Does your Mercedes-Benz brake feel soft and weak? Learn how to fix the problem by replacing your Mercedes-Benz’s front brake pads and rotors.
How to Replace Mercedes-Benz S-Class W221 Front Brake Pads and Rotors
What you will need
- W221 Front Brake Pads
- W221 Front Rotors
- Brake pad wear sensor
- 1-2 cans of brake clean
- Can of WD 40
- Brake grease
- Wheel blocks
- Jack stands
- Impact wrench
- 17 mm impact socket
- Punch (small diameter)
- Medium/ large flat-head screwdriver
- 10mm wrench
- 21mm impact socket
- Caliper hanger (wire or zip ties)
- Torque Wrench
- Prepare the vehicle for service by applying the parking brake. This can be done by pushing the parking brake button on the lower left side of the driver’s dash.
- Place a wheel block behind one of the rear wheels to prevent the vehicle from moving.
- Place the jack under the vehicle in a safe location to lift it. Jack up the front of the car until the wheels are off the ground.
- Place the jack under the vehicle’s lift point just behind the front wheels. Lower the jack until the car is resting on the jack stands.
- Remove the lug bolts and the wheel using the Impact and the 17mm socket.
- Now that the brakes are exposed, unplug the brake pad wear sensor by pulling on it gently.
- Grab the punch and a hammer. Use the hammer to tap on the punch and push the pins out of the caliper. Push the pins towards the inside of the vehicle. If there is difficulty removing the pins from the caliper, push in on the anti-rattle clip in the center.
- After removing the pins, place the flathead screwdriver between the pads and the rotor. Pry the pads away from the rotor as much as possible.
- Remove the brake pads from the caliper. They should easily slide out of the caliper. The flat head screwdriver may be used to help remove them.
- Using the 10mm wrench, remove the bolt that holds the wire and bracket on the caliper. This is where the pad wear sensor plugs in. Set it to the side where it will not be damaged.
- Grab the 21mm socket and impact, and remove the two bolts on the backside of the caliper that holds it to the knuckle. DO NOT remove the Torx bolts on the caliper, or damage will result.
- The caliper can now be removed from the rotor. It must be tied up using some wire or zip ties. DO NOT let the caliper hang from the brake hose, or damage to the hose may result.
- Remove the small bolt holding the rotor to the hub using the Allen head wrench.
- Tap on the rotor with the hammer. If it does not remove easily, more force may be required. WD-40 sprayed on the rotor’s center may also help loosen it.
- Using the brake clean and a rag, clean up the caliper pistons and hub surfaces.
- Install the new rotor. Rotors often come packaged with an anti-rust coating. This coating needs to be cleaned before installing the rotor. Brake clean, and a rag may be used.
- Install the caliper over the new rotor. Start the bolts by hand and then tighten them with the impact.
- Set the torque wrench to 133 ft-lbs. Once the torque wrench is set, tighten the bolts until the torque wrench clicks.
- Place caliper grease on the back of the pads where the pads will come in contact with the piston.
- Install the pads into the caliper. Ensure that the pad material is facing the rotor. If the pads do not slide in easily, push the caliper pistons in with the screwdriver.
We hope you find the Mercedes-Benz S-Class W221 Front Brake Pads and Rotors guide helpful. Check these troubleshooting and repair guides for more help on your Mercedes-Benz.