All models except M3 need you to block both front wheels while loosening the bolts on the back wheels to 1.4 turns. Best way to do this: lift and stabilize the vehicle, then take off the back wheels without touching the brake caliper hose, holding up the caliper with mechanic's wire to protect the line from harm. Before working on the brakes, take off the brake caliper and its fitting. Insert a 6mm hex socket into any of the angled, recessed hex bolts. Place penetrating oil on rusty bolts, while applying a gentle burst of impact power from a hand-held tool helps loosen them. To get the frozen brake rotor off, slide the attaching bolt 3 turns and spray penetrating oil along where the rotor meets the hub. Secure the wheel with two strong bolts turned about 10 times, then hit the straight rotor-hub face without hitting the grinding surface. When replacing, look at the rotor disk to make sure it's in good shape. Make sure any protective film is off a new rotor before putting it on. Use light anti-seizing spray to clean the hub and brake rotor surfaces, then put in the braking rotor hold-down bolt and tighten it to 12 foot-pounds force (16 Newton-meters). Check and adjust the parking brake as necessary. Each wheel goes back on and lug bolt turns by hand until the vehicle reaches the ground. The tires then make contact, and lug bolts get tightened in a cross pattern to 66-81 foot-lbs force (90-110 Nm force). Do five slow, easy stops at 30 mph (50 km/h), let the brakes cool, then make five more stops at the same speed to make sure your brakes work completely. When checking the rear brake rotor, just like the front, you use the same steps.
