Bert

Having an odd problem here. About a week before going to the track, I had some ATE SuperBlue brake fluid put in my car. Brakes felt great...no problems at all. Went to the track, and after a few sessions, the Brake pedal starting feeling mushy. It was a hot day, and I was on the brakes hard, but I didn't really think I had boiled the ATE...maybe there was some air in the line.

Got home and bled the fluid a bit. Everything looked fine..no apparent boiling and no air in the fluid. Put it all back together and the brakes felt nice and stiff again, but only with the engine OFF. With the engine turned on, the brakes go mushy again and the pedal goes easily to the floor. Actual stopping power is ok, and I tested the ABS a couple of times, but it just doesn't feel right. Takes too much pedal action to get good braking.

Any ideas guys? I gotta get this figured out before going to the Driver's Edge event in September

thanks!
Bert

frayed

You boiled your fluid, which is remarkably easy to do.

I'd flush the entire system by the method of your choice (vacuum, pressure bleed, manual), then do a final bleed with two people (the old fashioned way).

Also, pick up some ATE Gold, so you can visually confirm that all the Blue is out of the system during bleeding.

Be sure not to drag your brakes, it only aggravates the situation. You want to spend the least possible time applying your brakes. As a novice, I boiled mine in 3 run sessions, running stock pads and ATE Superblue.

Bert

Is there any visual sign of boiled fluid? When we bled them after the track, it looked nice and clean. No apparent problems by looking at it.

frayed

Nope, no visual signs that I've ever seen. Mushy pedal at the track, after having good a pedal, is almost always boiled fluid. The times mine have boiled, bleeding got the pedal feel back, but it would deteriorate again. Only a full flush seemed to get it back.

JeffsS2k

I was running with Bert the entire time, and I have the OEM fluid and stock pads and I didn't seem to have any problems at all.

Did you end up warping your rotors like we thought???

cdelena

Maybe a little of both problems..

boiled fluid introduces some bubbles which result in a mushy pedal.

The stock pads are subject to heat fade..
They simply loose some friction properties and require more pressure to stop.

The combination of the two (common in track use of a stock car) reduce the stopping ability without clear cut symptoms.

(and you can run with someone else that does not have the problem.. just takes a few harder stops).

twohoos

[QUOTE]Originally posted by frayed
[B]Be sure not to drag your brakes, it only aggravates the situation.

Bert

Heheh...I was definitely braking later and harder. That was actually the most fun I had at the track because you would come over a hill and have about 50 feet before hitting a hard turn. I took pride in not braking or letting off the gas until my passenger(during one session) had say "WHOA!" at least 4 times

Jeff, Im pretty sure the rotors did not warp. Actual braking has been smooth since the track day and we gave them a pretty close inspection while bleeding the fluid.

At any rate...I plan on putting some Panther Plus pads on and flushing all the brake fluid before my next track day. Thanks guys!

B

Mikey

After track sessions I typically drive around for 5 minutes or so to cool down the brakes. Even after a cool down lap my pyrometer often reads over 600 deg f. A short 5 minute drive around the paddock or nearby road reduces the temperature by at least half.

This can be important because the boiling point of Ate blue is 536 deg. You don't want all that heat to migrate into your fluid.

BTW, the pedal mushiness you noticed is normal with track use, especially on hot days. I've often experienced it, but the brakes always continue to stop the car well.

s2kpdx01

good article about "warped" rotors. Someone passed it to me...now i;m passing it to you.
http://www.stoptech.com/whitepapers/warped...rotors_myth.htm

I used the garnite paper to fix mine..worked great. If you read the whole article you will know what i'm talking about.
cheers