Disassembly/Assembly

1. Remove oil pump as described under Oil Pump Engine, Service and Repair, then drain oil from pump.
2. Remove drive shaft, then the pump cover.
3. Remove pump gears, then the cotter pin, spring and pressure regulator valve. Pressure regulator valve spring may be under pressure. Use extreme caution when removing retaining pin. If valve is stuck, soak pump housing in carburetor cleaning solvent.
4. Clean all parts of sludge, oil and varnish.
5. Inspect for foreign material, pump housing and cover for cracks, scoring, casting imperfections and damaged threads.
6. Inspect idler gear shaft. If loose in housing, replace pump.
7. Inspect pressure regulator valve for scoring and sticking and pressure regulator spring for loss of tension or bending.
8. Inspect suction pipe and screen assembly for looseness or broken wire mesh or screen. If suction pipe is loose, bent or broken, pump body cover and suction pipe must be replaced.
9. Inspect gears for chipping, galling or wear and drive shaft and drive shaft extension for looseness or wear.
10. Measure gear lash, pump housing gear pocket, gears, gear side clearance and gear end clearance. When deciding pump serviceability based on end clearance, consider depth of wear pattern in pump cover.
11. Reverse disassembly steps to assemble pump. Tighten fasteners to specifications.