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      09-17-2010, 02:09 AM   #1
Virtualshock
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Concentric grooves on rotor

Hi -- I've got a 2010 328 xdrive coupe with about 4k miles on it. In the last two weeks, the left-front rotor developed a pair of concentric grooves inside of the area that comes into contact with the brake pads. (I assume they are grooves because it looks like rust has formed). They don't feel very deep if I slide my finger across, but I wanted to get some opinions on whether this warrants a trip to the dealer to have looked at. Any thoughts on what may be the cause?

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      09-17-2010, 06:48 AM   #2
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Looks like a small stone got caught in the pad for a bit. The stone is probably gone by now. I'd do a couple of reverse stops to be sure, then keep an eye on it. All BMW will do is tell you to leave it as is, or suggest a front end brake job at your expense (this is not normal wear covered by the pre-paid free maintenance program). I'd leave it be unless there is an excessive noise coming from the brake which would indicate a more serious problem. One last thing, in a clear area with no traffic, take your hands off the steering wheel and moderately apply the brakes and see if the car pulls to one side or the other. If it brakes straight then there is no issue.
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      09-17-2010, 06:57 AM   #3
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Looks like a small stone got caught in the pad for a bit. The stone is probably gone by now. I'd do a couple of reverse stops to be sure, then keep an eye on it. All BMW will do is tell you to leave it as is, or suggest a front end brake job at your expense (this is not normal wear covered by the pre-paid free maintenance program). I'd leave it be unless there is an excessive noise coming from the brake which would indicate a more serious problem. One last thing, in a clear area with no traffic, take your hands off the steering wheel and moderately apply the brakes and see if the car pulls to one side or the other. If it brakes straight then there is no issue.
+1, Drive more..worry less.
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      09-17-2010, 08:50 AM   #4
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+1, Drive more..worry less.
+100 This goes for a lot of threads on this forum!
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      09-25-2010, 09:48 PM   #5
jon328i
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i have the same issue with my front left rotors, at 800 miles, i have like 5-6 grooves, my brakes does not make noise at all and functions well, i just let it be, worry less and drive more.
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      09-25-2010, 10:08 PM   #6
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I got one of those and left my car in the garage for 3 weeks...too worried over here. goona find a cheap BBK.
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      09-26-2010, 07:08 AM   #7
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I wouldn't worry about the grooves. By now your pads have also developed grooves to mesh with the rotor - or at least I would think they would have.

If nothing else the rotor will act like a slotted rotor - expelling gas from the breaking action. Heh...maybe.
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