GM S10/S15/Sonoma Pick-Ups 1982-1993 Repair Manual

Lower Control Arm

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REMOVAL & INSTALLATION



2wd Vehicles

See Figure 1

  1. Remove the coil spring from the vehicle. For details, please refer to the procedure located earlier in this section.
  2.  
  3. If not done already, remove the tire and wheel assembly.
  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 upper joint/control arm. Use the tool to separate the 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: Lower control arm mounting-2wd vehicles

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. Also, support the lower control arm and guide it out of the opening in the splash shield.

  1. Remove the jam nuts from the back of each lower control arm pivot bolt.
  2.  
  3. Remove the pivot bolts (noting the direction in which they are facing), then remove the control arm from the vehicle.
  4.  
  5. If the bushings are beings replaced, use a suitable bushing service set to remove the bushings from the control arm. The front bushing is normally flared and the flare must be driven down flush with the rubber using a blunt chisel before attempting removal.
  6.  

To install:
  1. If the bushings were removed, use the bushing service set to install them to the control arms. If the front bushing is the flared type, use a flaring tool to produce an approximate flare of 45 degrees.
  2.  
  3. Position the control arm to the vehicle.
  4.  
  5. Install the pivot bolts as noted during removal. For most vehicles covered by this manual, that means they should be installed with the heads forward, facing the rear.
  6.  
  7. Install the jam nuts and tighten to 94 ft. lbs. (127 Nm) for the front nut on vehicles through 1992, and/or to 67 ft. lbs. for the rear nut on vehicles through 1992 or both nuts on 1993 vehicles.
  8.  
  9. 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 65 ft. lbs. (90 Nm) for vehicles through 1986 or to 61 ft. lbs. (83 Nm) for 1987-93 vehicles. Install a new cotter pin.
  10.  

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. Install the tire and wheel assembly.
  4.  
  5. Remove the jackstands and carefully lower the vehicle.
  6.  
  7. Check and adjust the front end alignment, as necessary.
  8.  

4wd Vehicles

See Figure 2

  1. Raise and support the front of the vehicle safely using jackstands.
  2.  
  3. Remove the tire and wheel assembly.
  4.  
  5. Remove the stabilizer bar. For details, please refer to the procedures earlier in this section. Installation of the stabilizer bar will require use of a torsion bar unloader tool.
  6.  
  7. Remove the shock absorber.
  8.  



Click image to see an enlarged view

Fig. Fig. 2: Lower control arm mounting-early model 4wd vehicles (late model similar)

  1. Remove the lower control arm-to-frame nuts, then withdraw the bolts, noting the direction they were facing for installation purposes. Remove the lower control arm from the truck.
  2.  
  3. If necessary, use a suitable bushing service set to remove the bushings from the lower control arm.
  4.  

To install:
  1. If removed, use the service set to install new bushings to the lower control arm.
  2.  
  3. Position the control arm in the vehicle, installing the front leg of the lower control arm into the crossmember before installing the rear leg into the frame bracket.
  4.  
  5. Insert the control arm retaining bolts in the direction noted during removal. For most vehicles, they should be inserted from the rear of the truck facing forward. On vehicles through 1992 the bolts may be threaded into a fitting on the frame/crossmember, if so they should be tightened to 148 ft. lbs. (200 Nm) while the suspension is at normal trim height.
  6.  

When tightening the lower control arm fasteners for these vehicles, the suspension must be held at normal trim height. This can be accomplished in various ways, including using a floor jack or jackstands to support the control arm at the proper height or loosely tightening the fasteners, installing the remaining components and placing the vehicle's weight on the wheels. If the second option is chosen, make sure the fasteners are tightened sufficiently to prevent components from pulling apart while the vehicle is supported by the wheels. Also, for safety should components come loose, position jackstands under the vehicle, in contact with the suspension but not taking any significant weight away from the wheels.

  1. Install the lower control arm retaining nuts and tighten them with the suspension at normal trim height to 92 ft. lbs. (125 Nm) for vehicles through 1992 or to 70 ft. lbs. (95 Nm) for 1993 vehicles.
  2.  
  3. Install the shock absorber.
  4.  
  5. Properly unload the torsion bar, then install the stabilizer bar. Adjust the torsion bar, as necessary. For details, please refer to the procedures located earlier in this section.
  6.  
  7. Install the tire and wheel assembly.
  8.  
  9. Remove the jackstands and carefully lower the vehicle.
  10.  

 
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