GM S-Series Pick-ups and SUV's 1994-1999 Repair Guide

Upper Control Arm and Bushing

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REMOVAL & INSTALLATION



2WD Vehicles

See Figures 1, 2 and 3

The following procedure requires the use of a ball joint separator tool such as J-23742 or equivalent.

  1. Raise and support the front of the vehicle safely by placing jackstands securely under the lower control arms. Because the vehicle's weight is used to relieve spring tension on the upper control arm, the floor stands must be positioned between the spring seats and the lower control arm ball joints for maximum leverage.
  2.  


CAUTION
With components unbolted, the jackstand is holding the lower control arm in place against the coil spring. Make sure the jackstand is firmly positioned and cannot move, or personal injury could result.

  1. Remove the tire and wheel assembly.
  2.  
  3. If equipped, remove the ABS wire and brake hose bracket(s) from the upper control arm.
  4.  
  5. Remove the brake caliper and support it from the vehicle using a coat hanger or wire. Make sure the brake line is not stretched or damaged and that the caliper's weight is not supported by the line.
  6.  
  7. Remove the cotter pin and retaining nut from the upper ball joint.
  8.  
  9. Position J-23742 or an equivalent ball joint separator tool between upper joint stud and the lower joint/control arm. Use the tool to separate the upper ball joint from the steering knuckle. Pull the steering knuckle free of the ball joint after removal.
  10.  



Click image to see an enlarged view

Fig. Fig. 1: Upper control arm mounting-2WD vehicles



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Fig. Fig. 2: Exploded view of the upper control arm and bushing components

After separating the steering knuckle from the upper ball joint, be sure to support the steering knuckle/hub assembly to prevent damaging the brake hose.

Before and during removal of the control arm-to-frame nuts and bolts, note the location of any shims.

  1. Unfasten the upper control arm-to-frame nuts and bolts, then lift and remove the upper control arm from the vehicle.
  2.  
  3. Clean and inspect the steering knuckle hole. Replace the steering knuckle if any out of roundness is noted.
  4.  
  5. If replacement is necessary, mount the control arm in a vise, then remove the pivot shaft nuts and washers. Use a control arm bushing fixture (C-clamp like tool) along with a slotted washer and a piece of pipe (slightly larger than the bushing) to remove the old bushings.
  6.  

To install
  1. If removed, position the pivot shaft to the control arm and install the bushing using the fixture tool, washer and a length of pipe with the same outer diameter as the bushing.
  2.  
  3. Tighten the tool until the bushing is positioned on the shaft as shown in the illustration. Loosely install the bushing retaining nuts and washers. Tighten the bushing nuts to 85 ft. lbs. (115 Nm).
  4.  



Click image to see an enlarged view

Fig. Fig. 3: Upper control arm bushing installation-2WD vehicles

  1. Loosely install the control arm to the frame using the bolts and nuts. Position the shims as noted during removal, then tighten the retainers to 67 ft. lbs. (90 Nm) on 1994-95 models and 85 ft. lbs. (115 Nm) on 1996-99 models.
  2.  

On most vehicles, the left upper control arm shaft must have the depression facing inboard.

  1. Remove the support from the steering knuckle, then install the ball joint to the knuckle. Make sure the joint is seated, then install the stud nut. Install a new cotter pin.
  2.  

When installing the cotter pin, never loosen the castle nut to expose the cotter pin hole.

  1. Reposition and secure the brake caliper.
  2.  
  3. If equipped, attach the ABS wire and brake hose bracket(s) from the upper control arm.
  4.  
  5. Install the tire and wheel assembly.
  6.  
  7. Remove the jackstands and carefully lower the vehicle.
  8.  
  9. Check and adjust the front end alignment, as necessary.
  10.  

4WD Vehicles

See Figures 4, 5 and 6

  1. Raise and support the front of the vehicle safely using jackstands.
  2.  
  3. Remove the tire and wheel assembly.
  4.  
  5. Remove the cotter pin from the ball joint, then loosen the retaining nut.
  6.  

After separating the steering knuckle from the upper ball joint, be sure to support the steering knuckle/hub assembly to prevent damaging the brake hose.

  1. Position a suitable ball joint separator tool such as J-36607 or equivalent, then carefully loosen the joint in the steering knuckle. Disengage the tool and the retaining nut, then remove the joint from the knuckle.
  2.  

The 4WD vehicles covered by this information do not use shims to adjust the front wheel alignment. Instead, the upper control arm bolts are equipped with cams, which are rotated to achieve caster and camber adjustments. In order to preserve adjustment and ease installation, matchmark the cams to the control arm before removal. If the control arm is being replaced, transfer the alignment marks to the new component before installation.

  1. Unfasten the front and rear nuts retaining the control arm retaining bolts to the frame, then remove the outer cams from the bolts.
  2.  



Click image to see an enlarged view

Fig. Fig. 4: Exploded view of the upper control arm mounting-4WD vehicles



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Fig. Fig. 5: Matchmark the cams to the control arm before removal.



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Fig. Fig. 6: Loosen the end retaining nuts from the upper control arm bolts

  1. Remove the bolts and inner cams, then remove the control arm from the vehicle.
  2.  
  3. If necessary, remove the retaining nut and the bumper from the control arm.
  4.  
  5. If the bushings are being replaced, use a suitable bushing service set to remove the bushings from the arm.
  6.  

To install:
  1. If removed, use the bushing service set to drive the new bushings into the control arm.
  2.  
  3. If removed, install the bumper and retaining nut to the control arm. Tighten the bumper retaining nut to 20 ft. lbs. (27 Nm).
  4.  
  5. Position the control arm to the vehicle, then install the retaining bolts (from the inside of the frame brackets facing outward) and the inner cams. The inner cams must be positioned on the bolts before they are inserted through the control arm and frame brackets.
  6.  
  7. Position the outer cams over the retaining bolts, then install the nuts to the ends of the bolts at the front and rear of the control arm.
  8.  
  9. Align the cams to the reference marks made earlier, then tighten the end nuts to 70 ft. lbs. (95 Nm) on 1994 models. On 1995-99 models tighten the nuts to 85 ft. lbs. (115 Nm).
  10.  
  11. Remove the support from the steering knuckle, then install the ball joint to the knuckle. Make sure the joint is seated, then install the stud nut and tighten to 70 ft. lbs. (95 Nm) on 1994 models and 61 ft. lbs. (83 Nm) on 1995-99 models. Install a new cotter pin.
  12.  

When installing the cotter pin, never loosen the castle nut to expose the cotter pin hole, but DO NOT tighten more than an additional1/6turn.

  1. Install the tire and wheel assembly.
  2.  
  3. Remove the jackstands and carefully lower the vehicle.
  4.  
  5. Check and adjust the front end alignment, as necessary.
  6.  

 
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