Carbon Ceramic Brakes - Disc scoring

[CatalystV12V]

Hi,

Has anyone suffered from the pins in the brake pads [that holds the friction material on] making contact the discs resulting in scoring. If so, did the discs require replacement?

Thanks!

[Panamax]

CatalystV12V said:

Has anyone suffered from the pins in the brake pads that hold the friction material on making contact the discs resulting in scoring. If so, did the discs require replacement

I'm intrigued. Normal brake pads have been "bonded" for decades (no pins or rivets) but those Aston pads do indeed have pins. There's a useful Youtube video here that explains how uneven pad wear can lead to disc damage without the wear indicator being triggered.
https://www.youtube.com/watch?v=YrsvtYnIzp4

The video isn't absolutely specific but strongly suggests disc damage can be irreversible (and expensive).

To my mind the bottom line is likely to be whether your scoring is sufficiently severe to lead to MOT fail. In itself modest scoring on a disc should have little detriment in normal driving.

[CatalystV12V]

Yes, I've seen that video which lead me to make this post as it's unclear whether this type of damage is critical.

I'm looking at a car that has this problem. The seller, as you would expect, says it's not an issue. While I'm inclined to agree I was looking to find other views..

[Far Cough]

If they are anything like the Porsche ones the friction material is held in place with brass pins which supposedly are softer than the ceramic rotors. Would not like to test the theory though and says more about the seller and his mechanical sympathy.

I suppose any AM dealer would be able to give you the finer details as well as a replacement price if it's gone that far

[CatalystV12V]

Far Cough said:

If they are anything like the Porsche ones the friction material is held in place with brass pins which supposedly are softer than the ceramic rotors. Would not like to test the theory though and says more about the seller and his mechanical sympathy.

I suppose any AM dealer would be able to give you the finer details as well as a replacement price if it's gone that far

I've got a call scheduled with works service later today and will ask them too... I was looking to hear whether anyone else had had this issue and how they resolved it.

With regards to cost its 8k plus to swap front discs and pads

Edited by CatalystV12V on Thursday 2nd November 12:09

[Panamax]

CatalystV12V said:

With regards to cost its 8k plus to swap front discs and pads

Which is why I wouldn't be looking to change the discs unless absolutely necessary - taking me back to the "MOT" point mentioned earlier. Brakes don't need to look beautiful in order to work sufficiently in the real world.

IIRC pads are a lot cheaper than discs but if that's not the case you obviously get stuck with the question whether you're willing to risk a set of pads to avoid immediate expense on discs.

Is replacement with steel discs is a cheaper option? My belief is that the benefit of carbon-ceramic is only found in extreme driving where there's a lot of heat to deal with.

[JaseB]

I just about got away with it, you could see a very minor mark on the disc... No pics sadly and now the car is sold, brakes were deemed absolutely fine and I couldn't see the mark at all when I sold.

I always found it shocking that the pad sensor hit after the pins do!!

[CatalystV12V]

Panamax said:

CatalystV12V said:

With regards to cost its 8k plus to swap front discs and pads

Which is why I wouldn't be looking to change the discs unless absolutely necessary - taking me back to the "MOT" point mentioned earlier. Brakes don't need to look beautiful in order to work sufficiently in the real world.

IIRC pads are a lot cheaper than discs but if that's not the case you obviously get stuck with the question whether you're willing to risk a set of pads to avoid immediate expense on discs.

Is replacement with steel discs is a cheaper option? My belief is that the benefit of carbon-ceramic is only found in extreme driving where there's a lot of heat to deal with.

I agree, they don't need to look good.. that said.. nice discs do much better than poorly looked after discs and will work better too.. I've seen a lot..
My concern is whether the scoring will compromise the surface in any way which could be detrimental to the braking performance.

[CatalystV12V]

JaseB said:

I just about got away with it, you could see a very minor mark on the disc... No pics sadly and now the car is sold, brakes were deemed absolutely fine and I couldn't see the mark at all when I sold.

I always found it shocking that the pad sensor hit after the pins do!!

for comparison

[cayman-black]

How many miles on the car? I would be looking at a low mileage well look after example myself.

[CatalystV12V]

cayman-black said:

How many miles on the car? I would be looking at a low mileage well look after example myself.

The rest of the car is pretty much perfect... it's very low miles.. under 20k - if it weren't for this disc issue I would have made an offer already.

I've just got off the phone with AM Works and they aren't able to comment without seeing the car.. which is fair enough.. but getting this wrong could mean a big bill down the line.

[CSK1]

If you like the car enough to make an offer, I would suggest to the seller you are taking the car if it goes through an inspection by an AML dealer.
Either he pays for the inspection or you agree to split the cost.
Once inspected, you can choose to have an AML warranty too for extra peace of mind.
Just a thought.
Edited to say you don’t necessarily have to have new discs, you can have them refurbished.
There’s a company in Germany that specialises in carbon ceramic disc refurbishment.
https://www.rebrake.de/en/

Edited by CSK1 on Thursday 2nd November 17:58

[CatalystV12V]

CSK1 said:

If you like the car enough to make an offer, I would suggest to the seller you are taking the car if it goes through an inspection by an AML dealer.
Either he pays for the inspection or you agree to split the cost.
Once inspected, you can choose to have an AML warranty too for extra peace of mind.
Just a thought.
Edited to say you don’t necessarily have to have new discs, you can have them refurbished.
There’s a company in Germany that specialises in carbon ceramic disc refurbishment.
https://www.rebrake.de/en/

Edited by CSK1 on Thursday 2nd November 17:58

Thanks for the link.. couldn't see any pricing - anyone know how much this costs and does it actually work?

[cayman-black]

20K miles and new pads needed? Another nice looking example for sale right now, CBs.look good.

[CatalystV12V]

cayman-black said:

20K miles and new pads needed? Another nice looking example for sale right now, CBs.look good.

Yes that looks like the one from Nicholas Mee ... 29,000 miles. I does look nice.
I think I need to accept its time to move on from the one I've been looking at..

[cayman-black]

https://www.autotrader.co.uk/car-details/202310032...

Chiltern has an MF car with 25k miles also.

[DBA086]

CatalystV12V said:

Hi,

Has anyone suffered from the pins in the brake pads [that holds the friction material on] making contact the discs resulting in scoring. If so, did the discs require replacement?

Thanks!

I had some scoring on the inner face of my rear discs from worn handbrake pads (prefaced by a “tink” sound that the AM dealer couldn’t identify/ resolve). It was a factor in my decision to replace the discs and pads on the rear axle, as there were question marks about how long it would last on new pads - at the time, it was not substantially more for me to replace the discs and pads than the pads alone.

If there is scoring I would also inspect the calipers in case there is a sticky piston causing the pads to drag. No point replacing the pads alone (or leaving as is) if it will get worse over time.

The other thing to check for (and the bigger concern for me) is the impact of corrosion on the bolts that secure the disc to the hat / bell. I noticed some cracking on mine where those bolts had corroded over time.

Edited by DBA086 on Friday 3rd November 09:56

[Kawasicki]

I worked on stability control system development with the first generation of carbon brakes. We had instances of rapid brake pad wear, where the steel backing plate ended up in contact with discs, for hundreds of emergency stops, which wore the backing plates down to just a couple of mm thickness. We would stick new pads in and the braking distances from both high and low speeds would return to normal.

[CatalystV12V]

DBA086 said:

CatalystV12V said:

Hi,

Has anyone suffered from the pins in the brake pads [that holds the friction material on] making contact the discs resulting in scoring. If so, did the discs require replacement?

Thanks!

I had some scoring on the inner face of my rear discs from worn handbrake pads (prefaced by a “tink” sound that the AM dealer couldn’t identify/ resolve). It was a factor in my decision to replace the discs and pads on the rear axle, as there were question marks about how long it would last on new pads - at the time, it was not substantially more for me to replace the discs and pads than the pads alone.

If there is scoring I would also inspect the calipers in case there is a sticky piston causing the pads to drag. No point replacing the pads alone (or leaving as is) if it will get worse over time.

The other thing to check for (and the bigger concern for me) is the impact of corrosion on the bolts that secure the disc to the hat / bell. I noticed some cracking on mine where those bolts had corroded over time.

Edited by DBA086 on Friday 3rd November 09:56

Thanks DBA... I've decided this is too much of an issue for me. So I'm going to step away from this car, which is a shame.

Many thanks to all who contributed to this thread.

[Panamax]

Kawasicki said:

I worked on stability control system development with the first generation of carbon brakes.

Interesting. I was involved in carbon-carbon brakes and clutches for automotive use. Both the discs and the pads are made from identical material (carbon, not carbon-ceramic). The carbon material had been developed by Hitco in the US for use in the braking systems of fighter jets. For obvious reasons fighter brakes needed to be light and also able to tolerate extreme heat due to high landing speeds. Transition to F1 racing seemed a natural evolution once the material was de-classified, the braking requirements being broadly similar - apart from the duration of brake application.

In automotive use the issue with carbon-carbon is it works best when it's hot - hence F1 drivers warm up their brakes with some aggressive braking on the warmup lap. Carbon-ceramic is much better behaved at lower temperatures so more suitable for road use.