BMW 34216859678 Rear Brake Disc

To machine or replace brake discs, first of all, raise the car and make sure it is safe to work on it and remove the wheels. Next you have to remove the brake caliper carrier bolts and support the brake caliper on the chassis using stiff wire and keep the hydraulic brake line joined to it. Turn the brake disc counterclockwise and unscrew the brake disc mounting screw and take off the disc and check for any crack or indication of overheating or scoring. The minimum allowable thickness is indicated staked on the disc hub; with a micrometer measure the braking surface eight to ten times, and comparison should be made using the smallest of the measurements to the standard specification. If the disc thickness does not meet the service minimum or if any damage is observed it should be replaced. Before installation clean the disc with brake cleaner, and always set the parking brake when changing rear brake discs.