OldGuy

My Porsche Dealer has been absolutely fantastic in treating me well with warranty work. I had a wet rear seal and they said 'lets replace it'. They allowed me to buy the RS clutch and flywheel parts and upgrade while the rear seal was out and no cost to me (except parts from Viper Bob). So I felt embolded to ask them about cracks in my front PCCB rotors. My hope was to get Gen II upgrades under warranty. I know -obviously -there has been some problems with some Gen I's and I was/am worried about mine. 4curves has tracked his heavily with Gen I PCCBs with no problems by switching to Carrera GT front pads on his wifes GT3 (before his Cup car). Anyway this is the result-They called regional and PCNA reps and got these techincal bulletins explaining different issues with these things. The cracks are specifically covered and this is what the tech bulletins said:

****start bulletin

Cracks(Stress-relief microstructure) in the brake disc friction surface:

Cracks in the brake dics surfaces are viewed differently to cracks in cast irons brake discs. Cracks in PCCB brake discs do not constitute a wear criterion but exist already in new brake discs because of the way in which they are manufactured.

Note:

Due to the composition of different materials in the friction layer and support body, the friction surfaces (even when new) are coated with uncritical crack pattern(stress-relief microstructure). Individual relaxation cracks sometimes run along the perforated bores.

The stress-relief microstructure results from the way in which the brake disc surface is manufactured and does not pose a risk to safety. There is also no danger of the friction layers flaking off from the support body, since friction layers are almost free of internal stresses as a result of the stress-relief microstructure.

The stress-relief microstructure is sometimes clearly visable in new brake discs and the brake disc chamber side and the side that is opposite to the chamber can differ significantly from one another.

****end bulletin

sounds like hooey to cover the PCCBs that did flake apart, as some of you have shown-but I wanted to put this out here as there are alot of you looking at picking up a 996 GT3 with PCCBs.
I think I would not shy away from them and upgrade to the CGT pads as 4Curves did ($500+) Of course Porsche change to Gen 2 PCCBs so there must be some problem.
The bulletin goes on to cover discs with coating as may occur on vehicles that are tracked and it says **Use the appropriate pads if vehicle is being used on a racing circuit AND make sure disc bore holes are clean and exposed** and then covers surface roughness and disc thickness.

Anyway I thought I would share that.

RK1

I have PCCB on mine and I have no problems at all. One of the first upgrades I did was Cup brake ducts to improve cooling.
I always do a proper cool down lap after DE sessions and never use the E-brake after a session.
As part of pre track check I always make sure all the passages on the rotors are clean.
Changed the original pads to RS29 at half life.

Kevin

Mr Michael B

Hmmmm.

I dont have cracks, but I would like to think I could get Porsche to update me to Gen 2's before I go out of warranty.

What do you think our chances are?

OldGuy

Well Mike I wasnt successful in that. That was my goal instead- I ended up with the bulletin

Mr Michael B

OG, if your rotors started to flake what would you think they would say?

OldGuy

Michael thats a good question, but outside of the cracks, the rotors are perfect with
11K miles-the rears are almost pristine. I think I could have got somewhere with
flaking but then thats a catch 22. instead of the good PCCBs I have- I would have ones that are suspect.

bora

I bought my 05 brand new literally sitting right next to a Carrera GT on the showroom floor. The PCCBs when new had very small cracks on the surface. I thought this was fairly normal.


I think your chances of getting Porsche to spend this kind of money on replacement rotors is pretty much nill. When (and if) your PCCB discs wears out, just call our good friend Bob and get him to send you a set of cup rotors and you will be all set. This is not worth losing sleep over.

OldGuy

Bora I think youre right but hey it was a reason to get out and drive (my dealer is 100miles away) and it didnt cost me anything to ask.
And according to the bulletin you are correct cracks are normal.
looks like the CGT has gen 1's is that true?

AndyMarson

Hey OG. Can you post the rest of the techncal bulletin that covers surface roughness etc if it's not too much trouble? Thanks.

OldGuy

I may be able to I will look it up when I get home tonite
or email me so I dont forget and I can send it to you directly

OldGuy

Andy
I looked at the bullentin last nite on the roughness section
They talk about roughness being less than 8 uMeters (micro meters) as a new disk and have a pic showing the example. The pics did not come in the bulletin I got so I dont know if what I have will help you. Basically it talks about replacement when surface roughness gets over 100uM but I dont know if I could measure that myself even if I had the pics.
Also it talks about total disk replacement at over 180uM roughness. I can give you more detail if you want but I dont know if it helps

JasonAndreas

OG,
What is the date and/or number of the TSB?

OldGuy

Jason the number on top is WM 465402

AndyMarson

Thanks OldGuy, thats perfect.

roberga

the shop uses the pictures for guidelines on replacement of the rotors. It is not part of a warrenty decision. Your dealer service guys are your only hope in getting any help on the cost of replacement rotors.