'80 300SD Front Caliper Rebuild

[P.E.Haiges]

I have to rebuild the front brake calipers on my '80 300SD Mercedes because thay are leaking brake fluid.

Are there any tips or special instructions to do this job or it just a simple act of separating the halves popping out the pistons and replacing the parts from the repair kit?

P E H

[vince]

I do not separate the halves when replacing the seals. I force out the pistons, one at a time, with air pressure. I clamp a piece of bar stock with a piece of rubber gasket material attached on the side of the caliper opposite one piston and apply air. The free piston will slide out. I then blank the open side and repeat the process. DO NOT use sandpaper, crocus cloth or the like to clean the parts. I use chrome polish. Place the new piston seals and lube them with brake fluid. Carefully reinstall the pistons. You need to make a driver to properly install the dust covers (the rubber seals you see at the circumference of the piston when looking into the opening). You also need to make a gauge to ensure the proper orientation of the metal shields. Frankly, unless you just love to do this type of thing, the time spent making up the tools makes new calipers attractive to most folks. Some of the old M/B Factory Manuals described the process (like the Passenger Cars from August 1959 up).