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      11-30-2011, 07:05 PM   #34
swartzentruber
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Drives: 2011 E90 M3
Join Date: Oct 2008
Location: Chicago NW suburbs, IL

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Quote:
Originally Posted by bruce.augenstein@comcast. View Post
One thing that hasn't been mentioned in this string is that when you pull in with hot brakes and just park it, it's possible to "heat treat' the rotors at a spot just under the hot calipers/pads. Once this happens, the coefficient of friction at that spot will be different than the rest of the rotor, and you'll get some pulsing. Once this happened to me on my '95 (rotors replaced under warranty), I always pushed the car for a foot after a minute or two, then repeated twice more. All done in five minutes, and no more problems.
Bruce
I heard this too in the past from an instructor, and try to do that with my track car. That's really about the only way I can think of for warping the rotors; that, or incorrectly torqued wheels or manufacturing defect. Did you torque them manually by hand yourself?

Otherwise, the pad deposit issue seems the most likely, and if that's the cause, it wouldn't surprise me that it has persisted. Unless you try deliberately (like the Stoptech link), it's difficult to brake aggresively enough on the street to remove track pad deposits. If a pad that lasts 50k miles of normal usage goes by in 500 track miles (speaking very generically), you can imagine how track laid deposits could take a while to wear off on the street.
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