Xantia 2 HDi 90 Rear Brake Pads

Gregg1100 · Post by **Gregg1100** » 10 Aug 2008, 16:26

Hi,
I removed rear pads on N/S of sons car today. The old pads had worn down at an angle. When I looked harder at setup, I noticed that the brake disk is touching the calliper on the inner pad side, whereas there is a good 1/4" gap where the outer pad goes. There is only fractionally run out of true on disc.
If I were to replace disc, it would rub hard on the calliper, due to the thicker disc (unworn). The calliper is fixed properly to back plate, so cannot understand why there is so little clearance on the one side. I can't get the inner pad in as it should be, it stops 3/4 of way in, then the disc won't turn.
Anyone had any of this aggro, and what did you find was wrong?.
Thanks,
Greg

rory_perrett · Post by **rory_perrett** » 10 Aug 2008, 16:37

This is due to corrosion between the alloy caliper and the steel arm to which it is bolted - common Xantia problem. Put the pad retaining bolt back in as it holds the 2 halves of the caliper together when you undo the fixing bolts. Take the caliper off the arm and clean up arm and caliper. It should now sit back on square. New pads (and disks) and you are sorted.

Post by **myglaren** » 10 Aug 2008, 16:47

When reassembling make a polythene or similar gasket to go between the steel arm and the aluminium caliper to prevent further corrosion due to EMF. At least smear the back of the caliper with Coppaslip if nothing else.

MikeT · Post by **MikeT** » 10 Aug 2008, 18:30

I think copperslip is a bad idea because I've read it can accelerate the corrosion. I discussed this with GSF when I went hunting for aluminium grease and they sold me a tube of metal-free brake grease - can't recall the name now but it might be worth using in place of copper grease.

Gregg1100 · Post by **Gregg1100** » 10 Aug 2008, 20:04

Hi,
I don't understand how a calliper can grow out, especially with two largish diameter bolts to hold it from doing so. To even out the gap either side of disc to calliper, it needs nearly 3/16" - going back inwards.
I will try the cure, but can't get head around the cause/symptom.

Greg

JohnD · Post by **JohnD** » 11 Aug 2008, 12:00

It's a well-documented cause/symptom and it's been around since the first BX came on the market

Gregg1100 · Post by **Gregg1100** » 17 Aug 2008, 17:34

Hi,
I did the cure on sons car, and with new disks, everything is hunky dory. Still can't understand why it can happen, with tight bolts, but there it is.

Thanks for your help again, chaps.
Regards,
Greg