GM Full-Size Trucks 1988-1998 Repair Information

Upper Control Arm and Bushings-C-Series

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REMOVAL & INSTALLATION



See Figure 1

  1. Raise and support the truck on jackstands.
  2.  



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Fig. Fig. 1: Installing the upper control arm-C-Series

  1. Support the lower control arm with a floor jack.
  2.  
  3. Remove the wheel.
  4.  
  5. Remove the air cleaner extension (if necessary).
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  7. Unbolt the brake hose bracket from the control arm.
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  9. Remove the cotter pin from the upper control arm ball stud and loosen the stud nut until the bottom surface of the nut is slightly below the end of the stud.
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  11. Install a spring compressor on the coil spring for safety.
  12.  
  13. Using a screw-type forcing tool, break loose the ball joint from the knuckle.
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  15. Remove the nuts and bolts securing the control arm to the frame brackets.
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  17. Tape the shims and spacers together and tag for proper reassembly. The 35 Series bushings are replaceable. The 15/25 Series bushings are welded in place.
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To install:

Installation is the reverse of removal but please note the following important steps.

  1. Place the control arm in position and install the shims, bolts and new nuts. Both bolt heads must be inboard of the control arm brackets. Tighten the nuts finger tighten for now.
  2.  

Do not tighten the bolts yet. The bolts must be torqued with the truck at its proper ride height.

  1. Install the ball stud nut. Tighten the nut to specification.
  2.  
  3. Lower the truck. Once the weight of the truck is on the wheels:
    1. Lift the front bumper about 38mm and let it drop.
    2.  
    3. Repeat this procedure 2 or 3 more times.
    4.  
    5. Draw a line on the side of the lower control arm from the centerline of the control arm pivot shaft, dead level to the outer end of the control arm.
    6.  
    7. Measure the distance between the lowest corner of the steering knuckle and the line on the control arm. Record the figure.
    8.  
    9. Push down about 38mm on the front bumper and let it return. Repeat the procedure 2 or 3 more times.
    10.  
    11. Re-measure the distance at the control arm.
    12.  
    13. Determine the average of the 2 measurements. The average distance should be 95.0mm plus or minus 6mm.
    14.  
    15. If the figure is correct, tighten the control arm pivot nuts to 88 ft. lbs. (120 Nm) on 1988-90 models; 140 ft. lbs. (190 Nm) on 1991-98 models.
    16.  
    17. If the figure is not correct, tighten the pivot bolts to 88 ft. lbs. (120 Nm) on 1988-90 models; 140 ft. lbs. (190 Nm) on 1991-98 models and have the front end alignment corrected.
    18.  

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