Condition of PCCB

Condition of PCCB

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Discussion

fredt

Original Poster:

847 posts

146 months

Monday 13th April 2015
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What would you say about this disc? Is it possible to get a accurate idea of it's condition fron these pictures only?

Thanks! smile



PTT

664 posts

120 months

Monday 13th April 2015
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Is it pitted? Is it making a grinding noise while breaking?
It looks on its way out in mine opinion.

Edited by PTT on Monday 13th April 12:40

fredt

Original Poster:

847 posts

146 months

Monday 13th April 2015
quotequote all
Not sure what term to use, but I think flaking is the best to describe the small lighter grey patches.

Makes no noise, seems to brake fine. Never used or seen ceramics before so not sure what I'm looking at. Had OPC inspecting the car (mistake) and of course they said because of the mark at the edge of the edge of the disc the official line would be to replace, but it was implied that functionality and/or reliability in the real world was not necessarily affected.

m33ufo

4,959 posts

230 months

Monday 13th April 2015
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They're well on their way out. The rough surface means that your pads won't last and you'll get more dust.

fredt

Original Poster:

847 posts

146 months

Monday 13th April 2015
quotequote all
Bin ASAP or can you run them further?

Does PCCB's degrade like conventional steels, or is catastrophic failure a risk?

PorscheGT4

21,146 posts

264 months

Monday 13th April 2015
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they will have a weight on them and a thickness you can use them too, so just weigh them and put some calipers on them.

phone up your OPC to get the weight loss and thinkness lost you are allowed to have.

Slippydiff

14,742 posts

222 months

Monday 13th April 2015
quotequote all
fredt said:
Bin ASAP or can you run them further?

Does PCCB's degrade like conventional steels, or is catastrophic failure a risk?
They're scrap. The more you use them, the more heat you'll generate and the more they'll delaminate. They won't fail catastrophically, the wearing face will just start to disappear in bigger and bigger chunks. The substrate the wearing faces are glued onto is made from a very coarse, stable and hard wearing material. Once the wear face has gone, you'll be left with a very efficient, very coarse grade "grinding wheel" which will wear the brake pads out in less than 100 miles of hard use.

m33ufo

4,959 posts

230 months

Monday 13th April 2015
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SICOM offer a refurbishment service. Wycoller (bought my GT2), is getting his fronts refurbished with them at the moment. Seems very cost effective.

sidicks

25,218 posts

220 months

Monday 13th April 2015
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Slippydiff said:
They're scrap. The more you use them, the more heat you'll generate and the more they'll delaminate. They won't fail catastrophically, the wearing face will just start to disappear in bigger and bigger chunks. The substrate the wearing faces are glued onto is made from a very coarse, stable and hard wearing material. Once the wear face has gone, you'll be left with a very efficient, very coarse grade "grinding wheel" which will wear the brake pads out in less than 100 miles of hard use.
But just think how quickly you'll be able to stop...
biggrin

Slippydiff

14,742 posts

222 months

Monday 13th April 2015
quotequote all
sidicks said:
Slippydiff said:
They're scrap. The more you use them, the more heat you'll generate and the more they'll delaminate. They won't fail catastrophically, the wearing face will just start to disappear in bigger and bigger chunks. The substrate the wearing faces are glued onto is made from a very coarse, stable and hard wearing material. Once the wear face has gone, you'll be left with a very efficient, very coarse grade "grinding wheel" which will wear the brake pads out in less than 100 miles of hard use.
But just think how quickly you'll be able to stop...
biggrin
Regrettably the µ of the substrate is low (hence the reason the wear faces are made from a different material with a much higher µ .....)

Here are mine less than 24 hours after I purchased my car (after Reading had inspected it and given it a clean bill of health) hehe W*ankers shoot



On the near 200 mile journey home the brakes got less and less efficient (to the point they wouldn't stop the car from 100mph) Unfortunately the "clean bill of health" given by Reading was verbally over the phone, rather than written down in black and white or via an email. Caveat emptor, Reading are a bunch of to**ers and not be trusted when presented with a conflict of interest .......

Edited by Slippydiff on Monday 13th April 19:49

sidicks

25,218 posts

220 months

Monday 13th April 2015
quotequote all
Slippydiff said:
Regrettably the µ of the substrate is low (hence the reason the wear faces are made from a different material with a much higher µ .....)
Please don't let the facts spoil a vaguely amusing joke..
;biggrin

fredt

Original Poster:

847 posts

146 months

Monday 13th April 2015
quotequote all
Scrap hey?

Pic was taken by the OPC, to be fair they said it should be changed because of the 'chip' on the edge, and when I questioned the condition of the disc it was implied that the 'chip'(doesn't look like a chip to me but thats how they described it) was the only issue, not that the disc was actually scrap.
(no mention of the disc on the opposite side that looks identical apart from the 'chip'). And further use was my risk, but no real reason to think it would get worse. Only when i saw it myself did i start to wonder.

Can only blame myself for going OPC route, but if it is as clear cut as you guys make out (is it really..?) then surely this is a straightforward issue that should have been brought to my attention and under no uncertain terms? Specially given the costs involved.

To be clear, this was a private sale OPC only inspected the car.

ClarkPB

818 posts

199 months

Monday 13th April 2015
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Put it this way, if my PCCB's started to look like that I think I'd cry...

fredt

Original Poster:

847 posts

146 months

Monday 13th April 2015
quotequote all
ClarkPB said:
Put it this way, if my PCCB's started to look like that I think I'd cry...
It's only a brake disc dude, no need to get upset!

Was looking for a less emotional, more factual view on how long a disc in this condition might last?
Slippy what did you disc look like when you got the car?
Has anyone else with experience of running these discs this far any input?
What is the verdict in SICOM? Anyone with experience?

Thanks


m33ufo

4,959 posts

230 months

Monday 13th April 2015
quotequote all
fredt said:
Scrap hey?

Pic was taken by the OPC, to be fair they said it should be changed because of the 'chip' on the edge, and when I questioned the condition of the disc it was implied that the 'chip'(doesn't look like a chip to me but thats how they described it) was the only issue, not that the disc was actually scrap.
(no mention of the disc on the opposite side that looks identical apart from the 'chip'). And further use was my risk, but no real reason to think it would get worse. Only when i saw it myself did i start to wonder.

Can only blame myself for going OPC route, but if it is as clear cut as you guys make out (is it really..?) then surely this is a straightforward issue that should have been brought to my attention and under no uncertain terms? Specially given the costs involved.

To be clear, this was a private sale OPC only inspected the car.
I had a couple of chips on the PCCB rotor of a Boxster Spyder. At the time Porsche had guidelines which stated more than a few chips over a certain diameter (sorry, can't recall the exact size), would mean that the rotor required replacement. Obviously they weren't carrying out a warranty inspection for you (I assume the car is beyond 9 years?), but they should be well aware of the guidelines.



Slippydiff

14,742 posts

222 months

Monday 13th April 2015
quotequote all
fredt said:
It's only a brake disc dude, no need to get upset!

Was looking for a less emotional, more factual view on how long a disc in this condition might last?
Slippy what did you disc look like when you got the car?
Has anyone else with experience of running these discs this far any input?
What is the verdict in SICOM? Anyone with experience?

Thanks
I've got an official document in PDF form (IIRC) from Porsche which tells you what size of delamination areas are permissable on a PCCB (and the size of the chips that are allowable on the outer circumference) It's on my desktop PC so I'll have to search for it. Once I've found it I'll post it on here.

Whilst the document lists what's permissable and what's not in terms of surface delamination, in my experience it's not a reliable method of assessing the serviceability of a disc unless you know exactly how thick the wear faces are. As I found out to my cost, 200 miles of hard road use on discs which are at the very edge of their wear limits, results in a catastrophic failure of the surface which in turn means massively reduced braking efficiency.


Edited by Slippydiff on Tuesday 14th April 08:30

fredt

Original Poster:

847 posts

146 months

Monday 13th April 2015
quotequote all
m33ufo said:
I had a couple of chips on the PCCB rotor of a Boxster Spyder. At the time Porsche had guidelines which stated more than a few chips over a certain diameter (sorry, can't recall the exact size), would mean that the rotor required replacement. Obviously they weren't carrying out a warranty inspection for you (I assume the car is beyond 9 years?), but they should be well aware of the guidelines.
No they DID say according to guidelines it (no mention of the other side) should be changed, but I know what car dealer guidelines can be like and often the recommend changing things way before you actually need to, so I asked the technician what they were actually who implied they will be fine, when he should have just told me they were scrap not to be used!

Correct, it wasn't a warranty inspection, they just checked the car over for me (111 test). (Interestingly the 111 test doesn't cover checking engine numbers etc! This I also only found out afterwards).

m33ufo

4,959 posts

230 months

Monday 13th April 2015
quotequote all
They're not in great shape but I have seen lots worse. I'd use them for the moment and keep an eye on them.

Slippydiff

14,742 posts

222 months

Monday 13th April 2015
quotequote all
http://workshop-manuals.com/porsche/911_turbo_cabr...

And click on "next page" for further information.

fredt

Original Poster:

847 posts

146 months

Tuesday 14th April 2015
quotequote all
m33ufo said:
They're not in great shape but I have seen lots worse. I'd use them for the moment and keep an eye on them.
Thanks! That's what I'll do and weigh up my options. Would like to stay on ceramics but I'm not sure if the limited (for me) upside warrants it.


Slippydiff said:
http://workshop-manuals.com/porsche/911_turbo_cabr...

And click on "next page" for further information.
So my discs basically look like the middle picture, abused but not yet completely fubard.

Gonna measure them up for my own amusement, not like OPC will give a st anyway, as they clearly didn't do anything wrong..