Strange brake problem. Problem?

[SoCalSHO]

I have been out 1/8 mile racing quite a bit lately. Here is what happens. At the end of my full throttle blast down the track, I have to get on the brakes hard, so I dont overshoot the first return lane. I hit the brakes hard, and in return I get a hard pedal feel. I press down, and I hardly get any movement. I do slow enough (barely), but I really have to put my foot in it. It is like there are no power brakes. Although it is not just racing, I have had it happen a few times on the freeway, kinda scary. Any suggestions as to what the problem could be?

[DJE624]

My problem at the end of a run is like the brakes are too cold.  I kinda have to ease into them and slow down just in time for the turn.  The rotors are probably warped a little but only enough to notice on high speed slow downs.

[FoMoCoSHO]

I have been out 1/8 mile racing quite a bit lately. Here is what happens. At the end of my full throttle blast down the track, I have to get on the brakes hard, so I dont overshoot the first return lane. I hit the brakes hard, and in return I get a hard pedal feel. I press down, and I hardly get any movement. I do slow enough (barely), but I really have to put my foot in it. It is like there are no power brakes. Although it is not just racing, I have had it happen a few times on the freeway, kinda scary. Any suggestions as to what the problem could be?

That sounds like brake fade, I wonder if you have a stuck caliper or sticking ebrake...

[SoCalSHO]

Brake fade as I know it, would go all the way to the floor. This will hardly even let me press on the brake. Kinda like when you have new pads and rotors, you get a feel pretty much when you put your foot on the brake. And This does not happen when staging, only at the end of the track. And only after a high speed run. Lower speeds fine. If I let off the brakes, and then reapply them, it is a little better. By the time I pick up my time slip, Brakes are back to normal. But thanks. And my rotors have no warpage. I can slow down on the freeway from 85ish MPH and not have the problem.

How about a vacuum leak somewhere? The fast acceleration, then 8.4 seconds later, full braking? The ABS does not even kick in when I am having the problems.

[FoMoCoSHO]

http://www.crashforensics.com/brakefailure.cfm
   
"As previously discussed, friction is the mechanism used to convert kinetic energy into heat in a brake system. Friction is the resistance of motion between two objects that are in contact with each other. If friction at the friction surface is reduced to an unacceptable level, the ability to convert kinetic energy into heat will also be reduced. When a reduction in the friction at the friction surface occurs as the result of heat it is called Friction Fade. When friction fade occurs in a hydraulic brake system, the pedal will still feel hard to the driver, but he will notice a difference in the braking response of the vehicle".

[FoMoCoSHO]

Brake fade as I know it, would go all the way to the floor. This will hardly even let me press on the brake. Kinda like when you have new pads and rotors, you get a feel pretty much when you put your foot on the brake. And This does not happen when staging, only at the end of the track. And only after a high speed run. Lower speeds fine. If I let off the brakes, and then reapply them, it is a little better. By the time I pick up my time slip, Brakes are back to normal. But thanks. And my rotors have no warpage. I can slow down on the freeway from 85ish MPH and not have the problem.

How about a vacuum leak somewhere? The fast acceleration, then 8.4 seconds later, full braking? The ABS does not even kick in when I am having the problems.

Yeah the fact that you don't have any issue on the highway after prolonged 85 mph speeds kills the friction fade theory.

Weird. Good luck tracking this down fast.

[SHOdded]

In addition to FoMoCoSHO's suggestions ...  Checked your brake fluid levels?  Dropping slowly?  Vacuum leaks?  Booster could be starting to go bad. 

Since the EBrake assembly is usually on the rear left, if it is sticking, the wheel on that side will likely be warmer/hotter than on the right.  Or you could get yourself an IR temp reader to get precise readings.

[crash712us]

Maybe a vacuum issue, such brake booster check valve. 

[EcoPowerParts]

Do your brakes work normally every other time but after a couple of passes back to back they stop working? That's brake fade. If you're having an issue all the time it's a vacuum line, or something with the brakes such as fluids etc.
I used to have to wait around 15 minute between 1/4 mile passes with stock brakes or the Flex wouldn't stop, now with the changed pads and rotors it's fine, in fact the hotter the brakes the better they stop.

[05yellowgt]

Sounds like a check valve issue to me.

[SoCalSHO]

Thanks All. Fluid Is At A Good Level. It Has Happened In Other Emergency Braking Situations. It Also Happens On My First Run Down The Strip. I Will Check WhAt I Can, Then, Into The Shop. Thanks. And Yes, I Am At The Track, And It Is Doing It Again.

[DJE624]

I'm hoping to hear about some sub 8.5 times.

[SoCalSHO]

Down To 8.41. Now It Is About 45 Minutes Between Runs though.

[DJE624]

YAY!  Hurry up and change your signature! 

[SoCalSHO]

LOL, I Hope To Change It To 8.3 Tonight.