Chevrolet Chevette/1000 1976-1988 Repair Guide

Disc Brake Pads and Caliper

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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



1976-82 Vehicles


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Fig. Fig. 1Use a 7 in. or larger C-clamp to bottom the piston into the caliper



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Fig. Fig. 2If the caliper is being removed for replacement or overhaul, disconnect the brake hose by removing the bolt at the inlet fitting, then plug the hose



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Fig. Fig. 3Unfasten the two brake bolts, but do not remove the mounting bolt in the center



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Fig. Fig. 4If the caliper is being removed for pad replacement, hang it from the suspension with a suitable piece of wire. DO NOT let the caliper hang by the brake hose



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Fig. Fig. 5View of the inboard shoe, retainer and wear sensor-1976-82 vehicles



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Fig. Fig. 6Installing the inboard shoe and lining-1976-82 vehicles



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Fig. Fig. 7Use a suitable vise to bend the tabs on the shoe



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Fig. Fig. 8Exploded view of the caliper and brake shoes-1976-82 vehicles



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Fig. Fig. 9Position a suitable C-clamp to bottom the piston out in the caliper



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Fig. Fig. 10Use a brush to clean the area around the caliper inlet fitting



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Fig. Fig. 11If the caliper is being removed for overhaul or replacement, disconnect the inlet fitting



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Fig. Fig. 12Remove the two caliper mounting bolt covers



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Fig. Fig. 13Unfasten the top allen head mounting bolt ...



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Fig. Fig. 14... then remove the lower mounting bolt



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Fig. Fig. 15Remove the caliper from the rotor



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Fig. Fig. 16Remove the outboard pad from the caliper. It may be necessary to use locking pliers to straighten the bent over shoe tabs



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Fig. Fig. 17Remove the inboard brake pad from the caliper

  1. Siphon off about one half of the brake fluid in the master cylinder. This is necessary because the new, thicker pads will push the caliper pistons in farther and cause the master cylinder to overflow.
  2.  
  3. Jack up the front of the car and support it safely on jackstands. Remove the wheels.
  4.  

Always replace brake pads on both wheels. Never replace one pair. Replace pads when worn to within 1 / 32 " of the metal pad backing.

  1. Mount a 7 in. C-clamp on the caliper with the solid end on the caliper housing and the screw end on the metal back of the outboard shoe (pad). Tighten the C-clamp to bottom the piston in the cylinder bore and remove the clamp.
  2.  
  3. If the caliper is to be removed for overhaul purposes disconnect the brake hose at the inlet fitting by removing the bolt and washers. If only the shoe and lining are to be replaced so not disconnect the brake hose.
  4.  
  5. Remove the two bracket bolts and remove the caliper from the rotor. Do not remove the socket head bolt which may have a cover on it on later models. Hang the caliper from the front suspension with a chain or heavy wire. A coat hanger wire should be sufficient. Don't let the caliper hang with the brake hose as its support.
  6.  
  7. Remove the old pads. If the shoe retaining spring doesn't come out with the inboard pad, remove it from the piston.
  8.  
  9. Blow any dirt out of the caliper and check that the piston boot isn't damaged or leaking fluid.
  10.  

To install:

  1. Install the new pads in the same locations as the old ones. Before installing the inboard pad, be sure that the retaining spring is properly positioned. Push the tab on the single leg end of the spring down into the pad hole, and then snap the other two legs over the edge of the pad notch.
  2.  
  3. Position the caliper over the rotor (disc). Install the two retaining bolts and tighten them to 70 ft. lbs.
  4.  
  5. Using a large pair of locking pliers, cinch the outboard pad to the caliper. Position the lower jaw of the pliers on the bottom edge of the outboard pad. Place the upper jaw of the pliers on the outboard pad tab. Squeeze the pliers firmly to bend the tab. Cinch the other end of the outboard pad the same way. The tabs may also be bent by placing the shoe in a vise and bending slightly. The purpose is to have zero clearance between the shoe and the caliper.
  6.  
  7. Install the wheels and lower the car.
  8.  
  9. Refill the master cylinder with fresh fluid.
  10.  
  11. Pump the brake pedal several times to push the pads in on the rotor. Check the fluid level in the master cylinder after this has been done. Do not move the car until a firm pedal is obtained.
  12.  
  13. Carefully road test the car.
  14.  

1983-88 Vehicles


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Fig. Fig. 18If the caliper is being removed for pad replacement, hang it from the suspension with a suitable piece of wire, such as a coat hanger. NEVER let the caliper hang from the brake hose



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Fig. Fig. 19Before installation, lubricate the bushings and sleeves with silicone grease-1984-88 vehicles shown, 1983 similar



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Fig. Fig. 20Install the outboard shoe



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Fig. Fig. 21Install the inboard shoe



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Fig. Fig. 22Check the clearance between the caliper and the brake stops



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Fig. Fig. 23Carefully wedge a large prytool between the outboard shoe flange and the hat section of the rotor



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Fig. Fig. 24Check the angle of the shoe tabs



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Fig. Fig. 25Bend the outboard shoe tabs with a hammer

  1. Remove 2 / 3 of the brake fluid from the master cylinder assembly.
  2.  
  3. Raise the car and support with jackstands.
  4.  
  5. Mark the relationship of the wheel to the axle, then remove the wheel.
  6.  
  7. Position a C-clamp as shown in the illustration and tighten until the piston bottoms in the bore, then remove the C-clamp.
  8.  
  9. Remove the bolt holding the inlet fitting.
  10.  

If only the shoe and lining are being replaced, do not remove the inlet fitting.

  1. Remove the two bolt covers and allen head mounting bolts.
  2.  

If the mounting bolts show signs of corrosion replace them with new ones.

  1. If only the shoe and linings are being replaced, remove the caliper from the rotor and suspend it from the suspension so that there isn't any tension on the brake hose.
  2.  
  3. Remove the shoe and lining assemblies from the caliper. To remove the outboard shoe and lining, use 12 inch locking pliers to straighten bent over shoe tabs.
  4.  
  5. Remove the sleeves from the mounting bolt holes.
  6.  
  7. Remove the bushings from the grooves in the mounting bolt holes.
  8.  
  9. Prior to installation, lubricate and install new bushings and sleeves.
  10.  

To install:

  1. Install the inboard shoe and lining positioning the shoe retainer spring into the piston.
  2.  
  3. Install the outboard shoe and lining with the wear sensor at the leading edge of the shoe during forward wheel rotation.
  4.  
  5. Position the caliper over the rotor in the mounting bracket.
  6.  
  7. Coat the threads and shoulder of the mounting bolts with silicone grease. Install the mounting bolts and tighten to 21-25 ft. lbs.
  8.  
  9. Check the clearance between the caliper and bracket stops as shown in the illustration and if necessary, file the ends of the bracket to provide the proper clearance.
  10.  
  11. Install the inlet fitting if removed and tighten to 18-30 ft. lbs.
  12.  
  13. Cinch the outboard shoe by performing the following steps:
  14.  
    1. Wedge a prying tool between the outboard shoe flange and the hat section of the rotor to seat the shoe flange in the caliper.
    2.  
    3. Have an assistant lightly press on the brake pedal to clamp the outboard shoe tightly to the caliper. Maintain pressure on the hydraulic system to keep the tool wedged in place during the remaining steps.
    4.  


Make sure the master cylinder is filled to the proper level and the cover is in place before performing the previous step.

    1. c. Bend the outboard shoe tabs and cinch the shoe to the caliper by positioning an 8 ounce machinists hammer as shown in the illustration, then striking it with a 16 ounce brass hammer.
    2.  
    3. Check that the shoe tabs are bent to an angle of approximately 45 degrees. After both tabs are bent and hydraulic pressure released, check that the outboard shoe is locked tightly in position. If not, repeat steps a through c.
    4.  



CAUTION
Outboard shoe and linings that have been cinched as described in the preceding steps should be replaced if uncinched for any reason. Bleed the system if the inlet fitting and hose were removed.

CALIPER OVERHAUL





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Fig. Fig. 26Exploded view of the caliper and shoe assembly-1983 vehicles



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Fig. Fig. 27Exploded view of the caliper and shoe assembly-1984-88 vehicles



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Fig. Fig. 28Carefully remove the piston boot, using a suitable prytool



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Fig. Fig. 29Install the piston and boot into the caliper using a bushing driver-the tool for 1976-82 vehicles is shown. For 1983-88 vehicles, use tool J-29077

  1. Remove the caliper as previously described. Disconnect the brake line and remove the brake pads.
  2.  
  3. Clean all dirt from the brake hose-to-caliper connection.
  4.  
  5. Seal the brake line fitting to prevent dirt from entering the caliper.
  6.  
  7. Clean the outside of the caliper using fresh brake fluid and place it on a clean work surface.
  8.  
  9. Drain all brake fluid from the caliper.
  10.  
  11. Remove the mounting back cover and bolt and slide the mounting bracket off the caliper.
  12.  
  13. Remove the sleeve and two bushings, one from the retainer bolt and one from the groove in the caliper mounting hole. If the clips do not fall off when the bracket is removed, take them off and remove the cushions.
  14.  
  15. Use rags to cushion the inside of the caliper and remove the piston by applying compressed air into the caliper inlet hole. Use just enough pressure to ease out the piston; excessive pressure may cause damage to the piston when it flies out of the caliper. Another method of removing the piston is to depress the brake pedal slowly and gently with the hydraulic lines still connected. This will push the piston out of the caliper.
  16.  


CAUTION
Never place your hands in the way of the piston as it can fly out with considerable force!

  1. Use a suitable prytool to pry the piston boot out of the caliper, being careful not to scratch the housing bore. Extend the prytool across the caliper bore, under the boot, and pry it up. Be careful not to gouge the cylinder bore, or the caliper will have to be replaced.
  2.  
  3. Use a piece of wood or plastic (a plastic knitting needle is perfect), to remove the seal from its groove in the caliper bore. Using a metal tool will damage the bore surface.
  4.  
  5. Remove the bleeder valve from the caliper.
  6.  
  7. Buy a high quality caliper rebuilding kit, preferably original equipment type.
  8.  
  9. Clean all metal parts in fresh brake fluid. Never use other solvents for cleaning, as gasoline or paint thinner will ruin the rubber parts.
  10.  
  11. Inspect all parts for rust or other damage. The caliper bore should be free from corrosion or nicks. Replace any suspect parts. Minor stains or corrosion can be polished out of the caliper bore with crocus cloth, but heavily damaged pieces should be discarded.
  12.  

To assemble:
  1. Lubricate the caliper bore and the new piston seal with fresh brake fluid. Position the seal in the caliper bore groove.
  2.  
  3. Lubricate the piston with fresh brake fluid and assemble a new boot into the piston groove so that the fold faces the open end of the piston.
  4.  
  5. Insert the piston into the caliper being careful not to dislodge the seal. Force the piston down to the bottom in the bore. This requires about 50-100 lbs. of force.
  6.  
  7. Place the outside diameter of the boot in the caliper counterbore and seat it with a bushing driver of the same diameter as the boot.
  8.  
  9. Install the bleeder screw.
  10.  
  11. Fit new cushions on the caliper lugs. Stretch the cushions over the lugs, fitting the heavy section in the lug recess, with the sawtooth edges of the cushions pointing out.
  12.  
  13. Liberally lubricate the sleeve and bushings, inside and out, and the unthreaded portion of the retainer bolt with silicone lubricant.
  14.  
  15. Fit the larger bushing in the caliper mounting hole groove and install the sleeve.
  16.  
  17. Position the smaller bushing in the groove in the retainer bolt.
  18.  
  19. Clamp the caliper in a vise, mounting lug up, across the pad openings. Fit the clips over the cushions and squeeze the mounting bracket down over the clips, lining up the retainer bolt hole.
  20.  
  21. Move the bracket against the retainer boss on the caliper and install the retainer bolt. Tighten the bolt to 25 ft. lbs.
  22.  

It may be very difficult to squeeze the bracket over the cushions and clips on the caliper. Start with the open end of the bracket over the ends of the clips near the boot and move the bracket towards the closed end of the piston housing.

  1. Install the caliper. Use new copper gaskets on the brake hose connection. Bleed the brakes.
  2.  

 
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