Jeep Wrangler/YJ 1987-1995 Repair Guide

Brake Caliper

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REMOVAL & INSTALLATION



1987-89 Vehicles

See Figures 1 and 2


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.

  1. Remove 2 / 3 of the brake fluid from the front reservoir.
  2.  
  3. Raise the vehicle so that the wheel to be worked on is off the ground. Support the vehicle with jackstands.
  4.  
  5. Remove the front wheels.
  6.  
  7. Place a C-clamp on the caliper so that the solid end contacts the back of the caliper and the screw end contacts the metal part of the outboard brake pad.
  8.  
  9. Tighten the clamp until the caliper moves far enough to force the piston to the bottom of the piston bore. This will back the brake pads off the rotor surface to facilitate the removal and installation of the caliper assembly.
  10.  
  11. Remove the C-clamp.
  12.  

Do not push down on the brake pedal or the piston and brake pads will return to their original positions up against the rotor.

  1. Remove the caliper mounting pins and lift off the caliper. Don't disconnect the brake line unless the caliper is being removed for service! Don't allow the brake line to support the weight of the caliper! If you disconnect the brake line, cap it to prevent fluid loss.
  2.  
  3. Clean the caliper with a rag and solvent made for cleaning brake surfaces. Avoid disturbing the dust boot.
  4.  
  5. If there are any indications of fluid leakage, the caliper must be rebuilt.
  6.  
  7. Clean the anchor plate and caliper mounting surfaces with a wire brush.
  8.  
  9. Coat the mounting surfaces with a light coating of caliper lubricant.
  10.  
  11. Install the caliper and tighten the mounting pins to 30 ft. lbs. (41 Nm).
  12.  
  13. Connect the hose to the caliper, using a new copper gasket under the hose union. Torque the bolt to 25 ft. lbs. (34 Nm).
  14.  
  15. Fill the master cylinder and press firmly on the brake pedal to seat the pads.
  16.  
  17. Install the wheels, and lower the vehicle.
  18.  

If the brake fluid hose was disconnected, it will be necessary to bleed the hydraulic system.

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Fig. Fig. 1: Removing the caliper mounting pins



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Fig. Fig. 2: Removing the caliper from the support bracket

1990-95 Vehicles

See Figures 3, 4, 5, 6 and 7



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Fig. Fig. 3: Use a socket to loosen the caliper slide pins (mounting bolts)



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Fig. Fig. 4: Removing the caliper slide pins (mounting bolts)



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Fig. Fig. 5: Tilt the caliper outboard to remove



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Fig. Fig. 6: Carefully lift the caliper off the rotor and knuckle



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Fig. Fig. 7: Attach a support wire to the caliper and hang it from the vehicle suspension to relieve tension on the brake hose


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.

  1. Raise and support the vehicle safely. Remove the wheel(s) on the side to be worked on.
  2.  

For vehicles equipped with an Anti-lock Brake System (ABS), refer to the proper procedures concerning brake system servicing.

  1. Drain a small amount of the brake fluid from the front reservoir. Use the bleeder screw at the front outlet port to drain the fluid.
  2.  
  3. Remove the front wheels.
  4.  
  5. Place a C-clamp on the caliper so that the solid end contacts the back of the caliper and the screw end contacts the metal part of the outboard brake pad.
  6.  
  7. Tighten the clamp until the caliper moves far enough to force the piston to the bottom of the piston bore. This will back the brake pads off of the rotor surface to facilitate the removal and installation of the caliper assembly.
  8.  
  9. Remove the C-clamp.
  10.  

Do not push down on the brake pedal or the piston and brake pads will return to their original positions up against the rotor.

  1. Remove both of the Allen head mounting bolts. Tilt the top of the caliper outward and lift off the rotor.
  2.  
  3. Remove the brake pads from the caliper.
  4.  

If the caliper is not being removed for overhaul, it is not necessary to remove the caliper assembly entirely from the vehicle. DO NOT remove the brake line. Suspend the caliper with a piece of wire. DO NOT allow the brake hose to support the weight of the caliper.

  1. Remove the caliper fitting bolt and disconnect the front brake line at the caliper. Discard the fitting bolt washers, they are not reusable. Cap or tape the open ends of the hose to keep dirt out.
  2.  

To install:
  1. Clean all the mounting holes and bushing grooves in the caliper ears. Clean the mounting bolts. Do not use abrasives on the bolts it will destroy their protective plating. Replace the bolts if they are corroded or if the threads are damaged.
  2.  
  3. Reconnect the brake hose to the caliper. Tighten the bolt to 23 ft. lbs. (31 Nm).
  4.  
  5. Install the brake pads and position the caliper over the rotor.
  6.  

Before securing the caliper, ensure the brake hose is not twisted, kinked or touching any chassis parts.

  1. Lubricate the caliper pins and bushings with silicone grease. Line up the mounting holes in the caliper and the support bracket and insert the mounting bolts. Make sure that the bolts pass under the retaining ears on the inboard shoes. Push the bolts through until they engage the holes of the outboard pad and caliper ears. Thread the bolts into the support bracket and tighten them to 30 ft. lbs. (41 Nm).
  2.  


CAUTION
On models without anti-lock brakes, pump the pedal until the caliper pistons and brake shoes are seated. On models with anti-lock brakes, turn the ignition ON and allow the booster pump to build pressure, then pump the brake pedal until the shoes are seated and the indicator lights turn off.

  1. Fill the master cylinder with brake fluid and pump the brake pedal to seat the pads.
  2.  
  3. Install the wheel assembly and lower the vehicle. Check the level of the brake fluid in the master cylinder and fill as necessary.
  4.  

OVERHAUL



See Figures 8 through 14


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.

  1. Remove the caliper assembly and the brake pads. If the pads are to be reused, mark their location in the caliper.
  2.  
  3. Wash the exterior with clean brake fluid, then drain any residual fluid from the caliper and place it on a clean work surface.
  4.  


CAUTION
Removal of the caliper piston requires the use of compressed air. Do not, under any circumstances, place your fingers in front of the piston in an attempt to catch or protect it, instead use several clean cloths.

  1. Pad the interior of the caliper with clean cloths. Use several cloths and pad the interior well to avoid damaging the piston when it comes out of the bore.
  2.  
  3. Insert an air nozzle into the inlet hole in the caliper and gently apply air pressure on the piston to push it out of the bore. Use only enough air pressure to ease the piston out of the bore.
  4.  
  5. Pry the dust boot out of the bore with a screwdriver. Use caution during this operation to prevent scratching the bore. Discard the dust boot.
  6.  
  7. Remove the piston seal from the piston bore and discard the seal. Use only non-scratching implements such as a wooden stick or a piece of plastic to remove the seal. Do not use a metal tool as it could very easily scratch the bore.
  8.  
  9. Remove the bleeder screw. Remove and discard the sleeves and rubber bushings from the mounting ears.
  10.  
  11. Clean all parts with clean brake fluid. Blow out all of the passages in the caliper and bleeder valve. Use only dry and filtered compressed air.
  12.  
  13. Examine the piston for defects. Replace the piston if it is nicked, scratched, corroded. Examine the caliper piston bore for the same defects as the piston. Minor stains or corrosion can be polished with a fiber brush.
  14.  
  15. Lubricate the bore and new seal with brake fluid and install the seal in the groove in the bore.
  16.  
  17. Lubricate the piston with brake fluid and install the new dust boot into the piston groove so that the fold in the boot faces the open end of the piston. Slide the metal portion of the dust boot over the open end of the piston and push the retainer toward the back of the piston until the lip on the fold seats in the piston groove. Then push the retainer portion of the boot forward until the boot is flush with the rim at the open end of the piston and snaps into place.
  18.  
  19. Insert the piston in the bore, being careful not to unseat the piston seal. Push the piston to the bottom of the bore.
  20.  
  21. Install the bleeder screw.
  22.  
  23. Connect the brake line to the caliper using new gaskets.
  24.  
  25. Install the brake pads.
  26.  
  27. Install the caliper. Bleed the hydraulic system.
  28.  



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Fig. Fig. 8: Caliper components



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Fig. Fig. 9: Removing the caliper piston with compressed air



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Fig. Fig. 10: Removing the caliper piston-1990-95 shown



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Fig. Fig. 11: Carefully pry loose the piston dust boot



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Fig. Fig. 12: Removing the piston dust boot



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Fig. Fig. 13: Carefully pry loose the caliper piston seal using a non-scratching implement (such as a wooden stick or a piece of plastic). A metal tool, such as the one shown, could very easily scratch the bore



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Fig. Fig. 14: Installing and seating the caliper piston and dust boot

 
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