Power Steering Pump: Testing and Inspection

POWER STEERING: VANE PUMP: INSPECTION

INSPECTION

1. INSPECT VANE PUMP SHAFT





(a) Using a micrometer and a caliper gauge, measure the oil clearance.
Maximum clearance:
0.07 mm (0.0028 in.)
If clearance exceeds the maximum, replace the vane pump assembly.
2. INSPECT VANE PUMP ROTOR





(a) Using a micrometer, measure the thickness of the vane pump plates.
Standard thickness:
1.405 to 1.411 mm (0.05531 to 0.05555 in.)





(b) Using a feeler gauge, measure the clearance between a side face of the vane pump rotor groove and the vane plates.
Maximum clearance:
0.03 mm (0.0012 in.)
If clearance exceeds the maximum, replace the vane pump assembly.
3. INSPECT FLOW CONTROL VALVE





(a) Coat the flow control valve with power steering fluid and check that it falls smoothly into the flow control valve hole under its own weight.
If it lacks smoothness, replace the vane pump assembly.





(b) Check the flow control valve for leakage. Close one of the holes and apply compressed air, 392 to 490 kPa (4 to 5 kgf/cm2, 57 to 71 psi), into the opposite side hole, and confirm that air does not come out from the end holes.
If air leaks, replace the vane pump assembly.
4. INSPECT FLOW CONTROL VALVE COMPRESSION SPRING





(a) Using vernier calipers, measure the free length of the compression spring.
Minimum free length:
36.9 mm (1.453 in.)
If the length is less than the minimum, replace the vane pump assembly.
5. INSPECT PRESSURE PORT UNION
If the union seat in the pressure port union is severely damaged, it may cause fluid leakage. In that case, replace the vane pump assembly.