See Figure 1
Fig. Fig. 1: Rear brake caliper mounting position
Most BMW original equipment brake pads are a non-asbestos formulation. If the brake pads have been changed or it is unknown the history of the brake pads, take all precautions as if the pad are asbestos type. Asbestos can cause lung disease and cancers. Never clean the brake surfaces with compressed air and avoid breathing brake dust. Use a commercial brake cleaner and dispose of any rags contaminated with brake dust.
The rear disc brakes utilize sliding caliper similar to the front disc brakes. The parking brake assembly is mounted in the brake rotor hat. This is known a drum in disc design. This allows a simpler caliper design than those that incorporate the parking brake mechanism in the rear caliper. Most of the maintenance procedure are the same as the front disc brakes.