Service Handbook High-Pressure Washer Pump 3.532
Contents
1. For Karcher Pressure Washer Parts Call 606 678 9623 or 606 561 4983 Service Handbook High Pressure Washer Pump 3 532 785 0 4 10 00 www mymowerparts com For Karcher Pressure Washer Parts Call 606 678 9623 or 606 561 4983 Pump 785 9 28 01 3 06 PM Pag o www mymowerparts com For Karcher Pressure Washer Parts Call 606 678 9623 or 606 561 4983 Pump 785 9 28 01 3 06 PM Page 3 A TROUBLESHOOTING OVERVIEW How to Use This Manual It is not necessary to read this entire manual to find a solution to a problem This manual identifies four basic ways the pump may malfunction Find the section that defines the malfunction of the pump Turn to that section s overview page and identify the specific problem Then go to the solutions page for that Tools Necessary to Service the specific problem If you don t know what the problem is work your KARCHER High Pressure Washer Pump way through the problems listed until you find and correct the Part 3 532 757 0 problem Special Tools e Valve pliers ccc cece 4 901 062 i e Installation tool 0 0 00 ee 2 901 034 Water Leaks Section 2 HP seal oil seal Silicon grease 6 eee 6 288 044 Oil Leaks Section 3 for packing and O rings Lithium grease 1 eee 6 288 079 for O rings on bypass valve Non detergent pump oil 6 288 050 0 Low Water Pressure Section 1 Detergent Delivery Failure Section 4 Gen2. 7 401 909 5 332 258 6 388 216 4 862 032 5 411 150 5 413 067 6 365 340 5 115 465 6 365 434 5 112 576 5 115 744 7 303 047 5 003 983 28 Water inlet housing 29 Water inlet filter 30 Detergent check valve 31 O ring 32 Ball bearing 33 Spring 34 Detergent tube 35 Detergent filter 36 Retainer nut 37 Thermal relief valve 38 Low pressure oil seal 39 Seal retaining ring 40 Bushing seal 414 Bushing 42 Scraper ring 43 Piston guide retaining screw 44 High pressure valve slide High pressure valve cage spring 47 48 plate and seat Pump head bolts Spring Ball bearing seat Ball bearing gt on oo ow N colo 7 306 047 5 332 446 5 411 070 7 401 909 5 983 164 7 306 105 Safety relief valve 28 29 30 31 32 33 34 35 36 37 38 39 41 42 43 44 0 1 2 3 4 5 Water outlet bolt NOT PICTURED IN DIAGRAM Garden hose connection 9 154 009 B E Piston spring retaining clip N wo ng A 3 oo o www mymowerparts com For Karcher Pressure Washer Parts Call 606 678 9623 or 606 561 4983 Pump 785 9 28 01 3 06 PM Page 7 A SECTION 1 LOW WATER PRESSURE 1 0il reservoir vent cap 2 filter 3 0il reservoir 4 0 ring __ 7 0il bath housing _ 8 Pump shaft seal __ 31 Detergent check valve __ 9 Forward O ring amp pe _ 32 0 ring A 7 383
3. diagram is adjustable This adjustment is made by turning the pressure volume control 17 downwards This causes the bypass valve 18 to be pushed open in a continuous movement A part of the pump s capacity then flows from the pressure chamber into the water inlet housing 29 and the operating pressure drops to the amount that has been set by turning the pressure volume control 17 Thermal Protection Device If the pump should continue to run in the bypass mode for an extended amount of time max 5 min the water circulating within the pump will reach a temperature level that will cause internal damage This is prevented by the thermal relief valve 38 The thermal relief valve will release the hot water and then automatically reset itself Detergent Delivery System In this system there is a nozzle insert 24 in the water outlet 22 The entire pump capacity flows through the nozzle insert to the spray gun Detergent can only be drawn in by the nozzle insert 24 if the nozzle of the spray wand has been set to low pressure This causes the pump pressure to fall to approximately 435 PSI low pressure and the greatest degree of negative pressure 11 6 PSI is generated at the lateral hole in the nozzle insert so that detergent can be drawn into the unit via the detergent suction tube 35 and detergent filter 36 If the spray nozzle on the spray wand is set for high pressure operation the hole in the nozzle insert 24 does n
4. Cause Oil Leaks Drain Plug A loose drain plug 6 or damaged drain plug ring 5 Oil Reservoir A damaged oil reservoir 3 missing oil reservoir filter 2 or damaged O ring 4 If the oil bath housing 7 is overfilled oil will leak from vent cap 1 Weep holes If oil is leaking from the weep holes 15 there is either a leak in the low pressure seals 39 or the high pressure seals 20 or there is piston 13 damage Pump Shaft Seal A damaged or worn pump shaft seal 8 www mymowerparts com For Karcher Pressure Washer Parts Call 606 678 9623 or 606 561 4983 Pump 785 9 28 01 3 06 PM Page 14 o SECTION 3 OIL LEAK SOLUTIONS A Drain Plug B Oil Reservoir C weep holes Oil Seals A Drain Plug figure 20 C weep holes Oil Seals 1 Check drain plug Tighten or replace if necessary 1 Unscrew the oil drainage plug and drain the oil into 2 Inspect drain plug seal Replace if necessary a suitable container Drain Plug Piston Housing Retaining Screws Drain Plug Seal figure 20 figure 22 3 Reassemble and reinstall the drain plug 2 Remove piston housing figure 22 B Oil Reservoir Figure 21 e Remove four pump head bolts 1 If oil is spurting from oil reservoir vent cap the oil level is too high with an allen wrench and remove the pump head Drain to specified level See note in Section 2 See Section 2 figure 12 2 Inspect oil reservoir seal and fil
5. 5 Detergent tube 6 0il drain pug pe 11 Swash plate ball bearin _ 12 Swash _ 13 Piston 3 __ 14 Piston spring 3 15 Weep holes 3 gt 16 Piston housing A 17 Pressure volume control knob K SSZ _ 39 Low pressure oil seal 3 37 Retainer nut 7 _40 Seal retaining ring 3 S m 2 ol a Busting seal 3 38 Thermal relief valve 18 Bypass valve gt _42 Bushing 3 oan b 43 Scraper ring 3 _ 44 Piston guide retaining screw 2 20 High pressure seal 3 __ 45 High pressure valve slide f 46 High pressure valve seat 3 19 Bushing 47 High pressure valve plate 3 _ 48 High pressure valve spring 3 _ 49 High pressure valve basket 3 21 Pump head ____ 22 Water outlet 23 Non return check valve _ 50 High pressure valve cap 3 24 Nozzle insert ___ a 25 Low pressure check valve basket 3 t Ss 51 Pump head bolt 4 26 Low pressure check valve spring 3 t Z 27 Low pressure check valve plate 3 B 52 Spring 28 Low pressure check valve seat 3 _ 53 Ball bearing seat 29 Water inlet _ ae 30 Water inlet filter _ Problems That Cause Water Leaks Thermal Relief Valve The thermal relief valve 38 protects the pump from hot water temperatures in bypass mode If the thermal relief valve is damaged or does not reset there
6. Ball bearin 5 0il drain p ng plug ring n5 _ 34 Spring ps 35 Detergent tube A 10 Swash assembly 6 0il drain j l Peg _ 11 Swash plate ball bearings _ 12 Swash _ 18 Piston 3 __ 14 Piston spring 3 5 Weep holes 3 16 Piston housing 2 17 Pressure volume control knob K r _ 39 Low pressure oil seal 3 rbk 37 Retainer nut _ 40 Seal retaining ring 3 S pea D a a eee 38 Thermal relief valve 18 Bypass valve 3 43 Scraper ring 3 19 Bushing oF 45 High pressure valve slide A High pressure valve seat 3 21 Pump head Q y 47 High pressure valve plate 3 22 Water outlet Av Z Se _ 48 High pressure valve spring 3 High pressure valve basket 3 23 Non return check valve __ High pressure valve cap 3 24 Nozzle insert ___ 25 Low pressure check valve basket 3 gt 51 Pump head bolt 4 26 Low pressure check valve spring 3 27 Low pressure check valve plate 3 52 Spring 28 Low pressure check valve seat 3 a _ 53 Ball bearing seat 29 Water inlet a T _ 54 Ball bearing 30 Water inlet filter _ i a _ 55 Safety relief valve Problems That Cause Low Water Pressure Water Supply A problem with the water supply Use cold water only Worn Nozzle A worn nozzle on the spray wand Water Inlet Filter A clogged water inlet filter 30 By
7. drop per piston per minute is allowable during high pressure operation If oil is leaking from the weep holes 15 there is either a leak in the oil seals or there is piston damage Low Pressure and High Pressure Check Valves Each piston works with one low pressure check valve 25 28 and one high pressure check valve 46 49 Each of these check valves is constructed of the same basic components the valve cage spring valve plate with guide shaft and the valve seat with O ring The sealing surface between the valve plate 27 amp 47 and the valve seat 28 amp 46 is conical The valve plate and valve seat are manufactured from either plastic or stainless steel depending upon the particular unit involved When the piston 13 is forced backwards by the spring 14 in the oil bath housing 7 the high pressure check valve 46 49 closes and water is drawn in through the supply line suction chamber at the water inlet 29 through the inlet filter 30 and through the open low pressure check valve 25 28 ei KARCHER OVERVIEW When the piston 13 is pushed forward by the swash assembly 10 the low pressure check valve 25 28 closes and water is conveyed through the open high pressure check valve 46 49 to the water outlet 22 The pressure that is generated is dependent upon the flow rate and the orifice diameter of the high pressure nozzle Bypass Valve with Pressure Adjustment When the trigger of the spray gun is p
8. e figure 27 figure 29 1 Check that nozzle is in low chemical position 5 Remove tube from nipple figure 27 e Remove detergent non return check valve figure 29 e Inspect non return check valve for clogs Note Leaving detergent in pump will cause ball to stick 6 Reinstall non return check valve nipple metering knob and hose B Nozzle Insert figure 28 2 Check that metering valve on pickup filter is open figure 28 3 Check pickup filter for clog 4 Check detergent tube for holes and kinks figure 34 1 Remove nozzle insert with a screwdriver 2 Pull out nozzle insert figure 34 3 Check nozzle for wear and damage 4 Check that opening through nozzle is not clogged Clear opening if necessary www mymowerparts com
9. e volume control knob 19 Bushing gt p 20 High pressure seal 3 _ 46 High pressure valve slide _ 46 High pressure valve seat 3 eS 47 High pressure valve plate 3 _ 48 High pressure valve spring 3 High pressure valve basket 3 21 Pump head ___ 22 Water outlet 23 Non return check valve ___ High pressure valve cap 3 24 Nozzle insert ____ 25 Low pressure check valve basket 3 26 Low pressure check valve spring 3 27 Low pressure check valve plate 3 ____________ 5 52 Spring 28 Low pressure check valve seat 3 Ball bearing seat 29 Water inlet _ Px Ball bearing 30 Water inlet filter _ Safety relief valve Detergent Delivery Failure A Pump Not Drawing Detergent or Water Exiting Detergent Tube Detergent filter 36 or Detergent non return check valve 31 may be clogged or damaged Nozzle insert 24 may be worn Nozzle of the spray wand has been set to high pressure Pump Is Cycling Non return check valve 23 or Nozzle insert 24 is damaged and must be replaced www mymowerparts com For Karcher Pressure Washer Parts Call 606 678 9623 or 606 561 4983 Pump 785 9 28 01 3 06 PM Page 17 o SECTION 4 DETERGENT DELIVERY FAILURE SOLUTIONS A Pump Not Drawing Detergent or Water Exiting from Detergent Tube B Nozzle Insert A Pump Not Drawing Detergent or Water Exiting Detergent Tub
10. eric Tools Allen Wrench 8mm Always wear safety rated eye protection and clothing For any other problems contact KARCHER technical support at 1 800 877 2424 Allen Wrench 6mm Torx TX30 Socket Wrench Needle Nose Pliers Rubber Mallet Pliers Flat Head Screwdriver Phillips Head Screwdriver Hammer Safety Goggles www mymowerparts com For Karcher Pressure Washer Parts Call 606 678 9623 or 606 561 4983 Pump 785 9 28 01 3 06 PM Page 4 A MASTER DIAGRAM Oil reservoir vent cap Oil filter 3 0il reservoir i O ring 7 0il bath housing B 8 Pump shaft seal Detergent check valve 9 Forward O ring O ring i 31 A 32 5 0il drain lt a 33 a 34 ee Ball bearing plug ring 40S swash assembly Spring 35 Detergent tube 6 0il drain plug _ 11 Swash plate ball bearings g 36 Detergent filter 13 Piston 3 tr 14 Piston spring 3 15 Weep holes 3 16 Piston housing 17 Pressure volume control knob iG K A 39 Low pressure oil seal 3 37 Retainer nut 40 Seal retaining ring 3 at io Bushine a 3 38 Thermal relief valve 43 Scraper ring 3 44 Piston guide retaining screw 2 18 Bypass valve 19 Bushing Q 20 High pressure seal 3 lt 45 High pressure valve slide igh p 3 oS e et gh p 46 High pressure valve seat 3 21 Pump head ___ X A 47 High pressure
11. gure 6 E Low Pressure Check Valve 2 Remove low pressure check valve including valve disk and spring G Hign Pressure Check Valve with special valve pliers figure 7 KA IET cans Pump Cycling 3 Check the valve for wear debris and pitting Note If any one low pressure valve is damaged all three valves should be replaced 4 Lightly grease O rings with silicone grease figure 6 5 Reassemble and reinstall figure 9 Note Low pressure check valves must be ordered as a unit 2 Remove 3 plastic valve caps Individual check valve parts cannot be ordered separately 3 Check the valve for wear debris and pitting Replace if necessary figure 10 4 Grease O rings lightly with silicone grease and reassemble figure 10 O ring H Water Leaks See Section 2 Water Leaks I Pump is Cycling See Section 4 Detergent Delivery Failure figure 8 1 Remove valve plate in tapping plate with screw driver www mymowerparts com For Karcher Pressure Washer Parts Call 606 678 9623 or 606 561 4983 Pump 785 9 28 01 3 06 PM Page 10 A SECTION 2 WATER LEAKS 1 0il reservoir vent cap 2 Oil filter 3 0il reservoir __ 7 0il bath housing apo BeRump shaft seal __ 31 Detergent check valve _ 9 Forward O ring g O ring 5 0il drain lt Ball bearing plug ring i p 10 Swash assembly _ 34 Spring er 3
12. in oil oil type 15W40 non detergent The oil level should be just above the high side of the swash plate 12 It is important that the machine is on level ground when checking the oil level In order to drain the oil the drain plug 6 located beneath the oil bath housing 7 will have to be removed To add oil remove the vent cap 1 from the oil reservoir 3 and add to the required level Note Some pumps do not have a drain plug or oil reservoir In order to add oil in this case the pump head 21 and piston housing 16 will have to be removed Pistons With Seals The three pistons 13 are pressed against the swash plate 12 of the swash plate assembly 10 by powerful springs 14 These three pistons are manufactured from tempered surface hardened steel and are non corrosive with regards to detergents and rust The pump delivery capacity is determined by the rotational speed of the motor the diameter of the pistons the length of the piston stroke The pistons 13 in industrial units are fitted with a high pressure seal 20 and a low pressure seal 39 Non industrial units have only a high pressure seal 20 The three pistons each have an oil seal 39 mounted in the piston housing 16 These three oil seals along with the shaft seal 8 retain the oil in the oil bath housing The weep holes 15 are in the piston housing 16 and allow water or oil to drip out into the open A water leakage rate of one
13. mp head e Place brass sleeve in pump head e Put installation tool into sleeve and press until seal pops into place figure 15 e Remove tool and then remove sleeve inset figure 15 figure 13 3 Carefully remove the 3 high pressure seals figure 13 4 Check seals and pistons for wear and tear and replace if necessary See Section 3 Oil Leaks D weep holes for piston replacement 5 Replace all three seals using installation tool ma www mymowerparts com For Karcher Pressure Washer Parts Call 606 678 9623 or 606 561 4983 Pump 785 9 28 01 3 06 PM Page 12 o SECTION 2 WATER LEAK SOLUTIONS C weep holes Low Pressure Seals C weep holes Low Pressure Seals Scraper Ring Washer Bushing Seal Circulation Holes figure 17 figure 19 7 Place bushing back on piston 1 Remove low pressure bushing from piston Circulation holes must line up with weep holes figure 17 figure 19 2 Remove washer from bushing figure 17 figure 18 3 Remove low pressure seal figure 18 4 Inspect scraper ring Replace if damaged 5 Inspect O ring on bushing 6 Apply silicone grease to seal ma www mymowerparts com For Karcher Pressure Washer Parts Call 606 678 9623 or 606 561 4983 Pump 785 9 28 01 3 06 PM Page 13 A SECTION 3 OIL LEAKS 1 0il reservoir vent cap 2 Oil filter 3 Oil reservoir _____ 4 0 ring I _ T Oil bath housing _ 8 Pu
14. mp shaft seal __ 81 Detergent check valve s _ 9 Forward O ring d O ring Jf f sl Ball bearin 5 Oil drain 9 plug ring _ 10 Swash assembly Spring _ 35 Detergent tube 6 0il drain plug F 11 Swash plate ball bearin __ 36 Detergent filter 12 Swash _ 18 Piston 3 _ 14 Piston spring 3 _ 15 Weep holes 3 16 Piston housing __ 39 Low pressure oil seal 3 ae 40 Seal retaining ring 3 R 41 Bushing seal 3 _42 Bushing 3 _43 Scraper ring 3 _ 44 Piston guide retaining screw 2 17 Pressure volume control knob 97 Retainer nut ee 88 Thermal relief valve 18 Bypass valve 19 Bushing 20 High pressure seal 3 __ _ 45 High pressure valve slide High pressure valve seat 3 21 Pump head ___ 22 Water outlet __ 23 Non return check valve __ 24 Nozzle insert __ 25 Low pressure check valve basket 3 26 Low pressure check valve spring 3 27 Low pressure check valve plate 3 28 Low pressure check valve seat 3 29 Water inlet _ 30 Water inlet filter High pressure valve plate 3 High pressure valve spring 3 High pressure valve basket 3 High pressure valve cap 3 51 Pump head bolt 4 52 Spring po 53 Ball bearing seat 54 Ball bearing __ 55 Safety relief valve Problems That
15. ot create any www mymowerparts com Pump 785 9 28 01 3 06 PM Page 6 For Karcher Pressure Washer Parts Call 606 678 9623 or 606 561 4983 KARCHER OVERVIEW negative pressure and no detergent can be drawn into the unit The detergent check valve consists of a small spring 31 with a ball O ring and nipple When operating in the detergent mode the negative pressure created by the nozzle insert causes the ball to be drawn o away from the O ring against the tension of the spring Detergent can then be drawn into the unit When operating in the high pressure mode the ball seals off the detergent connection so that no water can flow into the container of detergent PART NUMBERS High Pressure Washer Pump 3 532 785 0 ITEM S DESCRIPTION PART QTY IN PUMP 1 2 4 Oring i 6362 168 0 1 6 Oildrainplug i 7 382 085 0 1 8 Pumpshaftseal_ 7 387 018 0 1 o Forwardo ring osoro 1 P Cplinderbearing 7 401 027 0 1 Couplingelement 4120 1920 1 PT Safrano a E 3 14 3 15 Spindle 4 401 079 0 Bypass valve multiple numbers top o ring set piston spring valve seat 1 6 362 454 0 5 553 383 0 5 332 425 0 5 581 242 0 valve seat o ring 6 362 169 0 threaded spindle 5 305 274 0 E i 19 3 i i 24 25 Low pressure check valve basket 4 580 371 0 3 26 27 spring plate and seat DESCRIPTION PART QTY IN PUMP 1 5 063 897 6 414 252 5 443 448 6 362 175
16. pass Valve Worn O rings on the bypass valve 18 or the bypass valve is hanging up Safety Relief Valve The safety relief valve 55 opens if the bypass valve 18 is not working Low water pressure can result if the valve 55 does not seal or does not reseat Low Pressure Check Valve Low pressure check valve 26 28 fails to function properly High Pressure Check Valve High pressure check valve 46 49 fails to function properly Water Leaks See Section 2 Water Leaks Water leaks Pump is Cycling See Section 4 Detergent Delivery Failure Non return check valve 23 or Nozzle insert 24 is damaged and must be replaced www mymowerparts com For Karcher Pressure Washer Parts Call 606 678 9623 or 606 561 4983 Pump 785 9 28 01 3 06 PM Page 8 SECTION 1 LOW WATER PRESSURE SOLUTIONS A Water Supply B Nozzle C Water Inlet Filter D Bypass Valve E Safety Relief Valve A Water Supply 1 Check faucet 4 0 gpm is required 2 Outside diameter of hose should be 3 4 3 Maximum length of hose should be 50 4 The inlet water pressure should not exceed 90 psi 5 Hose should not be kinked or damaged B Nozzle 1 Check function and setting of original nozzle by using an in house nozzle If pump functions properly with in house nozzle but malfunctions with original nozzle replace nozzle C Water Inlet Filter 1 Remove filter with pair of valve pliers figure 1 2 Clean fil
17. should face oil e Place seal in housing using installation tool figure 25 e Do not grease groove in oil seal e Push until seal hits bottom D Pump Shaft Seal figure 24 7 Remove the 3 oil seals with flat head screwdriver figure 24 8 Inspect and replace oil seals if necessary figure 26 Forward O ring 1 Remove swash plate assembly figure 26 2 If oil seal on shaft is worn out call 1 800 KARCHER 3 To remove oil seal push shaft through swash plate www mymowerparts com For Karcher Pressure Washer Parts Call 606 678 9623 or 606 561 4983 Pump 785 9 28 01 3 06 PM Page 16 A SECTION 4 DETERGENT DELIVERY FAILURE 1 0il reservoir vent cap 2 Oil filter 3 Oil reservoir 4 0 ring __ 7 0il bath housing __ 8 Pump shaft seal _ 31 Detergent check valve _ 9 Forward O ring amp e ae _ 32 0 ring Pee T 38 Ball bearing 5 Oil drain ya plug ring en A f 10 Swash assembly Bae 34 Spring ae 35 Detergent tube 6 0il drain plug s _ 11 Swash plate ball bearin _ 36 Detergent filter _ 12 Swash _ 18 Piston 3 _ 14 Piston spring 3 5 Weep holes 3 _ 16 Piston housing A 39 Low pressure oil seal 3 37 Retainer nut Seal retaining ring 3 S ee Sapa pep 38 Thermal relief valve 18 Bypass valve 5 _43 Scraper ring 3 I 44 Piston guide retaining screw 2 17 Pressur
18. ter 3 Replace filter if it is torn bent or missing 4 Reinstall filter Note If water inlet filter is missing or damaged further damage may have occurred inside the pump D Bypass Valve 1 Unscrew pressure volume control assembly figure 2 ea 2 Remove brass bushing figure 3 Note that bushing is positioned with large side down figure 3 3 Pull out bypass valve inset figure 3 4 Inspect bypass valve for damage and lubrication Inadequate lubrication will cause valve to hang up 5 Inspect O rings for nicks or cuts Replace if necessary Large O ring Small O ring ar EZ figure4 6 Grease only large O rings with lithium grease figure 4 7 Replace bypass valve if necessary E Safety Relief Valve figure 5 1 Unscrew the safety relief valve screw cap figure 5 2 Remove spring valve seat and ball inset figure 5 3 Check for wear or pitting 4 Replace valve if necessary 5 If valve seat in the cylinder head is defective the entire safety relief valve must be replaced 6 Reassemble and replace screw cap making sure ball is in seat Note Pitting will occur if inlet filter is damaged or missing P www mymowerparts com For Karcher Pressure Washer Parts Call 606 678 9623 or 606 561 4983 Pump 785 9 28 01 3 06 PM Page 9 c F Low pressure Check Valve SECTION 1 WATER PRESSURE SOLUTIONS 1 Remove water inlet housing with torx TX30 bit 5 bolts fi
19. ter for damage e Re install two of the pump head bolts with a 1 2 shim 3 Replace if necessary composed of washers or a metal sleeve about 3 8 i in diameter into two diagonally opposing weep holes of piston guide housing y F gt Oil Vent Cap figure 22 Y gt 7 e Remove the two piston guide retaining screws O ring e Back off the housing by loosening up on the two pump head bolts until spring tension in the piston guide housing is relieved inset figure 22 e Alternate between nuts after every few turns to keep housing level Oil Vent e Remove the two pump head bolts and shim when spring Nipple tension is relieved figure 21 4 Check that vent nipple is cut 5 Check O ring under oil reservoir If pitted or deformed replace 4 www mymowerparts com For Karcher Pressure Washer Parts Call 606 678 9623 or 606 561 4983 Pump 785 9 28 01 3 06 PM Page 15 c SECTION 3 OIL LEAK SOLUTIONS D weep holes Oil Seals E Pump Shaft Seal a Gia Lih 4 l Forward O ring figure 23 figure 25 3 Pull out piston guide assembly Soak new oil seals in water figure 23 for 10 minutes inset figure 25 4 Inspect forward O ring and seal Replace if necessary Make sure housing is clean and dry 5 Remove and inspect pistons for wear or scoring e Place oil seal into recessed end of installation tool Replace if necessary Sleeve is not used Groove in seal
20. ulled the entire pump capacity flows through the nozzle insert 24 to the water outlet 22 At this time the bypass valve 18 remains in the upper position and closes off the path between the pressure chamber and the suction chamber When the trigger of the spray gun is released water ceases to flow through the nozzle insert 24 The non return check valve 23 closes and the pressure in the high pressure hose is maintained between the trigger actuated valve in the spray gun and the non return check valve 23 The pressure instantly rises in a surge which causes the bypass valve 18 to be pressed downwards This opens the path between the pressure chamber located above the bypass valve 18 and the water inlet housing 29 The pump continues to run only in bypass mode The safety relief valve 55 will open if the bypass valve 18 fails to activate When the trigger of the spray gun is again pulled the pressure in the high pressure hose drops suddenly The spring inside the bypass valve 18 together with the restricted pressure at the entrance to the nozzle insert 24 pushes the bypass valve upwards This causes the circulation between the pressure chamber and the water inlet 29 to close and the pump builds up pressure once more This pump has a pressure volume control 17 that enables you to adjust the pressure and water flow at the pump Other pumps have a fixed pressure rating and are non adjustable The pump shown in the
21. valve plate 3 22 Water outlet wwe ps 48 High pressure valve spring 3 A o G 49 High pressure valve basket 3 23 Non return check valve 50 High pressure valve cap 3 24 Nozzle inset Ry Soe 25 Low pressure check valve basket 3 ________ Is 51 Pump head bolt 4 26 Low pressure check valve spring 3 _ RO a 27 Low pressure check valve plate 3 52 Spring 28 Low pressure check valve seat 3 53 Ball bearing seat 29 Water inlet 54 Ball bearing 30 Water inlet filter Safety relief valve Water outlet bolt 4 www mymowerparts com For Karcher Pressure Washer Parts Call 606 678 9623 or 606 561 4983 Pump 785 9 28 01 3 06 PM Page 5 Swash Plate Assembly The three pistons 13 are driven by the swash plate assembly 10 which is mounted to the engine shaft In the case of a vertically configured machine a drive bolt is screwed into the engine shaft and then inserted into the pump shaft As soon as the engine shaft rotates the swash assembly 10 rotates as well This causes the pistons 13 to move backwards and forwards The piston stroke depends upon the angle of the swash assembly 10 The greater the angle of the swash plate the longer the piston stroke One revolution of the swash plate gives the pistons one suction stroke and one pressure stroke Oil Bath The swash plate assembly and pistons are bathed
22. will be a continual leak Check thermal relief valve 38 Note It is normal for the thermal relief valve to release hot water if the pump continues to run in the bypass mode for an extended amount of time which causes the water circulating within the pump to reach a temperature level that will cause internal damage Once the valve releases the hot water it will automatically reset itself weep holes High Pressure Seals Water leaking from the weep holes 15 can indicate a leak in the high pressure seals Check seals for damage weep holes Low Pressure Seals Water leaking from the weep holes 15 can indicate a leak in the low pressure seals 39 Check the seals for damage www mymowerparts com For Karcher Pressure Washer Parts Call 606 678 9623 or 606 561 4983 Pump 785 9 28 01 3 06 PM Page 11 o SECTION 2 WATER LEAK SOLUTIONS A Thermal Relief Valve B weep holes High Pressure Seals A Thermal Relief Valve C weep holes Low Pressure Seals 1 Remove thermal relief valve screw cap figure 11 2 Disassemble thermal relief valve inset figure11 figure 14 3 Inspect and replace with new valve if necessary e Place seal flat side down on installation tool B weep holes High Pressure Seals e Fill groove with silicone grease figure 14 Brass Sleeve figure 12 1 Remove 4 pump head bolts using 6mm allen wrench figure 12 figure 15 2 Remove pu
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