RE: shudder when braking

[Eric Billing <eric.billing@sdrc.com>]

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


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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
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