Hydraguide™ Hydrostatic Steering System
Contents
1. 25 21 Install commutator ring 33 over assembly posts Figure HGA 23 and onto manifold 32 make sure slot side is down See Figure HGA 26 19 Install rotor set 31 over assembly posts and 22 Install rotor seal 36 and seal retainer 35 over onto spacer plate 29 Note One of the seven rotor set 31 and down against housing holes in the rotor set may be smaller than the 23 To allow for washer 37 assemble commutator other six holes Position this hole if applica 34 with counterbore up into commutator ring ble over one of the assembly posts See 33 with slotted hole in commutator engaging Figure HGA 24 Warning vane springs nose of drive link 30 Align commutator outside 31C must be down in their slots with no part diameter concentric with inside diameter of of spring protruding out either side of meter commutator ring See Figure HGA 27 ing element 16 24 25 26 Figure HGA 27 Apply a small amount of clean grease to wash er 37 and install over pin in end cover assem bly 38 Grease should hold washer 37 to end cover assembly Assemble end cover assembly 38 with wash er 37 attached over assembly posts and onto HGA unit Install five of the special bolts 39 finger tight Remove two assembly posts and assemble the other two special bolts per steps 1 and 2 as fol lows and do not over torque as it will cause unrepairable damage 1 Torque all sev2. Hydraulics Hydraguide 1 Hydrostatic Steering System HGA Service Manual Service Manual 2751 Hydraulic Pump Motor Division TYPICAL OIL FLOW E p TERES Pm a nme pi al STEERING WHEEL IMPUT i Aotation T es i rx III sureiy PRESSURE From Power Pump Lj RETURN CHL FLOW To Reservoir zs METERED OIL FLOW To Cylinder Table of Contents Section SV STON Deh ANON 3 De Omano FUNGUO m ms page 3 amp Tm m page 4 eee E E E page 4 ROLO ODAO ee E T page 4 Power Steering Operation nennen sss nnn nnns page 5 Manual Steering nennen nnns page 5 Exploded VIEW NN TREO T page 6 SEV Pans uiuit e page 7 Section OBVIOS PIOOBOHPE meri ebn UM EDU UNE CUM DIRIO DUE page 8 WOK relire ed Tm page 8 zd eo gt RR RO E TTE DIS page 7 Seal Replacement Instructions page 9 wire AGA NERO OTT page 9 Disassembly page 10 Section Iie
3. 020 0025 from the adjacent counterbore surface If within spec no additional shimming required If not within 0025 add or remove shims 9 until this requirement is satisfied repeating assembling steps as outlined n above See Figure HGA 21 Figure HGA 21 The correct shimming must be checked on the vehicle or on a suitable hydraulic test stand The amount of steering effort required to steer the vehicle when the vehicle is at rest on dry pave ment must be equal within two inch pounds For example if twenty one inch pounds is required to steer to the right not less than thirteen or more than twenty three inch pounds should be required to steer to the left If a test stand is available to place a load between cylinder ports in the same manner as on the vehicle a test stand should be used Add shims to increase steering efforts in a left turn subtract shims to increase steering effort in a right turn With the drive link 30 installed as described above assemble two assembly posts into the housing 25 as shown in Figure HGA 22 These 15 heads off of two bolts similar to the special bolts 39 N Figure HGA 24 20 Install manifold 32 over assembly posts and igure HGA 22 onto rotor set 31 make sure circular slot side of manifold is up See Figure HGA 25 18 Assemble spacer plate 29 over assembly posts and onto housing 25 with plain side up See Figure HGA 23
4. 2 00 5 62 6 00 6 50 2 00 5 62 6 00 11 Thrust Washer 400100 23 Ball 5 16 dia 400013 38 End Cover 402803 A1 19 Spacer 477248 178 477248 184 477248 196 477248 209 477248 221 477248 234 477248 196 477248 221 477248 209 477248 234 SECTION Il SERVICE PROCEDURE For service information on the steering pump engine driven and power cylinder see information provided by the manufacturer of these units For servicing the HGA unit and the system see instructions in the following sections Servicing of HGA Unit Page 9 Filing and Air Bleeding the System When Drained of Oil Page 19 Hydraulic Fluid Page 19 CLEAN WORK CONDITIONS is a must that the system be kept free of dirt or for eign matter in the oil circuit Cleanliness in serving WARNING SINCE SOLVENTS ARE FLAMMA BLE BE EXTREMELY CAREFUL WHEN USING THEM EVEN A SMALL EXPLOSION OR FIRE COULD CAUSE DEATH OR INJURY WARNING EYE PROTECTION SHOULD BE WORN this power steering system is absolutely necessary If it is necessary to disassemble any of the units make sure that a clean work bench or table is used A piece of clean wrapping paper makes an excellent disposable top Outside dirt should be cleaned off before disconnect ing lines and port holes should be plugged immedi ately after disconnecting lines Finish cleaning off outside dirt before placing on work bench When disassembled parts should be cleaned only
5. System Operation WARNING ALWAYS CAREFULLY INSPECT ANY STEERING SYSTEM COMPONENT THAT MAY HAVE BEEN STRUCK OR DAMAGED DURING OPERATION OR IN AN ACCIDENT REPLACE ANY COMPONENT THAT IS DAM AGED OR THAT IS QUESTIONABLE Ross extends close technical cooperation and assistance If steering problems occur which you cannot solve please contact our Ross Field Service Department Our phone number and address are on the back cover of this manual 20 dr F m 48 eo bh bat zc Left Hand Turn OIL FLOW From Recirculating Valve i RETURN OIL To Recirculating Valve METERED OIL FLOW To Cylinder HGA Service Manual 044 Ross Operation 2745 Snapps Ferry Road Greeneville TN 37745 USA Tel 423 639 8151 Fax 423 787 2418 Sales 2500 1 96 BB
6. The HGA unit consists of a fluid control valve sec tion and a fluid metering section which are hydrauli cally and mechanically inter connected C CONTROL VALVE The control valve section contains a mechanically actuated linear spool which is torsion bar centered The function of the control valve section is to direct the fluid to and from the metering section to and from the cylinder and to regulate the pressure supplied to the cylinder The valve is provided with unique pres sure chambers which insure effective circuit isolation D METERING SECTION The metering section consists of a commutator and bi directional gerotor element which contains an orbit ing rotor and a fixed stator The commutator rotates at orbit speed with the rotor and channels the fluid to and from the rotor set and the valve section The rotor incorporates unique sealing vanes which are spring and hydraulically forced into sealing con tact between the rotor and stator to reduce leakage across the metering section Le e o o nma mm a e ee The function of the metering section is to meter the oil to the power cylinder maintaining the relationship between the hand wheel and the steered wheels An additional function of the metering section is to act as a manually operated pump providing manual steering in the event of an inoperative engine driven pump Figure HGA 2 E ROTOR OPERATION I
7. GO BELOW FILL LINE ON DIPSTICK BEFORE ADDING NEW FLUID COMPLETELY DRAIN OLD OIL FROM THE SYSTEM IT MAY BE NECESSARY ALSO THAT YOU FLUSH THE SYSTEM WITH CLEAN OIL 19 TIPS FOR MAINTAINING THE HYDROSTATIC STEERING SYSTEM Top up fluid level in reservoir as necessary Maintain correctly inflated tires Always use a puller to remove the steering wheel Do not use a hammer torch or crow bar nvestigate and correct immediately any play rattle shimmy or other unusual occurrence in the steering system Remove cause of steering column misalign meni Encourage all drivers or operators to report any malfunction or accident that may have damaged a steering system part not attempt to weld any broken steering component Replace the component with origi WARNING DO NOT WELD BRAZE OR SOL DER ANY STEERING SYSTEM COMPONENT WARNING MAXIMUM OPERATING PRESSURE MUST NOT EXCEED VEHICLE MANUFACTUR ER S RECOMMENDED PUMP PRESSURE CAPACITY nal equipment only not cold straighten hot straighten or bend any steering part Prevent dirt or other foreign matter from enter ing the hydraulic system Clean off around filler caps before checking oil level nvestigate and correct any external leak in the steering system no matter how minor the leak Comply with manufacturer s specifications for cleaning or replacing the filter WARNINGS for Proper Steering
8. b O Ring 25 c 26 Ball 32 ifold 27 O Ring 33 Commutator Ring 28 Plug 34 Commutator 29 Spacer 35 Seal Retainer 30 Drive Link 36 Seal 31 Rotor Set 37 Washer 31a Stator 38 End Cover 31 b Rotor 39 Special Boplt 31c Spring 31d Vane Vanes are optional on units with 75 or larger rotor widths Vanes are specified on units with rotor widths smaller than 79 Figure HGA 6 Torsion bars are unit specific To select the correct replacement measure the diameter of the center section of the bar and the length between holes then select the correct base number from the following chart 1 Wheel Nut 026045 12 Thrust Bearing 063979 24 Spring 401412 22 amp 25 Series HGA 07 HGA 08 HGA10 HGA 12 HGA 14 HGA 16 HGA 20 HGA 24 HGA 28 HGA 32 2 4 amp 5 Seal Kit HG500007 13 Thrust Washer 400075 25 A amp B Plug amp O Ring 036147 X1 31C D USE WITH HGA SERVICE MANUAL EXPLODED VIEW 3 Snap Ring 401233 14 Spring Bearing 401366 25C amp 26 Ball 1 4 dia G453570 6 Screw 4 ea 021434 15 Spacer Washer 477277 27 amp 28 Plug Assy 415395 A2 7 8 Upper Seal Cover HGAO016005X1 032840X1 16 16 16 Pinhole Wheel Mount Fully Washer Shaft 089181 089180 089193 29 32 Spacer Manifold 477235 HGA015001 9 Shim Kit 033157 X2 17 Needle Roller 040114 32 amp 34 Commutator Ass
9. washer 11 Coat seal 8 with clean grease and place in upper cover 7 counterbore Assemble upper cover onto input shaft 16 and rotate to align punch marks previously made during disassem bly Note If a new upper cover is used no angular orientation is required However it is necessary to align the upper cover 7 and housing 25 Replace without screws finger tight and then use a pilot ring or a worm drive type hose clamp tightened around the upper cover flange and the body pilot diameter to achieve the required alignment Now tighten screws to 18 22 ft lbs torque See Figure HGA 20 16b 16c ls NOTE If any of the input shaft 16 housing and spool torsion bar or upper cover 7 have been replaced the following procedure for checking and shim adjustment must be used He assemble as in a above using the required new parts After torquing the four screws 6 revolve unit in vise so that the input shaft is pointing downward In order to determine that the unit is shimmed correctly the drive link 30 must be in in its proper position To do this grasp the input shaft 16 pull downward and prevent rotation Engage drive link splines in spool 22 and rotate to position spool essential ly flush with end of housing 25 Remove drive link and orient drive link slot to engage torsion bar needle roller 21 and insert drive link Observe relationship of spool end to body The valve spool must protrude
10. 12 Insert the input shaft 16 into the spool engaging the helix and ball with a counter clockwise motion This operation is best done while holding the spool in a horizontal position Using the mid section of the torsion bar 20 as a gage insert the gage between the spool end and the thrust washer 13 See Figure HGA 17 This will position the spool in the necessary radial relationship with the input shaft spline teeth for assembly of drive ring 18 Place the input shaft 16 and spool 22 assem bly in a vertical position with the shaft end on the table surface Figure HGA 17 10 Tes 19 14 SPACE p SHAFI FT Figure HGA 18 NOTE Rotate the input shaft 16 out of the valve spool 22 until input shaft will no longer rotate There will be a gap of approxi mately 350 between end of valve spool 22 and thrust washer 13 if the drive ring 18 is assembled properly Insert the drive ring 18 into the spool 22 end by visually aligning an internal space on the drive ring with a tooth on the input shaft 16 split and allow the drive ring to drop to the limit of its travel If the drive ring does not engage the input shaft spline a slight rotation of the input shaft will allow the drive ring to become fully engaged Remove torsion bar 20 gage See Figure HGA 18 CAUTION The will not function proper ly if the correct relationship of spool drive ring and input shaft is not ach
11. ES SHOULD NOT BE USED IN ATTEMPTING TO MANUALLY STEER THE VEHICLE AS THEY MAY GENERATE FORCES IN EXCESS OF 125 FT LBS THEREBY DAMAGING THE UNIT INTERNALLY WHICH COULD RESULT IN A COMPLETE LOSS OF STEERING WARNING ALL STEERING MECHANISMS ARE LIFE AND LIMB ITEMS AS SUCH IT IS IMPERATIVE THAT THE INSTRUCTIONS IN THIS BOOKLET ARE FOLLOWED TO THE LETTER FAILURE TO OBSERVE THE PROCEDURES SET OUT IN THIS PAMPHLET MAY RESULT IN LOSS OF STEERING SECTION I A SYSTEM OPERATION This literature with the illustrations shown covers a standard basic design of the HGA unit Variations may be engineered to suit special requirements The description of the operation of the HGA unit and the illustrations explain the functioning of the system for the utilization of the hydraulic power generated by the engine driven pump for power steering The func tioning of the system for manual operation is also described CYL Satisfactory performance of this system requires a well engineered installation designed for the par ticular type of vehicle and the type and kind of service for which it will be used Ross Engineering advice and assistance is available and we welcome requests Information on the required engine driven pump capacity and the power cylinder size and connecting lines are provided through engineering contacts A balanced cylinder design is preferred HGA STEERING UNIT SUPPLY PUMP Figure HGA 1 B DESIGN amp FUNCTION
12. N THE ROTOR action between the rotor and the stator there are 42 SET See Fig HGA 3 fluid discharging actions in one revolution of the Each lobe of the rotor has a diametrically opposite rotor When the rotor is moving fluid is always flow lobe therefore when one lobe is in a cavity its oppo ing out of three of the cavities while fluid is flowing site lobe is at the crest of the stator s convex form into three other cavities and one of the cavities is opposite the cavity As the rotor is rotated each lobe inactive as it changes from one of discharging fluid to in sequence is moved out of its cavity to the crest of one of admitting fluid The commutator rotates with the stator s convex form and this forces each oppo the rotor and channels the fluid from and to the valve site lobe in sequence into a cavity Due to the inter section and to and from the rotor set METERING ELEMENT rotor lobe stator fluid cavity convex configuration Figure HGA 3 POWER STEERING OPERATION When the spool is in center or neutral position the hydraulic oil from the engine driven pump circulates through the valve section directly back to the reser voir with sufficient pressure only to overcome friction of valve channels and lines There is no circulation of engine driven pump oil to or from the cylinder Note the center diagram showing neutral position See diagram on inside front cover on which no direction al arrows appear in the mete
13. application has a column sup port clamp this clamp should be loosened at this time If there is a horn contact assembly on the col umn remove the 4 small screws from the metal cover if applicable and remove the metal cover and gasket Remove the 2 small screws from the horn contact assembly Pull the jacket tube 6 and bearing assembly 7 off of the wheel tube 5 Remove the retaining springs 3 and discard Lightly tap out the pins 4 with brass rods and hammer Do not hit the pins with heavy hammer blows as this may damage the needle bearing in the HGA unit Remove the wheel tube 5 Remove the coupling 2 Remove the clamp assembly 1 fel AY 040050 089142 096245 2 9 06 0 E P A B 4 nl Ek __ 7 063980 8 026045 6 87 096245 1 TO ASSEMBLE COLUMN 1 10 Ti Assemble the clamp assembly 1 onto the HGA unit Do not tighten Assemble the coupling 2 and align pin hole Assemble one of the pins 4 and one of the new retaining rings 3 Assemble the wheel tube 5 and align pin hole Assemble the other pin 4 and retaining ring 3 Apply a small amount of clean grease to the inside of bearing assembly 7 Assemble the jacket tube 6 and bearing assembly 7 over the wheel tube through the clamp assembly 1 and onto the HGA unit upper cover Tighten the clamp assembly 1 bolt to 15 20 ft Ibs Assemble the steering
14. e steering column if applicable 13 Assemble the steering wheel and wheel nut torque the wheel nut to 35 ft 108 SERVICING OF HGA UNIT Refer to exploded view Figure HGA 6 for parts iden tification The spool 22 and the housing 25 the commutator 34 and commutator ring 33 as well as the rotor 31B and the stator 31A are not separately replaceable because they are selectively fitted at the factory If the spool or housing need replacement the complete housing assembly must be replaced If the commutator or the commutator ring need replacement both must be replaced as a matched set If the rotor or stator need replacement the com plete rotor set 31 must be replaced The pin in the end cover is not separately replaceable If the pin or end cover need replacement the end cover and pin assembly 38 must be replaced DISASSEMBLY PROCEDURE Plug the four port holes and clean the exterior of the unit thoroughly Then remove the plugs 1 10 To prevent possible distortion or damage to unit if placed directly in vise the following procedure should be used Insert ring tube fitting with tube nut or fitting cap attached into one of the four threaded ports in the housing Clamp the fit ting in a vise in a manner which will locate the seven end cover bolts in an upright position See Figure HGA 7 Figure HGA 7 Unscrew the seven special bolts 39 from the end cover 38 Note Special ca
15. en special bolts to 2 3 ft lbs in sequence as shown in Figure HGA 28 27 28 29 30 31 32 33 2 Torque all seven special bolts to 15 19 ft lbs in sequence as shown in Figure HGA 28 Note Rotate input shaft during step 2 to prevent binding Figure HGA 28 Relocate unit a vise with the input shaft up Cover end of input shaft with cellophane tape to protect new seal 5 when it is assem bled over sharp edges of input shaft Lubricate and install new seal 5 with lip side first onto input shaft Assemble new washer 4 with small end first onto input shaft and push new washer and new seal down into upper cover 7 A short piece of metal tubing 15 16 minimum 1 0 x 1 3 16 maximum O D or a 7 8 deep well socket may be used to push these parts into place Assemble retaining ring 3 into upper cover 7 groove Be sure rounded edge of retaining ring is faced inward Assemble new dirt seal 2 into upper cover 7 counterbore Note If the HGA unit is to be stored plug the cylinder ports and fill the inlet port with clean oil Rotate input shaft until oil appears at outlet port Plug the port holes to prevent entrance of dirt This completes assembly of the HGA unit COLUMN 475109 1 4 403813 9 401362 6 TO DISASSEMBLE COLUMN 1 2 18 Remove steering wheel and wheel nut 8 Loosen clamp assembly 1 on upper cover of HGA unit If the
16. er via the metering section using cylinder movement to accomplish the steering maneuver G MANUAL STEERING OPERATION In the absence of system pressure the driver s man ual effort displaces the spool axially When the spool is displaced within the body fluid channels are selected connecting the rotor set which is now act ing as a pump via the commutator to one side of the cylinder The return flow from the other side of the cylinder is channeled through a recirculation valve so that the oil will flow to the intake side of the rotor set via the commutator instead of back to the reservoir See Figure HGA 5 The recirculation valve is a ball check valve in a channel connecting the return flow chamber to the engine driven pump pressure inlet chamber The recirculation valve is closed during power operation WARNING ALL STEERING MECHANISMS ARE LIFE AND LIMB ITEMS AS SUCH IT IS IMPERA TIVE THAT THE INSTRUCTIONS IN THIS BOOK LET ARE FOLLOWED TO THE LETTER FAIL URE TO OBSERVE THE PROCEDURES SET OUT IN THIS PAMPLET MAY RESULT IN LOSS OF STEERING aoe e Nut Seal Retaining Ring Backup Washer Seal Screw Upper Cover Seal Shim Retaining Ring Thrust Washer Thrust Bearing Thrust Washer Spring Washer Spacer Input Shaft Needle Roller Drive Ring Spacer Torsion Bar Needle Roller 7 Spoo Spring Housing Assembly 25 a Plug 25
17. erse the steering wheel rotation to actuate the HGA valve spool in the opposite direction Keep rotating the steering wheel left and right from stop to stop of the road wheels to bleed out air Replenish oil as necessary The air will bleed out only at the reservoir therefore the oil must be circulated in both directions repeatedly until the air has bled out NOTE The oil in the lines to the power cylinder reaches a dead end at the piston The oil in the cylinder does not flow in a cir cuit As the piston moves back and forth the oil moves back and forth in the lines Therefore air in these lines and the cylinder may be slow moving into the control valve and to the reservoir CAUTION Do not operate vehicle until air is bled out When the oil in the reservoir is clear not cloudy or creamy the system is free of air Slight creep or drift of the steering wheel is normal Adjust the oil to recommended level in reservoir and assemble reservoir cover Always fill reservoir to recommended level HYDRAULIC FLUID Keep the steering system filled with one of the following Automatic Transmission Fluid Type Automatic Transmission Fluid Dexron Il Hydraulic fluid as recommended by the vehicle manufacturer WARNING DO NOT MIX OIL TYPES ANY MIX TURE OR AN UNAPPROVED OIL COULD DETERIORATE THE SEALS ENOUGH FLUID COULD THEN LEAK TO CREATE A LOSS OF POWER STEERING ASSIST DO NOT ALLOW FLUID LEVEL TO
18. face break down 7 Thrust bearing 12 and thrust washers 11 and 13 Inspect for pitting of rolls and faces of thrust washers 8 Drive link 30 pin slot Width of slot must not exceed 001 inch difference at any point in its length 9 Drive link 30 teeth 10 Torsion bar and needle roller assembly 20 Difference in diameter of needle roller 21 should not exceed 001 The following parts may show a polish pattern due to the rotor action and the circular motion of the com mutator The sides of these components are ground and lapped and should be free from nicks burrs and scoring 1 Spacer 29 2 Manifold 32 3 Rotor 31 4 Commutator 34 and Commutator Ring 33 Note Thickness difference between commu tator and commutator ring 33 shall not exceed 002 inch 5 End cover and pin assembly 38 Note The rotor set 31 requires special attention in handling to avoid nicks and scratching It is recommended that the rotor 31B stator 31 vanes 31D and springs 31C be checked in the assembled condition To inspect the rotor set place the assembly face down on the lapped face of the end cover 38 and check for freedom of rotor rotation within the stator The action of the spring loaded vanes may be observed during Figure HGA 15 rotation The vanes should move freely in their slots without bind due to the forces of the springs See Figure HGA 15 Using a feeler gage check t
19. four ports in the Hydraguide unit and pressurize the other port with air pressure to force the seal package out Discard these parts 5 Note Clean the Hydraguide unit input shaft 16 and upper cover 7 seal bore to remove parti cles of dirt felt lint etc with a clean lint free rag Caution excessive particles of felt or lint can cause the new seal package to leak 6 Cover the end of the Hydraguide unit input shaft with cellophane tape to protect the new seal 5 when it is assembled over the sharp edges of the input shaft 7 Lubricate the new seal using hydraulic oil and install the new seal 5 with lip side first onto the Hydraguide unit input shaft 8 Remove the cellophane tape from the Hydraguide unit input shaft 9 Assemble the new washer 4 with small end first onto the Hydraguide unit input shaft and push the new washer and the new seal 5 pre viously installed down into the Hydraguide unit upper cover A short piece of metal tubing 15 16 minimum 1 0 x 1 3 16 maximum or a 7 8 deep well socket may be used to push these parts into place 10 Assemble the previously used retaining ring 3 onto the Hydraguide unit input shaft and down into the Hydraguide unit upper cover groove Be sure the rounded edge of the retaining ring 3 is faced inward 11 Assemble the new seal 2 onto the Hydraguide unit input shaft and down into the Hydraguide unit upper cover 7 counter bore 12 Assemble th
20. he rotor 31B to the sta tor 31A clearance as shown in figure HGA 16 If there is more than a 007 inch clearance the rotor set 31 must be replaced Note This applies to rotor sets with and without vanes Figure HGA 16 Carefully lift the rotor set assembly 31 from the end cover 38 and measure the thickness of the rotor 31B and stator 31A Thickness difference between the rotor and stator shall not exceed 002 inch The internal splines in the rotor should not allow abnormal wear or damage 13 14 SECTION IV ASSEMBLY PROCEDURE IMPORTANT Before starting assembly clean all parts with clean petroleum base solvent and air dry Do not wipe dry with rags Be sure all dried paint chips have been removed from edges of lapped surfaces Unless otherwise indicated DO NOT oil parts before assembly 1 2 Insert ball 26 into its cavity in the housing Install new ring 27 on plug and roll pin assembly 28 and install in the housing 25 to 10 14 ft lbs torque housing 25 in the vise as shown in Figure HGA 11 Assemble thrust washer 13 thrust bearing 12 thrust washer 11 and retaining ring 10 on input shaft 16 If the retaining spring 24 has been removed install a new retaining spring The spring must fit tightly Insert actuator ball 23 into ball seat located inside spool 22 Assemble wave spring washer 14 over thrust washer 13 and thrust bearing
21. id in reassembly of unit Remove seal 2 retaining ring 3 using proper 17 18 19 snap ring pliers Discard seal 2 Remove and discard backup washer 4 Remove and dis card seal 5 Remove the retaining ring 10 thrust washer 11 thrust bearing 12 thrust washer 13 and spring washer 14 from input shaft 16 Note Retaining ring is twisted design Do not straighten ring Remove the needle roller 17 by using a pin punch of 125 inch max diameter for a mini mum of 625 length The input shaft 16 should be placed on a block of wood to avoid shaft damage and the needle roller 21 removed by impact using light hammer blows See Figure HGA 12 Remove the torsion bar 20 and spacer 19 by inverting the spool assembly and allowing the parts to fall free Do not remove needle roller 21 from torsion bar See Figure HGA 13 Figure HGA 12 Figure HGA 13 12 20 Remove the drive ring 18 by placing end of the spool 22 on a table surface Rotate the input shaft 16 to extremes of travel until the drive ring falls free See Figure HGA 14 Figure HGA 14 21 22 23 With the spool assembly in the same position as the step above rotate the input shaft 16 in a clockwise direction until the actuator ball 23 disengages from the helical groove in the input shaft Lift out input shaft Caution The actua tor ball may fall free and care should be used to no
22. ieved Install spacer 19 over torsion bar and pin assembly 20 and insert the assembly into the spool 22 end Align the cross hole in the torsion bar 20 with the cross hole in the input shaft 16 and insert a 120 diameter pin punch to maintain alignment Insert the needle roller 17 into cross hole in input shaft 16 and while retracting the pin punch engage the pin in the torsion bar 20 cross hole Initiate press of needle roller 17 into torsion bar 20 with a few light impacts Press needle roller flush with outside diameter of input shaft 16 using a 1 2 drive socket of 11 16 size for sup porting the input shaft See Figure HGA 19 With a few light impacts on a 120 diameter pin punch drive needle roller 17 approximately 1 32 below the input shaft 16 O D See Figure HGA 12 19 16a dL Figure HGA 19 Assemble spacer 15 over valve spool 22 against spring washer 14 If so constructed the inside lip end of spacer must be toward the spring washer Place assembly spool end first into housing 25 Caution Avoid applying side forces to the spool which would cause binding of the closely fitted assembly Note If neither the input shaft 16 or upper cover 7 are replaced the original shims 9 may be reused However if in the inspection of parts damage is found to the shims dis card these shims and replace with new parts of equal thickness Place shims on top of the thrust
23. in clear clean petroleum base solvent and blown dry with clean dry air Other solvents may cause deterio ration of rubber seals Avoid wiping parts with cloth and never steam clean hydraulic steering assem blies WARNING OSHA MAXIMUM AIR PRESSURE REQUIREMENTS SHOULD BE COMPLIED WITH TO PREVENT INJURY SEAL REPLACEMENT INSTRUCTIONS For numerous installation you may want to purchase the J26910 tool kit available from KENT MOORE TOOL DIVISION 29784 Little Mack Roseville Michigan 48066 Phone 800 345 2233 Caution Follow the Instruction and do not disas semble the Hydraguide unit upper cover 7 to replace the shaft seal 5 1 Remove the steering wheel nut 1 steering wheel and steering wheel column if applicable Refer to page 18 for instructions on removal of steering wheel column 2 the dirt seal 2 over the end of the Hydraguide unit upper cover if applicable Discard this part 3 the retaining ring 3 do not discard this part must be reinstalled during assembly procedure 4 Remove the seal package parts 4 5 from the Hydraguide unit by one of the following methods Hydraguide unit has not been removed from the vehicle rotate the Hydraguide unit input shaft either clock wise or counter clockwise to pressurize the system and force the seal package out Discard these parts b Ifthe Hydraguide unit has been removed from the vehicle plug three of the
24. oduct features specifications designs avail ability and pricing are subject to change by Ross Operation and its subsidiaries at any time without notice HYDRAGUIDE STEERING MODEL HGA For over half a century Ross has anticipated and met the changing and increasing needs for better steering of automotive construction industrial and agricultural machines This hydrostatic steering system described herein is further evidence of this fact Hydraguide is the Ross name given to hydrostatic steering systems In the HGA type Hydraguide steering System an engine driven pump relief valve cylinder reservoir filter fluid lines and an HGA control unit are needed An automotive type steering wheel is attached to the HGA unit and the cylinder is connected by suitable means to the steered wheels The driver has power steering control at all times so long as system components work together system integrity is maintained and adequate fluid is present If there is a failure in the high pressure circuit a loss of power steer ing will result The HGA however is designed to have some manual steering capability depending on the instal lation If you can t manually steer the vehicle without using extraordinary measures such as leaving your seat or pushing with your legs don t try it Repair the failure in the power circuit Some vehicles may be impossible to steer manually because of their weight and size WARNING EXTRAORDINARY MEASUR
25. parate rotor set from spacer Use extreme caution to keep vanes 31D and springs 31C from falling out When han dling the rotor set pressure should be applied to the rotor 31B by gripping the rotor set between the fingers and urging the rotor into contact with the stator 31A See Figure HGA 10 Carefully protect against damage to side faces Note The rotor 31B and the stator 31A must be kept in a matched set 10 11 13 14 9 16 10 Reverse the HGA unit in the vise to place the input shaft 16 in a vertical position Using a prick or center punch mark the upper cover flange 7 in relation to a similar mark placed on the port face of the housing 25 to facilitate reassembly See figure HGA 11 Figure HGA 11 Remove the four special cap screws 6 by using a 5 16 12 point socket Grasp the input shaft 16 and with a smooth upward motion remove the input shaft 16 upper cover 7 and spool 22 assembly from the housing 25 Note Avoid applying side forces to the spool which would cause bind ing of the closely fitted assembly Never use excessive force to remove the spool from the housing and discard seal 8 Remove the upper cover 7 with shaft seal package Items 2 thru 5 intact Remove spacer item 15 Remove shims 9 from either upper cover 7 cavity or from face of thrust washer 11 Count and record the number of shims to a
26. pecti n EE EENE AREE eE 13 Section IV ASSembly PROC OMAN E cunc eoa ite mea page 14 Column Assembly and Disassembly page 18 Filing and Air Bleeding page 19 Hydraulic FN M page 19 Tips for Maintaining the System page 20 FAILURE OR IMPROPER SELECTION OF IMPROPER USE OF THE PRODUCTS AND OR SYSTEMS DESCRIBED HEREIN OR RELATED ITEMS CAN CAUSE DEATH PERSONAL INJURY AND PROPERTY DAMAGE This document and other information from Ross Operation its subsidiaries and authorized distributors pro vide product and or system options for further investigation by users having technical expertise It is important that you analyze all aspects of your application and review the information concerning the product or system in the current product catalog Due to the variety of operating conditions and applications for these products or systems the user through its own analysis is and testing is solely responsible for making the final selec tion of the products and systems and assuring that all performance safety and warning requirements of the application are met The products described herein including without limitation pr
27. re should be used in the following steps to insure protec tion of the ground and lapped faces of the components Avoid scratching or nicking of finished surfaces Hemove end cover 38 by bumping it sideways with a soft hammer to loosen it from the rotor seal 36 and seal retainer 35 and lift from unit Caution The washer 37 and commuta tor 34 may adhere to the end cover and may be removed with the end cover Do not attempt to remove pin because pin is press fit in the plate and is non serviceable See Figure HGA 8 Remove the rotor seal 36 and seal retainer 35 by bumping the can sideways with a soft hammer to loosen it from the housing and lift off the rotor seal and seal retainer Discard the rotor seal If the wear washer 37 and commutator 34 were not removed with the end cover 38 remove these parts from the HGA unit Hemove the commutator ring 33 from the man Figure HGA 8 ifold 32 by a sliding and lifting motion Care should be used in the handling of this fragile component Remove the manifold 32 from the rotor set 31 by sliding and lifting motion Remove the rotor set 31 spacer 29 and drive link 30 as an assembly by grasping the spacer and removing the assembly with a sliding and lifting motion See Figure HGA 9 Separate drive link 30 by sliding the rotor set 31 on the spacer 29 allowing the drive link teeth to clear the spacer hole Remove drive link and se
28. ring channels The oil pressure at the two cylinder ports is equal and pro duces ineffective forces in the cylinder In order to accomplish a power steering maneuver the operator must rotate the steering wheel in the direction of the steering maneuver The initial rotation of the steering wheel rotates the input shaft which tends to rotate the drive link and rotor set through the torsion bar centering spring Rotation of the rotor set and spool which are coupled by the drive link is resisted by the cylinder pressure required to over come the steering forces As the input shaft is rotat ed relative to the spool the centering spring is tor sionally deflected Axial shift of the spool is inducted by the ball which is captive in the spool and engaged in the helical groove provided in the input shaft When the spool is axially displaced within the body fluid channels are selected connecting the engine driven pump to the intake side of the rotor set via the commutator The exhaust side of the rotor set is con nected through commutator to one side of the cylinder while the other side of the cylinder is con nected to the reservoir See Figures HGA 1 and 2 Further axial displacement of the spool results in increased system pressure to provide the level of pressure required A portion or all of the hydraulic fluid at the required pressure from the engine driven pump depending upon the speed of steering is directed to the cylind
29. t lose it Do not remove the ball retainer spring 24 unless replacement is required If necessary to remove this spring discard the retainer 24 if moved A screwdriver may be used to assist in the pry ing of the spring over the shoulder of the spool 22 Care must be used to avoid scratching or nicking of the spool outside diameter and con trol edges The following procedure is optional Return to the housing 25 which is mounted in the vise Remove the plug and roll pin assembly 28 A steel ball is captivated by the plug and roll pin assembly Care must be used to avoid the loss of the ball Remove ball by shaking after housing is removed from the vise Discard ring 27 This completes the disassembly of the HGA unit SECTION Ill INSPECTION AND REPLACEMENT Visually inspect all parts and replace those parts which are not in good condition The following fin ished surfaces should be inspected for abnormal wear scoring or damage 1 Housing 25 bore and ends 2 Valve spool 22 outside diameter Some bur nishing due to use may be observed 3 Valve spool 22 control edges 4 Valve spool 22 splines 5 Input shaft 16 seal area Check for rust pitting and excessive wear Light circumferential pol ishing due to seal contact may be observed 6 Input shaft 16 helical groove Note the contact pattern created by the actuator ball 23 Surface should be free from pits chipping or sur
30. wheel and tighten the wheel nut to 32 5 37 5 ft Ibs If the application has a column support clamp it is extremely important that the jacket tube 6 align with this clamp in the free state If mis alignment is evident the HGA unit must be shimmed at the mounting surface to eliminate the misalignment or damage may result to the HGA unit If applicable assemble the horn contact assem bly cover gasket and metal cover on the jacket tube 6 FILLING AND AIR BLEEDING THE SYSTEM WHEN DRAINED OF OIL 1 Fill reservoir nearly full Be ready to add oil when the engine is started Do not let oil level drop below the inlet to the power pump so that the power pump will not suck air into the sys tem otart engine and let it idle Immediately add oil to the reservoir as needed NOTE This oil will now be circulating only from the power pump to and through part of the control valve and to the reservoir and back to the power pump When no more oil can be added and oil is clear proceed as follows With one finger on a spoke of the steering wheel spin wheel as rapidly as possible to bleed the air in the steering cylinder s and lines Immediately upon HGA valve spool actuation oil must be added to the reservoir to replenish the oil moving into the circuit Keep rotating the steering wheel to keep the HGA valve spool actuated Do this until the road wheels have reached the stop in that direction then quickly rev
31. y HGA014000 A1 Housing amp spool are non serviceable due to select fit if either needs replaced the entire unit must be replaced STANDARD PARTS THAT CHANGE WITH DISPLACEMENT 31 35 Vane Kit 506608 506607 506606 506611 506610 506609 Rotor Set HGA077010 HGA087010 HGA107010 HGA127007 HGA147005 HGA167005 HGA207005 HGA247005 HGA287005 HGA327004 Seal Retainer 099069 099070 099071 099072 099073 099074 099075 099076 099077 099095 36 Seal Before Date 39 20 amp 21 10 Snap Ring 401367 18 Drive Ring HGA013003 37 Washer 028395 30 Bolts 7 ea After Date Code195 94 195 94 032625 032626 032618 032619 032627 032628 032620 032629 032621 032759 021269 021428 021269 021428 021280 021356 021283 021311 021290 021306 021292 021382 021294 021357 021295 021307 021296 021358 021349 021435 Use number 020206 on assemblies manufactured prior to date code 195 94 Base Number 401360 401363 401368 401413 401432 401435 401627 0 147 0 160 0 160 0 154 0 147 0 139 0 139 Bar Center Diameter in Torsion BASE A1 506 BASE A1 506 BASE A1 525 BASE A1 538 BASE A1 550 BASE A1 562 BASE A1 525 BASE A1 550 BASE A1 538 BASE A1 562 Length Between Holes in Drive Link HGA013008 HGA013008 HGA013008 HGA013008 HGA013008 HGA013008 HGA013005 HGA013005 HGA013006 HGA013006 5 00 5 62 6 00 6 50 3 00 5 62
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