Oil Pump: Service and Repair

1. Disconnect battery ground cable.
2. Raise and support vehicle.
3. Drain crankcase, then remove oil pan.
4. Remove three oil pump attaching bolts and washers, then the pump and gasket.
5. Carefully clamp oil pump body in vise.
6. Remove three bolts holding pickup housing to pump housing and remove pickup.

Fig. 12 Exploded View Of Oil Pump:

7. Remove spring, relief valve and cover, Fig. 12, the slide driveshaft with drive gear and driven gear out of housing.
8. Clean all disassembled parts in suitable solvent and blow dry with compressed air.
9. Check housing and cover for cracks and the intake pickup and oil duct for clogging.
10. Reverse steps 6 and 7 to assemble pump.
11. Check backlash between gears. Backlash is .006 inch for new pump and maximum allowable backlash is .010 inch.

Fig. 13 Checking Gear Tooth To Pump Housing Clearance:

12. Check gear tooth to pump housing clearance, Fig. 13. Clearance should be .004-.007 inch on new pump with maximum allowable clearance being .010 inch.
13. Replace housing and gears if maximum clearances are exceeded in steps 11 and 12.

Fig. 14 Checking Clearance Between Gears & Cover Mating Surface:

14. Check clearance between gears and the cover mating face. Using straightedge and feeler gauge, Fig. 14. Clearance range should be .008-.0041 inch. If a value of more than .006 inch is found, gears and/or pump housing must be replaced.
15. To determine if gears are worn, measure their length. The range for new gears is 1.101-1.102 inches. The drive gear is mounted on its shaft with an interference fit. Check for signs of play.
16. Clearance between driven gear and its shaft is .0006-.002 inch with a maximum allowable clearance of .004 inch.
17. Check clearance between pump drive shaft and pump housing. Clearance range is .0006-.002 inch with a maximum allowable clearance of .004 inch.
18. Reverse steps 1 through 4 to install oil pump, installing all new gaskets and ensuring pump is properly seated before tightening bolts.