Rear
NOTE:- If the wear of the brake pads is excessively high or one-sided, check the pistons for easy motion. If the pistons are hard to move then you should recondition the caliper.
- Pads should be replaced when they are down to 2 mm or if they are greasy/oily. Use pads approved by Mercedes-Benz.
- If the pads are worn beyond permissible wear limits down to the back plate, damage may result to the fixed caliper because the web between the sealing ring and the dust cap can break out resulting in a leak. In this case, carry out a high and low pressure test.
- Brake discs with severe lining deposits on the braking surfaces (visible by grey or blue discoloration) must be cleaned using Mercedes special disc cleaning pads before installing new pads.
1. Knock out retaining pins with punch and remove spring lining clip.
2. Remove brake pads using special removal lever tool 123589133300, or equivalent.
3. Force back piston with resetting special tool (31) 000 589 52 43 00, or equivalent.
4. Clean brake pad guide with special brake caliper brush tool No. 000 589 26 68 00, or equivalent.
5. Check dust caps for damage and if needed remove caliper and disassemble.
6. Check piston position with special gauge tool 000 589 35 23 00, or equivalent, and correct with piston tongs 000 589 50 37 00, if required.
7. Check rotors for wear and observe dimensions using Vernier gauge 140 589 05 19 00 and replace rotors if needed.
8. Coat side contact surfaces of brake pad lining backplate with brake pad paste 0019891051 before installation.
9. After installing pads actuate brake pedal several times. Then check and correct brake fluid level in reservoir.
12. Carefully break in new brake pads by braking the vehicle several times from 80 km/h to 40 km/h using only slight pedal pressure and allowing sufficient time for brakes to cool slightly between each deceleration. Brake at high deceleration rates only after pads have been properly broken in.
Vehicles with ASR have a wear indicator on the rear axle as well. the contact sensor wires must be positioned as illustrated in image. Install transperant-type temperature-resistant contact sensors.
The lining quality and dimensions of pads are the same as those on vehicles without ASR. the only difference is that they have a recess for fastening the wear sensors.
On Bendix and Girling fixed calipers, the retaining pins are secured with retaining eyes.
On fixed calipers located behind the center of the axle on diagonal swing axles, the high spot on the fixed caliper piston must point upward, to prevent squealing. On calipers located in front of the center of the axle on diagonal swing axles (with anti-squat control), the high spot must point downward.
Special Tools:
