LEAVINU

Figure you guys will know best for sure and wondered your thoughts on this:

So yesterday we did some high speed runs at a private airstrip. I noticed after many consecutive runs, while activating ABS a few times, that my brakes seem to drag a bit. Reason I noticed this is because as I was pulling back to the parking area for a rest the car came to a stop without any braking from me from an idle cruise. I got out of the car and tried to move the car and it was very hard to move. Could almost hear brakes still grabbing slightly. After about 15mins of cool down I tried to move the car again and it rolled normal while in nuetral.

Went out did some more runs and same thing when I went to park and same thing after some cool down time.

Is this a need for more cooling at the caliper? I'm running the SL6 Wilwood kit w/ RBF600 up front and thats what seems to stick. Once it sits/cools all seems fine. Even went in the garage this morning and with the wheels off the ground they spin fine.

What do you guys think?

bobmoore2

I'm stumped. That has never happened to me, and I've never heard of it happening to anyone else.

Have you taken the wheels off while the brakes were hot, and taken a good look at the brakes? It could be just one wheel, too.

LEAVINU

No I didn't but I may next time. It only seems to be after the ABS activates I think.

mr.beachcomber

This is new to me; however, given your statement above, try checking out the ABS system to make sure that it's working properly. You might try writing to Chevrolet engineering to see if they have an idea of what it might be also.

During your high speed runs, did you experience any amount of pedal fade just before the ABS came on? Just wondering if by chance you were starting to heat soak your calipers long enough for the brake fluid to start forming vapor bubbles enough to activate the ABS. Maybe that condition had enough pressure to force the pistons out further than normal resulting in pad drag sufficient to stop the car like you explained. Since everything returned to normal after the cool down period, that's the first place I would look. A quick flush of the brake fluid inside each caliper might help.

Good Luck!

PeOR

I have experienced similar phenomenon on both my Corvette and my M3. When I have used up most of the material on the pads and the calipers are hot, the pads are applied to the rotor. And when everything is cool, then it is just like you say. I don't have a very good explanation for this but my thoughts are that for some reason the pistons do not retract as easy when they are almost fully out and the calipers are hot. Every time I have changed to full pads, the problem has disappeared.

You might still want to add some cooling. Corvettes are as fast as many true race cars, but 40% heavier. So, these brakes are suffering from the worst conditions..

PeO.

LEAVINU

I'll look into the ABS module and see what I find if anything.

As for the pads the last time I checked they had a ton of material left but I'll check again.

Guess I should shop around for a simple duct system now regardless.

trackboss

Not sure if this is your problem, but the old wilwood superlight calipers(the cast ones) had the worst drag of any caliper I've ever seen. It was nearly impossible for one to push a car with them alone even with cold brakes. I believe it was the seals that resisted piston retraction.

mgarfias

Which SL6R are you using?

LEAVINU

This one in front with 4-pistons in rear.
http://www.wilwood.com/BrakeKits/Bra...tte&option=C-6

I noticed the W6A kits use a Thermlock piston, wonder if mine have these?

mgarfias

Thats the "skinny" SL6R which has had some issues for some. If you're running it, make sure you put in the thermlocks. I really doubt you have them as they nearly double the cost of the caliper.

LEAVINU

Yeah, looks like I dont have those so researching that now.

longdaddy

check that the caliper is centered over the rotor.

LEAVINU

Most definitely is. Had that issue before.