Power Steering Control Unit

DISASSEMBLE

Fig. 20 Exploded View Of Control Valve Body Unit:

1. Drain power steering fluid, then remove gearbox shield.
2. Using suitable flare nut wrenches, disconnect four hydraulic lines from valve body.
3. Remove two valve body to gearbox attaching bolts.
4. Remove O-rings and port orifices from gearbox.
5. Remove three valve body cap to valve body attaching bolts, Fig. 20.
6. Remove pressure control valve and spring from valve body.
7. Remove pressure control valve and spring from valve body, then check pressure control valve surface for any scoring or scratches. Slip it back into the valve body, and ensure that it slides smoothly without drag and without side play.
8. Remove gain control valve and spring from valve body.
9. Inspect gain control valve surface for any scoring or scratches, then slip valve back into valve body and ensure it slides smoothly without drag or slide play.
10. Separate valve body and port housing.
11. Remove rollers from control valve by pushing valve out one side of valve body, then the other. When removing rollers, hold plungers with your fingers to keep them from popping out.
12. Remove plungers, return springs and 4-way valve from valve body.
13. Remove O-ring from 4-way valve.
14. Inspect plunger surface for any scoring or scratches, then slip each plunger back into valve body and ensure it slides smoothly without drag or slide play.
15. Inspect 4-way valve surface for any scoring or scratches, then slip 4-way valve back into valve body and ensure it slides smoothly without drag or slide play.
16. Using a 1/64 inch drill bit, remove sensor orifice and O-ring from valve body.

ASSEMBLE
1. Ensure all parts are thoroughly clean and coat plungers, pressure control valve, gain control valve and 4-way valve with power steering fluid.
2. Install 4-way valve, plungers, return springs and rollers into valve body.
3. Coat port seal with power steering fluid and install into groove of port housing.
4. Install valve body onto port housing.
5. Install pressure control valve, gain control valve and valve springs into valve body.
6. Coat cap seal with power steering fluid and install into groove of valve body cap.
7. Install valve body cap on valve body. Ensure that mating surface of valve body and cap are flush at the upper side.
8. Torque attaching bolts to 7 ft. lbs.
9. Ensure 4-way valve moves smoothly and returns to its neutral position.
10. Coat O-rings with grease and install them together with the orifices.
11. Install valve body unit onto gear housing. Be careful not to hit pinion holder pin and ensure O-rings are in place and not pinched.
12. Torque attaching bolts to 16 ft. lbs.
13. Tighten hydraulic lines to valve body as follows:
a. Torque line to oil cooler to 21 ft. lbs.
b. Torque line to speed sensor to 9 ft. lbs.
c. Torque line to reservoir to 9 ft. lbs.
d. Torque line from pump to 28 ft. lbs.