I'm at Watkins Glen right now with Trackmasters for a two-day HPDE.

My brakes are spongy as heck after coming in for the day and yet they were fine on-track.

Running Ferodo DS3000 in the front with DS2500 in the rear on slotted stock sized rotors and SS lines, Motul RBF600 (which I put in last week with a Motul PowerBleeder), and Tyrolsport calipers.

After parking the car in the 1st gear and letting it sit there for a few hours, the brakes became real spongy and sloppy. This happened every time after my first three track events at LRP....and the Glen is pretty darn hard on the brakes, maybe a bit harder.

Do you think I have air in the lines??

Do you think I should flush my fluid out?

I was thinking that perhaps I did not disconnect the powerbleeder correctly when I flushed the old fluid out last Sunday.....because I just loosened the cap on the bottle when I was done with all the bleeders closed. This created some bubble action in the tube of the bleeder itself and a sucking noise..... but I'm pretty sure I followed the instructions on the bottle....

It held out fine on the street for the past week and was great during my track session....had the instructor LAUGHING about how he thought I was going to run out of brakes but never did....

Someone suggested that perhaps it was due to me parking the MINI and not driving around at all for a few hours with the calipers still hot as heck and perhaps that boiled up the fluid?

In any case, I'll be at the track tomorrow at 6am to try and sort this out before the day starts.

I'm going to try gravity bleeding the brakes. If that doesn't do it I suppose I'll have to flush them again.

Any help is appreciated. Thanks.

 

It's a common problem. I don't know 100% why it happens (I'll leave that to the experts).

Definitely bleed the brakes after every day. Just find someone in the garage to pump the brake pedal 2 or 3 times for each caliper. No matter what, this can't hurt.

 

How often do you bleed the brakes? Just prior and just after a track day or weekend at the track?

Air does get in the lines, but how? Well, it depends on the fluid you are running, the way you bleed the brakes and if you've hit ABS as well and that fluid creates the bubbles.

With Motul 600, you should be fine, but keep in mind, since it has a higher boiling temperature, it is more susceptible to moisture and thus, it will cause the brakes to hold air causing your brakes to be a bit more spongy than normal. If you run Motul 600 or ATE Super Blue/Gold, you might need to bleed more often than usual.

I'd recommend going with one fluid and then another for fully bleeding out the system. i.e. - ATE Super Blue to ATE Gold, where you can see the different fluid change at each flush. Of course, the old Ford's HD fluid (not found at every ford dealership) also works well, and is much cheaper too.

I've used a few powerbleeders, but I always dig the tried and true open/pump/close/lift method with a friend in the car.

 

Something that might help you is to put "Speedbleeders" on each brake, makes for fast bleeding and you can bleed your brakes a different way then you are doing now. I always bleed before a track day and after. Same changing engine oil.