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      04-20-2013, 08:47 PM   #15
r53s65e90
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Drives: r53 s65e90
Join Date: Mar 2009
Location: San Jose, CA

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Quote:
Originally Posted by The HACK View Post
I'm going to go the OTHER way and suggest it's not pad deposit, since if it really IS pad deposit, the vibration issues would surface even when brake system is cold.

I suggest taking the brake rotor off and inspect the fasteners and make sure each one is torqued to specifications. Sounds to me like the rotor isn't expanding at consistent rate, or one or multiple fastener is binding the rotor preventing it from expanding, resulting in unbalanced rotor when it heats up, and unbalanced rotor causes enough "wobble" that translates into a vibration in the front end on braking.

I had similar "symptoms" on my MZ4 Coupe with 2 piece floating rotors, normally the first few laps the brake feels fine, then when I brake the front end shakes, but once the system cools off the car feels fine. It's only when I was removing my rotor rings to replace with new rings did I notice one of the fasteners appears to have bound up and was 10X more difficult to remove than all the others. Swapping to OEM rotors solved the problem, still yet to see if new rotor ring will prevent it.
Great point. This probably explains why later kits (like the US 365 and 380 kits) have fasteners that look like the attached image: no matter how hard you torque this fastener, the disc will still be able to float unobstructed. Also explains why BMW probably designed their own rotor for the GTS kit, which is essentially the euro M monobloc caliper.

I still think a race pad would be the first thing to try out. Stock brembo pads behave very similarly to the OEM stock pads: when they overheat they create deposits that eventually should go away with normal driving.
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