Oil Pump: Service and Repair

REMOVAL
1. Remove oil pan as described previously.
2. Remove pump to rear main bearing cap bolt, then remove pump and extension shaft.

Fig. 15 Exploded View Of Oil Pump:

DISASSEMBLY
1. Drain oil from pump, then remove driveshaft, Fig. 15.
2. Remove pump cover, Do not remove pickup tube from cover unless loose or broken.
3. Remove pump gears, then the pressure regulator valve. The pressure regulator valve spring is under pressure. Exercise caution when removing the retaining pin, as bodily injury may result.
4. Remove plug, spring and valve. If valve is stuck, soak the pump housing in carburetor cleaning solvent.

Fig. 16 Measuring Oil Pump Gear Lash:

Fig. 17 Measuring Gear Side Clearance:

Fig. 18 Measuring Oil Pump Gear Pocket:

Fig. 19 Measuring Oil Pump End Clearance:

INSPECTION
Thoroughly clean all oil pump components and check them for excessive wear or damage.
1. Using a straightedge and feeler gauge, check oil pump clearances as shown in Figs. 16 through 19.
2. Install gears and measure in several places, gear lash should be within .004-.008 inch.
3. Measure depth and diameter of oil pump gear pocket, depth should be 1.195-1.198 inch and diameter should be 1.503-1.506 inch.
4. Measure gear side clearance, side clearance should be .0015-.004.
5. Measure gear end clearance, end clearance should be .002-.006. When deciding pump serviceability based on end clearance, consider depth of wear pattern in the pump cover and/or cover plate.

ASSEMBLY
1. Lubricate all internal parts with engine oil during assembly.
2. Install pump gears. To avoid engine damage, all pump cavities must be packed with petroleum jelly before installing gears to assure priming.
3. Install oil pump cover and gasket.
4. Install pressure regulator valve, spring and retaining pin.
5. Torque pump cover bolts to specifications. Whenever the oil pump is overhauled, clear the oil pan of oil and sludge, replace oil filter and fill crankcase with clean oil.

INSTALLATION
1. Install pump and extension shaft, then torque main bearing cap bolt to specification.
2. Install oil pan.