Rebuild Brake Caliper 240D - PeachParts Mercedes-Benz Forum

Chris Haney · #1 10-07-2003, 10:20 AM

I need to rebuild a leaking caliper. I have the two halves apart but need some guidance as to removing the piston.

Does it turn?

Ken300D · #2 10-07-2003, 10:30 AM

From what I hear and have done myself, the best approach is to leave the caliper assembled, and use compressed air to carefully blow out the pistons with air pressure. I have an air gun attachment that has a rubber "nose" to it, and that seals well enough to the brake hose inlet on the caliper.

Get one piston started and then hold it enough to let the other one move too. Try to keep it even as they move outward. When one finally gets pushed all the way out there will be a pretty good POP from the air pressure, so be prepared for that noise.

I seem to remember being able to pop out the second piston with air pressure even after the first had been removed. Perhaps I was able to apply the air gun to an internal passageway somehow in order to force out the second piston.

Generally, you're not supposed to break the calipers into halves during service - its a potential cause of leaking.

Ken300D

Wasuchi · #3 10-07-2003, 10:35 AM

Also be VERY careful when using the compressed air. The pistons will come out with a lot of force even when you are using a fairly low pressure, I mean cannon force! A C-clamp can be used to keep the pistons from coming all the way out... this might make it easier to get them both out, did for me anyway.

Chris Haney · #4 10-07-2003, 10:54 AM

Thank you both.

Air it is.