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09-08-2018, 05:10 PM | #1 |
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OEM Caliper Piston Dust Boots Damaged from Heat
Just did my first track day in my M3 and ran Hawk DT-70 pads front and rear in stock calipers. Swapped the stock pads back in today and found the dust boots/seals on the caliper piston torn in all but one of my calipers. Wondering if this was caused by heat? Rotors look good (brand new oem) and fluid looks good (RBF660) and brakes performed excellently.
So now what? Can I replace that boot? Is this going to happen again? Am I way too hard on the brakes!? I was lapping Buttonwillow 2:12 and it was 100deg ambient off track. BBK is not an option for now. I do about 2 track days per year.
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Last edited by Bimmer Barney; 09-09-2018 at 10:29 AM.. |
09-08-2018, 08:57 PM | #2 |
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this can be caused by time, but it is most likely caused by heat in your case.
it will happen again if you keep beating on the brakes. you can rebuild them. sometimes this can cause uneven pad squeeze or taper.
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09-08-2018, 11:09 PM | #3 |
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Burned up dust boots are a common problem for a car on the track. Many of the more serious BBKs don't even have them. Without the boots (or with damaged ones), you risk more contaminants getting into the caliper, such as salt, dust, brake dust, etc.
Some use titanium shims to add an extra barrier and prevent thermal transfer. If you don't have decent brake cooling, and are on a track that's hard on the brakes, it's going to happen. You'll be more prone to burn up those seals if you run the pads way down as well. You can replace them. Get a rebuild kit.
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09-09-2018, 06:01 AM | #4 |
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I’d look into titanium shims. Beware they may not fit with new rotors and new pads since the shims add thickness. However there are multiple thicknesses available and you could run double thin shims and take one out if the pads and rotors are brand new and add it back later.
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09-09-2018, 10:03 AM | #5 | |
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09-09-2018, 10:58 AM | #6 |
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I'd say, don't worry about it. I drove my car more than 90K miles with toasted brake piston boots (torn and burned). This was only a problem on the fronts and not the rears. This car is also my daily driver and has no effect whatsoever on brake performance or durability. Perhaps the pistons will wear more quickly since they are exposed to more dirt and grime but I think 90K miles and 3-6 track events per year is pretty good.
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09-09-2018, 01:52 PM | #7 |
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I wouldn't worry about it. When it happened with my first track car(e46m3), I was advised to rebuild that caliper, but it happened again very soon.
Fast forward 12 years of tracking different cars and I never did rebuilding of calipers ever again and never had problems. BTW, most club racers remove those dust boots/seals
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09-09-2018, 10:08 PM | #8 |
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i'm not so sure i would ignore it.
when my rear boots gave up, i started to notice a rust ring around the inner diameter of the rear brakes. it started near the hat and extended out (faded) towards the middle of the rotor. this is indicative of uneven pad squeeze. the pistons were also very hard to retract the last time i swapped pads. if you're going to continue to run them, keep the above in mind and keep an eye on them.
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09-11-2018, 10:00 AM | #9 | ||
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09-11-2018, 12:18 PM | #10 |
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I’ll send you a pm
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09-13-2018, 09:02 AM | #11 |
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Just keep an eye on the shims. There have been some posts on here about them binding.
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09-17-2018, 03:31 PM | #12 |
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Just throwing this in as a data point - I started this track season with a torn boot on my front right caliper. After burning through 4 sets of DTC-70 pads since March, I have observed slightly uneven wear on the inside Front-Right pad. It's not enough where the inner pad is significantly worse than the outer pad but certainly keep an eye on it when bleeding your brakes before events. Hope this helps!
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