Xantia rear brake pads - looking bad

MikeT · Unread post by **MikeT** » 06 Sep 2010, 13:26

I thought I'd change my brake pads and started at the rear only to find they've worn unevenly and actually have a pronounced lip on the top.

If you compare the new pads, the old ones appear to be too long, hence the lip that hasn't been worn.

As for the angled wear, I would naturally assume it's down to the infamous caliper corrosion but before I embark on fixing that, can anyone confirm that is indeed the problem and the surfaces I need to derust are as indicated by the tip of my screwdriver?

I know it's been covered before and I'll make a search if need be but feel free to add any gotcha's or pointers I need to watch for.

Xaccers · Unread post by **Xaccers** » 06 Sep 2010, 13:34

The angled wear is indeed down to the corrosion pushing the caliper out at an angle.

Remove calipers, some people have had the bolts snap, I haven't on either Dex or Cassy, but I don't think replacement ones are that expensive so if you'd have no way of getting to a dealer if they do snap then buy a set before you start.
I used a cold chisel and a wire brush to clean up the backs of my calipers, then some grease between them and the arm to reduce the rebuild up of corrosion.

Unread post by **Old-Guy** » 06 Sep 2010, 14:15

From the photo, it looks to me as though the old pads are for larger diameter discs, but the new ones seem to be nearer the right size.

A hatchback Xantia should have 224 x 9 discs. Could it be that it has these discs but calipers for the larger size?

MikeT · Unread post by **MikeT** » 06 Sep 2010, 14:47

I've got the bolts out ok - using a half turn out, quarter turn in method but the brake feed pipe doesn't want to come out

I'm with you Old-Guy, the old pads are too large for the discs. I'll measure the discs to make sure they're the right size. The inner disc surface has a bad groove worn into it too so might need to change them at some point - not this year though.

VertVega · Unread post by **VertVega** » 06 Sep 2010, 15:34

I also had this unusually carved rear brake pads! Never before and never after, I'm sure it was a production mistake.
I used the same pads one more season, by filing away the top "lips"

White corrosion is a known issue and it needs to be cleaned.
As Xac said, after cleaning, apply some grease (copper or aluminum paste is also fine) on both surfaces (1 and 2).

Unread post by **myglaren** » 06 Sep 2010, 15:50

MikeT wrote:I've got the bolts out ok - using a half turn out, quarter turn in method but the brake feed pipe doesn't want to come out

I'm with you Old-Guy, the old pads are too large for the discs. I'll measure the discs to make sure they're the right size. The inner disc surface has a bad groove worn into it too so might need to change them at some point - not this year though.

Have you soaked them in Plus-Gas Mike?

wotwot · Unread post by **wotwot** » 06 Sep 2010, 16:16

I did my rear brakes amonst other things before I went on a recent trip to liverpool.how bizzare that they corrode this way.
My calipers came off quite easily and all cleaned up nicely,had to put a new disc on, as one side was completly knackered,had "one" in the boot when I got the car yes only "one".tried to get hold of another "one" but they are only sold in pairs (as you would expect).Wonder how the muppet I got the car from got hold of only "one".Anyway I would only replace as a pair but was desperate and it was on the back.
The real reason to reply was to give this link. http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... K:MEWAX:IT
Very cheap and I wish this had been available when I did my brakes.
please dont slate me off for being cheap but can these items be that bad

Unread post by **myglaren** » 06 Sep 2010, 16:20

Wonder how the muppet I got the car from got hold of only "one".Anyway I would only replace as a pair but was desperate and it was on the back.

Probably bought a pair and only fitted one - perhaps one was scored or cracked and the other one was OK as possibly that brake wasn't working properly.

wotwot · Unread post by **wotwot** » 06 Sep 2010, 16:37

Good point but I would still fit the pair if I had bought a pair.
Shame the link does not cover my estate though,

dnsey · Unread post by **dnsey** » 06 Sep 2010, 16:38

Some factors do supply them singly, but fitting individual discs isn't recommended, of course.

citronut · Unread post by **citronut** » 06 Sep 2010, 19:08

the price of those disc's and pads is abit to cheap for my likeing, £60 quid all inclusive four disc's and two sets of pads and carridge,

regards malcolm

NewcastleFalcon · Unread post by **NewcastleFalcon** » 06 Sep 2010, 19:12

You may find my experience useful. Eventually it was all sorted but three of the 4 caliper bolts snapped, and the stubs had to be removed from the radius arm by welding on a nut to each in turn.

Xantia rear brake caliper bolts removal

regards

Neil

wotwot · Unread post by **wotwot** » 06 Sep 2010, 19:26

citronut wrote:the price of those disc's and pads is abit to cheap for my likeing, £60 quid all inclusive four disc's and two sets of pads and carridge,

it does seem vcheap but an email and a couple of questions to the seller to find out brand and avaiability might reveal all.At those prices it would be cheap enough to replace all pads and discs every couple of years.

MikeT · Unread post by **MikeT** » 07 Sep 2010, 09:48

I got the brake pipe out with brute force after learning there's piece of rubber hose inside used as a seal. I was just being too delicate with it. Toby kindly fetched me new seals from the stealer bringing back four for a fiver.

Mr Haynes says there should be an anti-rattle spring and two pad shims per caliper - is this correct for the MK2 as mine are absent from the N/S caliper and rain stopped play before I could play with the O/S caliper?

After pondering the deep groove on the inner face of the disc, I can only assume the previous pad (it seems the inner wears quicker) had been allowed to get to bare metal but whoever changed them, just fitted new, oversize pads sans shims and spring?

I also want to question the wisdom of using copperslip where corrosion occurs between two dissimilar metals? Would a tri-metal meet be even worse?

Unread post by **Old-Guy** » 07 Sep 2010, 10:15

I have to agree with you, Mike. Being higher up the galvanic scale copper should make matters worse by increasing the galvanic voltage.

I know it's common practice to use copper-slip between rear caliper and suspension arm. The thinking is that it's designed to resist high temperatures - the flaw in this is that the copper is designed to remain as a low-movement, high-load, lubricant when brakes get so hot that the grease boils off.

In practice, it probably works OK in temperate climates because Xantia rear brakes rarely work hard enough (except when towing?) for the calipers to get at all hot. Any HMP grease would do to make the surfaces water-proof - probably just any grease.

When I come to do mine - still on the same pads after 3½ years and 33,000 miles (quite possibly the factory originals!) - I intend to paint the swinging arm surface with at least 2 coats of black heat-proof (wood-burner) paint.

The real cure would be to have the calipers anodised - but that's a bit OTT.