For what its worth, brake rotor warping is a perennial problem for many
vehicles using original parts as well as aftermarket units. BMW in
particular can't seem to make their replacement rotors last more than 10 or
15k (even though the originals *usually* go 50 or 60k.
Intuitively, brake rotor material needs to be more chemically 'pure" than
the average metal part, considering the tolerances that must be maintained
to avoid brake pedal pulsing under heavy use. The continuous heating/cooling
cycles have to be a difficult condition for the metallurgical engineers to
conquer.The usual fix is to go get them "turned', which is a short-term
solution at best, as now you are dealing with a thinner and more susceptible
to failure part.
As was mentioned previously, improper tightening sequence and too much
torque will often contribute to disk, (and wheel) warping, depending on the
wheel hub/disc design. Its a wise owner who insists on proper wheel
tightening using a torque wrench in a criss/cross pattern to avoid these
difficulties.
Dave
----- Original Message -----
From: "Bullwinkle" <yd3@nvc.net>
To: "Eric" <eric@erickson.on.net>
Cc: "MGs" <mgs@autox.team.net>
Sent: Monday, July 16, 2001 12:56 PM
Subject: Re: Warped front discs
> Eric:
>
> <<<snip>>>
> I can only guess that it is 'warping', so I can try to prevent it
> happening again?
> <<<snip>>>
>
> 1) Turned rotors that are now too thin.
> 2) Running through water when the rotors are VERY hot.
> 3) Stuck floating caliper assembly, or stuck piston on one side.
> 4) ?
>
> I heard on Car Talk, a USA radio talk show, that one guy was
> having persistant problems with some new car with warped rotors.
> After alot of questions, the MCs found out that the owner WASHED
> the car right after returning home from his daily commute.
>
> Blake
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