Ceramic Disc/Pad Problem - Replaced but then immeddestroyed?

After tracking the car at the Nurburgring, Castle Combe and Brands - the brake wear warning sensor came on. I found that one of the old pads (Drivers side outer) had completely worn away to the base metal. I replaced the pads, sensors and damping pads and then went for a "bedding in" drive, after only a few miles the sensor came back on, I assumed that it must have been down to my (bad) fitting of the new sensors and that one had popped out. Without having the time to check it - I had to drive about 100 miles that night so hoped that at worse; a loose sensor although with wires clipped in the right places would be ok till morning. I checked the problem in the morning, expecting to find the loose sensor and found that the (same) Drivers side outer pad had been completely destroyed (eroded back to the base metal again!) - although the other 3 pads all look fine! The pad had not worn consistently accross it's surface - it has worn in the same way as the first one came out (the outer part of the pad with the most wear). Have I've knackered the surface of the ceramic disc? so much so that it will constantly consume that pad? Or does it sound like a piston/caliper issue? Or any other help/suggestions or recommendations/suppliers appreciated!

Firstly, are you 100% sure your fitted ceramic pads and not std GT3 pads? If so the only explainations could be: Sticking piston which kept pressure on the pad. This can be caused be excessive(prev?) heat build-up. or The pad material has sheared off.......it can/does happen if you do not give the pads at least 200 miles to bed-in before really using the PCCB's as intended. Did you bed them in properly? Q; Who supplied the pads and what colour are the pad plates? Also, if you have taken off the top layer of ceramic(ie the PCCB is now dull and rough) then it acts like a grinder on the pads and effectively "eats" them......sadly your PCCB is shot and will just keep eating pads. I have some spare 350mm PCCB(some are nearly new with <1,000 miles on) which I may consider selling??

Thanks for your reply and help. I think it may be a bit of both - not bedding them in properly and the ceramic disc working as a grinder. I am hoping there are fixes available for the disc - ie. polishing / skimming as their is still loads of material on them. I spoke to my local Porsche dealer before; about the replacement pads and price of discs - he said (parts and service department) that in the five years he had worked there - he had only ever once had to replace a disc as it had cracked. I haven't gone back to them with the car, knowing that they just fit parts - but they may see problems with a cylinder that I have missed....? The Pads came from type 911 - they are branded Porsche parts (PAGID) with Black plates, - I didn't want to mess around with any of the other compounds available just in case they did in fact damage the disc. The other pads look ok, in terms of wear (and they fitted!) so I assume I have the correct ones. Anyway, day off tomorrow - more investigation will be done - I may need to get back to you about your secondhand discs....... Thank you for your help, and if anyone else? has had the same issue I would be glad to hear from you too.

PCCB discs cannot be skimmed/polished or otherwise repaired. If its shot(which it sounds like it is) then bin it as its useless now. Once the pads metal plate makes contact with the disk face under braking its all over......no if's buts or maybe's.

Understood. Thanks Wizard. What have you heard about these PAGID/Floating replacement PCCB sets? - Is that what you've got, hence the reason for the spares ?

I sometimes use the cup discs with PF race pads on short circuits with lots of braking :thumb: The full benefit of the floating disks is more apparent on the 2wd GT cars as you are already lugging a 4wd system around on the 996TT axle. If you fit std 350mm(f)/330(r)mm steels to your car, fit the PF race pads and use race brake fluid with the higher boiling point......you will be pleased with the results. You also won't care about jumping on the brakes on entry and keeping the pedal planted with the ABS chattering it's head off!.....re no worries about the PCCB disc being used at the max! Also the brake bias on the 996(vs the 997) is a bit mixed-up. With steels up front the car won't lock up so easily until you hit the pedal....unlike the PCCB's which bite hard after just a few cm of pressure and often fires-up the ABS a tad early . Another combo I have used is the cup rotors up-front and PCCB's on the rear......I like it :thumb: