XM sinking at rear when parked

[trebor]

Sorry if this is an old one, but my N reg 215 000 mile 2.5 TD Exclusive sinks at the rear (only) when parked - right down to the bump stops overnight. Three of the leading specialist organisations have not cured it. It's had all spheres recharged (twice), and new brake, height corrector and anti-sink valves. Diagnostics show no electrovalve problems and it doesn't leak. Has anybody else had this expereince and have THE cure please?

[robertmnorton]

Hi trebor, do a search under "stiffness regulator" or "rear sinks" and this will take you through the associated threads.The citroen file relating directly to this fault is here and also in the "self help" files.It points to the hydractive pilot valve seal.
robertm

[Dieselman]

Well remembered robert.

If it's not that then it's likely to be a leaking ram allowing fluid return via the leak off pipe..

[Peter.N.]

Could be the height control valve leaking, my red one does that only in the first 30 seconds. I wouldn't worry about it as long as it comes up again when you start it, you could spend a fortune and its not going to make any difference to the way the car drives.

Peter

[trebor]

If any of you remember this one from last year
I've just had it sorted after 2 1/2 years (and I suspect 5 years in total going by the service history passed to me when I got the car).
Having had about three specialists look at it, it seems that 5 years ago some numpty fitted a new anti sink valve ... the wrong way round. There seem to be different versions of the valve - which has asymetric bolt holes for the mounting.
I was alerted to the possibility when a(nother) replacement valve was fitted and the mechanic mentioned the difference in the mounting holes; but he fitted the replacement the same way as that which was fitted (but which itself had previously been changed ...).
Wolsey House had previously diagnosed that the rear suspension pipes on top of the subframe were corroding and needing replacing. When they did this, they installed the anti-sink the same way round as the pattern off a scrapper which they had and bingo! everything is right at last.
I don't mind running old cars as long as they are right, and it's close on sacrilege to have an XM which doesn't work as it should.
There is a lesson here about trying to fix a problem when another hand has already been at work ...
In this case it was even more difficult because (a) I couldn't find a good, complete hydraulic circuit drawing and (b) even if I had, the pipes are impossible to trace on top of the subframe (unless you take it down).
Here's to another 228000 miles in one of the 2.5s.

[Peter.N.]

The aforementioned red estate had the n/s rear suspension cylinder fail a few weeks ago, since I replaced it it stays up

Peter

[robert_e_smart]

Well done Robert,

It was nice meeting you at the weekend and hearing of your success.