PCCB pad wear

[BertBert]

So as I was mooching around my new to me 997 GT3 this afternoon, thinking about the noise question (other thread here), I looked at the front pads - in that what else needs checking before a track day mood. The front pads are significantly tapered - see in the pic below.

Is that normal. What should I do? The thick bit looks like plenty of pad left, the thin bit looks horrid!

Cheers
Bert

IMG_20190112_144610 by BertBert, on Flickr

[D.no]

https://rennlist.com/forums/991-gt3-gt3rs-and-911r...

Post by JRitt@essex half way down would suggest this is normal.

My discs and pads are brand new, and I don't have enough miles under my belt to offer first hand experience I'm afraid, but I hope the thread above helps nonetheless.

[BertBert]

Is that discussion about front to back taper? Leading edge to trailing edge. Mine have radial taper.

Bert

[D.no]

Ah, yes. I see that now, and I'm baffled.

Worth checking that the pad slides freely on it's guides and isn't binding anywhere but I can't imagine a scenario where pads could wear like that unless the pistons have dug into the backing material. Certainly some inefficiencies going on, and worthy of further investigation before heading onto the track, in my view.

[HokumPokum]

its normal to have some tapering. just keep an eye on it under the track day and then change after.

unfortunately CCB downside is perpetual worry about thin pads heating up the disc too much vs a thicker fuller pad. But a few track outings should do it no harm if you are not being brutal with the car.

[BertBert]

How long do pccb pads last?

[ChrisW.]

It depends how hard you work them ...

I used to get two track days at which point the half pads that were left had the consistency of sugarloaf ...

Hence I changed to ST discs and my pads now last a very long time ... but maybe I am too hard on my brakes ?

Edited by ChrisW. on Sunday 13th January 18:06

Edited by ChrisW. on Sunday 13th January 18:07

[Porsche911R]

Sadly a taper that much most likely means the ceramic pucks will be also cracked.
PCCB pads need changing 1/2 worn and swapping side to side 1/4 worn.

[APOLO1]

Porsche911R said:

Sadly a taper that much most likely means the ceramic pucks will be also cracked.
PCCB pads need changing 1/2 worn and swapping side to side 1/4 worn.

Did over 40 track days in my 91RS, Around 8k Track Mikes. Used to change pads when down to just below 1/2 Worn. Never changed pads from side to side. Zero problem's with CCBDs, from a wear point, still within 111 Inspection range, at 12k Miles. But had to change front ones due to stone Chips.

[D.no]

Porsche911R said:

Sadly a taper that much most likely means the ceramic pucks will be also cracked.

I'm not familiar with the intricacies of the PCCB calipers but if the pucks you mention sit between the piston and the backing plate of the pad, and have deteriorated in some way, that's a good shout, as it could potentially impart a load on the pad which is not equal across the pistons or around the axis of each individual piston and that would do the trick nicely (radial tapered wear)

[BertBert]

I'll have a chat with Matt at Fearnsport as he knows the car well and PPId it for me
Bert

[Porsche911R]

On a fresh look this morning over a pissed up look late last night, Is that not just pad shape over pad taper, what’s the bottom of the pad look like ?

[BertBert]

Not sure where 'bottom' is! Using my annotated pic, you can see the difference in pad material (10mm v 2mm) and the area of the disk that looks to be in use. All looks very odd to me!
Bert

[Porsche911R]

it's the pad shape oem, taper wear you would have to look at the other end of the pad.






this is taper wear which causes expensive issues on the pucks :-(

Edited by Porsche911R on Sunday 13th January 13:17

[BertBert]

Doh, thanks!

[CrashBang]

May be of use, there are a set of new PCCB discs and pads advertised on race cars direct.

[Cunno]

What’s the view on titanium pucks, these guys claim they are as good as ceramic pucks for stopping heat transfer

https://www.autoquestcars.com/custom-08
Very expensive for that they are, but cheaper than a caliper

[D.no]

To get that sort of taper Bert, my money's still on some sort of puck issue now that I've become an expert courtesy of Google

I don't think anyone could call it normal at any rate, and I wouldn't have thought they'd be operating at full efficiency. Would be worth a caliper rebuild and some new pads just as an insurance policy for your PCCB's.

Let us know what Fearnsport say...

[HokumPokum]

BertBert
is yours a 7.2 gt3? I'm thinking of getting a Alcon or AP setup with new calipers and retiring the PCCB. Maybe the way to go?

[Porsche911R]

D.no said:

To get that sort of taper Bert, my money's still on some sort of puck issue now that I've become an expert courtesy of Google

I don't think anyone could call it normal at any rate, and I wouldn't have thought they'd be operating at full efficiency. Would be worth a caliper rebuild and some new pads just as an insurance policy for your PCCB's.

Let us know what Fearnsport say...

it's not a taper, he is only showing us what an OEM pad should look like :-)