BMW Cars 1999-06

Brake Caliper

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Overhaul



The rear brake caliper design is similar to the front brake caliper. For overhaul information, please refer to the front brake caliper overhaul procedures in this section.

Removal & Installation




NOTE
If the vehicle is equipped with ASC+T, the BMW Service Tester must be used to properly bleed the system. Due to safety and liability issues, this job should only be performed by a BMW dealer.

  1. Block the rear wheels and apply the parking brake.
  2.  
  3. Loosen the rear wheel bolts 1 / 8 of a turn.
  4.  
  5. Raise and support the vehicle. Remove the rear wheels.
  6.  
  7. If equipped, disconnect the brake pad wear sensor from the harness.
  8.  


NOTE
Do not loosen or disconnect the brake caliper fluid hose if the caliper is being removed to access or replace another component. Loosen and disconnect the fluid hose only if the caliper is to be replaced, completely removed or overhauled. If the fluid hose is to remain attached to the caliper, support the caliper assembly with mechanic's wire to avoid damaging the line.

  1. If the caliper is to be completely removed from the vehicle (replaced, disassembled or overhauled):
    1. Siphon the brake fluid from the reservoir and fix the brake pedal in the depressed position. Or, remove the reservoir cap and place a thin sandwich bag over the opening, then reinstall the cap without the fluid level float to captivate the system. This will prevent brake fluid from draining out of the brake lines while the line is disconnected from the caliper.
    2.  
    3. Using a flare nut wrench, loosen, but do not disconnect the flexible line to the caliper.
    4.  

  2.  
  3. Using a suitable prytool, carefully move the tensioning spring toward the brake caliper to release the two retaining tabs and remove the spring.
  4.  
  5. Remove the two plastic plugs from the caliper slide bolts and using a 7mm hex tool, remove the slider bolts.
  6.  
  7. Rock the caliper assembly side-to-side several times and then carefully remove the caliper along with the inner brake pad from the brake rotor.
  8.  
  9. If the brake fluid line is to be removed from the caliper, place a suitable drain pan under the caliper, disconnect and plug the fluid line and the caliper. Note, to avoid damage to the flexible brake line, hold the brake line with a flare nut wrench and spin the brake caliper. If the brake line is sealed to the caliper with a crush washer, replace the crush washer with the appropriate replacement part.
  10.  
  11. If the brake caliper mounting bracket is to be removed, remove the caliper bracket-to-knuckle mounting bolts and lift off the bracket. These mounting bolts typically require a sturdy 6 point 16mm socket.
  12.  


NOTE
The brake caliper bracket-to-trailing arm bolts may require a significant amount of effort to loosen. Use a proper fitting 6 point 1 / 2 inch drive metric impact socket and sturdy breaker bar to loosen the mounting bolts.



Click image to see an enlarged view

Fig. Move the tensioning spring and release it



Click image to see an enlarged view

Fig. Remove the protective plugs to access the caliper slide bolts



Click image to see an enlarged view

Fig. Remove the caliper slide bolts with a 7mm hex tool

To install:

  1. If the brake fluid line was disconnected, connect the brake line to the caliper and torque to 10 ft. lbs. (14.2 Nm). Note, to avoid damage to the flexible brake line, hold the brake line with a flare nut wrench and spin the brake caliper. If the brake line is sealed to the caliper with a crush washer, replace the crush washer with the appropriate replacement part.
  2.  
  3. If the caliper bracket was removed
    1. Support the caliper temporarily with mechanic's wire taking care to not damage the flexible brake hose.
    2.  
    3. Install the bracket on the trailing arm and torque the bolts to 48 ft. lbs. (65 Nm).
    4.  
    5. Install the brake pads in the caliper bracket as outlined in this section.
    6.  

  4.  
  5. Lower the brake caliper over the brake pads.
  6.  
  7. Lubricate the slider bolts with an approved brake grease.
  8.  
  9. Install the slider bolts and torque to 18-22 ft. lbs. (25-30 Nm).
  10.  
  11. Install the protective caps and the retainer spring.
  12.  
  13. If equipped, 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.
  14.  
  15. If the brake fluid line was disconnected, bleed the brake system as outlined in this section.
  16.  
  17. Install the wheels and hand tighten the lug bolts. Lower the vehicle carefully until the tires begin to contact the surface and torque the lug bolts to specification in a crisscross pattern to 66-81 ft. lbs. (90-110 Nm).
  18.  


WARNING
Failure to properly torque the wheels to the correct torque using the proper sequence could cause a brake pulsation and rotor warpage.

  1. Before servicing the vehicle, refer to the Precautions section.
  2.  
  3. Draw off brake fluid with a syringe.
  4.  
  5. Remove or disconnect the following:

    Hydraulic brake lines
     
    Rear wheels
     
    Caliper mounting bolts and disconnect the brake pad wear indicator plug
     
    Caliper assembly by pulling to the rear
     

  6.  

To install:

  1. Install or connect the following:

    Brake caliper onto the steering knuckle. Tighten the caliper mounting bolts to 42-48 ft. lbs. (56-66 Nm).
     
    Guide bolts to 22-25 ft. lbs. (30-34 Nm)
     

  2.  


NOTE
Make sure the brake wear indicator wire is held in the correct position by the tab of the dust cap.



Wheels
 
Hydraulic brake system lines and bleed the brake system
 

  1. Before servicing the vehicle, refer to the precautions in the beginning of this section.
  2.  
  3. Draw off brake fluid with a syringe.
  4.  
  5. Disconnect the hydraulic brake lines.
  6.  
  7. Remove the rear wheels.
  8.  
  9. Remove the caliper mounting bolts and disconnect the brake pad wear indicator plug.
  10.  
  11. Remove the caliper assembly by pulling to the rear.
  12.  

To install:

  1. Install the brake caliper onto the steering knuckle. Tighten the caliper mounting bolts to 42-48 ft. lbs. (56-66 Nm).
  2.  
  3. Tighten the guide bolts to 22-25 ft. lbs. (30-34 Nm).
    NOTE
    Make sure the brake wear indicator wire is held in the correct position by the tab of the dust cap.

  4.  
  5. Install the wheels.
  6.  
  7. Connect the hydraulic brake system lines and bleed the brake system.
  8.  

  1. Disconnect the negative battery cable. Draw off brake fluid with a suitable syringe.
  2.  
  3. Disconnect the hydraulic brake lines.
  4.  
  5. Raise and safely support the vehicle. Remove the rear tire and wheel assembly.
  6.  
  7. Remove the caliper mounting bolts and disconnect the brake pad wear indicator plug.
  8.  
  9. Remove the caliper assembly by pulling to the rear.
  10.  

To install:

  1. Install the brake caliper onto the steering knuckle; tighten the caliper mounting bolts to 42-48 ft. lbs. (56-66 Nm). Tighten the guide bolts to 22-25 ft. lbs. (30-34 Nm).
    NOTE
    Make sure the brake wear indicator wire is held in the correct position by the tab of the dust cap.

  2.  
  3. Install the front tire and wheel assemblies, then lower the vehicle.
  4.  
  5. Connect the hydraulic brake system lines.
  6.  
  7. Connect the negative battery cable, then bleed the brake system.
  8.  

  1. Before servicing the vehicle, refer to the Precautions section.
  2.  
  3. Draw off brake fluid with a syringe.
  4.  
  5. Remove or disconnect the following:

    Hydraulic brake lines
     
    Rear wheels
     
    Caliper mounting bolts and disconnect the brake pad wear indicator plug
     
    Caliper assembly by pulling to the rear
     

  6.  

To install:

  1. Install or connect the following:
    NOTE
    Make sure the brake wear indicator wire is held in the correct position by the tab of the dust cap.



    Brake caliper onto the steering knuckle. Tighten the caliper mounting bolts to 42-48 ft. lbs. (56-66 Nm).
     
    Guide bolts to 22-25 ft. lbs. (30-34 Nm)
     



    Wheels
     
    Hydraulic brake system lines and bleed the brake system
     

  2.  

 
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