savyboy

Five track days on Pagid P50 Greens, the PCCB "Motorsport" pads.

Rear brakes destroyed in bizarre fashion. Passenger side outboard pad beveled into oblivion. Inboard pad no bevel.

Driver side inboard pad badly beveled, outboard pad flat.

WTF is going on? This is crazy? Just how flexy are these calipers? Is the piston sizing totally screwed up? This is the kind of thing that really sticks in my craw given Porsche's "Racing, not Posing" marketing approach.

I am aware this is a known problem, so why doesn't Porsche step up and fix it? A pretty damning view of Brembo quality and engineering, that is for sure.

Furthermore, one caliper piston dust boot on each caliper is badly cracked. 6 month old car, 7000 miles.

If you are tracking, it is critical that you examine the leading edge of your inboard pads as you could easily get into the pad backing plate and destroy your rotors and never trigger a low brake pad warning on the dash.

As Peter (TrakCar) noted in a different thread, the new RS eats rear pads on a 2:1 ratio vs front pads.

This is wrong on so many levels

Larry Cable

I have to ask, especially since the pad wear is asymetric, were the calipers in question removed or adjusted during the rebuild?

This is way beyond my understanding of the braking system, but perhaps it indicates either some (static or dynamic) misalignment of the caliper wrt the rotor, or some issue with the piston pressures/operation or both?

savyboy

Hi Larry- when you mean rebuild, I am guessing you mean last pad replacement? The rear calipers must be removed to replace pads, and the caliper does not float, it is bolted solid to the hub/carrier. There is no opportunity for caliper misalignment. And even if it were, both pads would be worn asymetrically.

mooty

all my gt3 bevel, but NOT like that!
i, however, flip the pads, inside and outside every other 2-3 track days.

the dust cap... HAHAHA, my crack usually after two track days. i dont replace them, never did, never had issues.

Larry Cable

actually no I mean as a result of the damage repair!

rodjac

pete: I usually get more beveling from the front pads and it is much more uniform from inside to outside pads and from side to side. The shape of the rears on the side with the most beveling almost makes me think that the piston engagement is off form inside to outside with one side doing most of the stopping. As Mooty indiicates, the dust seals go quickly--they just don't seem to be able to stand up to the head from track usage and it really helps to flip the pads. By the way, five track days on a set of pads is very good. Also I notiiced better dust seal and brake pad wear since installing rear cooling ducts.

TRAKCAR

Hi Savy,

I THOUGHT they were wearing even, but after 8 track days (Flipped fronts after 4 days) I can report that the fronts are holding up better, but not 2:1. I would say 8-10 days of the front pads and 6-8 on the rear. Never SC ort TC on.
I have about 5mm of material left on the front pads and maybe 2mm (inside some bare to metal to meal). This is just eye balling, I will measure once I take them out and take some pics, also from rotors.

It was 95F at Sebring this weekend, VERY hot, we all had 4 smoke columns coming off the track if we momentarily could not move the car for cooling down... The holes in the rotors are about 50% welded shut looks like, but the cracking is not too bad yet.

roberga

unfortunately it looks pretty normal. More taper than most but taper is "normal" Even in the Pacific Northwet.

I do not understand why it NEVER happened in my 996GT3 with PCCB but I do not know a 997GT3 which does not have a taper. Porsche says it is normal.

rosenbergendo

I guess steel really is the only way to go!

scott40

This may be a very dumb question, but how do you check the inboard pad without removing the wheel and caliper?

brendo

I am so deep on this right now it's embarassing.

i had 3mm on 3/4 pads on the fronts, 5mm on the rears. the front inside wore so bad the backing plate did destroy the rotor. porsche replaced it. i got the brake warning in the paddock and cancelled my next day so i wouldn't do any harm. it was a big surprise to see the damage to the rotor in the left inside.

however, my rears are perfect. i usually leave PSM on (the car is still relatively new to me) but run with it off some to see if i'm engaging it because we suspected it was an issue engaging too much and building heat. i have the GT3 cooling ducts on the rears so i think the cooling increase there was critical. of course, i'm running a C2S so i may have a different bias, etc. i also have LSD.

on the fronts, i have GT3 scoops to drive more air but on a 100F day, they were not enough. i also cracked the pistons in the calipers and they are being replaced also.

to further increase cooling, i'm putting in "super-hot country" wheel well covers from tequipment. they're in customs now but i'll try to get some pics.

FWIW, i was not running motorsport pads but stock pads. i have run the PCCBs at length at PSDS and having been there a couple times, i am pretty certain they don't have the same issues.

roberga

saw your car today.... getting close :-)

mooty

jack up the car.
get under it.
crank your neck and look out just like you would do with outside pads.
otherwise, you can't see it.
that's why most of the damage to rotors are inside. b/c u chk outside and it looked fine so you assume inside is the same.

mooty

well, pad and rotor wear shows same lopsided pattern as well.
just replacement is cheaper.

TRAKCAR

Use a little flashlight too.