Re: Brake adjustment

[Pcarselle <pcarselle@worldnet.att.net>]

Jad Duncan wrote:
> 
> I have an '89 90 Quattra that is a great car exept for a weird brake
> problem.  After driving the car for about 10 miles on the freeway without
> using the brakes, they begin to apply themselves.  The pedal becomes rock
> hard, does not move and all four wheels seems to start dragging evenly.  A
> hard jab of the pedal releases everything and the car is fine.  The ABS
> switch has no effect on the problem and the brake system checks out fine by
> the dealer and an Audi specialist.  I believe, though grasping a bit, that
> the pedal is simply adjusted to high.  There is virtually no play, which is
> usually great, but as the fluid warms and expands I think it needs just a
> little more room.  The pedal has a threaded adjuster, but I have been unable
> to adjust it.  I can remove the U-joint from the brake pedal, but as I turn
> the adjust nut, the threaded rod turns as well.  I have tried to lock the
> rod with vice-grips, but access is limited and it still spins.  Is there
> something I am missing in trying to adjust this?  I am geeting really
> frustrated, but don't want to spend another $100 at the dealer to here the
> brakes seem fine.
> 
> Thanks for any advice.
> 
> *****************************************
> *** Jad Duncan ***********************
> *** Contract Administrator **********
> *** General Atomics *****************
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Jad:
Interesting problem. If your car has hydraulic booster and pressure accumulator(driven 
by Hydraulic pump), I would suspect the the brake booster or  the master cylinder. Some 
pressure may be reaching the booster or master cylinder and applying the brakes. Kicking 
the pedal may help close the valve or (as you say)someone adjusted the pedal pushrod too 
long. The pushrod has a threaded end, a locking nut and a clevis. You must  loosen the 
locking nut before you attempt to turn the pushrod. Use a wrench on the nut and another 
on the clevis. I don't believe the pushrod length is your problem. Did anybody reset the 
length ?. I am more inclined to suspect a hydraulic pressure issue, if your car has the 
system.
Good luck
Pablo