[urq] RE : Brake Judder

[Louis-Alain Richard]

Martin, 

I can confirm the StopTech theory. On the Saab, new Zimmerman discs and
ATE pads, after a long stop at the airport the brakes were feeling like
they were warped... Took a dial gauge just to find that there was no
runout at all. The solution came from inserting abrasive paper between
the pads and the discs, and gently rotate the wheels under the engine
power, after removing the ABS fuse (you'll see why if you don't...).
It's a poor man solution equivalent to resurfacing the rotors on a lathe
(...but I am sure everyone knows now that I am a cheap man...:-)).
Brakes are now fine, no pulsating at all.

Now, the root cause of your shudder might not be the wheels, or the
rotors, or any single part. It may just be the combination of some
parts... Do you have aftermarket wheels ? How big ? Are they hubcentric
? If the wheels are fine on the balancing machine, I'd look at the way
they are installed on the car.

Good luck !

Louis-Alain



> -----Message d'origine-----
> 
> Not strictly confined to Audi but I know the  readers of this list
have so
> much more experience than the usual repair techs!
>     There have been many articles written about  juddering under
braking,
> not
> the least by Stop Tech who essentially say warped  discs are not the
> problem.
> I put new discs, pads, and tyres on my Subaru within  the last month
and
> bedded them in in the usual manner. Brake as hard you like  from 55mph
and
> all is
> smooth. At running speeds in the 60-80mph range there is a  slight
> vibration
> through the steering normally associated with wheel balancing.  Brake
from
> the
> 60-80mph range and there is a sever judder until the speed drops
below 55
> or
> so.
>     Local technician, at very well respected servicing  outfit who
also
> installed the tyres, drove the car and said to replace the  discs.
>     Question?    Anyone experienced  another cause for the judder such
as
> tie
> rod ends, steering knuckle, or simply  alignment?
> 
>     Martin Dapot