BMW 318/325/M3/525/535/M5 1989-1993 Repair Information

Brake Caliper

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REMOVAL & INSTALLATION



See Figure 1



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Fig. Fig. 1: Removing the caliper mount. The upper housing of the caliper does not have to be removed from the mount to dismount the caliper

  1. Raise and support the vehicle. Remove the rear wheels.
  2.  
  3. Disconnect the brake pad wear sensor from the harness.
  4.  
  5. If the caliper is to be replaced, draw off the brake fluid from the reservoir and fix the brake pedal in the depressed position. This will prevent brake fluid from draining out of the brake lines while the line is disconnected form the caliper. Disconnect the line from the caliper.
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  7. Remove the caliper to knuckle mounting bolts and pull the caliper off.
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To install:
  1. Install the caliper and torque the bolts to 89 ft. lbs. (123 Nm).
  2.  
  3. Connect the brake line to the caliper and torque to 10 ft. lbs. (14.2 Nm).
  4.  
  5. Connect the brake wear sensor wire to the harness. Check for a good connection as most problems with the sensor circuit are caused by faulty connections. Check that the wire is held by the loop in the dust cover and the connector is held at the clips.
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  7. Clip the brake line into the holder. Bleed the brake system.
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  9. Install the wheels and torque to 65-79 ft. lbs. (90-110 Nm).
  10.  

OVERHAUL



The overhaul procedure covers replacement of the seal, dust boot and guide sleeves. If the piston or bore is found to be pitted or corroded, replacement of the caliper is recommended. Use a original manufacturer overhaul kit. Use all the parts contained in the kit. Work in a clean, dust free area. Use only alcohol and non-lubricated compressed air to clean the caliper and parts.

  1. Remove the caliper and brake pads. Remove the plastic caps and the guide bolts or slide pins.
  2.  
  3. Clean the exterior before further disassembly.
  4.  
  5. Place a piece of wood in the caliper and use compressed air at the hose connection to extend the piston out of the caliper body. Remove the piston.
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  7. Use a plastic pick to remove the seal from the bore.
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  9. Clean the bore and piston with alcohol and dry with non-lubricated compressed air.
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  11. Lubricate the parts with brake assembly paste. Install the new seal in the groove. Install the dust boot on the piston and slide the piston into the bore. Seat the boot into the grooves.
  12.  
  13. Install new guide bushing sleeves at the slides.
  14.  
  15. Assemble the caliper and install.
  16.  

 
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