Brake shake with freshly machined rotors?

Nate Nagel · 2009-06-20T19:29:07+00:00

Hi all,got a bit of a puzzlement. Ever since I've had it, my '08 Impala has had a pronounced steering shimmy under braking - the harder you brake, the more the wheel shakes back and forth.I finally took it in for its first service in my care today, and asked them to balance and rotate the tires and also to turn the front rotors. I ASSumed that this would take care of the issue (the tire balance was because I was also having a shake at highway speed, not to address this problem) but it did not - it's still doing it, and almost as badly as it was before. The rotors show clear signs of having recently been machined; there's obviously marks in the iron that are not circumferential (I'm guessing they must have dressed it with a sanding disc or similar while spinning on the brake lathe after turning) so it doesn't appear to be a halfassed job on the part of the shop.I'd suspected that the cause of this issue was because the car sat for several months unused before I started driving it, so I just ASSumed that the brake shake was due to rust buildup on the rotors (except of course where the pads had sat, causing the rotors to wear unevenly when the car was put back in service.) Of course, I suspect that also the rotors are undersized for the weight of the car, but that's typical, and if it were simply warping, wouldn't it take a while to reappear after machining?Any ideas as to why this could be?nate

Jun 20, 2009 122 Replies

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aarcuda69062 17 years ago

To do what, make a coffee table base out of it? What in your mind makes the rotor "defective?" Because it is no longer in specification?

They require their dealers -service departments- to have lathes so that brake drums and brake rotors can be machined back into tolerance.

It's not misapplied, you just don't know as much as you think you do.

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Tegger 17 years ago

gpsman wrote in news:396d3618-a8a6-4819-a6e9- snipped-for-privacy@g31g2000yqc.googlegroups.com:

What if the new vehicle in question sat around for a few months before being sold? Ever seen how much rust can accumulate in that time? Being in Cincinnati, you should know about winter's damage.

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