Rear Brake Calipers

Unread post by **Sir Clive** » 12 Sep 2005, 14:16

I've just overhauled the braking system on my C5, including new rear pads. I really wanted to take the rear discs off to clean/examine them as well. OK, so even with the pads out, you can't wangle the disc off with the caliper still in place. The two bolts that pass through the caliper body were partly corroded in place; alloy, steel, and road salt don't make a good mix. Anyhow, after masses of penetrating oil, and beating seven bells out of them with an impact driver, they did start to move.
So far so good, but as I slackened them off, I could see hydraulic fluid starting to leak out along the centre line of said caliper. From this I am assuming that the bolts that hold the caliper in place also clamp the two halves together, which seems a stupid idea to me. How do you get the calipers off without them falling in half, or don't you. ??
ISTR the same applies to the Xantia, though on my old BX you could get the disc out with the caliper still in place

Regards
Philip

Unread post by **RichardW** » 12 Sep 2005, 15:50

Assuming they are the same as the BX / Xantia ones, then the trick is to remove the pad securing bolt and pads, then refit the bolt, which will hold the caliper together whilst you take the mounting bolts out. If they're anything like the Xantia ones, then you may well find the back of the caliper is corroding, causing the caliper to twist. File off the corrosion to get it flat again and refit, using some high melting point grease to try and prevent it corroding again.

fastandfurryous · Unread post by **fastandfurryous** » 12 Sep 2005, 16:02

I've never seen a C5 brakes, but I don't think the C5 calipers are like the BX/Xantia ones, and the bolts you have undone aren't the ones that hold the caliper on.
Going from other calipers I've seen over the years, on other cars, you may now have a problem. The bolts that are used to hold caliper halves together are not supposed (EVER) to be removed. They are torque critical stretch bolts, and once removed, the caliper will probably need to be overhauled by a specialist. It would be well worth checking this out, as it's possible that if you undertorque them, they will leak fluid like a sieve, and if you overtorque them, they could snap under heavy braking, and leave you with no brakes.
Time for a new/Exchange recon caliper. Or at least some good advice from a specialist.
Some manufacturers are even putting ultra-special headed bolts in these locations these days, with pentagon heads etc.

Unread post by **Sir Clive** » 12 Sep 2005, 16:21

Duh..thanks for the tip Richard, now why didn't I think of that!
The calipers on the C5 are very definitely like the BX/Xantia ones. They are held on by two long steel through bolts, which of course corrode into the alloy body. Also, corrosion builds up on the mounting faces 'twixt body and suspension arm, causing the famous twisted caliper problem, another good reason for wanting to remove them and check/clean. There are NO seperate bolts which just hold the two halves together

Regards
Philip