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Scott Buttfield

Front Rotors Warping

I have a 2008 Audi RS 4 Sedan.  At ~50,000 a strong shimmy developed with the brakes - the steering wheel shook like crazy.  Had new rotors and pads put in, all four wheels.  Car ran fine for ~3,000 miles or so, and then the steering wheel shake came back.  My mechanic then replaced the rotors (Brembo) and checked the pads, as the problem is most certainly due to overheating.  The problem came back.  We checked everything again and found that there was a plate, apparently steel, at the bottom of the caliper that sat on what appears to be aluminum caliper.  A lot of corrosion had built up which apparently was keeping the pistons from fully retracting.  This was cleaned out and the problem appeared to be solved.  I then took the car on a ~1,000 mile trip, last week, and the problem came back.  At this point I am pulling my hair out.  Has anyone else had this problem and if so, do you have a solution?

Scott Buttfield
IchBautAuto

Re: Front Rotors Warping

Scott Buttfield wrote:
I have a 2008 Audi RS 4 Sedan.  At ~50,000 a strong shimmy developed with the brakes - the steering wheel shook like crazy.  Had new rotors and pads put in, all four wheels.  Car ran fine for ~3,000 miles or so, and then the steering wheel shake came back.  My mechanic then replaced the rotors (Brembo) and checked the pads, as the problem is most certainly due to overheating.  The problem came back.  We checked everything again and found that there was a plate, apparently steel, at the bottom of the caliper that sat on what appears to be aluminum caliper.  A lot of corrosion had built up which apparently was keeping the pistons from fully retracting.  This was cleaned out and the problem appeared to be solved.  I then took the car on a ~1,000 mile trip, last week, and the problem came back.  At this point I am pulling my hair out.  Has anyone else had this problem and if so, do you have a solution?

Scott Buttfield


Don't own that model so any secret causes aren't known to me. Broadly, a front shimmy could be caused by warped rotors, wheel balance, stuffed dampers or a defective steering component or a combination of a few. You have honed in on warped rotors but not said if it is one or both and what the run out was and whether F&R or just F. I would have thought that that was pretty essential to discount any other issues.

The frequency this occurs is a bit alarming, got to be something that is becoming more frequent with time which tends to indicate a contributing factor of wear somewhere.

I would suggest a caliper rebuild if nothing else. If the brakes are effectively remaining applied, all the new rotors in the world won't change that, and checking upstream for obstructions to the pressure releasing might be in order. Internal damage to brake hoses??? It sounds almost like a non return Vv in the system.
jockthedog

When the shaking starts, are the rotors red hot or cold?
Red hot = sticking piston.
cold = not that.

possible wheel bearing?
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