GM Storm/Spectrum 1985-1993 Repair Guide

Brake Drums

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CAUTION
Brake shoes contain asbestos, which has been determined to be a cancer causing agent. Never clean the brake surfaces with compressed air! Avoid inhaling any dust from any brake surface! When cleaning brake surfaces, use a commercially available brake cleaning fluid.

REMOVAL & INSTALLATION



Spectrum

See Figure 1

  1. Raise and safely support the vehicle.
  2.  



Click image to see an enlarged view

Fig. Fig. 1: Drum and hub assembly - Spectrum

  1. Remove the rear wheel and tire assembly.
  2.  
  3. Remove the dust cap and cotter pin. Remove the hub nut, washer and outer wheel bearing.
  4.  
  5. Remove the brake drum/hub assembly with the inner wheel bearing.
  6.  
  7. Installation is the reverse of the removal procedure. Check the clearance between the brake shoes and the drum. Properly adjust the wheel bearings as follows:
    1. Torque hub nut to 22 ft. lbs. (29 Nm) while rotating the hub assembly.
    2.  
    3. Completely loosen the hub nut.
    4.  
    5. Tighten hub nut finger tight.
    6.  

  8.  
  9. Install a NEW cotter pin, after adjustment. If the cotter pin holes are out of line, use a wrench to tighten the nuts just enough to align the cotter pin holes.
  10.  
  11. Apply grease to the inner area of the hub dust cap and install.
  12.  

Storm
  1. Raise and safely support the vehicle.
  2.  
  3. Remove the rear wheel and tire assembly.
  4.  

If necessary, insert a brake spoon or equivalent through the hole in the backing plate and hold the automatic adjusting lever away from the adjusting bolt. Use another brake spoon or equivalent, and reduce the brake shoe adjustment by turning the adjusting bolt.

  1. Remove the brake drum.
  2.  
  3. Installation is the reverse of the removal procedure. Adjust the rear brake, if necessary.
  4.  

INSPECTION

Pulsation in the brake pedal is usually corrected by servicing the front brake system. Service the rear brake system only if the problem persists.

  1. Remove the brake drum and clean it thoroughly.
  2.  
  3. Inspect the drum for scoring, cracks, grooves and out-of-roundness. Replace or refinish the brake drum, as required. Light scoring may be removed by dressing the drum with fine grit emery cloth. Heavy scoring will require the use of a brake drum lathe to turn or refinish the brake drum.
  4.  
  5. Using J 22364-01 drum-to-shoe clearance gauge or equivalent, measure the inside diameter of the brake drum.
  6.  

Measuring a brake drum for out-of-round, taper and wear it can be accurately measured with an inside surface and at right angles to each other.

  1. On Spectrum models, the standard inside diameter is 7.09 in. (180mm). The maximum inside diameter is 7.14 in. (181.4mm). If the brake drum exceeds the maximum diameter, replace it.
  2.  
  3. On Storm models, the standard inside diameter is 7.87 in. (200mm). The maximum inside diameter is 7.93 in. (201.4mm). If the brake drum exceeds the maximum diameter, replace it.
  4.  
  5. During manufacture, weights are used to balance brake drums. These weights must not be removed. Replace the brake drum if weights are missing.
  6.  

 
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