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

Ball Joints

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INSPECTION



See Figures 1, 2, 3 and 4

Before performing this inspection, make sure that the wheel bearings are adjusted correctly and that the control arm bushings are in good condition.

  1. Make sure the vehicle is parked on a level surface.
  2.  
  3. Raise and support the front of the vehicle safely by placing jackstands under each lower control arm as close as possible to each lower ball joint (as far outboard as possible). Make sure that the vehicle is stable and the control arm bumpers are not contacting the frame.
  4.  
  5. Wipe the ball joints clean and check the seals for cuts or tears. If a seal is cut or torn, then ball joint MUST be replaced.
  6.  
  7. If necessary on 2wd vehicles, adjust the wheel bearings before proceeding.
  8.  



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Fig. Fig. 1: Check total ball joint horizontal deflection by rocking the wheel (a dial indicator is used to measure play)

  1. Check the ball joints for horizontal deflection (looseness):
    1. Position a dial indicator against the lowest outboard point on the rim.
    2.  
    3. Grasp the tire (top and bottom), then pull outward on the top and push inward on the bottom; record the reading on the dial indicator.
    4.  
    5. Grasp the tire (top and bottom), then pull outward on the bottom and push inward on the top; record the reading on the dial indicator.
    6.  
    7. The difference in the dial indicator reading is the horizontal deflection of both joints. If the reading exceeds 0.110 in. (3.2mm), the lower ball joint should be checked for wear in order to determine what component(s) must be replaced.
    8.  

  2.  

The lower ball joints used on 2wd vehicles use wear indicators.

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Fig. Fig. 2: A dial indicator may also be used to check lower joint vertical deflection



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Fig. Fig. 3: Use a prybar to carefully pry between the lower control arm and outer race (NOT on the drive axle joint/seal)

  1. On 4wd vehicles (no wear indicators), check the lower ball joint for wear:
    1. With the vehicle still supported by jackstands, place a dial indicator against the spindle in order to measure vertical movement.
    2.  

  2.  

DO NOT pry between the lower control arm and the drive axle seal or damage to the seal will result.

    1. Pry between the lower control arm and the outer bearing race while reading the dial indicator. This reading will show vertical deflection (looseness).
    2.  
    3. The lower ball joint is not a pre-loaded joint and may show some looseness, but it should be replaced if movement exceeds 0.110 in. (3.2mm).
    4.  




Click image to see an enlarged view

Fig. Fig. 4: The lower joints on late model 2wd vehicles are equipped with wear indicators

  1. For 2wd vehicles check for lower ball joint wear using the indicators:
    1. Visually inspect the positioning of the grease fitting on the ball joint. The fitting is threaded into a small housing nub which projects approximately 0.050 in. (1.12mm) beyond the surface of the ball joint cover on new parts. As the joint wears, the nub will slowly retreat inward. If the housing nub is visible above the cover, then the joint is still good.
    2.  
    3. If necessary, scrape a screwdriver or fingernail across the ball joint cover and feel for the housing nub. If the housing is flush or inside the cover surface, the joint is worn and should be replaced.
    4.  

  2.  
  3. Finally, if the joints failed the initial combined test, but the lower joint is found good, the upper ball joint should be checked for looseness as it is probably the culprit:
    1. Disconnect the upper ball joint from the steering knuckle.
    2.  
    3. Check for any looseness or if the stud can be twisted by hand. If so, the joint should be replaced.
    4.  

  4.  

REMOVAL & INSTALLATION



2wd Vehicles

UPPER

See Figures 5, 6, 7, 8 and 9

The following procedure requires the use of a ball joint separator tool such as GM No. J-8742 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. 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.
  4.  
  5. Remove the cotter pin and retaining nut from the upper ball joint.
  6.  
  7. Position J-8742 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.
  8.  



Click image to see an enlarged view

Fig. Fig. 5: Use a ball joint separator tool to drive the upper ball joint from the steering knuckle.

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. Remove the riveted upper ball joint from the upper control arm:
    1. Drill a 1/8 in. (3mm) hole, about 1/4 in. (6mm) deep into each rivet.
    2.  
    3. Then use a 1/2 in. (13mm) drill bit, to drill off the rivet heads.
    4.  
    5. Using a pin punch and the hammer, drive out the rivets in order to free the upper ball joint from the upper control arm assembly, then remove the upper ball joint.
    6.  

  2.  



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Fig. Fig. 6: Drill a small guide hole into each ball joint rivet.



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Fig. Fig. 7: Then drill off the rivet heads.



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Fig. Fig. 8: Punch the rivets out and remove the ball joint.

  1. Clean and inspect the steering knuckle hole. Replace the steering knuckle if the hole is out of round.
  2.  

To install:

  1. Position the joint in the upper control arm, then install the joint retaining nuts and bolts. Position the bolts threaded upward from under the control arm. Tighten the ball joint retainers to 2 ft. lbs. (8 Nm).
  2.  



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Fig. Fig. 9: Service ball joints are bolted to the control arm.

  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 and tighten to 65 ft. lbs. (90 Nm) for vehicles through 486 or to 61 ft. lbs. (83 Nm) for 487-93 vehicles. Install a new cotter pin.
  2.  

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

  1. If not installed already, thread the grease fitting into the ball joint. Use a grease gun to lubricate the upper ball joint.
  2.  
  3. Reposition and secure the brake caliper.
  4.  
  5. Reposition and secure the brake caliper.
  6.  
  7. Remove the jackstands and carefully lower the vehicle.
  8.  
  9. Check and adjust the front end alignment, as necessary.
  10.  

LOWER

See Figures 10, 11, 12, 13 and 14

The following procedure requires the use of a ball joint remover/installer set (the particular set may vary upon application but must include a clamping-type tool with the appropriately sized adapters) and a ball joint separator tool, such as J-8742 or equivalent.

  1. Raise and support the front of the vehicle safely using jackstands under the frame so the control arms hang free.
  2.  
  3. Remove the tire and wheel assembly.
  4.  
  5. Position a floor jack under the spring seat of the lower control arm, then raise the jack to support the arm.
  6.  

The floor jack MUST remain under the lower control arm, during the removal and installation procedures, to retain the arm and spring positions.Make sure the jack is securely positioned and will not slip or release during the procedure or personal injury may result.

  1. Remove the brake caliper and support it aside using a hanger or wire. Make sure the brake line is not stressed or damaged.
  2.  



Click image to see an enlarged view

Fig. Fig. 10: Use a ball joint separator to drive the lower joint from the knuckle

  1. Remove and discard the lower ball joint cotter pin, then loosen and remove the stud nut.
  2.  
  3. Position J-8742 or an equivalent ball joint separator tool between lower joint stud and the upper joint/control arm. Use the tool to separate the lower ball joint from the steering knuckle.
  4.  
  5. Carefully guide the lower control arm out of the opening in the splash shield using a putty knife. Position a block of wood between the frame and upper control arm to keep the knuckle out of the way.
  6.  
  7. Remove the grease fitting from the control arm.
  8.  



Click image to see an enlarged view

Fig. Fig. 11: Press the lower joint from the control arm-early model tool set shown.



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Fig. Fig. 12: Driving the lower joint from the control arm-Late model tool set.

  1. Use the ball joint remover set along with the appropriate adapters to drive the ball joint from the control arm.
  2.  

To install:

  1. Clean the tapered hole in the steering knuckle of any dirt or foreign matter, then check the hole to see if it is out of round, deformed or otherwise damaged. If a problem is found, then knuckle must be replaced.
  2.  
  3. Using a suitable installation set, press the new ball joint until it bottoms in the control arm. Make sure the grease seal is facing inboard.
  4.  



Click image to see an enlarged view

Fig. Fig. 13: Installing a new ball joint-early model.



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Fig. Fig. 14: Installing a new ball joint-late model.

  1. Position the ball joint stud into the steering knuckle, then install the retaining nut and tighten to 90 ft. lbs. (15 Nm) for vehicles through 488 or to 83 ft. lbs. (113 Nm) for 489-93 vehicles. Install a new cotter pin.
  2.  

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

  1. If not installed already, thread the grease fitting into the ball joint, then use a grease gun to lubricate the joint.
  2.  
  3. Reposition and secure the brake caliper.
  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 6, 7, 8, 9 and 15

On 4wd vehicles both the upper and lower ball joints are removed in the same manner. Once the joint is separated from the steering knuckle the rivets are drilled and punched to free the joint from the control arm. Service joints are bolted into position with the retaining bolts threaded upward from beneath the control arm. In this manner, the joint is replaced in an almost identical fashion to the upper joints on 2wd vehicles.

  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.  



Click image to see an enlarged view

Fig. Fig. 15: Position the separator tool over the ball joint, then back the off the nut to force the ball stud out of the knuckle

  1. Position a suitable ball joint separator tool such as J-34011, or equivalent, then carefully loosen the joint in the steering knuckle. Remove the tool and the retaining nut, then remove the joint from the knuckle.
  2.  

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. Remove the riveted ball joint from the control arm:
    1. Drill a 1/8 in. (3mm) hole, about 1/4 in. (6mm) deep into each rivet.
    2.  
    3. Then use a 1/2 in. (13mm) drill bit, to drill off the rivet heads.
    4.  
    5. Using a pin punch and the hammer, drive out the rivets in order to free the ball joint from the control arm assembly, then remove the ball joint.
    6.  

  2.  

To install:

  1. Position the joint in the control arm, then install the joint retaining nuts and bolts. Position the bolts threaded upward from under the control arm. Tighten the ball joint retainers to 2 ft. lbs. (8 Nm).
  2.  
  3. 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). Install a new cotter pin.
  4.  

When installing the cotter pin, never loosen the castle nut to expose the cotter pin hole, but DO NOT tighten more than an additional 1/6 turn.

  1. Use a grease gun to lubricate the upper ball joint.
  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.  

 
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