Caution: The oil pump gears are matched in pairs and both gears must be replaced if necessary.
1. Apply a mark on the rear surface of the outer gear (larger) to ensure that it is installed in the same position relative to the inner gear (smaller) during assembly as it was removed from the factory packaging.
2. Remove the engine oil pan.
3. Remove the oil pump by unscrewing the three bolts securing the pump to the cylinder block.
4. Remove the oil pump cover and remove the gears, and also remove the oil supply line to the pump.
5. Punch a hole in the middle of the rubber plug of the pump bypass valve.
6. Remove the rubber plug using a bolt of the appropriate diameter.
7. Remove the bypass valve spring and piston.
8. Insert both gears into the pump body, ensuring that they are correctly aligned with each other.
9. Using a ruler and feeler gauge, measure the gap between the pump housing plane and the rear surfaces of the gears. If it exceeds the maximum permissible value, the pump housing should be replaced.
10. Using a feeler gauge, check the clearance between the outer gear and the pump body. If it exceeds the maximum permissible value, the pump body should be replaced.
11. Lubricate the bypass valve parts with engine oil and install the bypass valve.
12. Install the rubber bypass plug with the flat side facing out. It should be on the edge of the sealing surface of the oil supply line to the pump.
13. Lubricate both pump gears with engine oil.
14. Install the oil pump cover and tighten its bolts to the specified torque.
15. Insert the shaft transmitting the drive from the intermediate shaft (the end with the asymmetrical protrusion should be directed towards the ignition distributor) into the pump drive shaft and, turning it by hand, make sure that the pump gears interact without jamming.
16. Install the gasket and oil supply line to the pump.
17. Install the oil pump into the cylinder block, tightening the mounting bolts to the appropriate torque.
18. Attach the oil pan to the cylinder block. Start with bolt (A) to (B), then bolt (B) to (A).