S8 Ceramic discs judder
 

Hi, I am relatively new to using the forum although I have had my D3 S8 with ceramics, for almost 2 years now.
Te car has an intermittent brake judder at approx 80mph. the ceramic discs have been removed, checked and replaced to no effect. Judder worse when brakes warm, Non existent when wet and the judder can be avoided by braking really hard. So I wonder if it could be a suspension problem?
Does anybody have any ideas on the? Or suggestions on who would be best to take the car too?
Any thoughts gratefully received.
Thanks

Pads and tyres ok? Btw you have posted in the D4 section :)

If the pad has been inserted incorrectly or the backing clip on the pad is bent or damaged, then you can get these symptoms. And the inner pad may wear more quickly that the outer pad but if the discs have been checked then presumably they checked all that..

I had the same symptoms that you describe on my A6 which turned out to be a damaged pad backing clip.

Worn suspension bushes can produce the same symptoms as well, especially on the lower curved arm.

Thanks guys. Will now post in right section! Don't know how that happened
:)

Yes. I think good enough. Judder was there when tyres were new. Pads will need replacing quite soon but evenly worn.. Do you recommend any particular pad for replacement? Also, I understand my discs are ok (9ok miles) but is there a way to check how long they have left?

Thanks. Do worn suspension bushes not show up at an MOT test? If not how best to check them?

I read that the discs are good for 180k miles as long as they don't get damaged. Depends on use of course. And I think you have to weigh them to establish if they need to be replaced.

You can get these discs refurbished by the way

As standard, every new refurbished disc will get new nuts and bolts.

the process is something like this

- Discs are weighed and depending on wear and wear pattern and rotors are x-rayed and examined for structural damage.
- Brake pad residue or contaminates is chemically steamed off
- Discs are machined until they are level
- Napped are vacuum soaked in polymeric carbon
- Pyrolyze the discs at 1100°C
- The last two steps are repeated three times
- Discs are siliconized at 1500°C
- Top layer (ca. 1mm thick) is now restored, and trough the pyrolysis it is chemically and physically bonded with the structure
- Final sanding of top layer
- Disc is reassembled and weighed once more and precision-balanced
- The disc now has gained about 30-50g and is at desired value once more

I haven't had to replace mine yet but I would get them from Audi. Don't really know of any suitable replacements but haven't looked hard enough yet. As said, the proper way is to weigh them.

Do you know of any UK company that does this?