MB Medic Mercedes-Benz Repair Guides, Service, How To DIY
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This guide walks through replacing the rear brake pads on a Mercedes-Benz C-Class W203. The pads come out past a single retaining pin without unbolting the caliper, so the wheel usually takes longer than the pads do. That makes it a short job rather than a trivial one. Reassembly and the pedal check at the end are where brake jobs go wrong, so they are written out here in full. These instructions apply to the following Mercedes-Benz W203 C-Class models.
- Mercedes-Benz C230 2003-2007 w/ Sport Package
- Mercedes-Benz C240 2001-2002 Wagon
- Mercedes-Benz C240 2003-2005 Base; Wagon
- Mercedes-Benz C280 2006-2007
- Mercedes-Benz C320 2001-2002 w/ Sport Package
- Mercedes-Benz C320 2003-2005 Base; Sedan; Wagon; w/ Sport Package
- Mercedes-Benz C350 2006-2007 w/ Sport Package
Tools Required
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Jack Stands |
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Hammer. Yes, you will need one. |
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Pin Remover Removal Extractor Extraction Tool |
Parts Required
- W203 Rear Brake Pads. Ceramic Recommended 003 420 27 20 0034202720
- Wear sensors.
- Worth a check before ordering: give your VIN to a dealer parts desk and have the rear pad set confirmed for your car, since pad numbers differ between C-Class variants and model years.
- Brake pad anti-squeal grease.
- Rotors (if you plan on replacing them as well).
Step-by-step DIY instructions on how to change or replace rear brake pads.
- Slacken the rear lug bolts with the car still on the ground. Lift it at the jacking point, set it down on stands, and wedge chocks against the front wheels. The parking brake needs to be off for this: it clamps the rear wheels you are working on, so with it applied the hub cannot turn and the caliper is awkward to reach.
- Open the hood and remove the cap from the brake fluid reservoir. This will allow the brake fluid to return to the reservoir when you press the pistons into the brake caliper. Note the location in the top right corner, marked “Brake Fluid.”
Watch: Mercedes-Benz Rear Brake Pad Replacement Guide
Location of power steering fluid, coolant, brake fluid, and windshield washer. - Remove the rear wheels from your Mercedes-Benz C-Class (C320, C230, C350).
- Remove the brake pad wear sensor from the right brake pad.
- Use a hammer to remove the pin that holds the brake pads. As you extract the retaining pin, be careful not to hit the brake heat shield. If you hit the shield, you may bend it and cause it to make noise when you drive.
- Push the caliper piston back into the caliper body. A purpose made piston press does this squarely and a wide flat bar will do the same. If you reach for a screwdriver, let it press on the old pad only. The rubber boot sealing the piston must not be touched: a split in it holds water against the piston and the caliper will seize.
- Remove the old brake pads and clean the area where the brake pads make contact with the caliper.
- Install the new brake pads. Brake grease goes on the pad backing and the caliper contact points, and nowhere near the friction material or the rotor. Install the retaining pin. Align the brake pads and install the pin by gently hammering it into place.
Putting it back together, and the check that must not be skipped
The steps above stop at the new pads going in, so here is the rest of it. Refit the wheel and lower the car. Start the lug bolts by hand so the threads pick up cleanly, bring the car down off the stands, and tighten the bolts in two passes, each pass moving across the hub rather than to the bolt next door, then set a torque wrench to the figure your manual or the dealer quotes. Put the brake fluid reservoir cap back on and read the level while you are there, since pressing the pistons home sends fluid back up the system and can leave the reservoir above its mark.
Now get the pedal back, before the car goes anywhere. The pistons were pushed in to clear the thicker pads, which means the pads are sitting away from the rotors and the pedal has nothing to work against yet. Ignition off, press the pedal again and again: it will feel long and empty at first and then come up solid and stay there. Start the engine and press it once more to be sure. If you drive off without doing this, the first time you need the brakes you will not have them.
And treat the first few miles as part of the job. A new pad has to lay its own material onto the rotor before it grips like the set you removed, so keep the early stops light, leave yourself plenty of room, and do not go looking for the limit with one hard stop from speed. A pedal that is still long after a few gentle miles is telling you something: look into it before driving further.
Before you buy parts, scan every control module, not just the engine. It shows the root fault behind the warning lights and tells you whether the problem is still active. See how to do a full health check.
