Power Steering Pump: Service and Repair

Fig. 6 Exploded View Of Power Steering Pump. Celica w/4A-FE Engine:

Disassembly
1. Position power steering pump in suitable soft-jawed vise.
2. Using suitable tool, remove pump pulley and woodruff key.
3. Remove reservoir tank, bracket and O-ring.
4. Remove air control valve, Fig. 6.
5. Remove pressure feed tube, pressure port union and O-ring, then remove flow control valve and spring.
6. Remove rear housing snap ring, then using suitable plastic hammer, tap out rear housing, wave washer and O-ring.
7. Using suitable plastic hammer, tap out shaft end, then remove rear side plate and O-ring.
8. Remove pump shaft, cam ring and vane plates.
9. Using suitable screwdriver, remove pump shaft snap ring, remove rotor and front plate from pump shaft.
10. Remove front plate O-rings, then using suitable pin punch and hammer, drive out straight pin.

Inspection
1. Using suitable micrometer and calipers, measure oil clearance between shaft and bushing, .0028 inch or less should be indicated, if not replace entire power steering pump.
2. Using suitable micrometer, measure height, thickness and length of vane plates. Minimum height should be .315 inch, thickness, .0697 inch and length .5894 inch.
3. Using suitable feeler gauge, measure clearance between rotor groove and vane plate, maximum indicated should be .0012 inch.
4. If measurements are not as indicated in steps 2 and 3, replace vane plate and/ or rotor with one having the same mark stamped on cam ring.
5. Coat flow control valve with power steering fluid, ensuring it falls smoothly into valve hole.
6. Close one flow control valve hole, then apply compressed air (57-71 psi) to opposite side, ensuring air does not come out end holes.
7. If inspections are not as indicated in steps 6 and 7, replace flow control valve with one having same letter as on front housing.
8. Using suitable scale, measure flow control spring free length, 1.42-1.49 inch should be indicated, if not replace spring.
9. If required, replace oil seal as follows:
a. Using suitable screwdriver, pry out oil seal.
b. Using suitable socket and hammer, drive in new oil seal.

Assembly
1. Coat all sliding surfaces with power steering fluid.
2. Using suitable plastic hammer, drive short straight pin to front plate.
3. Install O-rings to front plate, then install front plate, rotor with inscribed mark facing toward rear and snap ring to pump shaft.
4. Coat oil seal lip with MP grease, install long straight pin to front housing, align front plate hole and straight pin, then using suitable plastic hammer, tap in pump shaft. Do not damage oil seal and O-rings.
5. Align cam ring holes with long straight pins, then install cam ring with inscribed marks facing outward.
6. Install vane plates with round end facing outward.
7. Install side plate O-ring, then align side plate holes with pins and install side plate.
8. Install rear housing wave washer so washer protrusions fit into slots on rear side of plate, O-ring, then using suitable press, install rear housing, press wave washer hard enough to compress it, then install snap ring.
9. Ensure pump shaft rotates smoothly without abnormal noise.
10. Temporarily install pulley nut and check rotating torque, 2.4 inch lbs. or less should be indicated.
11. Install spring, flow control valve, O-ring and pressure port union, tighten to specifications.
12. Install pressure feed tube, new gaskets and union bolt, tighten to specifications.
13. Install air control valve.
14. Install O-ring to reservoir tank, then install tank and bracket, tighten to specifications.
15. Install woodruff key to power steering pulley shaft, then install pulley and nut to shaft, using suitable tool, hold pulley and tighten attaching nut to specifications.