GM Celebrity/Century/Ciera/6000 1982-1996 Repair Guide

Wheel Cylinders

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CAUTION
Brake shoes may 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



See Figures 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 and 11

  1. Loosen the wheel lug nuts. Raise and support the car, and remove the wheel. Remove the drum and brake shoes.
  2.  
  3. Remove any dirt from around the brake line fitting. Disconnect the brake line, then plug the opening to prevent fluid loss and contamination.
  4.  
  5. If the wheel cylinder is retained with bolts, simply remove the bolts. If retained with clips, remove the wheel cylinder retainer by using two awls or punches with a tip diameter of 1 / 8 in. (3mm) or less. Insert the awls or punches into the access slots between the wheel cylinder pilot and retainer locking tabs. Bend both tabs away simultaneously. Remove the wheel cylinder from the backing plate.
  6.  

To install:
  1. If retained with bolts, simply install wheel cylinder and tighten the bolts to 9-15 ft. lbs. (12-20 Nm). If retained with clips, position the wheel cylinder against the backing plate, then hold it in place with a wooden block between the wheel cylinder and the hub and bearing assembly.
  2.  



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Fig. Fig. 1: Two slightly different types of drum brake assemblies are used. This one uses a spring to secure the wheel cylinder ...



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Fig. Fig. 2: ... while this type uses bolts to secure the wheel cylinder



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Fig. Fig. 3: If you remove the hub, install two of the bolts to secure the backing plate



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Fig. Fig. 4: Special tools are available for disengaging the return springs



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Fig. Fig. 5: Remove the hold-down springs by pressing down and turning 90 degrees



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Fig. Fig. 6: Removing the actuator lever, pivot and the pivot return spring



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Fig. Fig. 7: Spread the shoes apart to clear the wheel cylinder pistons, then remove the parking brake strut and spring



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Fig. Fig. 8: Remove the brake shoes. Note the parking brake cable is still attached to the lever



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Fig. Fig. 9: Disconnecting the parking brake cable from the lever



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Fig. Fig. 10: Remove the C-clip from the parking brake lever using a small prytool



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Fig. Fig. 11: Measure the width of the linings, then measure the inside width of the drum

  1. Install a new retainer over the wheel cylinder abutment on the rear of the backing plate by pressing it into place with a 1 1 / 8 in. (1mm) 12-point socket and an extension.
  2.  
  3. Install a new bleeder screw into the wheel cylinder. Tighten the bleeder screw to 89 inch lbs. (10 Nm). Attach the brake line, then tighten to 10-15 ft. lbs. (14-20 Nm).
  4.  
  5. Install the brake shoes and drum. Adjust the brakes.
  6.  
  7. Install the tire and wheel assembly. Install the lug nuts hand-tight.
  8.  
  9. Lower the vehicle. Tighten the lug nuts to 100 ft. lbs. (136 Nm).
  10.  
  11. Bleed the brake system.
  12.  

OVERHAUL



See Figures 12, 13 and 14

As is the case with master cylinders, overhaul kits are available for the wheel cylinders, however it is usually more economical to simply buy new or rebuilt wheel cylinders rather rebuilding them yourself. When rebuilding wheel cylinders, avoid getting any contaminants in the system. Always use new high quality brake fluid; the use of improper fluid will swell and deteriorate the rubber parts.

  1. Remove the wheel cylinders.
  2.  
  3. Remove the rubber boots from the cylinder ends. Discard the boots.
  4.  



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Fig. Fig. 12: Remove the wheel cylinders, then remove the rubber boots from the cylinder ends.

  1. Remove the pistons and cups. Discard the cups.
  2.  



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Fig. Fig. 13: After the pistons are removed, the cup seals and spring can be removed

  1. Wash the cylinder and metal parts in denatured alcohol.
  2.  



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Fig. Fig. 14: Inspect the wheel cylinder for scoring, nicks, corrosion, and wear


WARNING
Never use mineral based solvents to clean the brake parts.

  1. Allow the parts to air dry and inspect the cylinder bore for corrosion or wear. Light corrosion can be cleaned up with crocus cloth. Use finger pressure and rotate the cloth around the circumference of the bore. Do not move the cloth in and out. Any deep corrosion, pitting or wear warrants replacement of the part(s).
  2.  
  3. Rinse the parts and allow to dry. Do not dry with a rag, which will leave bits of line behind.
  4.  
  5. Lubricate the cylinder bore with clean brake fluid. Insert the spring assembly.
  6.  
  7. Install new cups. Do not lubricate prior to assembly.
  8.  
  9. Install the pistons.
  10.  
  11. Press the new boots onto the cylinders by hand. Do not lubricate prior to assembly.
  12.  
  13. Install the wheel cylinder.
  14.  
  15. Install the brake shoes and drum. Adjust the brakes.
  16.  
  17. Install the tire and wheel assembly. Install the lug nuts.
  18.  
  19. Lower the vehicle. Tighten the lug nuts until snug.
  20.  
  21. Bleed the brake system.
  22.  

 
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