Can anyone tell me how to tell how worn Porsche ceramic discs are?

Are they the same as Steel versions that develop a raised lip?

Thanks

 

Two ways to check wear that I know of:
1. Measure with a precision micrometer. New thickness is 34mm for front, with minimum 33.5mm. Rear new 28mm and minimum 27.5mm. Requires very good mic.
2. Appearance. The Turbo and GT2 shop manual describes and illustrates how usable rotors should appear and how much flaking or spalling of the semi-glossy surface is tolerable before replacing. Something like a few square cm is ok.

If you have pictures, a lot of people on this site can likely tell you whether the pccbs are usable or not.

 

thanks man,

I will invest in a micrometer.

Does anyone have a worn set that they could take a picture of?

Thanks!

 

Here are three photos:
New rotor has semi-glossy surface with light cross-hatched pattern. (photo of disc without hat)
Second photo is rotor with some heavy use, but thickness still in spec and functional. (rotor is mounted on car)
Third photo is rotor that is pretty much worn out. Semi-glossy surface gone. Would still stop the car but would eat pads quickly. This one was at or below the wear limit.

Hope this helps. Also would like to invite more experienced 6-speeders to comment.

 

Thanks so much for your efforts Superchicken!

So aside from the thickness it seems that the more shiney they get the more worn they are?

 

No, it's the other way around. The pic on the right is the newest rotor.

 

Correct, Adam. Photo on right is newest (about 1000 miles). Center photo about half-used up. Left- side photo is the worst.

Sorry for confusion.

 

Interesting and informative thread to come back from a while back. I was interested in seeing how to determine the wear pattern fro Gen 1 PCCB...is the same wear charectersitics for Gen 2 PCCB...that is what the replacement and many of the used take-offs seem to be nowadays...