[87roadracer]

I just registered my road racing Mustang with the DMV and have been driving it on the street to shake it down in prepartion for next years Time Trials at Lime Rock etc. I presently have 4 piston JFZ racing rotors with Hawk Performance BLACK pads installed. Once the rotors and pads are warmed up with some good stops and I then move on to some really hard stops. At that time sparks begin to fly out of my front drivers side rotor! I do have a brake bias valve and have turned it more toward the rear. I don't want it turned too much to the rear and lock up the back brakes first. Does anyone have any thoughts on this? Should I switch to a less severe racing pad? I removed the pads to see if anything was stuck to them and they looked normal. The car does stop well...if you don't mind having sparks flying out of the rotor.

Thanks.

[LoneGunman]

I don't think the temps that those pads like to operate at can be obtained on public streets. Those pads like to be HOT not warm. Still, the sparks are wierd.

Which rotors do you have? What are they made of?
What calipers?

[87roadracer]

I have 4 piston JFZ calipers and rotors. Not sure of the exact metal composition of the rotors. I do have some roads in my area that the brakes can be brought up to temperature. It seems that 3 or 4 hard stops from about 75 MPH the sparks seem to fly. Yes it is very weird. The pedal does feel good and I was wondering if I should bleed the system again. I have high temp brake fluid in the car.


Any thoughts?

Thanks!

[LoneGunman]

JFZ makes aluminum, steel, and cast iron rotors. Hopefully you have cast iron. If you get rust on your rotors, you have cast iron.

Are these the only pads you ever used with these rotors?
If not, what were the other pads?

[87roadracer]

I do have steel rotors and the Black performance pads are the first set of new pads I am using on rotors. I don't recall the type/brand of the former pads. I still have them as a backup. I think this weekend I'll swap in the used pads and see what happens. I'm also going to contact Hawk Performance to see what they say.

Thanks.

[LoneGunman]

I don't know if Hawk recommends there pads be used on steel rotors. That may be the problem. Also, Hawk recommends that the pads be used on new rotors or rotors that have only been used with their pads. If your previous pads were Performance Friction they recommend resurfacing the rotors before using their pads.

I personally think using steel rotors is bad. Steel is a very poor conductor of heat, so it doesn't cool down quickly. I hope you have some serious cooling ducts on you brakes.

Here is a link to some very good brake tech...

http://www.stoptech.com/technical/