I found an unusual (to me) situation when replacing the rear brake pads on one of my '95 E300D. A dealer replaced the disks and pads at some point just short of 300k mi, perhaps 2-1/2 years ago. It's now at 352k mi. The rear brakes started making noise, so today I started replacing the pads myself. When I removed the old pads on the left, the outboard pad was gone and metal was rubbing the disk. The inboard pad was still like new and seemed to be siezed in the caliper. The right rear brake is in similar condition, but not quite as bad. The outboard pad is down to about 1/4 and the inboard pad is maybe at 3/4.
To sort this mess out, I removed both calipers. There is no evidence of leakage. And when I forced each pistion back (two per caliper) it squirted fluid out the hose connections. So the pistons don't seem to be siezed. But there is a lot of rust/corrosion around the pad guides and pressure surfaces. Has anyone else experienced this? What is the source of this problem? How do I correct it and avoid a repeat? Can I cleanup and rebuild the calipers? Thanks Ned Kleinhenz '95 E300D x2 '85 300D '80 300TD
