Power Steering Pump: Testing and Inspection

POWER STEERING: VANE PUMP:

INSPECTION

1. INSPECT OIL CLEARANCE





(a) Using a micrometer and a caliper gauge, measure the oil seal clearance.
Standard clearance:
0.021 - 0.043 mm (0.0008 - 0.0017 in.)
Maximum clearance:
0.07 mm (0.0028 in.)
If it is more than the maximum, replace the vane pump assembly.
2. INSPECT VANE PUMP ROTOR AND VANE PUMP PLATES





(a) Using a micrometer, measure the height, thickness and length of the vane plates.
Minimum height:
7.6 mm (0.299 in.)
Minimum thickness:
1.405 mm (0.0553 in.)
Minimum length:
11.993 mm (0.4722 in.)





(b) Using a feeler gauge, measure the clearance between a side face of the vane pump rotor groove and vane plate.
Maximum clearance:
0.03 mm (0.0012 in.)
If it is more than 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 by its own weight.





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





(a) Using vernier calipers, measure the free length of the spring.
Minimum free length:
36.9 mm (1.453 in.)
If it is not within the specification, replace the vane pump assembly.
5. INSPECT PRESSURE PORT UNION
(a) If the union seat in the pressure port union is remarkably damaged and it may cause fluid leakage, replace the vane pump assembly.