ilko

This comes in the heals of me completely obliterating my rear brake pads at the track last weekend. My thinking is that if I keep my rear brakes cooler I can get less fade and my pads will last longer.

In the front, with larger pistons and higher pressure, my pads have 30% more surface left than in the rear. I've installed the RS brake cooling ducts in the front, which along with the stock air scoops provide excellent cooling. Can I achieve something similar in the rear?

Now I know the engine is in the rear and there is a lot more heat generated, but if there is any way to get some fresh air in there and someone has successfully done it I'm all ears. I thought of installing some ducts similar to the front and channel them around the trailing arms, but I'm afraid that would interfere with ground clearance.

Anyone been there, done that, and lived to tell about it?

Geoffrey

What kind of rotor temps are you experiencing? It really isn't typical for the rears to get overheated, especially if the stock pressure limiting valves are still installed.

ilko

Unfortunately I don't know the exact temps. Where are the limiting valves located, so I can check if they're still present? I am also running cross-drilled, vented rotors in the rear which doesn't seem to be helping my case much. Everything else is stock.

Geoffrey

The pressure limiting valves are located on the output of the ABS pump, under the black cover in the front trunk. Your car should have only one on the rear circuit since you have 3 channel ABS with 1 brake line feeding both rear brake calipers.

ilko

Thanks Geoffrey, I'll check over the weekend. I'm pretty sure nothing was done in that area by the previous owners but I'll post my findings.

Bill Verburg

I agree w/ Geoffrey. There is something wrong if the rears are getting that hot

ilko

Is it normal to have more pad wear in the rear than in the front on the stock brakes?

Bill Verburg

For your car stock and everything working right, no

Geoffrey

What brand pads are in the rear and which calipers do you have? If Tom put on the Porterfield RS-4s, they wear excessively fast.

ilko

I have (had) the OEM Mintex pads with Zimmerman rotors front and rear. I haven't had any problems in the front with that set up.

Steven C.

Yep, that ain't right. Were the rears locking up on the track? I agree with the others that it is either a proportioning valve problem or pad issue but I run rears almost all year compared to 2 sets of front pads on my race car.

Chris M.

Sounds like you have a sticking piston or other problem causing your pads to drag constantly on the rotors.

ilko

It's not a sticking piston, unless both rear brakes have sticking pistons, which is unlikely. Both rear pads wear out much faster than the fronts...

I don't experience any lock up in the rear at all at the track. I'll check the valves over the weekend and will let you guys know.

Bill Verburg

the only single thing affecting both rear brakes is the p/v. They rarely cause a problem but you never know. There are a couple of seals and a plastic bumper and a thin spring, any of which can cause a problem.

another possibility is oem rubber lines. Their usual failure mode is internal swelling. This allows the brakes to be applied but retains line pressure after release.

ilko

Thank you Bill, I'll check the lines as well this weekend when I install new pads.