GM Blazer/Jimmy/Typhoon/Bravada 1983-1993 Repair Guide

Brake Pads

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CAUTION
Brake shoes 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 1 / 3 in. (0.8mm) thick above the rivet (so that the lining is thicker than the metal backing in most cases) in order to prevent the rivet from scoring the rotor. On bonded brake pads, a minimum lining thickness of 1 / 3 in. (0.8mm) above the backing plate 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.



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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 have a built-in wear indicator

All models should be equipped with 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.

REMOVAL & INSTALLATION



See Figures 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 and 17

The following procedure requires the use of a C-clamp and channel lock pliers.

  1. If the fluid reservoir is full, siphon off about 2 / 3 of the brake fluid from the master cylinder reservoirs in order to prevent the possibility of spillage when the caliper pistons are bottomed. A common kitchen turkey baster may also be used to remove brake fluid, but make sure the tool is clean before inserting it in the reservoir.
  2.  



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Fig. Fig. 4: Caliper/Brake pad mounting - 1992 vehicle shown



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Fig. Fig. 5: Use a C-clamp to bottom the piston in the caliper bore (this provides clearance for new pad installation)



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Fig. Fig. 6: Loosen the caliper mounting bolts/pins



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Fig. Fig. 7: Remove the caliper mounting bolts



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Fig. Fig. 8: Remove the caliper from the mounting bracket



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Fig. Fig. 9: Remove the outboard pad from the caliper ears



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Fig. Fig. 10: Remove the inboard pad from the caliper piston



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Fig. Fig. 11: While working on the brakes, support the caliper to prevent damage to the brake line


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

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

Replacing the pads on just one wheel may cause uneven braking; always replace the pads on both wheels.

  1. Install a C-clamp on the caliper so that the solid frame side of the clamp rests against the back of the caliper and the driving screw end rests against the metal part (center backing plate) of the outboard pad.
  2.  
  3. Tighten the clamp until the caliper moves sufficiently to bottom the piston in its bore, then remove the clamp.
  4.  



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Fig. Fig. 12: Exploded view of a common caliper and brake pad assembly

  1. Remove the two Allen head caliper mounting bolts from the back of the caliper.
  2.  
  3. Remove the caliper from the mounting bracket and support from the vehicle's suspension using a coat hanger or length of wire. DO NOT allow the brake line to support the caliper's weight and be sure the line is not otherwise kinked or damaged.
  4.  
  5. Remove the inboard and outboard pads from the caliper.
  6.  
  7. Remove the inboard pad spring clip from the piston or pad. Remove the spring clip carefully as it must be reused upon installation of the new pads.
  8.  
  9. Remove the bolt ear sleeves and rubber bushings for cleaning, inspection and lubrication.
  10.  

To install:
  1. Check the inside of the caliper for leakage and the condition of the piston dust boot. If necessary, remove the caliper and overhaul or replace it.
  2.  
  3. Lubricate the sleeves and bushings using a suitable silicone lubricant, then install them.
  4.  
  5. Make sure the piston is fully bottomed in the caliper providing clearance for the new brake pads. If the piston is not compressed, install the old inboard pad and use the C-clamp on the pad and back on the caliper to bottom the piston. BE CAREFUL not to pinch and damage the piston boot.
  6.  



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Fig. Fig. 13: The spring clip must be properly installed on the inboard pad



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Fig. Fig. 14: Install the inboard pad to the caliper by carefully inserting the spring clip in the piston



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Fig. Fig. 15: Position the outboard pad over the caliper ears



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Fig. Fig. 16: Compress the brake pad ears using a pair of channel lock pliers



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Fig. Fig. 17: When the caliper is installed, check for proper caliper-to-knuckle bracket clearance

  1. Install the spring clip to the inboard pad, then install the pad to the caliper.
  2.  

Make sure that the wear sensor is facing in the proper direction. On most vehicles it should face 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. Place the caliper over the disc, lining up the hole in the caliper ears with the holes in the mounting bracket. Make sure that the brake hose is not twisted or kinked.
  4.  
  5. Carefully insert the mounting bolts through the bracket and caliper (bushing and sleeves), then tighten to 10 ft. lbs. (50 Nm).
  6.  
  7. Pump the brake pedal a few times to seat the linings against the rotors.
  8.  
  9. Use a pair of channel lock pliers to compress the pad ears so no clearance exists between the pad ears and the caliper.
  10.  
  11. Check the clearance between the caliper and steering knuckle. Clearance at each end of the caliper should be measured individually and the results added together. Clearance should not exceed 0.010-0.024 in. (0.026-0.60mm).
  12.  
  13. Install the wheels, then remove the jackstands and carefully lower the vehicle.
  14.  
  15. Check and refill the master cylinder reservoirs.
  16.  


CAUTION
DO NOT attempt to move the vehicle until a firm brake pedal is obtained.

  1. Pump the brake pedal to make sure that it is firm. If necessary, bleed the brakes.
  2.  

 
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