How to Replace the Rear Brake Pads on an Audi A4

1. Park your A4 on a flat, level surface. Place the vehicle in gear if it is a manual; if it is an automatic, ensure that the transmission is in “Park.”
2. Loosen the lug nuts that hold the rear wheels on. Raise the rear of the vehicle with a floor jack and lower it onto a pair of jack stands. Finish removing the wheels and set them aside.
3. Spray brake cleaner on the rotor, caliper and nearby areas and wipe them down with a clean, dry rag.
4. Remove the two large hex bolts that hold the caliper to the caliper bracket. These are located on the top and bottom of the caliper on the side that faces the wheel well. Use the proper hex bit and a ratchet to remove these bolts. You may need a breaker bar (an extension on the socket) to remove the bolts.
5. Slide the caliper off the rotor. Support the caliper while you work with a piece of wire tied to the suspension or on a platform of some sort to prevent damaging the brake line.
6. Remove the pads from the caliper. They may simply fall out when you remove the caliper from the rotor. Open the lid to the brake fluid reservoir, which is located in the engine bay. Remove some of the brake fluid with a turkey baster or syringe. Do not remove so much fluid that the air is allowed to enter the hole in the reservoir that the fluid goes through.
7. Use the special Audi caliper piston tool (see Resources) to retract the piston into the caliper to make room for the new, thicker brake pads. Place the tool in the indents in the piston and then carefully turn the tool. The piston should retract as it turns.
8. Install the new brake pads in the caliper. Slide the caliper over the rotor and install the two hex bolts that hold it on. Tighten the bolts. Reinstall the wheels. Lower the vehicle to the ground. Pump the brake pedal a few times or until it feels firm again. Check the level of the fluid on the reservoir and top up if necessary.