Brake pad installation questions
I know on the VW/Audi the rear can be a pain because you have to twist and push the piston back in. Is the E320 the same?
I know on the VW/Audi the rear can be a pain because you have to twist and push the piston back in. Is the E320 the same?
Mario
Assuming you do this yourself, I would not recommend (and nor does Mercedes or any ABS manufacturer) that you simply push the old fluid back into the system by compressing the piston. Rather, before you pull the pads, crack the bleeder screw on the caliper and have an assistant depress the brake pedal slowly and halfway down and hold it (this starts the fluid out of the bleeder screw, ensuring it's open, and also prevents against fluid being pushed back up; the only place it can go is out the screw). With the assistant still holding the pedal halfway down, you can then pull the pads and press the piston back in, forcing the accumulated fluid in the caliper out, rather than back into the system. Once the piston is compressed, you can then retighten the bleeder screw and your assistant can let the pedal up. You should not introduce any air into the system if you're careful about this process, but bleeding is never a bad idea once you're finished.
Note that you will not lose very much fluid through this process, but you should have a catch-can and a clear hose on the bleeder screw is always nice. I'd also recommend ensuring that you check and refill the master cylinder as necessary as you do each caliper.
Pushing old fluid back into an ABS-equipped car is asking for trouble as the impurities in the old fluid may block the pinhole passages in the system; I've had that happen -- once -- and won't ever do it again.
Good luck and enjoy the ride,
Greg


