GM Prizm/Nova 1985-1993 Repair Guide

Brake Shoes

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INSPECTION



See Figure 1

An inspection hole is provided in the backing plate of each rear wheel which allows the brakes to be checked without removing the drum. Remove the hole plug and check the lining thickness through the hole. If below minimum, the shoes will need replacement. Always replace the plug after checking and make certain it is properly seated and tight.



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Fig. Fig. 1: One brake shoe on each rear wheel can be check through the inspection hole, but complete inspection requires removing the brake drums

It should be obvious that this method doesn't provide a lot of information about how the brakes are wearing since it only shows one part of one shoe, but is a quick and easy first check. The only way to see the friction faces of the shoes is to remove the brake drums. No generalities can be drawn between the left and right side shoes, so both drums must be removed to perform a proper inspection.

With the drums removed:


CAUTION
Brake pads and 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 brake surfaces! When cleaning brakes, use commercially available brake cleaning fluids.

  1. Liberally spray the entire brake assembly with aerosol brake cleaner. Do not use other solvents, compressed air or a dry brush.
  2.  
  3. Measure the thickness of the friction surface on each shoe at several different locations. If any measurement is below the minimum thickness, replace all the shoes as a set.
  4.  
  5. Check the contact surfaces closely for any signs of scoring, cracking, uneven or tapered wear, discoloration or separation from the backing plate. Anything that looks unusual requires replacement.
  6.  
  7. If the shoes are in otherwise good condition except for glazing (a shiny, hard surface), the glaze may be removed by light sanding with emery cloth. Also lightly sand the inside of the drum to de-glaze its surface. Do not attempt to rub out grooves or ridges; this is best done with a resurfacing lathe. After sanding the components wash them thoroughly with aerosol brake cleaner to remove any grit.
  8.  

REMOVAL & INSTALLATION



See Figures 2 through 17

The brake shoes can be removed and replaced using everyday hand tools, but the use of brake spring tools and assorted specialty tools makes the job much easier. These common brake tools are available at low cost and can greatly reduce working time.

  1. Elevate and safely support the vehicle. If only the rear wheels are elevated, block the front wheels with chocks. Once the vehicle is firmly on stands, release the parking brake.
  2.  
  3. Remove the rear wheel.
  4.  
  5. Make an index mark showing the relationship between 1 wheel lug and 1 hole in the drum. This will allow the drum to be reinstalled in its original position.
  6.  
  7. Tap the drum with a rubber mallet or wooden hammer handle. Remove the brake drum. It will not come off if the parking brake is applied. If the brake drum cannot be removed easily:
    1. Insert a screwdriver through the hole in the backing plate and hold the adjusting lever away from the star wheel.
    2.  
    3. Using another screw driver or a brake adjusting tool, turn the star wheel to reduce the tension (increase the clearance) on the brake shoes.
    4.  

  8.  


WARNING
Do not apply the brake pedal while the drum is removed.

  1. Remove the return spring.
  2.  
  3. Disconnect and remove the retainers, hold down springs and pins.
  4.  
  5. Remove the anchor spring.
  6.  
  7. Use a pair of pliers to disconnect the parking brake cable from the parking brake lever.
  8.  
  9. Remove the adjusting lever spring.
  10.  
  11. Remove the shoes and adjuster as a unit.
  12.  
  13. Disassemble the adjustor, the parking brake lever and the automatic adjuster lever. The C washer holding the shoe to the adjuster may need to be spread a little before removal.
  14.  
  15. Clean all the parts with aerosol brake solvent. Do not use other solvents.
  16.  
  17. Closely inspect all the parts. Any part of doubtful strength or quality must be replaced.
  18.  

To install:
  1. Before reinstallation, apply high-temperature grease to the points at which the brake shoes contact the backing plate and to both the contact and pivot points on the adjuster strut.
  2.  
  3. Install the parking brake lever and automatic adjusting lever to the rear (trailing) shoe.
  4.  
  5. Install a new C-washer and use pliers to close it. Do not bend it more than necessary to hold in place.
  6.  
  7. Install the adjuster (strut) and return spring in place on the rear shoe and install the adjusting lever spring.
  8.  
  9. Using pliers, connect the parking brake cable to the lever.
  10.  


WARNING
Do not allow oil or grease to get on the lining surface.



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Fig. Fig. 2: Rear brake components



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Fig. Fig. 3: Backing off the adjuster



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Fig. Fig. 4: After backing off the adjuster remove the brake drum

  1. Pass the parking brake cable through the notch in the anchor plate.
  2.  
  3. Set the rear shoe in place with the end of the shoe inserted in the wheel cylinder and the adjuster in place.
  4.  
  5. Install the hold-down spring, retainers and pin.
  6.  
  7. Install the anchor spring between the front (leading) and rear shoe.
  8.  



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Fig. Fig. 5: Liberally spray the entire brake assembly with aerosol brake cleaner. Do not use other solvents, compressed air or a dry brush and always spray in a well ventilated area



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Fig. Fig. 6: Removing the return spring with a T-shaped brake spring tool



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Fig. Fig. 7: Use a pair of pliers and release the retainers on the hold down springs and pins

  1. Position the front shoe with the end of the shoe inserted in the wheel cylinder and the adjuster in place.
  2.  
  3. Install the hold-down spring, retainers and pin.
  4.  
  5. Connect the return spring.
  6.  



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Fig. Fig. 8: After releasing the retainer with the pliers remove the retainers, hold down springs and pins



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Fig. Fig. 9: Removing the adjusting lever spring



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Fig. Fig. 10: Removing the hold down spring and pin and removing the shoe



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Fig. Fig. 11: Disconnect the parking brake cable and remove the shoe and parking brake lever

  1. Measure both the brake diameter and the drum diameter as explained in Adjustments and adjust the brake shoes to the proper clearance.
  2.  
  3. Install the drum. Install the wheel.
  4.  
  5. Lower the car to the ground.
  6.  
  7. While not absolutely required, bleeding the brakes is recommended after replacing shoes.
  8.  



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Fig. Fig. 12: Exploded view of the rear brake components



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Fig. Fig. 13: Areas to be lubricated during reassembly



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Fig. Fig. 14: Installing the C-washer



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Fig. Fig. 15: Installing the return spring



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Fig. Fig. 16: Adjust the strut length to the shortest possible amount



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Fig. Fig. 17: Bleeding the rear brakes

 
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