420mm ceramic brake pistons

[Audi-RS6-R]

Hey,

I guess my pistons of my ceramic callipers are not movin correctly anymore...they are very rusty

Somebody knows if there is a chance to get the pistons of the callipers to buy?

Greetings

[IanH755]

The pistons need a special removal tool according to Alcon (https://www.alconkits.com/tools-and-sup ... ool-detail) and you need to know if the pistons are Aluminium or Steel and their size too.

As the Calipers are Audi OEM, Alcon may not give you any information on the piston as Audi hold the rights to all the info (same issue I had finding Brembo info out).

Sorry thats not a lot of help but it may be better just to give them to a refurbishment company instead and let them deal with Alcon.

[rs6_sid]

You would be able to do them your self if the seals are good and you have a fair mechanical know how , get the Pistons cleaned up chemically and re coated as I imagine they have some kind of finish on them

[Golfather]

I have a brand new set. PM sent.
However check your seals first - there was a recall to replace the seals on early calipers.

[Audi-RS6-R]

@Golfather...PM sent

I think the seals must be okay...I don't loose brake fluid...and according of my car history, they changed and replaced the disks & callipers twice

[TomRS]

Callipers changed twice? holy cow... must be something where you live that doesn't agree with your pistons.

[Audi-RS6-R]

Well, I don't live in the Sahara and neither in the North Pole

[TomRS]

Well, I don't live in the Sahara and neither in the North Pole

hahaha! terrible that though, two replacements... and now the 3rd set gone? surely there's something a miss?

[Quattro_RS6]

I guess they use salt on the roads during wintertime in Germany as weell?

The pistons are actually stainless steel, but it's the backing plate to the brake pad which corrodes and leave rust around the pistons. Also, even if the pistons are stainless, they will get dirty, pitted and eventually start to restrict free movement.

The problem with the Alcon 8 piston calipers are that they do not have dust seals. It may be that they have internal dust seals, but still, they are not as good protected as the normal design found on Brembo and standard calipers.

Shpend; i think you have to disassemble the caliper, clean the pistons or buy new ones, and reassemble with new seals and grease. New pads is also wise to install looking at your pictures..

I add a couple of pictures of my own calipers before they were sent to refurbishment. You can easily see the pitting on the pistons, but if they were not stainless steel they would have been very corroded and completely brown. (The calipers are also yellow/gold in colour, but that's due to heat input on last years track day

[IanH755]

The problem with the Alcon 8 piston calipers are that they do not have dust seals.

It might be because ceramic brakes get so hot (900'c) that they can't use external dust seals as they would melt and have internal seals only.

[TomRS]

Seems legit ian....

Although it seems odd that they would design something to be so... "bad" but again saying that ceramics are still very much a race car type addage and in those enviroments they are not suspect to salt/dirt.. they are also usually stripped and cleaned after every event.

Might be worth stripping down the calliper and cleaning it and the pistons every 5000 miles/ 6 months?

[IanH755]

It seems to be an issue with Alcons "early" pre 2006 designed OEM calipers. The newer C7 Brembo Ceramic calipers and newer aftermarket Alcon ones all come with dust seals now (no idea what it's made of).

[Quattro_RS6]

That could also be a reason for it, off course. Alcon is one of the leading provider of racing calipers, so i guess they know what they are doing

I actually burnt the rubber dampening plate on the pads last year at a track day..

[Quattro_RS6]

It seems to be an issue with Alcons "early" pre 2006 designed OEM calipers. The newer C7 Brembo Ceramic calipers and newer aftermarket Alcon ones all come with dust seals now (no idea what it's made of).

Here's some interresting reading: https://www.essexparts.com/cp9668-trail ... t-anodized

It may be that the C7 ceramic brakes with Brembo caliper is less track firendly, but more all year around-friendly.

[IanH755]

The Radi-Cal Calipers in the link above are what TomRS has had fitted (slightly different model) and what I'm getting fitted this month