Before you start replacing your rear disc brake pads you will want to raise the rear end of the car and secure it safely with jack supports. Then remove the lug nuts and wheel to gain access to the rear disc brakes. Make sure you have the new brake pads first so you can compare the new ones to the old ones. Remove the pads and clean and lubricate all surfaces. If the rotors are grooved, now would be a good time to replace them and for not much more money. It is recommended to replace rotors at the same time as the pads so both surfaces are new and will work well.