GM Caprice 1990-1993 Repair Guide

Power Steering Gear

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See Figures 1 through 8



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Fig. Fig. 1: Power steering system



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Fig. Fig. 2: Loosening the power steering gear adjuster plug locknut



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Fig. Fig. 3: Marking the housing even with the adjuster plug hole



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Fig. Fig. 4: Making the second index mark



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Fig. Fig. 5: Using a spanner wrench to align the adjuster plug with the second mark



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Fig. Fig. 6: Aligning the stub shaft parallel with the top cover



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Fig. Fig. 7: Checking the over-center rotational torque



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Fig. Fig. 8: Power steering gear assembly

ADJUSTMENTS



Adjust the worm bearing preload first, then proceed with the pitman shaft over-center adjustment.

WORM BEARING PRELOAD
  1. Disconnect the negative battery cable.
  2.  
  3. Remove the steering gear.
  4.  
  5. Rotate the stub shaft and drain the power steering fluid into a suitable container.
  6.  
  7. Remove the adjuster plug nut.
  8.  
  9. Turn the adjuster plug in (clockwise) using a suitable spanner wrench until the adjuster plug and thrust bearing are firmly bottomed in the housing. Tighten the adjuster plug to 20 ft. lbs. (27 Nm).
  10.  
  11. Place an index mark on the housing even with 1 of the holes in the adjuster plug.
  12.  
  13. Measure back counterclockwise 1 / 2 in. (13mm) and place a second mark on the housing.
  14.  
  15. Turn the adjuster plug counterclockwise until the hole in the adjuster plug is aligned with the second mark on the housing.
  16.  
  17. Install the adjuster plug nut and using a suitable punch in a notch, tighten securely. Hold the adjuster plug to maintain alignment of the marks.
  18.  
  19. Install the steering gear and connect the negative battery cable.
  20.  

PITMAN SHAFT OVER-CENTER
  1. Disconnect the negative battery cable.
  2.  
  3. Remove the steering gear.
  4.  
  5. Rotate the stub shaft and drain the power steering fluid into a suitable container.
  6.  
  7. Turn the pitman shaft adjuster screw counterclockwise until fully extended, then turn back 1 full turn.
  8.  
  9. Rotate the stub shaft from stop to stop and count the number of turns.
  10.  
  11. Starting at either stop, turn the stub shaft back half the total number of turns. This is the"Center" position of the gear. When the gear is centered, the flat on the stub shaft should face upward and be parallel with the side cover and the master spline on the pitman shaft should be in line with the adjuster screw.
  12.  
  13. Rotate the stub shaft 45 degrees each side of the center using a suitable torque wrench with the handle in the vertical position. Record the worm bearing preload measured on or near the center gear position.
  14.  
  15. Adjust the over-center drag torque by loosening the adjuster locknut and turning the pitman shaft adjuster screw clockwise until the correct drag torque is obtained: Add 6-10 inch lbs. (0.7-1.1 Nm) torque to the previously measured worm bearing preload torque. Tighten the adjuster locknut to 20 ft. lbs. (27 Nm). Prevent the adjuster screw from turning while tightening the adjuster screw locknut.
  16.  
  17. Install the steering gear and connect the negative battery cable.
  18.  

REMOVAL & INSTALLATION



  1. Disconnect the negative battery cable. Remove the coupling shield.
  2.  
  3. Remove the retaining bolts at the steering coupling to steering shaft flange.
  4.  
  5. Remove the pitman arm nut and washer. Mark the relation of the arm position to the shaft.
  6.  
  7. Remove pitman arm using special tool J-6632 or its equal.
  8.  
  9. Remove the fluid hoses and cap them to prevent foreign material from entering the system.
  10.  
  11. Remove the steering box to frame bolts. Remove the steering box.
  12.  

To install:
  1. Position the steering box and secure with the steering box-to-frame bolts.
  2.  
  3. Install the pitman arm to the match marks made earlier.
  4.  
  5. Install the pitman arm nut and washer. Install the power steering hoses.
  6.  
  7. Install the retaining bolts at the steering coupling to steering shaft flange.
  8.  
  9. Install the coupling shield.
  10.  
  11. Connect the negative battery cable.
  12.  

OVERHAUL



  1. Disconnect the negative battery cable.
  2.  
  3. Remove the power steering gear as previously directed.
  4.  
  5. Clean any external grease and dirt from the unit.
  6.  
  7. Rotate the stub shaft back and forth over a drain pan and remove any fluid remaining inside the unit.
  8.  
  9. Remove the pitman shaft adjuster lock nut and cover bolts.
  10.  
  11. Center the gear by turning the stub shaft.
  12.  
  13. Remove the side cover, gasket and pitman shaft as an assembly.
  14.  
  15. Remove the pitman shaft from the side cover by unscrewing it.
  16.  
  17. Remove the housing end plug by removing the retaining ring. Use a punch inserted into the access hole to unseat the ring.
  18.  
  19. Remove the adjuster plug nut using a punch and hammer against the edge of the slots.
  20.  
  21. Remove the adjuster plug from the housing using tool J-7624.
  22.  
  23. Remove the thrust washer bearing retainer from the adjuster plug by using a suitable tool and prying at raised area of bearing retainer.
  24.  
  25. Remove the bearing spacer, races and thrust bearing. Remove the O-ring and retaining ring.
  26.  
  27. Remove the needle bearing, dust and lip seals using tool J-6221.
  28.  
  29. Remove the stub shaft and valve assembly from the housing.
  30.  
  31. Tap the stub shaft lightly on a block of wood to loosen the shaft cap.
  32.  
  33. Pull the cap and valve spool out from the valve body 1 / 4 in. (6mm) and disengage stub shaft pin from hole in valve spool.
  34.  
  35. Remove the valve spool from the valve body by pulling and rotating from the valve body. Remove the valve spool O-ring seal, the valve body teflon rings and O-ring seals.
  36.  
  37. Turn the stub shaft counterclockwise until the rack piston extends out of the housing.
  38.  
  39. Remove the rack piston end plug. Insert tool J-21552 into the bore of the rack piston. Hold the tool tight against the worm shaft while turning the stub shaft counterclockwise. This tool will force the rack piston onto the tool and hold the rack piston balls in place.
  40.  
  41. Remove the assembly from the housing.
  42.  
  43. Remove the worm shaft, thrust bearing and races.
  44.  
  45. Remove tool J-21552 from the rack piston. Remove the rack piston balls.
  46.  
  47. Remove the screws, clamp and ball guide from the rack piston.
  48.  
  49. Remove the teflon ring and O-ring seal from the rack piston.
  50.  
  51. Remove the steering gear check valve from the inlet and return lines of housing, as required.
  52.  

To install:
  1. Clean all parts in a suitable cleaner and lubricate with power steering fluid during assembly. Replace any worn bushings, bearings, races or seals.
  2.  
  3. Install the steering gear check valve from the inlet and return lines of housing, as required. Install the teflon ring and O-ring seal onto the rack piston.
  4.  
  5. Install the rack piston onto the worm shaft fully and align the worm shaft groove with the rack piston and align the worm shaft groove with the rack piston ball return guide hole. Install the black and silver balls alternately while turning the wormshaft counterclockwise. Install the remaining balls to the ball guide using grease to retain the balls.
  6.  
  7. Install the ball guide, clamp and screws onto the piston. Insert tool J-21552 onto the rack piston while turning the wormshaft counterclockwise.
  8.  
  9. Install the worm shaft, thrust bearing and races.
  10.  
  11. Install the assembly into the housing. Insert the worm shaft into the rack piston by holding tool J-21552 tightly against wormshaft and turning the stub shaft clockwise until rack piston is fully seated on worm shaft. Ensure the rack piston balls are installed properly.
  12.  
  13. Install the rack piston end plug and torque to 111 ft. lbs. (150 Nm).
  14.  
  15. Install the valve spool O-ring seal, the valve body teflon rings and O-ring seals.
  16.  
  17. Install the valve spool onto the valve body by pushing and rotating until hole in valve spool for stub shaft pin is accessible from the opposite end of the valve body.
  18.  
  19. The notch in the stub shaft cap must fully engage valve body pin and seat against valve body shoulder.
  20.  
  21. Install the stub shaft and valve assembly into the housing.
  22.  
  23. Install the needle bearing, dust and lip seals using tool J-6221.
  24.  
  25. The needle bearing must be installed with the identification on bearing facing the tool to prevent damaging the bearing.
  26.  
  27. Install the lip seal and dust seal onto the adjuster plug using tool J-6221. bearing spacer, races and thrust bearing. Install the O-ring and retaining ring.
  28.  
  29. Install the thrust washer bearing retainer onto the adjuster plug.
  30.  
  31. Install the adjuster plug onto the housing using tool J-7624. Use care not to damage the seals.
  32.  
  33. Install the adjuster plug nut.
  34.  
  35. Install the housing end plug and the retaining ring. Place the retaining ring with the open end approximately 1inch from the access hole in the housing.
  36.  
  37. Install the pitman shaft by screwing it into the cover until fully seated.
  38.  
  39. Install the side cover, new gasket and pitman shaft as an assembly.
  40.  
  41. Center the gear by turning the stub shaft.
  42.  
  43. Install the pitman shaft adjuster lock nut and cover bolts. Torque the cover bolts to 44 ft. lbs. (60 Nm).
  44.  
  45. Perform all gear adjustments as previously outlined.
  46.  
  47. Install the power steering gear as previously directed.
  48.  
  49. Connect the negative battery cable.
  50.  

 
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