Note: The oil pump housing and cover must be ground at a service station with special equipment.
1. Unscrew the six cover mounting bolts and remove it from the pump body.
2. Remove the pump gears from the housing.
3. Using a screwdriver, remove the front crankshaft oil seal from the pump housing.
Note: Maximum permissible axial clearance of oil pump gears, mm:
- leading - 0.12;
- driven – 0.15.
4. Inspect the cover. Mill the cover surface with traces of wear from gears no more than 0.2 mm.
5. Install the drive gear into the pump body. Place a metal ruler on the pump body and measure the gap between the ruler and the gear with a feeler gauge.
6. Measure the axial clearance of the driven gear in the same way. If the clearances exceed the maximum permissible values, (see note), sand the surface of the body that meets the lid.
7. Unscrew the plug of the pressure relief valve from the oil pump cover and remove the plunger with the spring.
Pressure reducing valve details: 1 – plunger; 2 – sealing ring; 3 – cork; 4 – spring; 5 – oil pump
8. Measure the spring. Its free length should be 44.72 mm. If the length is less, replace the spring. A plunger with deep scratches and nicks should be replaced. Check the plunger: it should move easily in the hole of the cover. If there is jamming, replace the plunger and (or) the cover.
9. Lubricate all parts of the oil pump with engine oil and assemble the pump in the reverse order of assembly. Install the gears so that the chamfer on the tops of the teeth is directed inside the housing.
10. Press the seal into the pump cover as shown in the photo (the side of the seal with the spring must face the inside of the pump).