remove the supply hose 3 Remove the pressure hose from the fitting at the output port of the pump 4 Secure the pressure line safely out of the way 5 Remove two capscrews from the hydraulic pump mounting flange 6 Remove and discard the gasket Steering Pump Reinstallation All American With Air Brak
109. re are four teeth on the rack piston Rotate input shaft to position the rack piston so the space between the second and third tooth is in the center of the sector shaft opening This will center the rack piston for assembly of sector shaft If the rack piston is not centered when sector shaft is installed gear travel will be severely limited in one direction This could result in an accident N WARNING 22 Clean off any old tape on the serrations Reapply one layer of masking tape Install the sector shaft assembly into the housing The center tooth of the sector shaft must engage the center space be tween the second and third tooth of the rack piston Lightly tap on sidecover with a rubber hammer to seat cover against housing face N Til EA lf the serrations are not properly taped they will damage the output seal 41 in housing causing the seal to leak 3 APPENDIX 827 BLUE BIRD BLUE BIRD 50 SERVICE MANUAL 3 APPENDIX Install side cover bolts 1546 Socket Torque wrench Remove tape Install dirt amp water seal Grease 23 24 25 Install bolts in positions 3 and 4 first by hand Then install the remaining side cover bolts 48 into the side cover and torque them in the sequence shown If bolts must be replaced use bolts of the same design type and length as those you removed Do not use a substitute Lubricate side cover b
110. re removed If one poppet seat and sleeve assy 27 was left in rack piston it can be reset for automatic poppet adjustment by inserting a 3 9 52 mm diameter X 6 152 4 mm drill rod down through the poppet seat hole at the opposite end of the rack piston and against the adjuster seat to press the seat in until it bottoms against the adjuster sleeve Carefully apply Locquic T primer to the threads in poppet holes and threads on the new seat and sleeve assemblies 27 Allow to dry for ten min utes then carefully apply Loctite RC680 to same threads AN d ie Do not allow Loctite or Locquic to get on the adjuster seat component of the adjuster seat and sleeve assembly The poppets will not function properly AN WAIT TA Vear eye protection while assembling poppets as spring loaded poppets could eject and cause eye injury Place rack piston 28 in a soft jawed vise and turn one new poppet adjuster seat and sleeve assembly 27 slotted end out into the poppet hole in one end of rack piston From the other end of the poppet hole in the rack piston install one poppet 26 poppet spring 25 push tube 24 other poppet 26 and the other new poppet adjuster seat and sleeve assembly 27 The new components will stack up as shown below Torque both poppet seat and sleeve assemblies to 18 ftelb 25 Nem Return to step 25 page 40 STEERING Valve Housing Worm Screw Disassembly Tools Required
111. red e Wheelcut restricted e Not enough tums lock to lock 3 Steering Wheel Kick Steering Wheel Kick is when the road wheels hit a bump that the steering wheel reacts to The kick is usually dampened out quickly Common phrases used e Kickback e Backlash e Bump steer 4 Binding Darting and Oversteer Binding is a change or increase in steering wheel effort Binding will usually not require the effort levels described in Hard Steering unless it is severe Darting and oversteer are words that mean the driver suddenly gets more turning than he she wants 5 Directional Pull Common phrases used e Steering pulls to the nght or left e Truck pulls to the right or left e A constant force is required to keep the truck going straight 4 BLUE BIRD APPENDIX 10 STEERING y Definitions Road Wander Loose Steering Common phrases used e Lash in steering e Lost motion in steering e Continual corrections are needed at the steering wheel to keep the vehicle from wandering Non Recovery Common phrases used e Wheels don t return to straight ahead Shimmy A severe Shimmy condition can be felt at the steering wheel Typically once something triggers a Shimmy condition to occur it is sustained until the driver does something Such as slow down to dampen out the condition Common phrases used e Shake at steering wheel Noise Common phrases used e Steering Is noisy e Clicking or clunking sound is heard when stee
112. rew is flush with the nut Your steering gear and rotary cylinder will both have either fixed stop bolts or adjusting screws If the adjusting screw is already part of the gear or cylin der back the nut off of the adjusting screw until it is flush with the end of the adjusting screw 3 Make sure the engine is off and the road wheels are in straight ahead position Remove and discard the poppet fixed stop bolt if equipped and washer if equipped from the lower end of housing on both the gear and the cylinder If either unit has a poppet adjusting screw and sealing nut that need to be replaced remove and discard them 4 On both the master gear and the rotary cylinder turn the adjusting screw and sealing nut assembly without rotating the nut on the screw Into the housing until the nut is firmly against the housing using a 6mm THP PCF45 or 742 THP PCF60 allen wrench Tighten the sealing nut against the housing 5 Refill system reservoir with approved hydraulic fluid Do not mix fluid types Mixing of transmission fluid motor oil or other hydraulic fluids will cause seals to deteriorate faster N CAUTION 6 Place a jack under the center of the front axle and jack up the front end of the vehicle so the steer axle tires are off the ground This resetting procedure will work in most cases with at least 13 hand wheel turns from each side of center If you re making a large reduction in wheelcut and this proc
113. ring External Leakage Common phrases used e Loss of steering fluid e Continual adding of fluid in reservoir required 4 APPENDIX BLUE BIRD SERVICE MANUAL This page intentionally left blank BLUE BIRD APPENDIX Section 2 STEERING Flow Chart Diagrams Hard Steenng sessie MS ee ES AE EE Gee Ee 8 Reduced AL EE 9 Steering Wheel KICK nrrvrnrnnnnnrvrrnnnnnnnvnnnnnnnnrvnnnnnnnnerennnnnnnne 10 Binding Darting and Oversteer rrnrrvrnnnnnnnvvvnnnnnnrrennnnnr 11 Direcao PUll EE 12 Road Wander Loose Steering see ee ee EE 13 NOMRECOVETY EO EE EE Ed 14 SY N RE N N 15 NE 16 External OAK 0 cs cscsantlcanisndicienmtannssauenensaneyads 17 4 APPENDIX emm BLUE BIRD SERVICE MANUAL Preliminary Checklist 1 Power steering fluid in reservoir 2 Tire pressure values 3 Fifth wheel properly greased TEST 2 4 Vehicle has not been overloaded Yes Air in System Internal Leak TEST 9 TEST 7 No Intermittent Yes Is I Shaft Yes z loss of power Binding Intermittent Mechanical Replace I Shaft assist TEST 19 Verify problem has been corrected No Intermittent Hydraulic COMMENT K Does oil in reservoir smell hot or burnt Yes Restriction found Yes Replace Component or Hose Verify problem has been corrected No No Call technical No Pump Steering Pump service TEST 5 1 Restricted Line Inspect suspect componen
114. ring then shut it off 3 Check the reservoir and refill if the fluid level has dropped 4 Repeat at least three times checking and refilling the reservoir each time if necessary Do not allow the fluid level to drop significantly or run out of the reservoir This may induce air into the system D Start the engine and let it idle for 2 minutes without steering Shut off the engine and check the fluid level in the reservoir Refill if required Start the engine again Steer the vehicle from full left to full right several times Automatic bleed systems should now be free from trapped air Finally be sure to check the fluid level in the reservoir Refill if necessary before returning the vehicle to service Inverted Auto Bleed Plug Location Hex Head Torx Head Auto Bleed Plug Styles 2 APPENDIX BLUE BIRD SERVICE MANUAL Manual Bleed Gears 1 Fill the reservoir p 2 Start the engine let it run for 10 seconds without steering then shut it off 3 Check the reservoir and refill if the fluid level has dropped 4 Repeat this process at least three times checking and refilling the reser voir each time if necessary Manual Bleed Screw Location Do not allow the fluid level to drop significantly or run out of the reservoir This may induce air into the system 5 Start the engine and let it idle for 2 minutes without steering Shut off the engine and check the fluid level in the reservo
115. s in only one direction No tings Check the following Loose Defective Overtightened Damaged sealing surface Mismatched fitting Hose connection O ring fitting hardened Hoses Check the following Clamps loose Heat or age cracked Twisting or abrasion wear Misassembled end Loose fitting connection Wet or signs of weeping Test 5 1 eee Check the following Broken or cracked brackets filler tops connector dipstick Plugged vent hole in filler cap Improper oil level in reservoir Foaming due to filter element being improperly installed Drive shaft seal Cooler Steering Gear Check the following Poppet screw or sealing nut loose Input Output shaft seals Valve housing sealing areas Side cover seal vent plug bolts side cover gasket Porosity in housing side cover or valve housing END EXTERNAL LEAKAGE 4 APPENDIX Leakage 17 BLUE BIRD SERVICE MANUAL This page intentionally left blank BLUE BIRD APPENDIX Section 3 STEERING Test Procedures TELL 20 SU rv 21 ESE RE EE 22 TEL 23 ET 24 TE od EE EE AE 25 EG AE EE RR RE RE N 26 TeSt HO RE N EE EE anus 2 dd ale EE EE EE 28 KE ae AN OE RE RE N 29 TE il TE EE 30 TELT 31 Test OE ide Terr E tr ee ere rr ere 32 Test 20 9 ee Re EE Re ee ee ee Ee ee 33 4 APPENDIX y 19 BLUE BIRD SERVICE MANUAL Ny I Test 1 Steer Tire Check
116. sd SE EA EE BE rent rere rt 27 Reverse Mage aie es DES Ke DE DON RE GR 2 Reseal amp Repair Bls OY eta seas EE OE AA 34 PSCC ON een n EEE EE 42 SSS ana RE ee eet nen ee tere Ge Tne ere EE Ee 44 Internal Damage Repair by reference Poppet Component Replacement cccccccecceeeeeeeeee es 51 Valve Housing Worm Screw Disassembly ee sesse D3 Roller Bearing Replacement ee ee ee ee ee ee ee 60 Replace Housing Port Plugs Screws and Fittings 61 Fe MIG etl ed Suid Si ie AE EE Ie AE N N 62 Reinstallation FSS Call UO AE ETE EE EE OE EE shunts 65 Poppet Resetting EE EE EO de 65 TT EE EE RO EE OO Ee er 66 N AV TT eg All steering mechanisms are safety critical items As such it is imperative that the instructions in this booklet be followed to the letter Failure to observe the procedures set forth in this pamphlet may result in a loss of steering 3 BLUE BIRD APPENDIX STEERING er Section 1 General Information aie CHUNG TON EE sens 2 Oil Flow US TATION ss EE ee EE ei sei Ge ie 3 Can ge mB els AE N EE N 4 Ge Sia QO Sia O ea RE eee GEGEE ENE 5 ay Approved Hydraulic Fluids EE 6 Approved Grease re 6 Gear Specification Numbers si SR EE ER ie SE 6 dis ie di ie oa EE AE N 7 Exploded View occccccsccosccsscesscesetessesseseseesesesesereseveseteeeeseeeeeee 8 Service Parts LIST iss es RE oe EE se ee oe ee 9 F 783 3 APPENDIX BLUE BIRD B3 FE SERVICE MANUAL
117. ste ee ee ee ee ee ee ee 23 Dual Gear ME Ee ee ie Ee De 26 MTT 27 Reversed Image ee ee ee ee ee ee ee ee 29 3 APPENDIX T lt D IE D N mag O 795 BLUE BIRD B3 FE SERVICE MANUAL Filling and Air Bleeding the System Tools Required Materials Required 516 Socket Hydraulic fluid inelb Torque wrench Make sure poppets are set correctly before beginning this N CAUTION Run engine for 10 1 Fill the reservoir nearly full Do not steer Start and seconds turn off run the engine for 10 seconds then shut it off and fill reservoir Check and refill the reservoir Repeat at least three times checking the reservoir each time Hydraulic fluid AN dT il YES Do not allow the fluid level to drop significantly or run out of the reservoir This may induce air into the system Run engine for 2 2 Start the engine and let it idle for 2 minutes Do not minutes turn off steer Shut off the engine and check the fluid level and fill reservoir in the reservoir Refill as required Hydraulic fluid Steer vehicle 3 Start the engine again Steer the vehicle from full left to full right several times Add fluid as neces sary to the full line on the dip stick Automatic bleed systems should now be free trom trapped air Manual bleed systems continue with step 4 l Auto Bleed Plug Do Not Remove Allow air to bleed 4 With engine idling steer from
118. sure poppets relieve in both turns just before axle stop contact is made If not removed from vehicle and gear is being installed on the fe use resetting procedure beginning on page 23 same vehicle with no change in axle stops or linkage gt IF Poppets were replaced with new components or Use poppet setting procedure on page 13 reset during gear disassembly and are ready for auto matic positioning gt IF Poppets may have been moved during disassembly Use poppet resetting procedure beginning on page 23 or reassembly procedures or gear is being Installed on a different vehicle gt 65 3 APPENDIX BLUE BIRD P 2 E F SERVICE MANUAL Glossary Aerated Fluid Impact BLUE BIRD Fluid with air bubbles Automatic Bleed Systems Gears are mounted in such a way that trapped air can be forced out of the system automatically without loosening bleed screw Axial In out movement along an axis imaginary straight line on which an object moves Brinelling Dents Date Code Date the steering gear was built Julian date Discoloration Change in color External Leakage Fluid Leaking out of the system or steering gear Full Turn Hub contacts axle stop Integral Power Steering Steering gear has manual steering mechanism hydraulic control valve and hydraulic power cylinder all within gear housing 66 3 APPENDIX The application of torques and
119. t TEST 10 for blockage damage or improper hoses and fittings Flow Control Response TEST 6 1 Are any numbers input on chart below specifications ES Replace Pump Internal Leak Tes con Verify problem has TEST 7 No been corrected Replace Steering Gear No Verify problem has Call technical been corrected Yes Pump Vanes Reprime Restricted Line COMMENT A TEST 10 Check for these Conditions Cold start only No 1 Binding at input side of gear a U joint rubbing TEST 17 b Intermediate shaft binding TEST 19 2 Firewall boot interference cab mount drop TEST 18 3 Gear to frame interfernce TEST 4 4 Binding at king pins steer axle linkage TEST 3 Power Steering Pump TEST 5 Are any numbers input on chart below specifications Yes Replace Pump one Verify problem has been corrected No Chart TRW Steering Gear Flow Requirements Restricted Line TEST 10 us Air in System Yes ore TEST 9 Steering too Fast COMMENT B No COMMENT H No Check if correct pump has been Internal Leak installed for your TEST 7 application and consult your OEM truck representative END HARD STEERING 4 BLUE BIRD APPENDIX STEERING Reduced Wheelcut Set Axle Stops to OEM Specifications TEST 11 Pitman Arm Output Shaft TEST 12 Timing Mark Diagram Figure 12 1 Are poppets set correctly Mis
120. t to 33 37 ftelb 45 50 Nem 13 The poppets on both the master gear and rotary cylinder have now been completely reset Lower the vehicle Check the reservoir and fill if required AMA TN TE The length of the adjusting screw beyond the nut must be no more than 11 6 for proper thread engagement The length of adjusting screw beyond the sealing nut may be different for each vehicle 30 3 BLUE BIRD APPENDIX Section 4 STEERING Reseal amp Repair BEE Selge OE eee ee EE E 34 NNN 42 AE Sepie AO EE EE ee eee 44 Internal Damage Repair by reference Poppet Component Replacement ccecce 51 Valve Housing Worm Screw Disassembly 53 Roller Bearing or Retaining Ring Replacement 60 Replace Housing Port Plugs Screws and Fittings 61 Fe GUIS UN FS EE 63 3 APPENDIX J T 3 QO J gt gt mag BLUE BIRD B3 FE SERVICE MANUAL Disassembly Preparation Stop the vehicle with wheels pointed straight ahead Clean off all outside dirt from around fittings and hose connections before you remove the gear Remove input and output shaft connections per vehicle manufacturer s instructions N MP TER When using a chisel to spread a pinch bolt type pitman arm boss for assembly or removal from the shaft maintain a firm grip on the chisel at all times Failure to do this may result in the chisel flying loose which could cause an injury Never leave the chisel we
121. t which was previously noted Again reverse the assembly in vise Torque locknut while holding bearing adjuster in position estab 835 lished in step 22 with appropriate adjuster tool When using a torque wrench in locknut tool J37464 the torque wrench reading should be 112 ftelb 152 Nem Recheck input shaft torque It should match torque measured in step 22 Repeat steps 22 and 23 if necessary 5 3 APPENDIX BLUE BIRD BLUE BIRD 58 SERVICE MANUAL 3 APPENDIX Stake valve 25 housing and locknut Center punch Hammer 1346 Socket inelb Torque wrench Reposition 26 subassembly in vise Install input shaft 21 seal J37073 Hammer Insert retaining 28 ring Stake valve housing into the clockwise most corner of two opposing slots in lock nut 21 Stake the locknut into the adjuster 20 in two places 180 apart at threaded area Choose areas that have not been previously staked After staking torque required to rotate input shaft must be between 5 10 inelb 5 1 0 Nem greater than the torque noted in step 22 Torque value must not exceed 22 inelb 2 5 Nem Unstake and readjust if necessary Reposition worm screw valve housing subassembly in soft jawed vise clamping tightly against valve housing so the worm screw is pointing down Apply clean grease Exxon Polyrex EP2 P N 045422 to the outside and inside diameters fill cavity between the
122. tely to avoid damage to the steering system Record and report any malfunctions or accidents which may have damaged steering components Steering Column Assembly BLUE BIRD BLUE BIRD SERVICE MANUAL Setting the Steering Poppets To adjust the steering poppets refer to Appendix 5 Steering Poppets in this chap ter Refer to the Front Axle Appendix located in the axle chapter of this manual for the following steering related adjustments and lubrication points Axle Stop Adjustment Caster and Camber Adjustments Toe in Adjustment King Pin Lubrication Te Rod Lubrication Steering Column amp Steering Wheel Steering Column The All American steering column offers a tilt telescoping range of movement al lowing the steering wheel and stem controls to be placed with in a comfort range of the driver Adjustment of the steering wheel is accomplished by actuating a tile tele scoping control lever located at the bottom center of the steering column and mov ing the steering wheel into a new position The control lever is actuated by pulling downward until the lever rolls over center and locks in the release position With the control lever in the released position the steering wheel and column moves freely within its range of travel When the steering wheel has been placed in the desired position push the control lever upward to lock the position Actuating the control lever
123. the case of a linear cylinder first plug the disconnected lines and then disconnect the cylinder from the steering linkage making Sure it will clear the steered axle Figures 7 6 7 7 Repeat the internal leakage test If the internal leakage is less than 1 gpm 3 8 Ipm repair or replace the auxiliary cylinder If the internal leakage is greater than 1 gpm 3 8 Ipm repair or replace the gear When hydraulic tests are completed and fluid lines are reconnected check fluid level and bleed the air from the hydraulic system Test 8 Steering Column Binding 1 With the vehicle parked the engine off and the steer axde jacked up Slowly steer the vehicle until the binding position is located With the steering gear at this position remove the steering column assembly from the steering gear Note the correct position of the column and steering gear for reassembly after test Figure 8 1 Rotate the steering gear input shaft no more than 1 4 tum each direction and check if binding is still present Figure 8 2 If binding is not felt correct the steering column problem Test 9 Airin Hydraulic System 1 Inspect reservoir for foaming or air bubbles Figure 9 1 If foaming or bubbles are seen air is being sucked into the system through cracks or loose fittings Look for oil level changes engine off versus engine on if fluid level increases when the vehicle is shut off there is an air pocket trapped in the steering gear The
124. the tool into the side cover 45 with a force of 100 800 Ib 445 3560 N until it is seated against the bearing or bushing AN EAT Ed Make sure the OD of the seal and the ID of the bore are free from grease and dust for proper engagement of the seal Apply a generous amount of Exxon Polyrex EP2 P N 045422 to the short bearing area of the sector shaft Insert the sector shaft 41 into the side cover subassembly 45 and turn the sector shaft adjust ing screw 41A counterclockwise into the side cover until the screw reaches solid height Rotate the adjusting screw clockwise one half turn so the side cover will rotate freely on the sector shaft Install jam nut Assemble vent plug Install side cover o ring Center rack piston Install sector shaft and side cover into housing Masking tape STEERING 18 Install the sector shaft adjusting screw jam nut 46 onto the sector shaft adjusting screw 41A a few threads Final adjustment will be made later 19 Press the new vent plug 47 into the hole provided in the side cover until the plug is bottomed N AV Do not weld or otherwise plug this hole in any permanent manner This is a safety vent which functions only if the side cover seal fails If the seal fails and the plug cannot vent the steering gear may lock up or otherwise malfunction 20 Apply clean oil to the new side cover o ring 44 and assemble it onto the side cover 45 21 The
125. uld be safe and productive 3 APPENDIX STEERING er Oil Flow Illustration Left Hand Lead Right Hand Lead AUN Right Hand Turn steering Wheel Input Clockwise Rotation AY AN Straightline Running No Steering Action AY ER Left Hand Turn Steering Wheel Input Counter Clockwise Rotation Supply Pressure Return Pressure 3 APPENDIX BLUE BIRD B3 FE SERVICE MANUAL General Design Integral Power Steering THP PCF power steering gears are the latest design in The recommended minimum flow at 1 steering wheel the TRW Commercial Steering Systems family of integral turns per second is as follows hydraulic power steering gears Integral hydraulic power steering means that the gear contains a manual steering Gear Minimum Flow Rate mechanism a hydraulic control valve and a hydraulic power cylinder all in a single compact package THP PCF45 2 2 gal min 8 3 L min THP PCF60 2 6 gal min 9 8 L min Rotary Control Valve If the steering gear valve is controlling an auxiliary cylin The rotary control valve combines simplicity of construc der increased minimum flow is required generally at tion with desirable performance characteristics The least 75 based on the size of the auxiliary cylinder and speed at which the driver can turn the steering wheel the vehicle s steering geometry with
126. ve the ball cup that the bearing 12 rides on Do not remove the special spacer seal behind the ball cup Remove seal ring 9 Remove and discard seal ring 14 from valve housing 5 Small probe or pick 54 BLUE BIRD APPENDIX Remove retaining ring Screwdriver Remove seal 1 Socket Hammer Inspect input shaft valve worm assembly sealing areas Inspect thrust washer and bearings Place valve housing in vise 10 11 12 13 14 STEERING Turn over valve housing and remove retaining ring 3 AN EAT E Exercise special care when removing seal 4 to prevent damaging the valve housing seal bore Tap input shaft seal 4 out of valve housing Dis card seal The valve housing also utilizes a ball plug for manufacturing purposes that must not be removed Inspect the sealing areas of input shaft and valve 15 for nicks and run your fingernail edge across the sealing surfaces to detect steps Inspect for discol oration from excess heat Inspect input shaft ball track grooves for brinelling or spalling If any of these conditions exist you must replace the input shaft valve worm assembly valve housing and balls Also replace rack piston if brinelling or spalling is found Inspect the thrust bearing 16 rollers and ball bearing 12 for any deterioration Inspect thrust 833 washer 17 and ball bearing race in the valve housing for brinelling spalling or c
127. ver Parts Vary by Gear Size Item Description 22 Rack Piston Seal Ring 23 Rack Piston O ring 30 Ball Return Guide Halves 2 R H Br 35 Dirt and Water Seal Trunnion 39 Roller Bearing Trunnion 40 Output Seal 2 42 Washer 43 Side Cover Roller Bearing 38 Fixed Stop Screw 38A Poppet Adjusting Screw 38B Poppet Adjusting Screw Nut Part Number 023037 478044 478060 478050 401637 478076 052220 415437 A1 032200 153 411061 032829 400152 A1 032823 029128 070027 400144 029123 032200 158 400149 027007 080154 401662 040248 409118 A2 213684 X1 478042 400177 020228 037032 021397 23705 021426 032856 025150 036201 021434 THP PCF45 032828 032827 400158 400159 478098 070030 478105 028561 070031 023044 023045 027018 STEERING Parts Vary by Specification Item Description 5 Valve Housing 8 Relief Valve 15 Input Shaft Valve Worm Assy 28 Rack Piston 34 Housing 41 Sector Shaft Includes 41A 45 Side Cover Assembly Includes 40 42 43 Contact Service Sales for part numbers Kits Items Description Part Number 6 amp 7 Port Plug amp O ring 415437 A1 9 amp 10 Relief Valve Cap amp O ring 411061 A1 38A amp 38B Adj Screw amp Jam Nut THP PCF45 Kit 023045 X1 THP PCF60 Kit 021407 X1 2 2B 2C 3 4 Input Shaft Seal Kit THP000001 THP PCF45 Seal Kit THP450001 THP PCF60 Seal Kit THP600001 THP PCF60 032830 032831 400172 400173 478095 071033 478104 02855
128. w to use a PSSA you may refer to the video available through our website at www trucksteenng com This video compliments the tests in this book which require the use of the PSSA A WARNING Throughout this troubleshooting guide test procedures are recommended to help locate the cause of each complaint While performing these tests TRW advises that you TAKE NECESSARY PRECAUTIONS when working with internal vehicle components and hot hydraulic fluids TRW Inc 2002 4 APPENDIX BLUE BIRD SERVICE MANUAL This page intentionally left blank BLUE BIRD APPENDIX STEERING y Table of Contents 2 ESE S EE 3 Flow Chart Diagrams ee 7 Test Procedures REENEN EE EE OE AS EE EE 19 COEN oa EE NG GAD EG GE Te RE 35 TETTE ss EE Ee EE DO ee 39 BLUE BIRD APPENDIX SERVICE MANUAL This page intentionally left blank BLUE BIRD APPENDIX STEERING y Section 1 Preface MON 3 Understanding the Complaint Reading the Flow Charts Warranty Definitions cccccececcececcaccececaucucucauaucucauaususauauaesauauaesananes 4 5 Hard Steering Reduced Wheelcut Steering Wheel Kick Binding Darting and Oversteer Directional Pull Road Wander Loose Steering Non Recovery Shimmy Noise External Leakage 4 APPENDIX BLUE BIRD SERVICE MANUAL This page intentionally left blank BLUE BIRD APPENDIX STEERING Introduction Understanding the Complai
129. wrench Replace manual 4 bleed screw 546 Hex socket inelb Torque wrench If damaged remove and replace the poppet fixed stop screw 38 and washer Not shown if equipped Replace with poppet fixed stop screw 38 discard the washer Torque to 48 ftelb 65 Nem If damaged remove poppet adjusting screw 38A and sealing nut 38B without allowing the nut to change its position on the screw Assemble the new nut onto the new adjusting screw matching its position to the nut and screw removed Torque sealing nut to 35 ftelb 47 Nem If damaged remove and replace automatic bleed plug 38 Torque to 48 ftelb 65 Nem If damaged remove and replace permanent auxiliary port plugs 7 and o rings 6 Assemble new o rings on port plugs and torque to their respective ports in the housing or valve housing to 30 ftelb 41 Nem If damaged remove and replace manual bleed screw Not shown Torque to 45 inelb 3 4 Nem Possible manual bleed screw locations Return to inspection section page 42 61 3 APPENDIX BLUE BIRD fe 2 E F SERVICE MANUAL Final Adjustments Tools Reguired Materials Required Box end Screwdriver wrench Sockets ftelb Torque wrench inelb Torque wrench Center steering 1 To center the steering gear rotate input shaft valve gear worm assembly 15 until the timing mark on the end of the sector shaft 41 is in line with the timing a mark on t

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