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Pic explains, yours definitely were damaged by the brake fluids or other incompatible agent, like this Focus RS customer applied his brake grease.
Dust boots damaged by the heat should look like this.
Even the OE boots (on GTR), for a weekend enthusiast, typically would take 6-12 track days to get to this, not two track days.
After rebuilt with RB components (blue boots):
This thread was posted years ago and should be searchable, or if he is reading this thread can tell how these replaced boots last.
If you're tracking your car, dust boots are rather pointless. Even aftermarket ones tend to get cooked with the brake temps generated at the track. The one thing people typically don't understand is that dust boots and piston seals are NOT the same thing. Piston seals are are an internal feature. They sit inside the caliper body, and are designed to keep the fluid from seeping out around the pistons. Every caliper has them, and the pistons slide through those seals as they extend and retract. Since they are inside the caliper body, they aren't as exposed to the heat radiating directly from the discs and pads. OEM calipers tend to have moderately fragile piston seals, but even those do take a reasonable beating before they become brittle from heat and start to leak (while aftermarket racing calipers use special materials that are more durable and heat-resistant).
The bellows type dust boots under discussion above are an external feature. They are designed to keep debris off the sides of the pistons. The dust boots are directly hit with a great deal of radiated heat from the pads and discs. That means they typically cook, melt, fry much faster than the internal piston seals.
As noted above, the ONLY purpose of the dust boots is to keep debris off the sides of the pistons. Why, because if you push a piston back into the piston bore with dirt and debris on it during a pad change, you run the risk of cutting, nicking, or tearing your internal piston seals, which will cause the caliper to leak. You can accomplish the same function dust boots perform, by carefully wiping off the sides of the pistons before pushing them back into the caliper body during a pad change.
Below is a pic of an internal piston seal for reference.
Below is an image that shows how the dust boot covers the sides of the piston as it extends and presses on the brake pad. On the left is how it looks when the piston is retracted, and on the right when the piston extends to press the pads. Once the dust boot is compromised, it's just a piece of useless rubber hanging off the piston.
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'09 Carrera 2S, '08 Boxster LE (orange), '91 Acura NSX, Tesla Model 3 Performance, Fiesta ST
Jeff Ritter
Mgr. High Performance Division, Essex Parts Services Essex Designed AP Racing Radi-CAL Competition Brake Kits & 2-piece J Hook Discs Ferodo Racing Brake Pads Spiegler Stainless Steel Brake Lines
704-824-6030 jeff.ritter@essexparts.com
Last edited by JRitt@essex; 08-23-2021 at 09:16 AM.
https://rennlist.com/forums/997-gt2-...l#post12932164
Put in Racing Brake Kit on my 2007 GT3, in February 2015. Car is dedicated track car, about 10K track miles, 15K total miles. Very happy with the kit.
How the calipers looked after 10K track miles:
08-20-2021, 08:48 AM
