1. Loosen the lug nuts that hold the BMWs wheels on with a lug wrench. Raise the vehicle with a floor jack and lower it onto jack stands at all four corners. Finish removing the lug nuts and the wheels and set them out of the way.
2. Spray brake cleaner on the brakes at all four corners of the vehicle and wipe everything down with a clean, dry rag.
3. On the front drivers side, remove the pad-wear cable from the retaining clip. Remove the plastic covers on the caliper guide bolts, located on the side facing the wheel well on the top and bottom of the caliper.
4. Loosen the upper and lower guide bolts with a 7 mm Allen wrench. Push the bolts out with a thin screwdriver and set them aside. Pry out the anti-rattle clip on the caliper with a screwdriver.
5. Slide the caliper assembly off the rotor. Support the caliper with a piece of wire tied to the suspension or with a platform so there is no weight on the brake line. Disconnect the wear sensor wire from the inner brake pad. Remove the brake pads.
6. Compress the caliper piston to make room for the new, thicker brake pads. Remove the lid on the brake fluid reservoir. Remove some of the brake fluid with a syringe so the fluid does not spill out of the reservoir. Use a wooden handle leveraged against the piston to push it into the caliper. You can also use an adjustable wrench or a C-clamp to press the piston in.
7. Install the new brake pads in the same orientation that the old pads were removed. The inner pad is installed by pressing the metal clip into the caliper piston. The outer pad slides into the slot in the caliper carrier. Reconnect the pad wear sensor.
8. Slide the caliper over the rotor and install the caliper retaining bolts, tightening them firmly. Reinstall the anti-rattle clip and the caps that go on the caliper bolts. Reattach the pad sensor cable to the clip. Move to the rear.
9. Release the parking brake. On the passenger side remove the brake pad wear sensor cable from the retaining clip. Remove the plastic covers on the caliper guide bolts, located on the side facing the wheel well, on the top and bottom of the caliper.
10. Loosen the upper and lower guide bolts with a 7 mm Allen wrench. Push the bolts out with a thin screwdriver and set them aside. Pry out the anti-rattle clip on the caliper with a screwdriver.
11. Slide the caliper assembly off the rotor. Support the caliper with a piece of wire tied to the suspension or with a platform so there is no weight on the brake line. Disconnect the wear sensor wire from the inner brake pad. Remove the brake pads. Compress the caliper piston using the same method as you did on the front.
12. Install the new brake pads in the same orientation that the old pads were removed. The inner pad is installed by pressing the metal clip into the caliper piston. The outer pad slides into the slot in the caliper carrier. Reconnect the pad wear sensor.
13. Slide the caliper over the rotor and install the caliper retaining bolts, tightening them firmly. Reinstall the anti-rattle clip and the caps that go on the caliper bolts. Reattach the pad sensor cable to the clip. Replace the wheels and lower the vehicle to the ground. Check the brake fluid level. Top it off if necessary.