Astroman

I struggle with bad brakes almost every weekend and I've tried everything. Any advice (except "more gas, less brake") is welcome.

My car is E stock (stock calipers) with a minimum weight of 2900 lbs. I have all the usual brake cooling items: bumper mounted scoops and ducting through SRP manifolds, rotor backing plates. I even have the titanium shims. I use Motul 600 fluid and bleed after every weekend (at least).

The first pic is a PFC 97 pad after 2 race weekends (Putnam and Road America). The backing plate is bent which causes the pad material to crack and crumble. I gave up on these pads after many years of use in favor of a higher torque pad with less heat transfer (Pagid Black).

The second pic is the Pagid Black after ONE race weekend (CMP). It's worn all the way down to the bent backing plate and is destroyed. I thought I liked these pads (great bite) but obviously this kind of wear is unacceptable (and puzzling).

sig_a

Wild guess -- warped rotors cause excessive caliper vibration which moves the notched pistons off the 20 degree alignment. Rotors must look like hell. I bet the rear are normal looking.

coryf

Check the orientation of the caliper pistons. There is a particular way they need to be rotated in the piston bore. The reason is to keep the pads from taper wear which may be what is hapening. It is tapered so bad it is over wearing the leading edge. Have the calipers been rebuilt latley? It is easy to get the piston installed wrong without the factory tool to line it up.

It could also be the tracks you mentioned. CMP is HARD on brakes. The stock class carrera's allways had a big problem there. We had to make an effort to not use the brakes 100% to save from this type of problem. I have seen the piston seals melt on a E class 911 and a RS america in one day there. We had to totally rebuild the brakes after one event.

Astroman

The front rotors have 3 weekends on them. They look fine.

Thanks Cory. Could a slight variance in the 20 degree alignment cause a MAJOR problem? I just "eyeball it" myself when I rebuild my calipers. I didn't realize there was a factory tool.

I rebuild the calipers after every 2nd or 3rd weekend (I'm telling you, I do EVERYTHING just to get marginal brakes).

Matt Romanowski

Why are the backing plates bending? Even when overheated, they shouldn't do that, especially with the amount of material left on the PFC. Are the pads and shims able to release off the rotor ok?

coryf

Not sure how critical it is to be spot on with the angle. We allways use the tool so no experience with one that is slightly off. The tool is very simple, a stamped piece of steel with the correct angle on one side and a straight edge on the other. It sits against the side of the caliper and the other edge lines up against the cutt out on the piston when it is rotated correctly.

The brakes on those cars are definatley the weak point. Maybe backdate the car to 84-86 ecu specs and run it at a lighter weight? (80 pounds ?) Would take a little stress off the brakes.

sig_a

I think this may be the special tool CoryF is referring to.

This is a "Brake Piston Rotating Pliers" available from samstagsales.com $157.29. It allows you to firmly grip the piston from inside the open end so that you can work the piston back and forth to align exactly at 20 degrees while at the same time setting the piston flush into the caliper. I'm going to buy one.

paradisenb

Jack, don't use CMP as an example. Throw those results out. CMP is infamous for eating brakes.

Here is a picture of the tool: http://www.pelicanparts.com/techarti...er_rebuild.htm

I made my own using a protractor.

Race pads are only good for about 50% of pad thickness. The heat causes them to crack and crumble.

It seems you are having excessive heat issues.

Larry Herman

Jack, I ran a Carrera in DE and racing for 15 years. In the beginning the brakes were great. They had plenty of stopping power and with the cool brake kit, the pads would last for 3~4 events and I rebuilt them every other year. My first set of rotors lasted 6 years. As the tires got stickier, I needed higher torque pads to maximize that added grip for braking, and the wear and rebuild frequency increased to the point where the rebuilds would barely last one event, and on one brake intensive circuit I toasted a freshly rebuilt set of calipers in 3 sessions. The wheel bearing were smoking as well.

If you have to stay with the stock calipers, you have to maximize the air flow to them, the cool brake kit is not enough, and I recommend using a known insulative pad like the Pagid RS-19 or RS-29 that will generate less brake temperature and deflect more of it to the rotor than other pads.

At your point now, it is more about brake survival than ultimate brake performance.

MUSSBERGER

Turbo look and 930 brakes.

dave morris

Get more air to the brakes. Suggestion. Cut out the center panel on your valance, fab a collector box and run two air lines to each side.

J Smith

I came up with this solution on my '87 which seemed to work pretty well. There's just enough room behind the fuel tank to make it work. It definitely forced alot of air through the rotors, and the real nice part was that the airflow wasn't dependent on how fast the car was traveling. Everything was tucked up and out of harms way in case of and agricultural event. Another nice part was I could keep the fans running for a little bit after coming in off the track to cool everything down.

Larry Herman

Very nice Josh.

Astroman

I know CMP is hard on brakes but Road America isn't exactly friendly either. Granted, my PFC 97s sucked there, but at least I didn't wear 'em down to the backing plate.

I have no idea how I could be bending the backing plates. It's got to be the uneven wear but I double checked my piston angles and while it might not be exactly 20 degrees, it's gotta be really close.

I also checked my rears and they fared much better although they still wore down more than I would expect from a single weekend.

Josh, that's some trick sh*t you've got there for brake cooling! I was thinking about buying a set of rotor cooling plates that have two inlets and using my old A-arm scoops in conjunction with my bumper scoops.

Lord knows I wish there was a way to backdate to the '84-'86 Carrera and run 100 pounds lighter. But unless I'm willing to swap my G50 out for a 915, it's can't be legal. Same with the turbo-look Carreras with the 930 brakes... there is no such thing as a turbo-look G50 Carrera (only 915s).

I really liked how the Pagid RS-14s felt out there, even at CMP. Like Larry said, the higher torqe compound was much better suited for my relatively heavy car. I guess I'll give them another shot. Is there another Pagid front/rear combo that would transfer a little more bias to the rear to help spare my fronts? RS-29 in the front and RS-14 in the rear?

Thanks for the suggestions-

Matt Romanowski

With a single piston there is no reason it should bend the plates, especially if they are not full metallic. Do the pads slide in and out (to the rotor, not for replacement) without hanging up at all?