Piston Oil Seals and Pistons

Portable Pressure Washer Familiarization and Troubleshooting Guide Section 6 • Medium Frame Pump

Figure 6.23 — Bearing Race Assemblies and piston shoe bearing race. - The inside diameter of the outer cam bearing race is larger than the piston shoe bearing race. - The piston shoe bearing race may be thicker than the other races. The chamfered edge of the bearing races must face AWAY FROM THE BEARING ROLLERS, as shown in Figure 6.23.

Piston Oil Seals and Pistons Refer to Figure 6.24 for this procedure. 1. Pre-lubricate three (3) piston oil seals with 80W90 oil.

Figure 6.24 — Piston Oil Seals

Item Name 1 Engine adapter bearing race 2 Engine adapter bearing 3 Inner cam bearing race 4 Axial cam assembly 5 Outer cam bearing race 6 Axial cam bearing 7 Piston shoe bearing race

A Larger inside diameter

B Smaller inside diameter

C Chamfer faces this way Note: inset at lower left shows bearing race cross-section and locations of chamfers.

NOTE: Bearing race inside dimensions are different. Follow this procedure or the parts won’t go together. 6. Install the engine adapter bearing race, followed by the engine adapter bearing and the inner cam bearing race. - The inside diameter of the engine adapter bearing race is larger than the cam bearing race. - The chamfered edge of the bearing races must face

AWAY FROM THE BEARING ROLLERS. That is, the flat (unchamfered) side of the race must ride against the rollers, as shown in Figure 6.23. 7. Install the outer cam bearing race, the axial cam bearing Item Name 1 Pilot spacer tang engaged in crankcase locating notch 2 Crankcase locating notch 3 Pump crankcase 4 High pressure oil seal 5 Pilot spacer

2. Press a seal into one of the piston bores provided on the pump crankcase, with the writing on the face of seal toward the installer. Press the seal in until it bottoms.

Repeat this step for the two (2) remaining seals. 3. Install the three (3) pilot spacers over the piston oil seals, as shown in Figure 6.24: a. The larger diameter flange of the pilot spacer mates with the crankcase bore. b. The pilot spacer locating tangs must engage the crankcase locating notch, as shown in Figure 6.24.

Portable Pressure Washer Familiarization and Troubleshooting Guide Section 6 • Medium Frame Pump

3. Piston assemblies have an integral spring retainer ring. Install the small end of the tapered spring so that it contacts the spring retainer, as seen in Figure 6.25.

Figure 6.25 — Return Spring Orientation 6. Install the thermal bypass piston and spring into the socket cast into the upper portion of the pump crankcase, as shown in Figure 6.27. A small amount of petroleum jelly will hold these parts in the crankcase during subsequent assembly tasks.

Figure 6.27 — Thermal Bypass Spring and Piston

Item Name 1 Return spring 2 Piston

4. Apply a small amount of SAE 80W90 oil to the lip of the oil seals and the piston surface. 5. Install each piston through the spring, crankcase, oil seal, and pilot spacer, as shown in Figure 6.26.

Figure 6.26 — Piston Installation Item Name 1 Crankcase 2 Thermal bypass spring 3 Thermal bypass piston 4 Thermal bypass o-ring

Item Name 1 Return spring 2 Pump crankcase 3 Piston oil seal 4 Pilot spacer 5 Piston