[Shop-talk] brake shudder

[Karl Vacek]

I used to turn rotors.  And I used to buy super premium brake pads.  And I 
did lots of brake jobs.

When I finally began only buying OES (old GM designation for Original 
Equipment Service) parts I stopped doing so many brake jobs.  Two GMC's and 
a Ford - all with original-specification factory parts.

All the "lifetime" warrantees and high praise from magazines for this 
miracle brake pad or that wonderful rotor can't touch the reliability and 
satisfaction of original parts.

YMMV

Karl

On September 27, 2025 1:51:59 PM Pat Horne <patintexas at icloud.com> wrote:
> Something just came to mind. The O.P. Stated that he measured a maximum 
> deviation of .002”. How was that measurement taken? It could have been the 
> measurement between one surface of the rotor to a part of the car that is 
> stationary, or the thickness of the rotor. Variation in the thickness of 
> the rotor will produce more variation in the pedal than a warped rotor.
>
> As for not turning rotors any more, a local, highly regarded shop says to 
> turn older rotors, especially OEM rather than replacing them with 
> aftermarket rotors because the steel quality of old rotors was better.
>
> Peace, Pat
>
> Pat Horne
> We support Habitat for Humanity
>
>
> On Sep 27, 2025, at 12:24 PM, eric at megageek.com wrote:
>
> John,
>
> A couple of things,
> I didn't think you turn a modern rotor. There normally isn't enough 'meet'
> to remove them and have them be stout enough.  I think that is why
> you had a problem with the turned rotors so quickly.
>
> My other question,
> do you have speed bumps that you regularly have to go over?  What
> about pot holes?  I always learned that braking while going over large
> bumps or pot holes is a good way to warp a rotor.
>
> I'm just throwing
> these out there.  I have no other in sight.
>
> Have a great day.
>
> Moose
>
>
>
> From:
>       "john
> niolon" <jniolon at att.net>
> To:
>       "shop-talk"
> <shop-talk at autox.team.net>
> Date:
>       09/27/2025
> 10:59 AM
> Subject:
>       [Shop-talk]
> brake shudder
> Sent
> by:        "Shop-talk"
> <shop-talk-bounces at autox.team.net>
>
>
>
> well I carry tools
> in my suburban (shop content)
>
> Mt problem is a
> 2008 suburban that has always had a brake shudder (warped rotor) problem
> since I've had it... every year it seems it's
> replace rotor time.
>
> This year I know
> I had two  never turned rotors.  I put a dial indicator on rotors
> and saw no more than .002 runout.. so I decided to just get
> them turned just
> to see what difference it would make.
>
> Took them to a reputable
> shop that turned them and reinstalled.  First drive was thru the neighborhood
> with no shudder.
> Second drive was
> a ten mile trip on freeway... when exiting freeway I felt the shudder and
> it seemed worse than before I turned
> the rotors...
>
> I'm going to tear
> them back down next week to check everything but wondering if there is
> something else I need to check or be
> concerned about.
> I did try stopping with just the parking brake with no shudder so
> that eliminates the rear rotors causing the
> problem.  Pads
> look nearly new and fit in the caliper nicely... Caliper pistons are retracting
> as the should (pads are not bound to rotor when
> removing wheels.
> Lines look ok from the outside. Caliper pins are smooth and well lubricated.
>
> any ideas/suggestions/true
> life experiences/fantastic tales ???
> john_______________________________________________
>
> Shop-talk at autox.team.net
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>
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>
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