Remove the cover plate. The cover plate is only installed on front brakes of cars with solid brake discs (not ventilated) and 57mm calipers.
On models with the brake pad lining wear indicator, pull the cable sensors from the plug connections at the inside edge of the caliper.
Remove the sensors from the brake lining or backing plate.
If the contact pin insulation is worn, the clip sensor should be replaced.
On models with Teves (ATE) brake calipers, use a punch to knock the retaining pins out of the caliper. Remove the cross-spring.
On models with the Bendix (BX) caliper, remove the locking eyes, retaining pins and pad retaining springs.
On models with Girling calipers (usually only at rear axle), remove the locking eyes, the retaining pins and the pad retaining plates.
Pull the brake shoes out of the caliper. Mercedes-Benz recommends a special tool, an impact puller for this, but you can carefully grab the pad backing plate ears with pliers or a piece of bent welding rod and wiggle them out. It's best to leave one pad in the caliper always.
Use a small brush to clean the pad guides on the inside of the brake caliper. Check the dust boots for cracks or damage. If necessary, remove and overhaul the caliper.
When the pads are removed, the pistons will move forward slightly, due to hydraulic pressure in the system. To install the pads, the pistons must be pushed back slightly. Mercedes-Benz recommends a special tool to do this, but a flat piece of hardwood will do if used carefully. Other tools will increase the chances of damaging the piston or dust boots.
It should be relatively easy to push the pistons back.
Check the thickness of the brake disc. Refer to the brake specifications for tolerances.
Check the brake discs for scoring or cracks. Score marks up to 0.02 in. Deep can be accepted as normal scoring.
Clean the air passages of ventilated discs with a thin piece of wire. Blow out all loose dirt. Do not clean with solvent unless the disc is removed from the car.
Clean the rain groove in the backing plate and measure the thickness of the lining. See the Brake Specifications for minimum lining thickness.
To install: Apply a heat resistant, long-term lubricant to the backing plate as shown. Install the brake pad.
Depending on the type of caliper, install the cross-spring, retaining plate, retaining pins and locking eyes.
On cars with a brake pad wear indicator, connect the sensors into the brake lining and the cable to the plug connection.
If equipped, install the cover plate.
On vehicles with a pressure differential warning system (1976 and 1977), the warning indicator may light when pads are replaced. To extinguish the light, push the reset pin on the switch after replacing the lining. The switch is located on the outboard side of the master cylinder.
Wednesday, February 16th, 2011 AT 8:11 PM