Xantia rear caliper seal

mbunting · Post by **mbunting** » 26 Aug 2003, 20:54

I think the small seal which joins the two halves of the caliper together is shot. Each morning there is a puddle of varying sizes behind the rear right wheel. There doesn't seem to be a leak from the suspension, so the brakes come to mind.
Had the caliper off at the weekend, and there doesnt appear to be a leak from the main input pipe seal, so I can only suggest an 'plunger' seal problem, or the seal which sits in the join between the two halves.
I presume since the back brakes and suspension ( not anti-sink ) are linked, the fluid is finding a weak spot on it's way back to the reservoir ?
Any comments, and does anyone know where to get this seal on it's own without buying a complete caliper repair kit ?
Mat.

surfer · Post by **surfer** » 26 Aug 2003, 22:03

Mat,
This seal is available by itself for next to nothing from Citroen dealers, but I had to order them.
Mine weren't leaking but I had planned to overhaul the calipers.
Unfortunately they were so corroded that I replaced the whole lot instead.
Simon.

mbunting · Post by **mbunting** » 26 Aug 2003, 22:58

Thanks,
Anyone know if this is the same as a peugeot part for the rears ? It's just that there is a pug garrage just down the road from my work, which is handy for a few things ( although fun convincing them that an oil breather is the same ! ).
Mat.

blueboy2001 · Post by **blueboy2001** » 26 Aug 2003, 23:32

I can't say for sure, but I think Peugeot use different rear calipers. I've seen a 405, 306 and 406 rear disc/pads being changed and none of them looked anything like the Xantia rears.

Jonesy · Post by **Jonesy** » 27 Aug 2003, 00:12

Mat,
In my experience these 'o' rings very rarely leak, although what you describe does sound like it could be.
I'd be surprised if it wasn't leaking when under pressure if it is the 'o' ring. Don't forget when running about 1500 psi is being generated!
Are you sure its not from the hydraulic unit of the rear suspension as I have replaced these in the past?
These 'o' rings are readily available for a few pence.

AndersDK · Post by **AndersDK** » 27 Aug 2003, 00:33

Mat -
There is no pressure in the rear brakes calipers - unless you press the brake pedal. Have a good look for leaks elsewhere before deciding to dismantle it.
The rear calipers CAN be a nightmare of white rust - be prepared for a replacement unit.
AFAIR the BX rear calipers are the same - but unsure if it's true for later Xantia models.
The calipers are commonly offered as exchange parts (complete with pads & bits fitted) - if the old one removed is serviceable - and have NOT been dismantled.

mbunting · Post by **mbunting** » 27 Aug 2003, 01:22

The condition of the calipers is good, they're a flush fit both internally, and to the arm.
These are my experiences so far:
1) Small pool of liquid on the floor in the morning ( parked facing slightly up-hill )
2) Took the wheel off the other day, to be greeted by a pool inside the wheel, which was driping over the tyre to the ground.
3) The sphere is tight, no signs of leakage from the seal there.
4) The feed to the sphere ( and the returns ) are tight, no sign of leakage.
5) The feed to the brake **appears** to be dry, but I'll need to take another look ( this was my first thought ), so my thought was that perhaps the caliper was leaking. I'll need to give it a thorough check, although time is tight at the moment. I've got a list of 'niggles' that I'm working through before driving over 2000 miles on our honeymoon in september !

AndersDK · Post by **AndersDK** » 27 Aug 2003, 03:11

Mat -
I admit it seems likely the caliper is leaking then.
When you get to it - simply try if the caliper bolts are torqued up -
I've never seen a rear caliper leaking here.
Neither my BX'es nor my CX (same rear caliper) have had this problem.
On the CX the front calipers are sort of same construction - one half is part of the hub - the other half is the outer most part - the caliper held together with 4 bolts. 2 orifices & seals connects the caliper halfs.
These I've dismantled several times - using old seals - no problems ever.

Homer · Post by **Homer** » 27 Aug 2003, 13:01

Most likely the piston seals. these have a tendancy to sieze up especially if you don't often carry much weight in the back. Then when they free they seals can tear. Was a common problem on BXs and fairly easy to replace Xantia system is almost identical.

surfer · Post by **surfer** » 27 Aug 2003, 17:55

I doubt that a Peugeot part would be the same:
Unless they use a mineral oil in the brake system, LHM would destroy the seal quite quickly: seals are designed for oil OR brake fluid and are not interchangeable.
Also: the seal is not an O ring, strictly speaking. These are circular in cross section: this item is square; i.e. as though cut from tube.
Hope you find this useful.

mipster · Post by **mipster** » 27 Aug 2003, 18:31

The rear brakes aren't the same on the pug 405 - I had the same thought and tried a pug parts dealer for a caliper bolt.
mipster

mbunting · Post by **mbunting** » 27 Aug 2003, 19:11

Ordered a couple of seals from the citroen dealer, should be available tomorrow. Might take a closer look tonight.