blown brake caliper seals

[fredmeister]

I have a question regarding the seals on brake calipers. My '79 911SC continues to blow out the caliper seals on the front brakes about every 3 years or so. I rebuild them with new OEM ATE seal kits but like clockwork they leak catastrophically every 3 years. I use ATE Blue racing fluid only, and do mostly DE events with street driving.
Has anyone had a problem with ATE brake fluid eating up the seals every few years? What else might be the cause, as the piston surface looks ok?

[Steve Marshall]

How many times per year do you track the car? Is the track you run at a hard braking track? Do you run PF97's? If you're tracking the car a lot on a hard braking track, especially with PF97's, three years between rebuilds is not the bad.

Also, a common cause is built up crap near the far end of the pistons. When you are down to the end of your pads, and your pistons are at or near full extention, the crap will scraping the seal. If the leaks are coinciding with wearing out your pads this could be the cause.

[North Coast Cab]

I think 3 years is good. The SC and Carrera style brakes get so hot on the track the dust seals tend to dry and fall apart quickly. Mine would start to go within a few track days. Cooling will difinetly help too.

John