How to Replace Mercedes Parking Brake Shoes

The M-Class uses parking brake shoes inside the rear brake rotors. How do you know if you need to replace them? Inspect the parking brake if the pedal feels unusually easy to press or the vehicle does not stay in place on a hill. You can still have system issues even if you never use the parking brake.  If the parking brake is rarely used, the cables can also corrode and seize inside their housings. This DIY article is focused on replacing the rear emergency brake shoes. 

These instructions cover the W163 M-Class. U.S. applications include the ML320 from 1998 to 2003, ML350 from 2003 to 2005, ML430 from 1999 to 2001, and ML500 from 2002 to 2005.

Symptoms of Parking Brake Problems.

• The parking brake does not hold the car.
• The parking brake does not release.
• The parking brake warning light is on.

When you press the parking brake pedal, you activate the shoes in the rear rotors, which are in the inner part of the rotors of the ML. Although the regular rear brakes use a caliper and rotor, there are shoes in the back (inner part) of the rotor for the emergency brakes.

Replacing the rear shoes in the ML is a job you can tackle. Your biggest challenge will be the springs and clips holding the shoes in place; many will be rusted. We strongly recommend you get a new kit for around $20 and replace them. It will make your job easier, and you don’t have to worry about breaking the old rusted parts.

Before you start this job, get the new brake shoes for your ML. You can buy quality shoes on Amazon for around $20, see this link.  

 

Step by Step Instructions

1. Remove wheels. Secure the car with jack stands. Do not rely on the jack alone.
2. Remove the two 13 mm bolts in the back of the caliper.
   
3. Disconnect the brake wear sensor if you have one.
   
4. Remove the brake caliper with the pads installed. Support the removed caliper with a hook or wire. Do not let it hang from the brake hose.
5. Remove the two bolts shown below.
   
6. Remove the bolt that keeps the rotor centered.
   
7. At this point, you should be able to remove the rotor. If the rotor is seized to the hub, apply a small amount of penetrating oil only at the hub center and mating surface. Keep oil away from the rotor braking surfaces and the parking brake drum. Clean any residue with brake cleaner before assembly. See the wet rotor above? You can hit the rotor to get it loose, but that could cause damage to the rotors. In our case, we didn’t care about damaging the old rotors because we replaced them with new ones.  This is what you should see once you remove the rotors.
   
8. Remove the retaining clip and the pin. The pin comes out from the back.
9. Remove the spring on top of the adjusting mechanism. Retract the parking brake shoe adjuster and remove it if space allows.
   
   
10. Remove the remaining return spring.
    
11. Remove and discard the old shoes. Clean the backing plate, adjuster, and reusable hardware with brake cleaner.
12.  Apply lubricant on the expander bar sliding surfaces, adjuster threads, and appropriate contact points. Keep lubricant completely off the shoe linings and parking brake drum.
13. Install in reverse order.
    
    Put the shoes in place and install the pins and adjustment mechanism. Then install the springs.
    
14. You are supposed to release the automatic slack adjuster. The automatic cable slack adjuster is underneath the center of the vehicle. Below you can see a picture. You will need to lift the center holding clip using a screwdriver. This will allow the cable slack adjuster to reset itself automatically. If the parking brake pedal does not return after release, inspect the return spring and cable mechanism. A damaged or disconnected return spring can prevent the pedal from returning correctly.
    
15. Adjust parking brakes. Once you install the rotors, you can use a screwdriver to adjust the shoes. You will use the wheel bolt hole to turn the adjusting nut we looked at earlier. You can turn the nut both ways. Adjust the star wheel until the parking brake drum holds the hub, then back the adjuster off about five teeth. Adjust both sides equally. After adjustment, release the cable slack adjuster, operate the parking brake several times, and confirm that both rear wheels hold when applied and rotate freely when released.