Xantia MOT fail

PicassoPigeon · Post by **PicassoPigeon** » 24 Aug 2009, 15:03

So my Xantia has failed this years MOT on one thing and also had 3 advisory items:

FAIL:
Offside rear brake caliper [3.6.A.1]

Advisory items:
Exhaust has part of the system slightly deteriorated [7.1.1a]
(both front) Suspension arm rubber bush deteriorated but not resulting in excessive movement [2.4.G.3]
Oil leak

so now to the work side of things, it will have to wait for the sun to come out I'm afraid .
Any help points on tackling the above list?
gav

Keith J · Post by **Keith J** » 24 Aug 2009, 15:07

If you mean the rubber bushes on the wishbones, I had to replace the forward ones of the two and it was a right pain, as they have to be pressed in perfectly square and the wishbone is an odd shape. Luckily my friendly garage man did it for me in a very large vice, with a socket over the top of the bush to act a s a ram, but it took him a while to do it.

Post by **RichardW** » 24 Aug 2009, 15:08

3.6.A.1 appears to be a leak from the offending item. Could be anything from pipe leaking, pipe seal leaking, bleed screw leaking, seal between the two halves of the caliper leaking, the caliper gone porous, one (or both) of the pistons leaking. Until you get into it, you won't know. Best case: nip up the pipe

. Worst case: new caliper and pipe

Reality: Somewhere in between probably

citronut · Post by **citronut** » 24 Aug 2009, 20:31

Richard wrote
" Worst case: new caliper "

if the calliper seals are leaking you must be able to just dismantle, clean and reasemble with new seals, as the are very easy to strip down provided there not seized,

i will look on service citroen

regards malcolm

citronut · Post by **citronut** » 24 Aug 2009, 21:09

just in case rear calliper parts for a
saloon
piston 96025616 8.07
seal " " 615 2.45
" " " "613 1.98
" " 95587148 1.53
total 14.00

regards malcolm

PicassoPigeon · Post by **PicassoPigeon** » 25 Aug 2009, 09:05

citronut wrote:just in case rear calliper parts for a
saloon
piston 96025616 8.07
seal " " 615 2.45
" " " "613 1.98
" " 95587148 1.53
total 14.00

regards malcolm

Thank you. I am hoping to have a look at it today if the rain holds off, to see what I may need.
gav

PicassoPigeon · Post by **PicassoPigeon** » 25 Aug 2009, 10:37

I have had a look under there and its a right old mess. not dripping just covered with lhm. I cant tell where its coming from, the top of the caliper where the main pipe enters is dry but inside the caliper is very wet.

Its wet over and around the pistons and where the 2 halves join it is wet. Would the list above and a strip and clean sort this out. And why did they take away pr.net i liked to see the pictures.

gav

ps is there a how to overhaul rear calipers anywhere?

Post by **RichardW** » 25 Aug 2009, 12:09

Gav,

You need to get it jacked up, clean it all up with degreaser, then wedge the brake pedal down engine running and see where it is coming out. The rear calipers are very simple - Two halves bolted together (by the securing bolts), each with a straight forward piston in it. Take the pads out, refit the through bolt, undo the two securing bolts (carefully - they can snap easily!), remove the caliper. If you now take the pad bolt out, the caliper will come apart and you will see the seal between the two halves - you cannot buy this separately, but I'd have thought if it's giving trouble, then a slice cut from a suitable size LHM pipe seal would do. The pistons can be removed in the normal way - eg blow them out - then replace the seals. You may find that corrosion behind the caliper has already snapped one of the securing bolts, and this may have upset the seal between the two halves, hence the leak.

PicassoPigeon · Post by **PicassoPigeon** » 25 Aug 2009, 15:13

top bolt has snapped. have drilled it out as there was nothing to get hold of. Anybody know what size tap I need and also how to tap a new thread.
I have tried to put a new bolt that I bought just in case but it will not go through so a re-tap looks like it need to be done on the arm.
AAAAAAHHHHH

gav

PicassoPigeon · Post by **PicassoPigeon** » 25 Aug 2009, 15:54

Would any of these help do the thread?

HERE

Xantidote · Post by **Xantidote** » 25 Aug 2009, 16:02

Gav,

As Richard says, the rear calipers not difficult to overhaul, and he's come up with what strikes me as a good reason for the leak (bolt failure).

You have a new bolt, so can check tap size by measuring bolt diameter and thread pitch. Very recently, I had rear calipers off, and ran a tap through the thread in question. I was surprised how loose the tap was in the thread, though the bolts themselves were much tighter. Visualising, and looking at my taps, I'd reckon it's 10 x 1.5mm (run a die up the new bolt as check).

Without seeing the problem, I'd be drilling out carefully, going up incrementally in drill sizes, hoping to then pick out bits of the bolt from the first circle or two of thread, maybe just allowing the tap to get a grip on the original thread. All depends on how lucky you are in establishing the exact centre of the bolt. Don't rush it. Easy for me to say this, not so easy putting into practice!

As Richard says, bolt failure may have been due to corrosion behind the caliper, which you will see as white powder, this being aluminium oxide from the caliper, rather than rusting of the radius arm. Clean up with coarse emery, though a file better to retain flat profile of rear of caliper. I coat the mating surfaces with copaslip on re-assembly.

Good luck - Martin

Xantidote · Post by **Xantidote** » 25 Aug 2009, 16:36

Think I'd also try dowsing the broken bolt's threads with Plus Gas, from front and back, and trying a bit of heat - give it something to think about!

Martin

PicassoPigeon · Post by **PicassoPigeon** » 25 Aug 2009, 17:59

it was sheared before. That's is what was causing the leak i guess as the top half of the caliper was not tight together. I could pull it apart and LHM would ooze out.

It has now been removed split in two and all clean. The seal look ok but the thread on the suspension arm is not there I used a smaller drill bit than the stuck part. You can look through the hole but nothing will screw to it. So I thought it must need to be re tapped so that I can use my new bolt to pull the two parts of the caliper together tight and stop the small leak that must have been going for a while.
gav

Post by **RichardW** » 25 Aug 2009, 21:34

M9 x 1.25 tap needs a 7.9mm drill. I imagine if you drill it out to 8mm, then you might be able to pick out the remaining threads of the original bolt, and then you might be able to run the bolt carefully into the thread for a final clean up - do it carefully with plenty of oil! If you're not quite in the centre where you've drilled, then you'll need to re-tap it. There are usually 3 taps, one looks almost bare, one looks like a bolt with slots in it, and one inbetween. Start with the bare tap, screwing it in: half a turn in, back it off, half a turn more, back it off etc - plenty of oil. When you get the first through, use the second in between tap, same technique. Then run the 3rd through, same technique if it's still tight. You do NOT want to break the tap off in the hole - they're 'kin hard!

citronut · Post by **citronut** » 25 Aug 2009, 22:47

Richard wrote
"you will see the seal between the two halves - you cannot buy this separately"

oh yes you can its this one 95587148 1.53,

if you cant rethread/tap the arm cant you just use a high tensile nut and bolt right through the arm

regards malcolm