Xantia Rear Brakes

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Paxman Power
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Xantia Rear Brakes

Post by Paxman Power »

From checking the archive, it appears that I am suffering from corrosion between the rear caliper and hub carrier on my 1996 Xantia 19TD Hatch. (Occasional squealing noise from N/S/R brake and visual inspection reveals squint caliper and wedge shaped pads). There is a definite build up of corrosion between the caliper and the hub carrier.
Is it essential to replace the pipe seal (if I choose to remove the hydraulic pipe), or might I be able to clean up the face just by loosening the caliper retaining bolts enough to get it scraped clean? I will purchase new pads beforehand.
Any advice would be greatly appreciated.
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Post by RichardW »

You should replace the seal if you disturb it. I have just done the rear brakes on my Xantia, but I had to replace the pipes as well. I don't think the rear brakes had been serviced on mine since it was built (95 TD with 107k miles) as they were totally rusted up. The caliper was rubbing on the disc, the pad retaining bolt was seized in and had to be sawn off and driven out, and the inside pads were rusted into the caliper and had to be sawn in half. Having said that the 'rust' on the back of the caliper chipped off quite easily, so it should be possible to do without removing the pipe (others here have done just this). When I took the pipe unions out the pipe seal came with them and was pretty well chewed up. Take great care with the bleed screws if you do disconnect as they like snapping off.....
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AndersDK
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Post by AndersDK »

If you intend to DIY further on your Xantia - you better stock a few of these pipe seals.
They comes for 3.5mm & 4.5mm pipes, a few pence each - either at GSF or Citroen.
Get a couple of bleed screws while you're there [:p]
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davek-uk
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Post by davek-uk »

A scraping noise from the rear alerted me to the same problem. On investigation yesterday evening I found that the offside rear calliper had snapped the top retaining bolt! In the 30 miles back home the calliper and disk have rubbed pretty badly. Looking at the nearside reveals that the calliper isn’t sitting true so this must have the same problem.
Is it just a matter of cleaning the rust from the hub assembly underneath the calliper? Should it then be bolted back dry or would it be best to have a thin film of grease (or oil) to help prevent the rust later? Does anyone have a good way of freeing off the cylinders as one of mine looks as though it’s going to be a bit stiff.
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Post by RichardW »

Yes, just clean it out, then apply a thin film of copperease or high temp grease before refitting. You'll need to drill the end of the bolt out probably, but they go right through the arm, so even if you can't save the thread, you should be able put a longer bolt in and use a nylock on the back. I was very surprised that despite mine appearing to be totally rusted up (see my comments above about getting the pads out!), all four pistons were working OK, and I have had no problems with dragging brakes since rebuilding it. In fact, the brakes are much sharper, the car appears to go better, and the MPG seems to be up (hmm, maybe the last 2 are placebo effect!). To make life easier in your case I would probably take the calipers off to do the work - watch out for the snapping bleed nipples, and the small seal between the 2 halves of the caliper (I didn't renew, but no leaks so far) - the caliper falls in half when you take the mouting bolts and pad retaining bolt out at the same time.....
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Post by mipster »

<i> You'll need to drill the end of the bolt out probably, but they go right through the arm, so even if you can't save the thread, you should be able put a longer bolt in and use a nylock on the back.</i>
The bolt is a odd size (10mm shoulder with 9mm thread or somesuch). I had thought of the same solution when I snapped a bolt but ended up with a new trailing arm...
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Post by paranoid »

I found it easier to keep the pad retaining bolt in place when I took the caliper off, (caliper is in two pieces) then access behind the caliper aint to bad,Then removed pads etc and have a good clean up.
Except don't do what I did and use motorbike chain lube instead of brake cleaner[V][V][V] Identical tin and it was starting to rain. New pads please.
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Post by davek-uk »

Wow! I had a great time doing mine [:(]. I had to drill the bolt out in the end. It's now held in place by a sawn off AX head bolt! I'm so surprised at the thickness of the stuff that built up there. Reading this forum alerted me to the possibility and I should have checked months ago - but I didn't and paid the penalty. These Cits just don't like to be taken for granted do they?
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Post by Paxman Power »

Replying to my own message here!
Stripped both my back brakes last weekend. No particular problems. Made sure to replace the pad retaining bolt once I had removed the pads and before I removed the caliper mounting bolts in order that the caliper didn't split. Checked that the bleed sccrews would loosen before hand.
A good clean up - lots of corrosion but calipers both ok, copper grease on the mating faces, new pipe seals and new pads. What a difference! Car no longer nosedives under braking - rears must have been doing very little before.
Thanks to you all for your advice.
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Post by davek-uk »

It'll be interesting to see into the future... I put Hermatite blue on the mating surface between calliper and trailing arm rather than copper grease mainly because I wanted to use it up but also to try and prevent the two metals having contact. How long does it take to build up again, I wonder.
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Post by paranoid »

If its anything like mine, ooh I'd say about twenty minutes[:D][:D][:D][:D]
john alexander
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Post by john alexander »

Hi I,ve just read the postings on the rear caliper corrosion problems,does anyone have an exploded diagram for the rear calipers.If you split the caliper surely you have to bleed it after?? Regards John.
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Post by Dave Burns »

You don't split it, put the pad retaining bolt back in to hold the two halves together while the mounting bolts are out.
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Post by ghostrider »

Only Pics I have will be in Haynes, but bleeding the brakes on hydraulic Cits is a snap. For the rears set the suspension on high, so that you will definitely get pressure to the rear calliper, get a short length of clear plastic tube to fit over the nipple and a jar to collect the LHM, open nipple about a turn or so, with the engine running get someone to put their foot GENTLY on the brake pedal and allow fluid out until it has no bubbles and is reasonably clean, shut nipple off, press hard on brake pedal to check that nipple is not leaking.
If you have not freed it off during the calliper strip be VERY careful, good old Cit dissimilar metal corrosion can almost weld the thing in place.
The cure for that is a) Heat b)using an aluminium drift on the calliper alongside where the nipple is screwed in some hefty blows to the end of the drift often helps.
The nipple can sometimes be blocked with crap, I use a 1.5mm drill to clear that out and then a pin or needle in through the hole in the side of the nipple near the pointed bottom end. I also run an M8 tap down the nipple threaded hole. Or you can treat yourself to some new nipples from GSF for not much
Pete
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Last edited by ghostrider on 22 Feb 2011, 05:58, edited 1 time in total.
john alexander
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Post by john alexander »

If the caliper is badly corroded can they be swapped side for side,or is the drilling for the pipe and nipple different. Regards John.
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