Vibration issue - warped or other?

[CyberPMG]

I seem to be having a vibration issue when braking. At low speeds (40mph and under), the brakes behave normally with no real vibration. At faster speed, gradual braking would cause the steering wheel to shake back and forth. If I'm stronger in braking at higher speed, it doesn't seem to vibrate.

I have Stoptech brakes up front and had the rotor rings replaced last year due to heat checking. I bought the rings from RacingBrake.com and used their hardware kit to attach the ring to the aluminum Stoptech hat.

Some of the original bolts were stubborn to remove and required heating up the bolt to get it out. After replacement, I noticed a few bolts loose on the driver's side and had them tightened up (and properly torqued).

I'm wondering if the heating of the bolts for removal might have caused the aluminum hat to warp. Could it be the rotor ring(s) are warped, or could it be brake pad material on the rotor that's doing this?

I'm using Ferodo DS2500 pads with the Stoptech brakes.

[lookaught]

99% chance it pad depositions. Do you have any track pads? Swapping those in and going out for a hard bed in should take care of the deposits. I used to use porterfield R4's to do this when I had stoptechs, it worked great. Still have them in my garage actually.

[lookaught]

the stoptech hardware also comes with a seep in Loctite, did you use this???

[CyberPMG]

I used the hardware from RacingBrake.com (http://www.racingbrake.com/product_p/fk5-10.htm). It's their own design to attach their rotor ring to the hat. It's supposed to not need Loctite, but I found the driver's side getting loose. I got new hardware and used Loctite when installing (and properly torqued).

Don't have any track pads. I found the Ferodo DS2500 pads to hold up to track use and everyday street use. I've had no brake fade when doing a full day of lap sessions in July at Mid-Ohio. I may look into a set of track pads anyway since I also agree that it may be pad deposits causing this.