Citroen XM Forum

Hi all.

I have what i think maybe a small problem with the rear of my Xm !!! ( ohhh Matron ), after start up, and its up to correct height, when you pull away it all of a sudden drops down low at the rear, and then you hear the pump hissing , which then returns it to the correct height again, it's slightly annoying, but what would cause this ?? i have read on other topics that a hydroflush may be the answer !, if so how is this done ??, i will be changing the 4 corner spheres very soon, iv'e already done the front centre, and accumulator sphere in the last month or so, could it be air in the system still , as this is my first Xm i feel i still have a lot to learn.

Any advice !!

Nigel

Hi Nigel

Sticky height control valve I would suspect, give it a few doses of WD 40 over a few days, that should cure it.

Peter

+1 for that.

Thank you for that info, !

Not sounding to thick , and new to the xm, well a few months now , where is the corrector situated ??, and il'l put the old girl up on the ramps and sus it out !!

Mine has a similar problem, on start up it rises no problem, then it suddenly drops at the rear and then rises again. The thing is though if I get in and drive straight away the back is very bouncy and once it has done its drop and rise trick its super soft again. So i was thinking it might be down to a sticky rear hydractive valve rather than height control.

Does this make sense to anyone else? or am I thinking along the wrong lines?

Hi ian

My 2.1TD does exactly the same, usually only once at the start of a trip, but it happens so infrequently that I have learned to live with it. It is as if an 'empty' sphere (centre hydractive?) has suddenly been switched into the circuit and the pressure equalisation between it and the other spheres causes a sudden drop.
I agree that a slow acting rear hydractive valve might be a possible cause.

Ken

Hi Nigel

Look along the rear anti roll bar and you will find a clamp round it with a thin rod attached to it, follow this and it will lead you to the height corrector. The linkage has a couple of ball joints, these tend to stick.

Peter

Hi Peter,


I will shortly go out and have a look , armed with WD40, i did wonder if it was a flat rear centre sphere, i do have a spare centre one for the front , are they the same ??? if so i may change that as well, see if that makes any differance,

Nigel

The centre sphere is the one responsible for the soft ride and often get overlooked so its certainly worth changing it if it looks old. Don't know if front and rear are the same, they look the same but the pressure may be different. There is a list of sphere pressures somewhere on the forum. Its got to be better than a flat one anyhow.

Peter

I STAND DEFEATED !!!!

What a pain in the a****e job that is

Tried to get to the said sphere, well after taking off the spare wheel carrier, to enable me to remove the heat shield that sits over the exhaust box, ( which i did not want to remove ), i had depressuerised the system, and after a lot of p******g around trying to get my chain wrench round the bloody thing, i still couldn't get enough leverage on it to even get it to budge !! so after nearly an hour of trying to get it to move, and with piles of dirt and other detritis from under the old girl in my eyes and mouth , i decided to call it a day, so put everything back , but did find an oiled well the height corrector ,( thanks Peter for the directions )

I cannot see an easy way to do this , but even with a little encouragement from my 4lb lump hammer wouldn't budge it, and i guess the only way do to it is to remove the rear exhaust box , which would give more access, but trying to get them back on correctly i fine is a nightmere in it's own right !!!!...


Peter PM sent