4. If the piston assemblies use a lock ring and have been
disassembled, assemble them as follows:
a. Install a retainer ring into the groove at one end of
each piston.
b. Slide the piston spring retainer up the piston until it
contacts the retainer ring. Retainer must be installed
exactly as shown in Figure 7.34.
c. Springs are tapered. Install small end of tapered spring
so that it contacts the spring retainer.
3. If the piston assemblies have an integral spring retainer
ring, install the small end of the tapered spring so that it
contacts the spring retainer.
4. Apply a small amount of SAE 80W90 oil to the lip of the
oil seals and the piston surface.
5. With spring in place around piston as shown in Figure
7.34, install the piston through the crankcase, oil seal, and
pilot spacer, as shown in Figure 7.35.
6. Install the thermal bypass piston and spring into the bore
provided in the center of the pump crankcase, as shown
in Figure 7.36.
Section 7 • Large Frame Pump
Portable Pressure Washer Familiarization and Troubleshooting Guide
Figure 7.35 — Piston Installation
Item
Name
1
Lock ring
2
Spring retainer
3
Return spring
4
Piston
Item
Name
1
Return spring
2
Pump crankcase
3
Piston oil seal
4
Pilot spacer
5
Piston
Figure 7.36 — Thermal Bypass Components
Item
Name
1
Pump crankcase
2
Thermal bypass spring
3
Thermal bypass piston
4
O-ring
Figure 7.34 — Return Spring Orientation
95
