Disassembly and Assembly

Disassembly

Fig. 38 Exploded View Of Power Steering Pump. Pickup & 4Runner w/RN Series:

1. Position power steering pump in suitable soft-jawed vise.
2. Remove air control valve and union seat.
3. Remove suction port union and O-ring, Fig. 38.
4. Remove front housing attaching bolts, place installation alignment mark on front and rear housing, then using suitable plastic hammer, tap off front housing. Do not allow vane plates, rotor or cam ring to fall out.
5. Remove cam ring, rotor and vane plates.
6. Position front housing in suitable soft jawed vise.
7. Using suitable hammer and chisel, pry off oil seal, then remove snap ring.
8. Using suitable plastic hammer, remove rotor shaft from front housing.
9. Using suitable plastic hammer, tap bottom end of rear housing and remove rear plate and spring. Do not grip rear plate with pliers as damage may occur.
10. Temporarily install bolt to spring seat, using suitable snap ring pliers, remove snap ring, pull out bolt, using suitable tool, remove spring seat, then remove O-ring.

Inspection & Repair
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. If required, replace rotor shaft bearing as follows:
a. Using suitable snap ring pliers, remove snap ring.
b. Using suitable press, press out bearing.
c. Using suitable press, press in bearing.
d. Using suitable snap ring pliers, install snap ring.
3. Using suitable feeler gauge, measure cam ring clearance, maximum should be .0024 inch, if difference is not as indicated, replace cam ring with one with same letter as on rotor.
4. On 1989 models, using suitable micrometer, measure height, thickness and length of vane plates. Minimum height should be .307 inch, thickness, .067 inch and length .5894 inch.
5. On 1990-92 models, using suitable micrometer, measure height, thickness and length of vane plates. Minimum height should be .319 inch, thickness, .0707 inch and length .5901 inch.
6. On all models, using suitable feeler gauge, measure clearance between rotor groove and vane plate, maximum indicated should be .0024 inch on 1989 models or .0012 inch on 1990-92 models.
7. If measurements are not as indicated in steps 5 and 6, replace vane plate and/ or rotor with one having the same mark stamped on cam ring.
8. Coat flow control valve with power steering fluid, ensuring it falls smoothly into valve hole.
9. Close one flow control valve hole, then apply compressed air (57-71 psi) to opposite side, ensuring air does not come out end holes.
10. If inspections are not as indicated in steps 8 and 9, replace flow control valve with one having same letter as on front housing.
11. Using suitable scale, measure flow control spring free length, 1.85-1.97 inch on 1989 models or 1.38-1.46 inch on 1990-92 models should be indicated, if not replace spring.

Assembly
1. Coat all sliding surfaces with power steering fluid.
2. Install O-ring to flow control spring seat, install spring seat to housing, then install snap ring.
3. Install spring, flow control valve, O-ring and pressure port union, tighten to specifications.
4. Using suitable plastic hammer, tap in rotor shaft to front housing, then install snap ring.
5. Coat oil seal lip with MP grease, using suitable tool and hammer, install oil seal.
6. Install O-ring and pin to front housing.
7. Align and install cam ring fluid passages and front housing and install cam ring.
8. Install rotor with inscribed letters facing upward.
9. Install vane plates with round end facing outward.
10. Install rear plate O-ring, then align rear plate fluid passages with cam ring and install rear plate and spring.
11. Align front and rear housing matchmarks, install reservoir tank and O-ring, install and temporarily tighten front housing bolts.
12. Position rear housing in suitable soft jawed vise, then tighten housing attaching bolts uniformly in several passes to specifications.
13. Install suction port union and O-ring and tighten to specifications.
14. Install new union seat, then air control valve.
15. Temporarily install pulley nut and check rotating torque, 2.4 inch lbs. or less should be indicated.