BMW Maintenance DIYs
Step 14: Remove both the inner and outer brake pads.
Step 15: Using a 16mm socket, remove the two brake pad carrier mounting bolts then remove the carrier. These two bolts are torqued on quite tight so you may have to use a long breaker bar to remove them.
Step 16: The rotor is only held on by a single 6mm hex bolt. Remove this bolt using the hex socket. If the bolt is difficult to remove, apply some WD-40 or similar lubricant.
Step 17: Under normal circumstances, the rotor should be able to be removed out at this point. Sometimes the rotor may be seized on and will not budge. The first thing to do is try hitting the back of the rotor (towards you) to release it.
Note: Unless you are replacing the rotors, cover the rotor with a cloth to protect the surface and use a plastic or rubber mallet to strike it. If you are replacing the rotors, use the largest hammer that you can get your hands on.
Step 18: If the rotor still isn’t budging, apply some WD-40 and let it sit for about 10 minutes before retrying.
Step 19: Once the rotor is out, set it aside. If you are going to remount the existing rotors place them on a cloth to protect the surface.
Step 20: Clean the anti-rattle clip and both caliper guide bolts in degreaser then brake cleaner. Make sure that all residue is removed from the caliper guide bolts. Dry all parts.
Step 21: Clean the rotors to be installed with a degreasing agent then follow with brake cleaner (both sides). Remove any residue with a clean cloth.
Step 22: Make sure to remove all traces of WD40 in the hub area if you used it.
Step 23: Clean the hub area with brake cleaner or with a wire brush.
Step 24: Clean off the parking brake shoes with a rag to release as much of the brake dust residue.
Step 25: Brush some anti-seize compound onto the centre part of the rotor that will be in contact with the hub.
Step 26: Mount the new rotor onto the hub. Try to avoid touching the rotor surface with your (dirty) hands and only hold the rotor by the edges.
Step 27: Rotate the rotor on the hub until the mounting hole lines up.
Step 28: Insert a new mounting bolt and tighten to 16 Nm.
Step 29: Reengage the parking brake (inside the car). If the parking brake handle rises more that about 4-5 “clicks”, the parking brake shoes will have to be adjusted. If this is not required, proceed to step 30.
Parking Brake Adjustment
Step i: The parking brake adjuster resides in the parking brake assembly which is located inside of the rear rotors. The adjustment for the parking brake shoes is done from a small adjustment wheel that is accessible through one of the wheel bolt holes on the rotor.
Step ii: Turn the rotor so that one of the wheel bolt holes is at 12:00. Using a light, you should be able to look into the bolt hole which is immediately down and to the rear of the car and see the adjustment wheel.
Step iii: Insert a flat screwdriver into the hole and spin the adjusting wheel as follows:
* On the passenger side of the car, spin the adjusting wheel downwards
* On the driver side of the car, spin the wheel upwards
Step iv: Continue spinning the adjusting wheel until it cannot be turned any more. At this stage, the parking brake adjustment for that wheel should be fully expanded and the rotor should not turn if you try to. If the rotor spins, the adjusting wheel is not expanded to its fullest position.
Step v: Turn the adjusting wheel in the opposite direction 4 times.
Step vi: Do the same procedure on the other wheel (noting the difference in directions from the opposite wheel). This assumes that you have similarly disassembled the brake on the other side of the car.
Step vii: When these steps are completed, both rotors should spin freely (as much as is normal) and the parking brake handle should only “click” about 4-5 times when lifted.
Step viii: Keep the parking brake engaged.
Step 30: Reinstall the brake pad carrier. Tighten bolts to 67 Nm.
Step 31: Apply anti-squeal lubricant to the areas of the brake pad carrier where the pads will touch. Also apply this to the back of the new brake pads.
Caution: Under no circumstances should any foreign materials such as grease get onto the rotor surface. If necessary, remove any excess anti-squeal lubricant or clean the rotor with brake cleaner.
Step 32: Insert the clips of the inner brake pad into the caliper piston making sure not to touch the brake pad surface material.
Step 33: Insert the outer brake pad into the outer slot in the brake pad carrier.
Step 34: Unclip the wire hanger from the caliper then move the caliper assembly into it’s original position and over top of both brake pads.
Step 35: Reinstall the upper and lower caliper guide bolts. Torque to 30 Nm.
Step 36: Reinstall the anti-rattle clip.
Step 37: Reinstall the plastic caliper bolts caps.
Step 38: Re-attach the brake wear sensor cable to the sensor cable clip.
Step 39: Perform the same procedure on the other side.
Step 40: Reinstall both wheels (torquing the lug bolts to 110 Nm).
Step 41: Remove the jack stands from both sides and return the car to the ground.
Step 42: Start the car and pump the brakes several times to ensure that the pads are seated properly.
Step 43: Take the care for a test drive and ensure that the brakes operate smoothly.
For the first few hundred kilometres, the brakes will seems somewhat less effective than usual – this is normal. During this break in period, avoid sudden, hard stops if possible. Normal braking performance will return after the break in period.
Step 44: Clean up your tools.
About The Author
Baden Smith (May 2004)