Contents: Removal ↡ Installation ↡
Removal
1. Mark the position of the front wheels relative to the hub with paint. This will allow the balanced wheel to be put back in place after removal so that the balance is not disturbed. Loosen the wheel bolts without raising the car, then place the front of the car on stands and remove the front wheels.
2. Pull the brake caliper outward with your hand, which will cause the brake pistons to be slightly pressed back.
3. Open the plug connection cover (56) by slightly lifting the retaining side tabs with a screwdriver. Do not overdo it.
4. Disconnect the plug (57) of the brake lining wear sensor wire (S10/1). Do not pull on the wire.
[Article was borrowed from the website www.mercedesman.ru]
5. Remove the lower brake piston housing mounting bolt while holding the guide bolt (37) with an open-end wrench.
6. Fold the piston housing (34) upwards and use wire to attach it to the suspension spring. When folding, make sure that the guide bolts do not bend. Never use the piston housing to change the steering angle.
7. Remove the brake shoe linings (43) from the brake caliper. Additional components: 44 – spring clip; S10/1 – wear sensor wire.
8. Remove the wear sensor from the base of the pad. The sensor is usually located on the outer pad. In the "taxi" modification, the sensor is on all pads.
9. If the wire insulation is worn through, replace the sensor.
Attention! Swapping the inner and outer pads, as well as the pads of the left wheel for the pads of the right wheel, is not allowed. It may lead to uneven action of the brakes. All pads of one axle are changed simultaneously. Different wear of the pads cannot be a reason for complaints. If the difference between the thickness of the inner and outer pad exceeds 2 mm, you should still check the guide bolts of the caliper for ease of movement and replace them if necessary.
Installation
Attention! When the pads are removed, do not press the brake pedal, otherwise the brake pistons will jump out of the housing. If this happens due to oversight, remove the caliper and assemble it in a specialized workshop.
1. Clean the guide surfaces, the place where the lining fits in the housing shaft with a suitable soft metal brush and a vacuum cleaner, or wipe with a cloth with alcohol. Do not use products containing mineral oil or tools with sharp edges. Before installing the linings, feel the brake disc with your fingers for unevenness, measure the thickness of the disc.
2. Check the dust boot (45) for cracks. Replace a damaged dust boot immediately, as penetrating dirt quickly disables the caliper. The floating caliper brake mechanism must be removed and disassembled in a specialized workshop.
3. Press the brake pistons with a special tool (031). A piece of wood will also do (hammer handle), however, be especially careful not to distort the piston or damage the piston surface and dust boots.
Caution! When the pistons are retracted, the brake fluid is squeezed out of the brake cylinders into the expansion tank. Monitor the fluid level in the tank. It is advisable to suck out the brake fluid using a siphon.
4. For suction, use a plastic bottle used only for storing brake fluid. Do not use drinking bottles. Brake fluid is poisonous and should not be sucked out by mouth. Use a suction siphon. After changing the pads, the brake fluid level should not exceed the maximum mark, since the liquid may splash out of the reservoir due to thermal expansion. The leaked liquid, dripping from the master cylinder, corrodes the paintwork, which leads to corrosion.
Attention! If the linings are heavily worn, check the ease of movement of the pistons. To do this, insert a suitable wooden block into the caliper and ask an assistant to slowly press the brake pedal. The brake pistons should easily come out and settle back. The second caliper must be assembled when checking. If, due to an oversight, the pistons have jumped out or are difficult to move, you need to remove the caliper and assemble it in a specialized workshop.
5. The next step is optional: to prevent brake squealing, lightly lubricate the back and ends of the pad base (arrows) with lubricants such as Plastilube, Tunap VC 582/S, Chevron SRJ/2, Liqui Moly LM-36 or LM-508-ASC. Under no circumstances should the lubricant get on the pad or brake disc. If necessary, wipe off the lubricating paste immediately and clean the pad with alcohol.
6. Insert both pads into the caliper, making sure that the spring clip is parallel to the top edge of the pad.
7. Place the wear indicator on the outer lining.
8. Return the piston housing to its original position and screw it to the shield with a new self-locking bolt with a torque of 35 Nm. At the same time, hold the guide bolt with an open-end wrench.
Caution! The self-locking fastening bolt can only be used once.
9. Twist the sensor's spiral wire and connect it to the plug connector on the caliper. Close the plug cover.
10. Position the front wheels so that the markings applied before their removal match. Clamp the wheels. Lower the car, tighten the wheel bolts in a cross pattern to 110 N·m.
Caution: Press the brake pedal vigorously and repeatedly until you feel strong resistance.
11. Check the brake fluid level in the reservoir and top up to the maximum mark if necessary.
12. Carefully break in the new brake pads. To do this, repeatedly accelerate the car to 80 km/h, then brake it to 40 km/h with light pressure on the pedal. Let the brakes cool down a little between braking.
Warning! Avoid emergency braking until the distance is 200 km.
13. Brake shoe linings are a special waste material and in each case, before throwing them away, you should find out whether this is permitted.