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Discussion Starter #1
I've searched enough to find out that warped rotors are intrinsic to Fox brakes, causing vibration when braking at speed but what exactly CAUSES the warping? For instance, if pad deflection, would stainless bushings cure? There has to be a cause/effect that can be addressed short of complete replacement.... :livid:
 

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According to brake industry experts, Rotors hardly ever "warp", what they do is suffer DTV (Disc Thickness Variation). DTV is caused by impurities in the steel, improper rotor seasoning, and more importantly, uneven deposits of brake pad material usually caused by overheating the pads. These all cause high spots which cause hot spots which cause hard spots which cause uneven wear in the rotor which leads to more high spots and the high spots come through as a pulsation which is what people think is caused by "warping".

IMHO once it starts there's no permanent cure except for new rotors, installed and treated properly.
 

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Discussion Starter #3
That's interesting- I had more of a picture of an unobtrusive wave shape to the disk. That explanation does make more sense considering the frequency of the vibration.
I just had my rotors turned, and replaced the pads with EBC Greenstuff. Sure enough, first time I slow down from 70 or so the vibration starts. Shouldn't turning the rotors take down the uneven spots?
According to this post even replacing the rotors won't fix the problem-

"Matt90GT
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Registered: Nov 1999
Location: Salem Oregon, USA
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Corral IM:




rotors are warped. Common issue on the pre 94 mustangs. It is the design of the rotors that causes it.

Only solution is to upgrade the brakes to the 94+ specs.

new rotors is only a temp solution."

Which is correct?
 

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Matt90GT's answer is always upgrade To 94+ Specs.

It just depends on what your doing and what your braking needs are.

I've been driving mine without having any rotor problems for about 30k miles now. I simply stoped getting cheap autozone/checker rotors and picked up some powerslots. Like MFE said if they arn't a good quality treated rotor they'll wear almost within the first few weeks you drive on them. Resurfacing usualy fixes the problem a bit but removing the metal only makes them get hotter and the problems happen again.

Also stainless bushings are a cheap and nice thing to throw in. It dosn't make a HUGE difference but things work alot better. Especialy even pad wear.
 

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I have physically observed "warped" discs move side to side as they pass the pads, and that runout problem is more common to the newer rotor-on-hub style brakes, but on rotors that are integral to the hub, if they were cast AND machined "true" in the first place then the problem is most likely hard spots causing DTV. And when I say machined true, when I still had stock fox-style brakes I got very particular about rotors and I have seen rotors where the vanes in the "center" of the rotor were not centered and in fact were out-of-true, they'd be closer to one side's face and then the other side's as you turned the rotor. THey were cast crooked and simply machined true. I didn't buy those ones ;)
 
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