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 clearance.
Standard clearance:
0.027 to 0.054 mm (0.0011 to 0.0021 in.)
Maximum clearance
0.07 mm (0.0028 in.)
If it is more than the maximum, replace the shaft and vane pump front housing.
2. INSPECT VANE PUMP ROTOR AND VANE PUMP PLATES CLEARANCE






(a) Using a micrometer, measure the height, thickness and length of the 10 vane plates.
Minimum height:
8.6 mm (0.33858 in.)
Minimum thickness
1.397 mm (0.05500 in.)
Minimum length
14.991 mm (0.59020 in.)






(b) Using a feeler gauge, measure the clearance between the vane pump rotor grove and vane plate.
Maximum clearance:
0.033 mm (0.00130 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 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 comes out from the end holes, 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:
32.1 mm (1.264 in.)
If it is not within the specification, replace the spring.
5. INSPECT PRESSURE PORT UNION
If the pressure union seat in the pressure port union is remarkably damaged and it may cause fluid leakage, replace the pressure port union.