[urq] an ABS issue?

[Brandon Rogers]

does the pulsing frequency change with speed?

Brandon

----- Original Message ----- 
From: "spot.ontheroad" <spot.ontheroad at virgin.net>
To: <urq at audifans.com>
Sent: Sunday, August 07, 2005 11:15 AM
Subject: [urq] an ABS issue?


> Afternoon/evening all. My apologies for the non-urq content but it is an 
> Audi problem.
> My good lady's 1993 Audi 100 Avant has a braking issue which I am trying 
> to solve. The problem is constant pulsing through the brake pedal whenever 
> the pedal is applied - just as if the ABS is engaging all the time. My 
> immediate thought was warped discs (rotors) so I bought some new ones. The 
> old ones were less than 1 year old and I presumed they must have been 
> inferior quality and had warped. Anyway the new (brembo) discs have made 
> no difference at all. There is still a constantly pulsing pedal.
> My thoughts are now that it is an ABS issue not a disc problem. There is 
> no provision on this car to turn off the ABS as far as I know.
> I intend to remove the fuse that handles the ABS and see if the pulsing 
> goes away.
> If it does - it points to it being an ABS problem for sure, but what do I 
> then check and how?
> If I pull each wheel sensor out one at a time, is it possible to tell 
> whether or not it is functioning perhaps by testing resistance?
> Can a wheel bearing problem cause this. We have the beginnings of a wheel 
> bearing whine but I can't tell which front wheel it is. There does not 
> seem to be any wheel bearing "play" yet in either wheel.
> Any suggestions of diagnosis methodology and possible fix will be greatly 
> appreciated.
>
> Many thanks
>
>
> Keith
>
> '87 WR
>
>
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