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RE: shudder when braking
Dear Eric,
My mechanic diagnosed such a shudder in the last moments before
stopping as an imbalance in the rotation sensors. He checked and
the output voltage on one sensor was way off 5mv, vs 3-3.5mv for the
other three. He put in a spacer which improved the picture, electrically
and behaviorally, but didn't have time at that meeting to come to
complete balance. I still have an intermittent shudder when I forget to
disengage the anti-lock system and I'm looking foreward to a fix on Friday.
Hope this helps.
Berthann Mulieri
1988 5000 TQCS
On Fri, 13 Jun 1997, Eric Billing wrote:
> Robert,
>
> Again, to provide additional information which was not present in my original post...
>
> The "shudder" characteristic only appears during the final moments prior to a full stop. In my opinion, I am exherting consistant braking during the entire process, and the shudder does not occur until the very end. Sort of like what happens in a manual tranny vehicle which is slowed without clutching...
>
> I'll follow through with a check of the rotors... but I'm still puzzled.
>
> Eric
>
>
> ----------
> From: Robert Myers[SMTP:rmyers@inetone.net]
> Sent: Friday, June 13, 1997 10:54 AM
> To: Eric Billing
> Subject: RE: shudder when braking
>
> Eric,
>
> Let me offer something cheap to try as a possible solution. Simply loosen
> the lug bolts and then retighten them. This time use a torque wrench set
> at 81 foot-pounds. Then drive the car for a while to see if that made a
> difference.
>
> Slightly warped rotors may not show up strongly noticeably except under
> fairly strong braking. If your wife drives as gently as mine she probably
> doesn't routinely exceed that threshold.
>
> I had a similar problem which developed after I had some new tires mounted
> at my local tire shop. The idiot high school dropout "mechanic" cranked
> those bolts down with an air impact wrench so tightly that it took three
> men and a six foot convincer bar on a wrench to finally loosen them. If
> this has happened to your car then re-torquing the bolts may provide the
> solution unless the rotors are *permanently* warped. Which, unfortunately,
> is a strong possibility. Since that experience, I carry my own torque
> wrench in my car for just this purpose.
>
> Good luck.
>
> At 08:56 AM 6/13/97 -0500, you wrote:
> >My original inquiry:
> >> I sometimes have encountered the following with our 93 100 CSQW
> >> While coming to a stop I will sometimes get a shudder which feels very
> similar to that which occurs in a manual transmission when the car is
> slowed without engaging the clutch. The feeling is that of the engine
> trying to continue to move the car forward which conflicts with the brakes
> being applied. My foot is NOT on the accelerator (oh no, not that).
> >> Also, although the sensation is similar to the ABS shudder, it occurs in
> dry, clean conditions where tire slippage is NOT occuring so I would not
> expect ABS to activate.
> >
> >
> >> Any others with similar experiances?
> >
> >Trisha replied:
> >Yep....warped rotors....and it seems that they do that a lot...
> >
> >Darin replied:
> >Our V8Q does it... I think it is called warped rotors my friend.
> >:(
> >
> >
> >
> >Trisha & Darin,
> >
> >Thanks for your replies...
> >
> >If the rotors were warped... why would the characteristic not consistantly
> happen all of the time. My wife is the primary driver so I don't get as
> much time as here, and she says she notices it about every other week. I
> typically get to drive it on our weekend ventures to the lake and have
> noticed it also. From the amount of stops and starts I do (far less than
> her amount), and the frequency in which I notice this symptom, I have a
> hard time suspecting the rotors.
> >
> >Then again, I'm not too smart in these matters... I just assume rotor
> warpage would create a more consistant shudder in all (or at least most)
> braking situations.
> >
> >
> >Eric
> >
> >
> >
> >----------
> >From: Trisha Blethen[SMTP:trishab@interwebb.com]
> >Sent: Thursday, June 12, 1997 9:56 PM
> >To: Eric Billing
> >Subject: Re: shudder when braking
> >
> >Eric Billing wrote:
> >>
> >> Listers...
> >>
> >> I sometimes have encountered the following with our 93 100 CSQW (auto
> transmission of course).
> >>
> >>
> >
> >
> >
> >
> >
> >
> >
> >
> >
> ___
> Bob
> *****************************************************************
> * Robert L. Myers rmyers@inetone.net Home 304-574-2372 *
> * Rt. 1, Box 57 FAX/Modem 304-574-1166 *
> * Fayetteville, WV 25840 USA WV tag Q SHIP *
> * Obligatory quattro and sleddog-L references: *
> * My 3 Siberian Huskies enjoy riding in my '89 200TQ *
> *****************************************************************
>
>
>
>