GM Chevy Mid-Size Cars 1964-1988 Repair Guide

Disc Brake Pads

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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.

INSPECTION



See Figures 1, 2 and 3

Brake pads should be inspected once a year or at 7,500 miles, whichever occurs first. Check both ends of the outboard pad, looking in at each end of the caliper; then check the lining thickness of the inboard pad, looking down through the inspection hole. On riveted pads, the lining should be more than 0.020 in. (0.51mm) above the rivet (so that the lining is thicker than the metal backing) in order to prevent the rivet from scoring the rotor. On all pads, a minimum thickness of 0.063 in. (1.59mm) should be used to determine necessary replacement intervals. Keep in mind that any applicable state inspection standards that are more stringent take precedence. All four front pads must be replaced as a set if one shows excessive wear.

All 1979 and later models have a wear indicator that makes a noise when the linings have worn to a degree where replacement is necessary. The spring clip is an integral part of the inboard pad and lining. When the brake pad reaches a certain degree of wear, the clip will contact the rotor and produce a warning noise.



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Fig. Fig. 1: Disc brake pad inspection



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Fig. Fig. 2: Relative size differences between a new and worn pad lining



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Fig. Fig. 3: Front disc brake pads on 1979 and later vehicles have a built-in wear indicator

REMOVAL & INSTALLATION



1966-68 Vehicles
  1. Siphon off about 2 / 3 of the brake fluid from the full master cylinder. A turkey baster may also be used to remove the brake fluid.
  2.  


WARNING
The insertion of the thicker replacement pads will push the caliper pistons back into their bores and will cause a full master cylinder to overflow causing paint damage. In addition to siphoning fluid, it would be wise to keep the cylinder cover on during pad replacement.

  1. Raise and support the front of the vehicle safely using jackstands.
  2.  
  3. Remove the front wheels.
  4.  

Replacing the pads on just one wheel will result in uneven braking. Always replace the pads on both wheels.

  1. Extract and discard the pad retaining pin cotter key.
  2.  
  3. Remove the retaining pin and open the bleed screw on the caliper in order to release some of the fluid, but do not allow all of the fluid to drain from the master cylinder reservoir. This will reduce the pressure and make it easier to push in on the pistons. Compress the piston into the caliper bore and tighten the bleeder screw. Remove the pads, then inspect and compare them with each other. They may be slightly different; if so, make sure that the replacement pads are installed correctly.
  4.  
  5. After installing the new pads, install the retaining pin and insert a new cotter pin.
  6.  
  7. Refill the master cylinder and bleed the system if necessary.
  8.  

1969 and Later

See Figures 4, 5, 6, 7, 8, 9, 10, 11 and 12

  1. Siphon off about 2 / 3 of the brake fluid from the full master cylinder. A turkey baster may also be used to remove the brake fluid.
  2.  


WARNING
The insertion of the thicker replacement pads will push the caliper pistons back into their bores and will cause a full master cylinder to overflow causing paint damage. In addition to siphoning fluid, keep the cylinder cover on during pad replacement.

  1. Raise and support the front of the vehicle safely using jackstands.
  2.  
  3. Remove the front wheels.
  4.  

Replacing the pads on just one wheel will result in uneven braking. Always replace the pads on both wheels.

  1. Install a C-clamp on the caliper so that the solid side of the clamp rests against the back of the caliper and the screw end is against the metal part (backing plate) of the outboard pad. Slowly tighten the clamp until the caliper moves enough to bottom the piston in its bore, then remove the clamp.
  2.  
  3. Remove the two Allen-head caliper mounting bolts so that the caliper may be pulled off the disc.
  4.  
  5. Remove the inboard pad and loosen the outboard pad. Place the caliper where it won't strain the brake hose. It would be best to wire it out of the way. NEVER hang the caliper by the hose or the hydraulic system could be damaged.
  6.  
  7. Remove the pad support spring clip from the piston or the rear of the inboard pad.
  8.  
  9. Remove the two bolt ear sleeves and the four rubber bushings from the ears.
  10.  

To install:
  1. Check the inside of the caliper for leakage and inspect the condition of the piston dust boot.
  2.  
  3. Lubricate the two new sleeves and four bushings with a silicone spray or a suitable grease.
  4.  
  5. Install the bushings in each caliper ear. Install the two sleeves in the two inboard ears.
  6.  
  7. Install the pad support spring clip and pad into the center of the piston.
  8.  

On models with wear sensors, make sure the wear sensor is toward the rear of the caliper.

  1. Place the outboard pad in the caliper with its top ears over the caliper ears and the bottom tab engaged in the caliper cutout.
  2.  
  3. After both pads are installed, lift the caliper and place the bottom edge of the outboard pad on the outer edge of the disc to make sure that there is no clearance between the tab on the bottom of the pads and the caliper abutment.
  4.  
  5. Place the caliper over the disc, lining up the hole in the caliper ears with the hole in the mounting bracket. Make sure that the brake hose is not kinked.
  6.  
  7. Start the caliper-to-mounting bracket bolts through the sleeves in the inboard caliper ears and through the mounting bracket making sure the ends of the bolts pass under the retaining ears of the inboard pad.
  8.  
  9. Push the mounting bolts through to engage the holes in the outboard pads and the outboard caliper ears and then threading them into the mounting bracket. Tighten the mounting bolts to 35 ft. lbs. (47 Nm).
  10.  
  11. Pump the brake pedal to seat the linings against the rotors.
  12.  
  13. With a pair of channel lock pliers placed on the notch on the caliper housing, bend the pad upper ears until no clearance exist between the pad and the caliper housing.
  14.  
  15. Install the wheels, lower the car, and refill the master cylinder with fluid. Pump the brake pedal to make sure that it is firm. Do not attempt to move the vehicle until and firm pedal is obtained.
  16.  



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Fig. Fig. 4: Use a C-clamp to seat the caliper piston before removing the old pads



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Fig. Fig. 5: The caliper may also be compressed using a prybar, but be careful NOT to damage any of the pry surfaces



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Fig. Fig. 6: Wire the caliper to the suspension-an old coat hanger may be easily adapted for this use



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Fig. Fig. 7: Most replacement pad kits will come with an anti-squeal compound which may be applied to the pad backing plates



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Fig. Fig. 8: Proper inboard pad retaining spring installation



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Fig. Fig. 9: Installing the pad support spring-1970 and later vehicles



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Fig. Fig. 10: Install the inboard brake pad and lining



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Fig. Fig. 11: Caliper bolts must go under the pad retaining ears



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Fig. Fig. 12: Use pliers to fit the brake pad to the caliper housing

 
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