Path: utzoo!utgpu!alliant.com!UUCP Reply-To: british-cars@alliant.com Errors-To: british-cars-request@alliant.com Sender: british-cars-request@alliant.com Return-Path: Date: Fri, 2 Feb 90 18:01:35 EST From: mason@vax.ftp.com (Nark Mason) Message-ID: <9002022301.AA22752@vax.ftp.com> To: british-cars@alliant.alliant.com Subject: Disc brakes Newsgroups: list.british-cars Distribution: ut Approved: devnull@gpu.utcs.toronto.edu About 2 months ago I replaced the brake pads on my TR250. The old ones were almost compeltely worn so I had to push the pistons back into the caliper body to make room for the new pads. About 30 miles later, while driving up a large hill, I pushed down on the brake pedal and almost nothing happened. I took this opportunity to rebuild the brakes, among other parts, and found out what had caused the failure. The pistons had rusted and pitted up to, but not past, the sealing gasket in between the caliper body and the piston. When I pushed the pistons back into the body the seal was now resting on the pitted area of the piston which didn't make a good oil seal, and the brake fluid squirted out through the rust. I guess the piston boot can be expected to keep out only *almost* all of the moisture.