Chevrolet Full-size Cars 1968-1978 Repair Guide

Brake Pads

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INSPECTION




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.



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Fig. Fig. 1 Exploded view of the front disc brake assembly



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Fig. Fig. 2 Disc brake pad inspection points



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Fig. Fig. 3 Examples of new and worn brake pads



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Fig. Fig. 4 When the brake pad wears down, the wear indicator will contact the rotor and cause a squealing sound while driving



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Fig. Fig. 5 Front disc brake assembly

Brake pads should be inspected once a year or at 7,500 miles, whichever occurs first. Check both ends of the outboard shoe, looking in at each end of the caliper; then check the lining thickness of the inboard shoe, looking down through the inspection hole. Lining should be more than 0.020" thick above the rivet (so that the lining is thicker than the metal backing). Keep in mind that any applicable state inspection standards that are more stringent take precedence. All 4 pads must be replaced if one shows excessive wear.

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

REMOVAL & INSTALLATION





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Fig. Fig. 6 Caliper bolts must pass under the pad retaining ears



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Fig. Fig. 7 Gently pry on the caliper if you have trouble freeing it from the rotor



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Fig. Fig. 8 Installing the inboard brake pad retaining spring



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Fig. Fig. 9 Proper retaining spring installation



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Fig. Fig. 10 Installing the inboard brake pad assembly-the retaining spring will snap into the caliper piston



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Fig. Fig. 11 Use pliers to tighten the outboard shoe ear to the caliper housing-the tighter the outboard pad is to the caliper, the less noise will be created from the shoe rattling



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Fig. Fig. 12 Siphon out about 2/3 of the brake fluid from the brake master cylinder



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Fig. Fig. 13 Use a large enough C-clamp to seat the caliper piston into the brake caliper



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Fig. Fig. 14 Loosen the brake caliper mounting bolts ...



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Fig. Fig. 15 ... then remove them from the brake caliper



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Fig. Fig. 16 Lift the brake caliper off of the rotor ...



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Fig. Fig. 17 ... then remove the brake pads from the caliper

1968 Models
  1. Siphon off about 2 / 3 of the brake fluid from the full master cylinder.
  2.  

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 the vehicle and support it with safety stands. Remove the wheels.
  2.  

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, while removing one pad, insert its replacement before the piston has time to move outward. If you were too slow and the pistons were too fast, it will be necessary to use a wide-bladed putty knife to hold in the pistons while inserting the new pads. If this gives you difficulty open the bleed screw on the caliper and release some of the fluid, but do not allow the fluid to drain from the master cylinder. This may reduce the pressure and make it easier to push in on the pistons. After removing the outboard pad, inspect it and compare it with the inboard pad. 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 Models
  1. Siphon off about 2 / 3 of the brake fluid from a full master cylinder.
  2.  

The insertion of the thicker replacement pads will push the piston back into its bore and will cause a full master cylinder to overflow causing paint damage. In addition to siphoning off fluid it would be wise to keep the cylinder cover on during pad replacement.

  1. Raise the vehicle and support it with safety stands. Remove the wheels.
  2.  

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 so the screw end rests against the metal part (shoe) of the outboard pad.
  2.  
  3. Tighten the clamp until the caliper moves enough to bottom the piston in its bore. Remove the clamp.
  4.  
  5. Remove the two allen-head caliper mounting bolts enough to allow the caliper to be pulled off the disc.
  6.  
  7. 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.
  8.  
  9. Remove the pad support spring clip from the piston.
  10.  
  11. Remove the two bolt ear sleeves and the four rubber bushings from the ears.
  12.  
  13. Brake pads should be replaced when they are worn to within 1 / 32 " of the rivet heads.
  14.  
  15. Check the inside of the caliper for leakage and the condition of the piston dust boot.
  16.  

To install:

  1. Lubricate the two new sleeves and four bushings with a silicone spray.
  2.  
  3. Install the bushings in each caliper ear. Install the two sleeves in the two inboard ears.
  4.  
  5. Install the pad support spring clip and the old pad into the center of the piston. You will then push this pad down to get the piston flat against the caliper. While the assistant holds the caliper and loosens the bleeder valve to relieve pressure, you get a prybar and try to force the old pad in, make the piston flush with the caliper surface. When it is flush, close the bleeder valve so that no air gets into the system.
  6.  

On vehicles 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 shoes 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 shoe.
  8.  
  9. Push the mounting bolts through to engage the holes in the outboard shoes and the outboard caliper ears and then threading them into the mounting bracket.
  10.  
  11. Torque the mounting bolts to 35 ft. lbs. 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 caliper upper ears until no clearance exist between the shoe 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. If it is not, bleed and adjust the brakes.
  16.  

 
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