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This guide provides step-by-step procedure on how to change the front pads and rotors on Mercedes-Benz S-Class W221.

Table of Contents

What you will need


  1. 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.
  2. Using a wheel block, place it behind one of the rear wheels to prevent the vehicle from moving.
  3. 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.
  4. Place jack stands under the vehicle’s lift point just behind the front wheels. Lower the jack until the car is resting on the jack stands.
  5. Using the Impact and the 17mm socket, remove the lug bolts and then the wheel.
  6. Now that the brakes are exposed unplug the brake pad wear sensor by pulling on it gently.
  7. 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 any difficulty removing the pins from the caliper, push in on the anti-rattle clip located in the center of the caliper.
  8. After the pins are removed, place the flat head screwdriver between the pads and the rotor. Pry the pads away from the rotor as much as possible.
  9. 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.
  10. Using the 10mm wrench, remove the bolt that holds the wire and bracket on top of the caliper. This is where the pad wear sensor plugs in. set it to the side where it will not be damaged.
  11. 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 caliper damage will result.
  12. 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.
  13. Using the Allen head wrench, remove the small bolt holding the rotor to the hub.
  14. Tap on the rotor with the hammer. If it does not remove easily, more force may be required. WD-40 sprayed on the center of the rotor may also help to loosen it.
  15. Using the brake clean and a rag, clean up the caliper pistons and hub surfaces.
  16. 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.
  17. Install the caliper over the new rotor. Start the bolts by hand and then tighten them with the impact.
  18. Set the torque wrench to 133 ft-lbs. Once the torque wrench is set, tighten the bolts until the torque wrench clicks.
  19. Place caliper grease on the back of the pads where the pads will come in contact with the caliper piston.
  20. Install the pads into the caliper. Ensure that the pad material is facing the rotor. If the pads do not slide in easily, use the screwdriver to push the caliper pistons in all the way.