Recomended replacement rear calipers (siezed) for UrS6?

[Animal Mother]

My rear calipers have developed the dreaded siezing handbrake mechanism.

As far as I know there is no real fix, so, what should I replace the calipers with?

A6? S6? S4? S8? RS4? RS6? V8?

[Error404]

there is a fix, but it means stripping and rebuilding the calipers which is a PITA (BTDT).

Try www.brakeparts.co.uk

[Animal Mother]

Great site thanks.

[GazzaG60]

a problem common to vw mk2, corrado and mk3. the use of alloy mk4 calipers sorted that somewhat. not sure if there is a an audi equivilent.

[twoqu]

Well they certaintly didn't fix it for the alloy A8 calipers. The steel actuating lever sits in the bare alloy of the caliper. It only takes a little bit of moisture to get past the seal and you have the same problem plus the electoyltic action! Nice!

[Animal Mother]

Well they certaintly didn't fix it for the alloy A8 calipers. The steel actuating lever sits in the bare alloy of the caliper. It only takes a little bit of moisture to get past the seal and you have the same problem plus the electoyltic action! Nice!

Yep, that's exactly the recipe for disaster and the problem I have.

Re. the worm gear that the handbrake actuators operate, is this totaly seperate from the hydraulic brake system?
If it is, can a small hole not be drilled into the handbrake part and then lubed/cleaned appropriatly? If possible, this could then be tapped and plugged and will allow access at later dates for further lube. Maybe even a grease nipple.

[Error404]

in the Audi calipers there is a nylon sleeve that sits in the lever bore between the lever rod and the caliper body.
When the grease is depleted or lost through the seal, moisture gets in, the nylon sleeve is damaged and then corrosion sets in.

[twoqu]

Hmm.. dont recall seing any nylon sleeve but I had to get a nut welded to the lever so that I could use a slide hammer to get it out.
In theory that bore should be sealed off from the brake hydraulics and be dry. Not sure what effect pumping grease into would have.
I was think of using something like a bronze liner to stop the corrosion and repair the damage already done. The other problem is that with the lever on top it sort of encourages water to collect in the depression of the seal.

[Nuvo]

I've already replaced both calipers once already with faulty handbrake mechanisms. This time around I coated the area between the caliper body and the cam with marine grade greas in the hope to prevent any moisture or crud from getting in the bore and galvanic corrosion from setting in.

Only time and regular use will tell how successful this preventative maintenance proves to be.

[twoqu]

I have also found that whatever grease is in there has hardened, due to the heat I guess!

[Error404]

Hmm.. dont recall seing any nylon sleeve but I had to get a nut welded to the lever so that I could use a slide hammer to get it out.
In theory that bore should be sealed off from the brake hydraulics and be dry. Not sure what effect pumping grease into would have.
I was think of using something like a bronze liner to stop the corrosion and repair the damage already done. The other problem is that with the lever on top it sort of encourages water to collect in the depression of the seal.

Thats not the way to disassemble the caliper mate

You have to remove the piston, threaded piston shaft and spring assembly from the main bore and remove the little pushrod that sits in a section of the handbrake lever, and acts on the piston shaft - that is what means you can't simply pull the handbrake lever out to clean and lubricate it.
There is a seal on the bottom of the piston shaft that is the barrier between the handbrake lever bore and the main piston bore.
The handbrake lever shaft & bore IS supposed to be greased as well as having a nylon sleeve in it.

EDIT: this is on a S2 coupe rear caliper BTW

[quattro20v]

Grease nipple has been done, here is a page in swedish that has pictures:

NordicAudi

[twoqu]

Thats not the way to disassemble the caliper mate

You have to remove the piston, threaded piston shaft and spring assembly from the main bore and remove the little pushrod that sits in a section of the handbrake lever, and acts on the piston shaft - that is what means you can't simply pull the handbrake lever out to clean and lubricate it.
There is a seal on the bottom of the piston shaft that is the barrier between the handbrake lever bore and the main piston bore.
The handbrake lever shaft & bore IS supposed to be greased as well as having a nylon sleeve in it.

EDIT: this is on a S2 coupe rear caliper BTW

I am aware of that. The slide hammer was necessary just to remove the handbrake lever as it was so corroded in there! This was the last operation after disassembly of the brake piston compoments. Pretty sure on the alloy caliper there was no sleeve as I thought it was pretty stupid to have a steel component in an alloy bore. Whatever grease was in there had hardened.
I don't recall seing a sleeve in other Girling 43 calipers I have disassembled Although it would make sense to have something like that. Then again they wouldn't be able to rip you off for new ones if they lasted for ever.

[mcandmar]

A good tip i read was to fit a stronger return spring on the handbrake mechanism, apparently they can be sourced from a Ford Granada/Scorpio rear caliper.

[twoqu]

Here is a good example of what to expect:

http://www.20v.org/brakere.htm

It doesen't show any sleeve in the exploded diagram.
The Audi rebuild kit doesn't contain the handbrake seal! You can source all manner of seals in the correct size from various places.
Trickiest bit is removing/replacing the circlip. No need to disassemble the brake piston assembly. It depends on the amount of damage to the handbrake lever bore. If its only started to get stiff/sticky it might be worth trying to get some more life out of them.