DFac Boy

I recently replaced the front and rear brake pads and discs on my C55. All parts are from the dealer since I had quality reservations about some aftermarket disc rotors and I had heard that contemporary M-BZ pads don't dust as much. While at it, I performed a bleed and flush of the brake fluid. The results are great - there is much improved pedal feel and big time stopping performance with no fade (the rotors were under minimum thickness and the fluid was ten years old).

Parts Used (no affiliation with vendor)
Front disc (345mm) (2) - 2034210912
Rear disc (2) - A210423081264
Brake pad wear sensor (2) - 2115401717
Rotor set screw (4) - 2204210171
Front pad (1) - A0019899451
Rear pad (1) - A0034203020
Paste grease for pads (2) - A0019899451
Brake Fluid (500 ml) - A000989080713

Tools Used (no affiliation with vendor)
17mm socket - Caliper retaining bolts
Torx 30 - Rotor set screw
E12 - Brake pad wear sensor bolt
11mm Line wrench - caliper bleed nipples
Drift punch for caliper slide pins (3mm)
Motive Power Bleeder
Genesis cable bleeder bottle

The Mercedes discs arrive covered with a coating to protect from rust. Common guidance seems to be leave this in place. I wanted to paint the disc centers so I masked off the braking surfaces and used a combination of acetone and bronze wire brush to strip this coating.

I sprayed the rotor set screws with WD-40 and left for an hour or two. Despite worries, these came off easily as did the discs. I re-used all brake pad hardware (slide pins, springs) after soaking them in a solvent and cleaning them. I applied the Mercedes grease paste to the backs and sides of the pads using the pattern of the pads that I removed. For the slide pins and springs I applied a generic disc brake grease to the slide pin and spring friction/contact surfaces. I torqued the caliper retaining bolts to 41 ft-lb.

For the brake fluid flush, I removed 180ml of old fluid from the master cylinder using a large syringe and topped it up with new fluid. I then attached the Motive Power Bleeder with 500 ml of new fluid in the reservoir and pressurized to 25psi. I started at the left rear (my car is RHD) caliper with the listed cable bleeder bottle connected to the bleed nipple. I was shocked at the dark fluid and tons of air bubbles that came out. I bled this location until it flowed clear and likewise for the other three calipers.



Front Disc with OE coating - center prepped for painting




New front disc with painted center. Caliper paint is original - just needed cleaning.





Rear caliper painted with high heat silver.





Rear disc center painted





Front disc after test drive - coating came right off.





Vintage brake fluid!

Khan 55

Nice work. Appreciate the write up and post.