GM Chevy Mid-Size Cars 1964-1988 Repair Guide

Caliper

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CAUTION
Brake pads 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 and 6

  1. Raise the front of the vehicle and support safely using jackstands.
  2.  
  3. Remove the tire and wheel assembly from the side on which the caliper is being removed.
  4.  
  5. Disconnect the brake hose from the caliper. Tape or cap the end of the line to prevent system contamination or excessive fluid loss.
  6.  
  7. On 1968 and earlier vehicles, remove the cotter pin from the brake pad and retaining pin, then remove the pin. Then, remove the brake pads and identify them as inboard or outboard if they are being reused.
  8.  
  9. If applicable, remove the U-shaped retainer from the hose fitting and pull the hose from the bracket.
  10.  
  11. Remove the two caliper retaining bolts, then remove the caliper from its mounting bracket. For 1969 and later vehicles, the brake pads will be removed with the caliper, if necessary, separate them from the caliper assembly.
  12.  

To install:
  1. If removed on 1969 and later vehicle, install the brake pads to the caliper.
  2.  
  3. Install the caliper to the mounting bracket and secure using the retaining bolts.
  4.  
  5. Remove the cap or tape, then install the brake hose into the caliper, passing the female end through the support bracket.
  6.  
  7. If applicable, install the hose fitting into the support bracket and install the U-shaped retainer.
  8.  
  9. Turn the steering wheel from side to side to make sure that the hose doesn't interfere with the tire. If it does, turn the hose end one or two points in the bracket until the interference is eliminated.
  10.  
  11. For 1968 and earlier vehicles, install the brake pads, retainer pin and cotter pin.
  12.  
  13. Properly refill and bleed the hydraulic brake system. Be sure to check the brake line for leaks.
  14.  
  15. Install the wheel, then remove the jackstands and lower the vehicle. Do not attempt to move the vehicle until a firm brake pedal has been obtained.
  16.  



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Fig. Fig. 1: The tire and wheel assembly must be removed to access the caliper



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Fig. Fig. 2: Loosen and disconnect the brake line fitting at the caliper



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Fig. Fig. 3: Most caliper brake lines fittings consist of a banjo bolt, fitting and washer(s)



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Fig. Fig. 4: A banjo fitting may be capped using a C-clamp a 2 smooth, flat pieces of plastic or rubber



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Fig. Fig. 5: Remove the caliper mounting bolts



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Fig. Fig. 6: Remove the caliper from the mounting bracket and brake rotor

OVERHAUL



1966-68
  1. Remove the caliper assembly from the vehicle.
  2.  
  3. Separate the caliper halves. Remove the two O-rings from the fluid transfer holes in the caliper.
  4.  
  5. Push the piston all the way down into the caliper. Using the piston as a fulcrum, place a screwdriver under the steel ring in the boot and carefully pry the boot from the caliper half.
  6.  
  7. Remove the pistons and springs, being careful not to damage the seal.
  8.  
  9. Remove the boot and seal from the piston.
  10.  
  11. Clean all metal components with clean brake fluid or denatured alcohol.
  12.  


WARNING
Do not use gasoline, kerosene, or any other mineral based solvent for cleaning. These solvents form an oily film on the parts which leads to fluid contamination and the deterioration of rubber parts.

  1. Blow out all fluid passages using compressed air.
  2.  
  3. Discard and replace all rubber parts.
  4.  
  5. Inspect all bores for scoring and pitting and replace is necessary. Minor flaws can be removed with very fine crocus cloth but do so with a circular motion.
  6.  
  7. Using a feeler gauge, check the clearance of the piston in its bore. If the bore is not damaged and the clearance exceeds the maximum limit below, then the piston must be replaced.

    For a 2 1 / 16 in. diameter, there should be a 0.0045-0.0100 in. clearance.
     
    For a 1 7 / 8 in. diameter, there should be a 0.0045-0.0100 in. clearance.
     
    For a 1 3 / 8 : in. diameter, there should be a 0.0035-0.0090 in. clearance.
     

  8.  
  9. Insert the seal in the piston groove nearest the flat end of the piston. The seal lip must face the large end of the piston. The lips must be in the groove and may not extend beyond.
  10.  
  11. Place the spring in the piston bore.
  12.  
  13. Coat the seal with clean brake fluid.
  14.  
  15. Install the piston assembly into the bore, being careful not to damage the seal lip on the edge of the bore.
  16.  
  17. Install the boot into the piston groove closest to the concave end of the piston.
  18.  
  19. The fold in the boot must face the seal end of the piston.
  20.  
  21. Push the pistons to the bottom of the bore and check for smooth piston movement. The end of the piston must be flush with the end of the bore. If it is not, check the installation of the seal.
  22.  
  23. Seat the piston boot so that its metal ring is even in the counterbore. The ring is even in the counterbore. The ring must be flush or below the machined face of the caliper. If the ring is seated unevenly dirt and moisture could get into the bore.
  24.  
  25. Insert the O-rings around the fluid transfer holes at both ends of the caliper halves.
  26.  
  27. Lubricate the bolts with brake fluid, connect the caliper halves, and tighten the bolts securely.
  28.  
  29. Make sure the pistons are fully retracted, then mount the caliper over the disc. Be careful not to damage the piston boots on the edge of the disc.
  30.  
  31. Install the two mounting bolts and tighten them securely, then finish caliper installation.
  32.  

1969 and Later

See Figures 7, 8, 9, 10, 11 and 12

  1. Clean the outside of the caliper with denatured alcohol.
  2.  
  3. Remove the caliper from the vehicle.
  4.  
  5. If not done already, remove the outboard and inboard shoes from the caliper assembly.
  6.  
  7. Drain any remaining brake fluid from the caliper.
  8.  



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Fig. Fig. 7: Exploded view of a common single piston caliper assembly

  1. Place clean rags inside the caliper opening to catch the piston when it is released.
  2.  
  3. Apply compressed air to the caliper fluid inlet hole and force the piston out of its bore. Do not blow the piston out; use just enough pressure to inch it out.
  4.  
  5. Use a small screwdriver to carefully pry the boot out of the caliper. Take great care to avoid scratching or otherwise damaging the bore.
  6.  
  7. Remove the piston seal from its groove in the caliper bore. Do not use a metal tool of any type for this operation.
  8.  

Replace (do not reuse) the boot, piston seal, rubber bushings, and sleeves.

  1. Blow out all passages in the caliper and bleeder valve. Clean the piston and piston bore with fresh brake fluid.
  2.  
  3. Examine the piston for scoring, scratches, or corrosion. If any of these conditions exist, the piston must be replaced because it is plated and cannot be refinished.
  4.  
  5. Examine the bore for the same defects. Light rough spots may be removed by rotating crocus cloth, using finer pressure, in the bore. Do not polish with an in-and-out motion or use any other abrasive.
  6.  
  7. Lubricate the piston bore and the new rubber pars with fresh brake fluid. Position the seal in the piston bore groove.
  8.  
  9. Lubricate the piston with brake fluid and assemble the boot into the piston groove so that the fold faces the open end of the piston.
  10.  
  11. Insert the piston into the bore, taking care not to unseat the seal.
  12.  
  13. Force the piston to the bottom of the bore (this will require a force of approximately 40-100 lbs.). Seat the boot lip around the caliper counterbore. Proper seating of the boot is very important for sealing out contaminants.
  14.  
  15. Install the brake pads to the caliper assembly.
  16.  
  17. Install the caliper assembly to the vehicle.
  18.  
  19. Properly bleed the hydraulic brake system. Do not attempt to move the vehicle until a firm brake pedal is obtained.
  20.  



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Fig. Fig. 8: Remove the outboard pad from the caliper



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Fig. Fig. 9: Remove the inboard pad by releasing the spring clip from the caliper piston



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Fig. Fig. 10: Use compressed air to free the piston-but KEEP YOUR FINGERS CLEAR when applying the air



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Fig. Fig. 11: Remove the piston from the bore



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Fig. Fig. 12: DO NOT use metal tools to remove the piston seal from the bore

 
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