# I think I have warped my rotors



## kowached (Jun 20, 2003)

Steve D said:


> I just sanded them with emery cloth to provide a new abrasive surface for the new pads to seat against.


I've done the same thing with Emery cloth, but now I'm concerned about:



DZeckhausen said:


> Get some "garnet" paper from a hardware store and attempt to remove the deposition layer from the rotor surface. Sandpaper has aluminum oxide and will react with the iron under heat, ruining the rotors. You MUST use garnet paper.


So, Dave Z. what say you about Emery cloth? Its not "sandpaper", but will its components react with the iron under heating?


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## Malachi (Sep 30, 2003)

DZeckhausen said:


> In general, replacement rotors from Brembo, Balo, ATE, or Zimmerman are so inexpensive that it makes more sense to just slap new ones on.


So you are saying that the above rotor manufacturers are about the quality and cost?

Do anyone of them look better than the other or are they your basic looking rotors? Looking for a tie breaker.


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## DZeckhausen (Mar 11, 2003)

Dan540 said:


> Turning a rotor on a $3000 Aimco lathe in the back of a dirty machine shop or installation shop is NOT going to produce the same parallelism, finish and accuracy! For sensative brake systems (Ford calls these 'Tuning Fork brake systems') the runout that would be introduced by these inferior and often worn machines will manifest as vibration and/or pedal pulsation. Most lathes have at least .001 runout on the shaft, with no weight. Add the various cones and adapters (which are usually worn) along with the rotor and that runout can easily be .010. I call this the train wreck, with all the various adapters and the rotors cinched together on the lathe.


Now combine this crummy, out of spec machinery with a chain like Pep Boys that hires kids to turn rotors for $5/each without giving them any training, and you get rotors that are far worse off than when you started.

I only trust a handful of people to turn my rotors. One of them is Steve D'Gerolamo at Ultimate Garage:


























You won't find such nice equipment and such attention to detail at most other places.


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## DZeckhausen (Mar 11, 2003)

Malachi said:


> So you are saying that the above rotor manufacturers are about the quality and cost?
> 
> Do anyone of them look better than the other or are they your basic looking rotors? Looking for a tie breaker.


The above are all very high quality. I would just grab the one that is available and/or costs less.

There are also some Asian foundaries that produce top quality rotors, but it's more difficult to figure out which are good and which are not. Dan540 is president of Centric, a massive brake wholesaler in California, and he supplies quality Asian rotors to retailers around the country. We're lucky to have such a key industry insider right here on the Bimmerfest board! 
:thumbup:


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## Dan540 (Oct 6, 2003)

Thanks!  Just here to learn and help where I can.


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## VANF (Oct 2, 2003)

When the rotors do not need to be turned, but have deposits on them which sanding and direction method do you use with the emory cloth.

Thanks, VANF


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## DSPTurtle (Oct 4, 2003)

When you "scuff" a rotor it is supposed to be in a non-directional manner. I have no idea why, but I do know that is the recomendation. Think "wax-on, wax-off". -


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## DZeckhausen (Mar 11, 2003)

DSPTurtle said:


> When you "scuff" a rotor it is supposed to be in a non-directional manner. I have no idea why, but I do know that is the recomendation. Think "wax-on, wax-off". -


And use garnet paper or make sure your emory cloth doesn't have aluminum oxide.


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