Karcher-Pressure-Washer-Repair-Manuals/Karcher-Pressure-Washer-Parts-and-Basic-Repair-Service-Manual-Pump-757-HD3500DB-HD3500DH-HD3500DH-QC-HD3500G-HD3501DK-HD3600DH
Karcher Karcher-Pressure-Washer-Repair-Manuals/Karcher-Pressure-Washer-Parts-and-Basic-Repair-Service-Manual-Pump-757-HD3500DB-HD3500DH-HD3500DH-QC-HD3500G-HD3501DK-HD3600DH Repair Manuals
Service Handbook
High-Pressure
Washer Pump
3.532-757.0
10.00
For Karcher Pressure Washer Parts Call 606-678-9623 or 606-561-4983
Pump 757 9/28/01 3:33 PM Page 1
www.mymowerparts.com
For Karcher Pressure Washer Parts Call 606-678-9623 or 606-561-4983
Pump 757 9/28/01 3:33 PM Page 2
www.mymowerparts.com
TROUBLESHOOTING OVERVIEW
Tools Necessary to Service the
KARCHER®High-Pressure Washer Pump
Part 3.532-757.0
Special Tools
•
Valve pliers . . . . . . . . . . . . . . . . . . . . . . . . . 4.901-062
•
Installation tool . . . . . . . . . . . . . . . . . . . . . . 2.901-034
(HP seal, oil seal)
•
Silicon grease . . . . . . . . . . . . . . . . . . . . . . . 6.288-044
(for packing and O-rings)
•
Lithium grease . . . . . . . . . . . . . . . . . . . . . . 6.288-079
(for O-rings on bypass valve)
•
Non-detergent pump oil . . . . . . . . . . . . . . . .6.288-050.0
Generic Tools
•
Allen Wrench 8mm
•
Allen Wrench 6mm
•
Torx TX30 Socket Wrench
•
Needle Nose Pliers
•
Rubber Mallet
•
Pliers
•
Flat Head Screwdriver
•
Phillips Head Screwdriver
•
Hammer
•
Safety Goggles
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
specific problem. If you don't know what the problem is, work your
way through the problems listed until you find and correct the problem.
Low Water Pressure . . . . . . . . . . Section 1
Water Leaks . . . . . . . . . . . . . . . . . Section 2
Oil Leaks . . . . . . . . . . . . . . . . . . . Section 3
Detergent Delivery Failure . . . . . Section 4
Always wear safety rated eye protection and clothing.
For any other problems contact KARCHER
®
technical support
at 1-800-877-2424.
3
For Karcher Pressure Washer Parts Call 606-678-9623 or 606-561-4983
Pump 757 9/28/01 3:33 PM Page 3
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MASTER DIAGRAM
For Karcher Pressure Washer Parts Call 606-678-9623 or 606-561-4983
Pump 757 9/28/01 3:33 PM Page 4
8...Oil level
sight glass
9...Oil drain
drain plug
7...Sight
glass seal
plug ring
10...Oil
1...Oil vent cap
2...Oil filter
3...Oil reservoir
4...O-ring
5...Oil bath housing
6...Pump shaft seal
20...Weep holes (3)
21...Oil seal (3)
22...Brass washer (3)
23...Low-pressure seal (3)
24...Bushing (3)
25...Scraper ring (3)
26...High-pressure seal (3)
27...Pump head
28...Water outlet
29...Nozzle insert
30...Bypass valve
31...Bushing
32...Pressure/volume control
33...Low pressure valve cage (3)
34...Low pressure valve spring (3)
35...Low pressure valve plate (3)
36...Low pressure valve seat (3)
37...Spacer (3)
38...Water inlet filter
39...Water inlet
40...Water inlet housing
11...Swash plate assembly
12...Swash plate roller bearing
13...Swash disk
14...Piston (3)
15...Piston spring (3)
16...Forward O-ring
17...Piston housing
18...Piston guide
retaining screw (2)
19...Circulation
hole (3)
64...Detergent non-return
check valve
57...Non-return check valve seat
58...Non-return check valve plate
59...Non-return check valve spring
60...Non-return check valve cage
42...Valve screw
62...Metering
valve knob
63...Detergent hose nipple
41...Water inlet bolt (5)
42...Valve screw (3)
43...High-pressure valve cage (3)
44...High-pressure valve spring (3)
45...High-pressure valve plate (3)
46...High-pressure valve seat (3)
47...Bushing
48...Thermal relief valve
49...Closing screw
50...Rubber cap
51...Ball bearing
52...Ball-bearing seat
53...Spring
54...Safety relief
valve screw
55...Detergent filter
with metering valve
56...Detergent tube
65...Pump head bolt (4)
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KARCHER OVERVIEW
When the piston (14) is pushed forward by the swash disk (13), the
low-pressure check valve (33-36) closes and water is conveyed
through the open high-pressure check valve (43-46) to the water outlet (28). 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 pulled, the entire pump capacity
flows through the nozzle insert (29) to the water outlet (28). At this
time, the bypass valve (30) 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 (29). The non-return check valve (57-60)
closes, and the pressure in the high-pressure hose is maintained
between the trigger-actuated valve in the spray gun and the nonreturn check valve (57-60). The pressure instantly rises in a surge,
which causes the bypass valve (30) to be pressed downwards. This
opens the path between the pressure chamber, located above the
bypass valve (30), and the water inlet housing (39). The pump continues to run only in bypass mode. The safety relief valve (51-54) will
open if the bypass valve (30) 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
(30), together with the restricted pressure at the entrance to the nozzle insert (29), pushes the bypass valve upwards. This causes the circulation between the pressure chamber and the water inlet (39) to
close, and the pump builds up pressure once more.
This pump has a pressure/volume control (32) 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
diagram is adjustable. This adjustment is made by turning the pressure/volume control (32) downwards. This causes the bypass valve
(30) 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 (39) and the operating pressure drops to the amount that
has been set by turning the pressure/volume control (32).
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 (48).
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 (29) in the water outlet (28). The
entire pump capacity flows through the nozzle insert to the spray gun.
Detergent can only be drawn in by the nozzle insert (29) 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 (56) and detergent filter (55).
If the spray nozzle on the spray wand is set for high-pressure operation, the hole in the nozzle insert (29) does not create any negative
pressure, and no detergent can be drawn into the unit.
Swash Plate Assembly
The three pistons (14) are driven by the swash plate assembly (11,12,13),
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 disk (13) rotates as well. This causes the pistons (14) to move
backwards and forwards. The piston stroke depends upon the angle of
the swash disk (13). 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 in oil (oil type 15W40
non-detergent). The oil level should be halfway up the sight glass (8)
located in the oil bath housing (5). It is important that the machine is on
level ground when checking the sight glass.
In order to drain the oil, the drain plug (10), located beneath the oil bath
housing (5) 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, oil reservoir and sight glass.
In order to add oil in this case, the pump head (27) and piston housing
(17) will have to be removed. If servicing a pump without a sight glass,
the oil level is just above the high side of the swash disk (13).
Pistons With Seals
The three pistons (14) are pressed against the swash disc (13) of the
swash plate assembly (11,12,13) by powerful springs (15). 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 (14) in industrial units are fitted with a high-pressure seal
(26) and a low-pressure seal (23). Non-industrial units have only a highpressure seal (26).
The three pistons each have an oil seal (21) mounted in the piston housing (17). These three oil seals, along with the shaft seal (6), retain the oil
in the oil bath housing. The slot holes (20) are in the piston housing (17)
and allow water or oil to drip out into the open.
A water leakage rate of one drop per piston per minute is allowable during high-pressure operation. If oil is leaking from the weep holes (20),
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 (33-36) and one
high-pressure check valve (43-46). 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 (35 & 45) and the valve seat
(36 & 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 (14) is forced backwards by the spring (15) in the oil bath
housing (5), the high-pressure check valve (43-46) closes and water is drawn
in through the supply line / suction chamber at the water inlet (39), through
the inlet filter (38), and through the open low-pressure check valve (33-36).
5
For Karcher Pressure Washer Parts Call 606-678-9623 or 606-561-4983
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The detergent non-return valve consists of a small spring (16) with a
ball, O-ring and nipple. When operating in the
detergent mode, the neg-
ative pressure created by the nozzle insert
causes the ball to be drawn
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.
6
KARCHER OVERVIEW
PART NUMBERS
High Pressure Washer Pump 3.532-757.0
ITEM #(S)
DESCRIPTION PART # QTY. IN
PUMP
1 Oil vent cap 5.063-651.0 1
2 Oil filter 5.132-107.0 1
3 Oil reservoir 5.070-194.0 1
4 O-ring 6.362-168.0 1
5 Oil bath housing 5.060-827.0 1
6 Pump shaft seal 7.267-011.0 1
7 Sight glass seal 6.362-585.0 1
8 Oil level sight glass 5.411-062.0 1
9 Oil drain plug ring 7.362-055.0 1
10 Oil drain plug 7.382-233.0 1
11 Swash plate assembly 5.120-324.0 1
12 Swash plate roller bearing 6.401-334.0 1
13 Swash disk (included with part #11) NA 1
14 Piston 4.553-173.0 3
15 Piston spring 5.332-403.0 3
16 Forward o-ring 6.363-963.0 1
17 Piston housing 5.060-676.0 1
18 Piston guide retaining screw 7.306-023.0 2
19 Circulation hole (incl. with item #24) NA 3
20 Weep holes (included with item #17) NA 4
21 Oil seal 6.365-322.0 3
22 Washer 5.115-493.0 3
23 Low pressure seal 6.365-351.0 3
24 Bushing 5.112-402.0 3
25 Scraper ring 5.115-492.0 3
26 High-pressure seal 6.362-408.0 3
27 Pump head 5.550-273.0 1
28 Water outlet (included with item #27) NA 1
29 Nozzle insert 5.769-141.0 1
30 Bypass valve (multiple numbers)
top o-ring set 6.362-977.0 1
valve top 5.553-363.0 1
spring 5.332-425.0 1
valve seat 5.581-214.0 1
valve seat o-ring 6.362-450.0 1
threaded spindle 5.305-263.0 1
31 Bushing 5.110-630.0 1
ITEM #(S)
DESCRIPTION PART # QTY. IN
PUMP
32 Pressure/volume control knob with 5.321-307.0 1
Spindle 5.291-073.0
Grooved pin 7.314-629.0
Spindle gasket 6.362-468.0
Valve Screw 5.583-147.0
Valve screw gasket 6.362-989.0
33,34 Low-pressure valve cage, spring, 4.580-329.0 3
35,36 plate and seat
37 Spacer 5.110-608.0 2
38 Water inlet filter 6.414-282.0 1
39 Water inlet (included with item #40) NA 1
40 Water inlet housing 5.060-809.0 1
41 Water inlet bolt 7.306-044.0 5
42 Valve screw 5.583-146.0 1
43,44 High-pressure valve cage, spring, 4.580-379.0 3
45,46 plate and seat
47 Bushing 5.115-876.0 1
48 Thermal relief valve complete 6.413-067.0 1
49 Screw cap 5.411-150.0 1
51 Ball-bearing 7.401-908.0 1
52 Ball-bearing seat 5.582-075.0 1
53 Spring 5.332-075.0 1
54 Safety relief valve screw 5.583-089.0 1
55 Detergent filter 4.862-032.0 1
56 Detergent tube 6.388-216.0 1
57-60 Non-return check valve housing 5.402-523.0 1
62 Detergent metering valve knob 5.321-318.0 1
63 Detergent hose nipple 5.443-281.0 1
64 Detergent non-return check valve with 5.402-523.0 1
top o-ring 6.362-151.0 1
gasket 6.326-383.0 1
ball 7.401-908.0 1
spring 5.332-124.0 1
retainer pipe 5.028-692.0 1
65 Pump head bolts 7.306-125.0 4
NOT PICTURED IN DIAGRAM
Garden hose connection 9.154-009.0 1
Piston spring retaining clip 7.343-478.0 3
For Karcher Pressure Washer Parts Call 606-678-9623 or 606-561-4983
Pump 757 9/28/01 3:33 PM Page 6
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SECTION 1 / LOW WATER PRESSURE
7
Problems That Cause Low Water Pressure
A. Water Supply
A problem with the water supply. Use cold water only.
B. Worn Nozzle
A worn nozzle on the spray wand.
C. Water Inlet Filter
A clogged water inlet filter (38).
D. Bypass Valve
Worn O-rings on the bypass valve (30) or the bypass valve is hanging up.
E. Safety Relief Valve
The safety relief valve (51-54) opens if the bypass valve (30) is not working.
Low water pressure can result if the valve (51-54) does not seal or does not reseat.
F. Low-Pressure Check Valve
Low-pressure check valve (33-36) fails to function properly.
G. High-Pressure Check Valve
High-pressure check valve (43-46) fails to function properly.
H. Water Leaks – See Section 2 / Water Leaks
Water leaks.
I. Pump is Cycling – See Section 4 / Detergent Delivery Failure
Non-return check valve (57-60) or Nozzle insert (29) is damaged and must be replaced.
12...Swash plate roller bearing
11...Swash plate assembly
16...Forward O-ring
6...Pump shaft seal
5...Oil bath housing
4...O-ring
3...Oil reservoir
2...Oil filter
1...Oil vent cap
32...Pressure/volume control
30...Bypass valve
41...Water inlet bolt (5)
14...Piston (3)
48...Thermal relief valve
26...High-pressure seal (3)
10...Oil
drain plug
9...Oil drain
plug ring
54...Safety relief
valve screw
51...Ball bearing
52...Ball-bearing seat
53...Spring
65...Pump head bolt (4)
49...Closing screw
15...Piston spring (3)
17...Piston housing
18...Piston guide
retaining screw (2)
28...Water outlet
39...Water inlet
29...Nozzle insert
38...Water inlet filter
31...Bushing
40...Water inlet housing
20...Weep holes (3)
55...Detergent filter
with metering valve
13...Swash disk
64...Detergent non-return
check valve
56...Detergent tube
8...Oil level
sight glass
7...Sight
glass seal
63...Detergent hose nipple
47...Bushing
62...Metering
valve knob
37...Spacer (3)
21...Oil seal (3)
22...Brass washer (3)
23...Low-pressure seal (3)
24...Bushing (3)
25...Scraper ring (3)
33...Low pressure valve cage (3)
34...Low pressure valve spring (3)
35...Low pressure valve plate (3)
36...Low pressure valve seat (3)
43...High-pressure valve cage (3)
44...High-pressure valve spring (3)
45...High-pressure valve plate (3)
46...High-pressure valve seat (3)
42...Valve screw (3)
57...Non-return check valve seat
58...Non-return check valve plate
59...Non-return check valve spring
60...Non-return check valve cage
42...Valve screw
50...Rubber cap
19...Circulation
hole (3)
27...Pump head
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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 filter.
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)
2. Remove brass bushing. (figure 3)
Note that bushing is positioned with large side down.
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.
6. Grease only large O-rings with lithium grease. (figure 4)
7. Replace bypass valve if necessary.
E. Safety Relief Valve
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.
8
SECTION 1 / LOW WATER PRESSURE SOLUTIONS
A. Water Supply
B. Nozzle
C. Water Inlet Filter
D. Bypass Valve
E. Safety Relief Valve
figure 5
figure 1
figure 4
figure 2
figure 3
Large O-ring
Small O-ring
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SECTION 1 / WATER PRESSURE SOLUTIONS
G. High-pressure Check Valve
1. Remove high pressure valve caps as shown (figure 8).
Use a 17 mm wrench or socket.
2. Remove high-pressure check valve. with special valve pliers
or needle nose pliers (inset figure 8).
3. Check the valve for wear, debris and pitting. Replace if necessary.
4. Grease O-rings lightly with
silicone grease and
reassemble.
(figure 9)
H. Water Leaks – See Section 2 / Water Leaks
I. Pump is Cycling –
See Section 4 / Detergent Delivery Failure
F. Low-pressure Check Valve
1. Remove water inlet housing with torx TX30 bit (5 bolts). (figure 6)
2. Remove low-pressure check valve, including valve disk and spring,
with special valve pliers. (figure 7)
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.
5. Reassemble and reinstall.
Note: Low-pressure check valves must be ordered as a unit. Individual
check valve parts cannot be ordered separately.
9
F. Low-Pressure Check Valve
G. High-Pressure Check Valve
H. Water Leaks
I. Pump Cycling
figure 7
figure 8
figure 9
figure 6
O-ring
O-ring
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10
Problems That Cause Water Leaks
A. Thermal Relief Valve
The thermal relief valve (48) protects the pump from hot water temperatures in bypass mode.
If the thermal relief valve is damaged or does not reset, there will be a continual leak.
Check thermal relief valve (48).
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.
B. weep holes – High-Pressure Seals
Water leaking from the weep holes (20) can indicate a leak in the high-pressure seals.
Check seals for damage.
C. weep holes – Low-Pressure Seals
Water leaking from the weep holes (20) can indicate a leak in the low-pressure seals (23).
Check the seals for damage.
12...Swash plate roller bearing
11...Swash plate assembly
16...Forward O-ring
6...Pump shaft seal
5...Oil bath housing
4...O-ring
3...Oil reservoir
2...Oil filter
1...Oil vent cap
32...Pressure/volume control
30...Bypass valve
41...Water inlet bolt (5)
14...Piston (3)
48...Thermal relief valve
26...High-pressure seal (3)
10...Oil
drain plug
9...Oil drain
plug ring
54...Safety relief
valve screw
51...Ball bearing
52...Ball-bearing seat
53...Spring
65...Pump head bolt (4)
49...Closing screw
15...Piston spring (3)
17...Piston housing
18...Piston guide
retaining screw (2)
28...Water outlet
39...Water inlet
29...Nozzle insert
38...Water inlet filter
31...Bushing
40...Water inlet housing
20...Weep holes (3)
55...Detergent filter
with metering valve
13...Swash disk
64...Detergent non-return
check valve
56...Detergent tube
8...Oil level
sight glass
7...Sight
glass seal
63...Detergent hose nipple
47...Bushing
62...Metering
valve knob
37...Spacer (3)
21...Oil seal (3)
22...Brass washer (3)
23...Low-pressure seal (3)
24...Bushing (3)
25...Scraper ring (3)
33...Low pressure valve cage (3)
34...Low pressure valve spring (3)
35...Low pressure valve plate (3)
36...Low pressure valve seat (3)
43...High-pressure valve cage (3)
44...High-pressure valve spring (3)
45...High-pressure valve plate (3)
46...High-pressure valve seat (3)
42...Valve screw (3)
57...Non-return check valve seat
58...Non-return check valve plate
59...Non-return check valve spring
60...Non-return check valve cage
42...Valve screw
50...Rubber cap
19...Circulation
hole (3)
27...Pump head
SECTION 2 / WATER LEAKS
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SECTION 2 / WATER LEAK SOLUTIONS
• Place seal, flat side down, on installation tool.
• Fill groove with silicone grease. (figure 14)
• Place brass sleeve in pump head.
• Put installation tool into sleeve and press until seal pops
into place. (figure 15)
• Remove tool and then remove sleeve. (inset figure 15)
A. Thermal Relief Valve
1. Remove thermal relief valve screw cap. (figure 11)
2. Disassemble thermal relief valve. (inset figure11)
3. Inspect and replace with new valve if necessary.
B. weep holes - High-Pressure Seals
1. Remove 4 pump head bolts using 6mm allen wrench. (figure 12)
2. Remove pump head.
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.
11
A. Thermal Relief Valve
B. weep holes – High-Pressure Seals
C. weep holes – Low-Pressure Seals
figure 12
figure 13
figure 14
figure 11
figure 15
Brass Sleeve
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C. weep holes - Low-Pressure Seals
1. Remove low-pressure bushing from piston. (figure 17)
2. Remove washer from bushing. (figure 17)
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
7. Place bushing back on piston. Circulation holes must
line up in the 12 o’clock position. (figure 19)
12
SECTION 2 / WATER LEAK SOLUTIONS
C. weep holes – Low Pressure Seals
figure 17
figure 18
figure 19
Scraper Ring
Washer
Bushing
Seal
Circulation
Holes
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SECTION 3 / OIL LEAKS
13
Problems That Cause Oil Leaks
A. Drain Plug
A loose drain plug (10) or damaged drain plug ring (9).
B. Sight Glass
A cracked sight glass (8) or damaged sight glass seal (7).
C. Oil Reservoir
A damaged oil reservoir (3), missing oil reservoir filter (2), or damaged O-ring (4).
If the oil bath housing (5) is overfilled, oil will leak from vent cap (1).
D. weep holes
If oil is leaking from the weep holes (20), there is either a leak in the low-pressure
seals (23) or the high-pressure seals (26); or there is piston (14) damage.
E. Pump Shaft Seal
A damaged or worn pump shaft seal (6).
12...Swash plate roller bearing
11...Swash plate assembly
16...Forward O-ring
6...Pump shaft seal
5...Oil bath housing
4...O-ring
3...Oil reservoir
2...Oil filter
1...Oil vent cap
32...Pressure/volume control
30...Bypass valve
41...Water inlet bolt (5)
14...Piston (3)
48...Thermal relief valve
26...High-pressure seal (3)
10...Oil
drain plug
9...Oil drain
plug ring
54...Safety relief
valve screw
51...Ball bearing
52...Ball-bearing seat
53...Spring
65...Pump head bolt (4)
49...Closing screw
15...Piston spring (3)
17...Piston housing
18...Piston guide
retaining screw (2)
28...Water outlet
39...Water inlet
29...Nozzle insert
38...Water inlet filter
31...Bushing
40...Water inlet housing
20...Weep holes (3)
55...Detergent filter
with metering valve
13...Swash disk
64...Detergent non-return
check valve
56...Detergent tube
8...Oil level
sight glass
7...Sight
glass seal
63...Detergent hose nipple
47...Bushing
62...Metering
valve knob
37...Spacer (3)
21...Oil seal (3)
22...Brass washer (3)
23...Low-pressure seal (3)
24...Bushing (3)
25...Scraper ring (3)
33...Low pressure valve cage (3)
34...Low pressure valve spring (3)
35...Low pressure valve plate (3)
36...Low pressure valve seat (3)
43...High-pressure valve cage (3)
44...High-pressure valve spring (3)
45...High-pressure valve plate (3)
46...High-pressure valve seat (3)
42...Valve screw (3)
57...Non-return check valve seat
58...Non-return check valve plate
59...Non-return check valve spring
60...Non-return check valve cage
42...Valve screw
50...Rubber cap
19...Circulation
hole (3)
27...Pump head
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A. Drain Plug (figure 20)
1. Check drain plug. Tighten or replace if necessary.
2. Inspect drain plug seal. Replace if necessary.
3. Reassemble and reinstall the drain plug.
B. Sight Glass (figure 21)
1. Check to see if sight glass is cracked. Replace if necessary.
2. Check sight glass seal. Replace if necessary.
3. Reassemble and reinstall.
Note: When pump is in horizontal position, sight glass should be half
full of non-detergent oil, part # 6.288-050.0.
C. Oil Reservoir (Figure 22)
1. If oil is spurting from oil reservoir vent cap, the oil level is too high.
Drain to specified level. (See note in Section 2. Sight Glass)
2. Inspect oil reservoir, seal and filter for damage.
3. Replace if necessary.
4. Check that vent nipple is cut.
5. Check O-ring under oil reservoir. If pitted or deformed, replace.
D. weep holes – Oil Seals
1. Unscrew the oil drainage plug and drain the oil into
a suitable container.
2. Remove piston housing. (figure 23)
• Remove four pump head bolts with an allen wrench and
remove the pump head. (See Section 2, figure 12)
• Re-install two of the pump head bolts with a 1/2” shim composed of washers or a metal sleeve about 3/8” in diameter
into two diagonally opposing weep holes of piston guide housing. (figure 23)
• Remove the two piston guide retaining screws.
• 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 23)
• Alternate between nuts after every few turns to keep housing
level.
• Remove the two pump head bolts and shim when spring tension is relieved.
14
SECTION 3 / OIL LEAK SOLUTIONS
A. Drain Plug
B. Sight Glass
C. Oil Reservoir
D. weep holes / Oil Seals
figure 20
figure 21
figure 23
Drain Plug
Seal
Drain Plug
Sight Glass
Sight Glass
Seal
figure 22
Oil Vent Cap
Oil Vent
Nipple
Piston
Housing
Retaining
Screws
O-ring
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SECTION 3 / OIL LEAK SOLUTIONS
E. Pump Shaft Seal
1. Remove swash plate assembly. (figure 27
2. Knock out the pump shaft seal from the rear of the
oil bath housing by tapping seal towards the front of
the oil bath housing using a suitable tool. (figure 28)
3. Clean surface and replace pump shaft seal if necessary.
• To replace pump shaft seal, place seal into oil bath housing.
Make sure that the groove of the pump shaft seal is facing
the front of the pump (figure 29).
• Push seal into place.
3. Pull out piston guide assembly. (figure 24)
4. Inspect forward O-ring and seal. Replace if necessary.
5. Remove and inspect pistons for wear or scoring.
Replace if necessary.
7. Remove the 3 oil seals with flat head screwdriver. (figure 25)
8. Inspect and replace oil seals if necessary.
• Soak new oil seals in water for 10 minutes. (inset figure 26)
• Make sure housing is clean and dry.
• Place oil seal into recessed end of installation tool.
Sleeve is not used. Groove in seal should face oil.
• Place seal in housing using installation tool. (figure 26)
• Do not grease groove in oil seal.
• Push until seal hits bottom.
15
D. weep holes / Oil Seals
E. Pump Shaft Seal
figure 27
figure 28
figure 29
figure 26
figure 24
Forward O-ring
figure 25
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16
Detergent Delivery Failure
A. Pump Not Drawing Detergent or Water Exiting Detergent Tube
Detergent filter (55) or Detergent non-return check valve (64) may be clogged or damaged.
Nozzle insert (29) may be worn.
Nozzle of the spray wand has been set to high pressure
B. Pump Is Cycling
Non-return check valve (57-60) or Nozzle insert (29) is damaged and must be replaced.
12...Swash plate roller bearing
11...Swash plate assembly
16...Forward O-ring
6...Pump shaft seal
5...Oil bath housing
4...O-ring
3...Oil reservoir
2...Oil filter
1...Oil vent cap
32...Pressure/volume control
30...Bypass valve
41...Water inlet bolt (5)
14...Piston (3)
48...Thermal relief valve
26...High-pressure seal (3)
10...Oil
drain plug
9...Oil drain
plug ring
54...Safety relief
valve screw
51...Ball bearing
52...Ball-bearing seat
53...Spring
65...Pump head bolt (4)
49...Closing screw
15...Piston spring (3)
17...Piston housing
18...Piston guide
retaining screw (2)
28...Water outlet
39...Water inlet
29...Nozzle insert
38...Water inlet filter
31...Bushing
40...Water inlet housing
20...Weep holes (3)
55...Detergent filter
with metering valve
13...Swash disk
64...Detergent non-return
check valve
56...Detergent tube
8...Oil level
sight glass
7...Sight
glass seal
63...Detergent hose nipple
47...Bushing
62...Metering
valve knob
37...Spacer (3)
21...Oil seal (3)
22...Brass washer (3)
23...Low-pressure seal (3)
24...Bushing (3)
25...Scraper ring (3)
33...Low pressure valve cage (3)
34...Low pressure valve spring (3)
35...Low pressure valve plate (3)
36...Low pressure valve seat (3)
43...High-pressure valve cage (3)
44...High-pressure valve spring (3)
45...High-pressure valve plate (3)
46...High-pressure valve seat (3)
42...Valve screw (3)
57...Non-return check valve seat
58...Non-return check valve plate
59...Non-return check valve spring
60...Non-return check valve cage
42...Valve screw
50...Rubber cap
19...Circulation
hole (3)
27...Pump head
SECTION 4 / DETERGENT DELIVERY FAILURE
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SECTION 4 / DETERGENT DELIVERY FAILURE SOLUTIONS
• Remove detergent non-return check valve. (figure 33)
• 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
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.
A. Pump Not Drawing Detergent or Water Exiting
Detergent Tube
1. Check that nozzle is in low/chemical position. (figure 30)
2. Check that metering valve on pickup filter is open. (figure 31)
3. Check pickup filter for clog.
4. Check detergent tube for holes and kinks.
5. Remove detergent metering knob, nipple
and non-return check valve.
• Remove detergent tube. (figure 32)
• Unscrew metering knob and hose nipple.
17
A. Pump Not Drawing Detergent or Water
Exiting from Detergent Tube
B. Nozzle Insert
figure 30
figure 31
figure 32
figure 33
figure 34
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C. Non-return Check Valve
1. Remove the non-return check valve cap. (figure 35)
2. Remove the non-return check valve with with special valve pliers
or needle nose pliers. (figure 36)
3. Inspect the non-return valve for wear, debris and pitting.
If any part is damaged, replace the complete valve assembly.
4. Grease O-rings lightly with silicone grease and reassemble.
(figure 37)
18
SECTION 4 / DETERGENT DELIVERY FAILURE SOLUTIONS
C. Non-return check valve
figure 35
figure 36
figure 37
O-ring
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