When servicing your brakes, one thing to consider is whether you should change just your brake pads or both the brake pads and rotors. Mercedes recommends changing them both at the same time.
We would recommend the same, but if your brake rotors still have a lot of life left in them, you could just change the brake pads.
Replacing rear brake pads on Mercedes W205 is a fairly easy job. The only specific step is releasing the electric parking brakes, as it uses the same caliper as the main brake. However, this can be done without any special tools.
What you will need
- While the vehicle is still on the ground and with the parking brake on, break free all rear-wheel lug nut bolts using a breaker bar and a 17mm socket.
- Open the hood and locate the brake reservoir. Extract a small amount of brake fluid from the reservoir to prevent it from overflowing during this procedure. Refit the brake fluid reservoir cap when you are done.
- Block front wheels to prevent the car from any movement
- Inside the car, turn on the ignition and press and hold both OK and Telephone buttons on the steering wheel until the vehicle data menu appears.
- Use the arrow button to navigate to brake pad replacement and press ok to move the rear brake caliper to the fitting position. You will hear the movement from the back as brake calipers retract. Also, the ABS light will illuminate, and the red brake warning light will flash to confirm the fitting position is active.
- Locate rear lighting points, and lift the rear of your car in the air using a jack and secure it with jack stands.
- Remove all wheel lugs and remove the wheel itself.
- Using a suitable screwdriver, remove the anti-rattle bracket.
- Using a thin screwdriver. Disconnect the brake pad wear sensor from its harness.
- At the backside of the caliper, remove the black plastic caps to gain access to guide bolts.
- Remove the guide pins using a 7mm hex key socket.
- Pull the caliper off the brake rotor. This may take some wiggling.
- Brake pads will remain seated within the bracket, so you need to slide them out.
- Using a brake pad spreader tool, spread out brake pistons to make enough room for new brake pads, which are thicker.
- Before installing new pads into the caliper, fit the new brake sensor to the outer one.
- Install new brake pads into the bracket and pull the sensor wire through the slot in the caliper
- Refit the brake caliper onto the bracket and tighten the bolts to 25 ft-lbs using a torque wrench
- Connect the brake pad wear sensor to its harness
- Refit all remaining parts in reverse order
- Repeat the procedure on the other rear wheel
- Lower the car on the ground and torque all-wheel bolts to 96 ft-lbs using a torque wrench
- Push the brake pedal several times until it gets hard, and then top off the brake fluid reservoir
- Back inside the car, exit the fitting position by pressing OK on the steering wheel. You will hear the movement from the back as the brake caliper squeezes and calibrates its position. After this is done, press OK to confirm.
- Start the engine and press the brake pedal several times until the pedal feels hard again.
- Wheel bolts: 96 ft-lbs
- Rear caliper guide bolt: 25 ft-lbs