DansBlkonBlkZ06

I had some serious taper in my Carbotech XP-10s when I got back from CMP last month. After the second day I had over half a pad left on one end and down to bare metal on the other end. It was exactly the same wear on both pads on both the right and left fronts. The rears didn't have much taper but did show some.
What is the cause of this and is there a fix? I know CMP is hell on brakes, but I'd like to get more than 2 days out of these pads if possible. Thanks for any feedback.

CHJ In Virginia

Three things come to mind immediately. 1) Caliper spread - measure the inside surfaces of the caliper to check that they are parallel. If not - replace calipers 2) Check sliders to make sure that they are moving freely and not frozen 3) most likely - check on freedom of piston movement in the bores - a frozen piston will cause the symptoms that you have - one pushing and the other frozen and not moving. Hope that this helps - Happy Holidays !

JimbeauZ06

Also, check your hubs just to be thorough.

AU N EGL

caliper spread

buy some new C6 calipers for your C5.

C6 PBRs are a bit beefier

edit

Normal winter mod / prep buy new calipers

dfinke23

I had this same problem a while back, and one slider was in a bind.

Sidney004

There are two types of pad taper. Radial taper, where the wear is the greatest at the OD of the rotor and decreases toward the ID; as the others have said, the calipers have spread and they are junk.
Longitudinal taper is across the length of the pad, greatest wear at the leading edge and decreasing; a mild amount of longitudinal taper is expected in a 2 equal piston design with a large pad. Which is it, can you post pics?

DansBlkonBlkZ06

It's longitudinal taper. I trashed the pads, so can't post photo. The strange thing is that the wear was identical for both right and left front as well as inside and outside pads. I wouldn't think sliders, hung piston, or bad calipers would do this for both sides at the same time. I'll check the above items next week and report back.

VTME13

I flip and rotate pads during events depending on the wear I see during post/pre session inspections. This will help even out tapering and let the pads last longer.

froggy47

How many laps at the end of 2 days? If it were calipers it is hard to believe both sides would have the same problem.

Maybe need a "harder pad" and flip them to even things out.

Bill Dearborn

Sounds like typical C5 Caliper Taper. Not due to spread since it can happen to a brand new caliper and can happen on the street. Move pads from right side of car to left side of car without flipping orientation (inside pad from right becomes outside pad on left) after each track day. This will equalize the taper and allow more pad life. You probably started getting a pretty long brake pedal toward the end. Found out about this kind of taper when I took my 97 out for its first track event and had the pedal go low. Bled the brakes several times could not get the pedal to come back. Since the car was new and only had 2700 miles on it I took it into the dealer and they warrantied the brake pads. One other thing to do to try and reduce the amount of taper per session is to ease onto the brake pedal till the pads seat on the rotor and then push hard.

Bill

brkntrxn

Don't buy C6 calipers if you expect to stay legal for NASA TTA/PTA. That would count as a modification.


-Kevin

Falcon

Damn, those aren't allowed? Greg is particular, huh?

You guys can remove half the weight from the car, but you can't substitute like parts.

Sidney004

I have found that the taper lessens when you switch to a pad compound with a higher working temperature. Also, my experience with jammed sliders is excessive wear on the inboard pad, very little wear on the outboard pad, no excessive longitudinal taper.

sothpaw2

Good info!

On the same set of calipers, I've seen some nasty longitudinal taper on non-race pads. Then, switch to the Wilwood H enduro pads...not taper at all. These are very long lasting pads...you do not have to pull your wheels and rotate the pads after each day. I do it after a 2 day event when it's convenient. These pads last a looooong time.

KNSBrakes

The pad is long and the pistons are the same size. Get used to flipping pads. I did it every 2 sessions.

-Ken