Originally Posted by rbahr

Hi all,

I posted this over on the nasioc site (Scary discovery for brakes on tracked car - Brakes, Steering & Suspension - NASIOC), but I wanted to broaden the audience... It also turns out I am not the only one to see this...

Hi All,

I have an 06 STi that is heavily tracked (it has ~10k miles on it), in fact this is what I mostly use the car for. I have a nice suspension, run R compounds, PF01 pads, PF front rotors, Valvoline Syntec brake fluid that I change out between events. I will run 20-25 days a year.



I have ALWAYS had brake cooling problems and actually run 3" ducts into the center of the rotors. This year my rear wheel bearings went bad largely from heat (one catastrophically while I was on the track, the other I replaced. Even with the ducts and the better rotors cooling was largely on the inside of the rotor. The pictures of the calipers show a very distinct change in color from inside to outside.



I spent the $$$ to get the Stoptech 355 mm setup for the front (great solution BTW) and as I was taking the old calipers off, I saw brake fluid on the back of a pad.

I was planning to rebuild the calipers and sell them off but found this instead:



These are no longer usable. The speckles you see on the pistons were present on all 8 pistons (in the front). I spoke to a bunch of folks, and ended up connecting with Brembo Racing in SC. The guy on the phone actually knew of this problem and explained it...

When you get certain brake fluids very hot they get extremely (relative term here) acidic. (Castrol is one of those and I guess Valvolene is another). This will essentially destroy the coating that Brembo puts on the pistons.

Now who is to blame here: Brembo claims that the fault of the brake fluid manufacturers, I have not spoke with them, Subaru doesn't care because if you get your brakes that hot you are probably doing something you should NOT be doing, and besides you cannot get just the pistons...

Castrol HAS changed their formulations (at least with SRF), so perhaps they are assuming some responsibility.

The folks at Brembo told me that the Brembo brake fluids, the AP 600 and the Motul did not have this problem...

Bottom line: These brakes ARE NOT DESIGNED FOR RACING- just good looks and heavy street use

Other thought, if you track your car and get the brakes real hot, you may want to do a rebuild and see how your pistons are holding up.

Ray

Originally Posted by scutzi128

Doesn't nissan and mitsubishi use the same calipers?

Originally Posted by CHAOS

suck? nah.... they just arent meant to be abused on a track every weekend...