PDA

View Full Version : Brake fade or what?



Evo442
10-15-2005, 07:00 PM
Ok, so I'm at Thill today, nice and cool out. All of a sudden, at the tail end of the 2nd session, the brake pedal goes almost all the way to the floor, like instant brake fade. Usually, in my experience, pad fade is a lot more gradual.

I take it easy and get the car back to the paddock. visually everything seems ok, drive the car around for a while to really let the brakes cool off well. Take the car out for the next session, and the brakes feel better, but not right, very mushy. Then, part way through the session, things firm up and the brakes are better for the rest of the day. they did seem a bit hard to modulate tho' and kind of inconsistent.

does this ring a bell with anyone? the brake fluid is ATE and was just changed. Brand new PF pads on front, and Ferrodo DS2500's on the rear. I'll admit I didn't properly bed the pads, was planning on bedding them at the track so to speak. The Pf's have done well for me in the past, I've never tried the Ferrodo's.

thoughts?

earlyapex
10-15-2005, 07:33 PM
sounds like you boiled the fluid.

How's the fluid look now? Was there any mushyness before the brake went to the floor?

Good have been worse, you could have crashed.

Pad fade, the car just doesn't brake but the pedal won't go to the floor. It is weird that they just came back to normal. I would almost suspect something funky going on with the master cylinder or a leak somewhere that healed itself. Maybe the seal is going in the master cylinder?

You also stated that you just bled the brakes, maybe a massive airbubble was still in there somewhere.

*edit* You really need to bed the pads off the track, as you bed new pads in, they experience "green" fade where the gases get released. Come to think of it, that might be what you experienced, since it was your 2nd session, and they came back after you cooled them off. In other words, you bed them in during the session and where lucky enough not to kill youself. :)

Evo442
10-15-2005, 07:55 PM
hmm... interesting thoughts. thx

guess its a good thing my life insurance is paid off!


hopefully its not a master cylinder problem. that would suck.


going to bleed the brakes tomorrow and see how everything feels.


You dont think it could have anything to do with the match between my front and rear pads, do you?

earlyapex
10-15-2005, 09:59 PM
You dont think it could have anything to do with the match between my front and rear pads, do you?

Nope, I run/ran the PFs in front and porterfield street pads in the rear.

I really think it was "green fade" that you expirenced since you didn't bed them in prior to the event

Evo442
10-16-2005, 05:34 AM
Ok. so some observations.

Had a lot of air in the brake lines when I bled them last night. Brake fluid level in the reservoire was high, ie near the top of the container. I know that I had it exactly at the "max" line when I last bled the brakes. My rotors are also pretty much done.

Maybe the rotors contributed to brake fluid boiling?

Cameron@xperformance
10-16-2005, 10:29 AM
how did you like the ds2500?

Evo442
10-16-2005, 02:16 PM
how did you like the ds2500?

They were on the rears, so its hard to tell. My brand new PF front pads were crumbling after only 5 twenty minute sessions, I'm wondering if the rear brakes with the DS2500's were'nt doing their share of the braking...

earlyapex
10-16-2005, 03:34 PM
I'm wondering if the rear brakes with the DS2500's were'nt doing their share of the braking...

No, you are just going alot faster now, and on r-compounds. I killed my PF's last event. They do crumble around the edges when you get them real hot, they still work though.