New Spheres Needed?

[magic carpet]

Hi on my xm estate when i park up and switch off, the car sinks down to a degree after perhaps 20-30 secs both front and rear. Is this normal? the car is not an anti sink model, and will then take a period of a few hours to sink the remaining travel. When driving i can't tell the difference whether in normal or sport, both electrovalves hum nicely, the car rises nicely and sits level. I haven't been in another xm or indeed any other hydraulic citroen to compare ride quality, although i would say it's good but not great. The front strut top spheres look newish, the accumulator is new, but the centre front and all the rear spheres look like they've been there a long time. When i bounce the front and rear of the car it sinks readily enough, and doesn't seem too hard. I have no detailed service history for the car, so i don't know when or what has been done on the hydraulics. I'm thinking the lhm probably want's changed, but without testing the sphere pressures, do any of the previous suggest sphere changes are needed? Thanks

[DerekW]

I assume your car sinking a small amount when you park and stop is after you have got out? If so, this is normal. As your weight is taken off the suspension it rises, after a short delay (built in) the height control valves sense the car is now too high and lowers it accordingly.

I think your car has hydractive 2, in which case you won't tell any difference when you switch from normal to sport. Unlike hydractive 1, which actually switched to sport when you selected it, hydractive 2 merely switches in lower parameters for the automatic change to sport when the conditions warrant it. In other words, when driving normally the suspension will remain in soft mode even if sport is selected, but if you drive more energetically, the suspension will become stiffer sooner.

As has been written before, the most important spheres for comfort are the centre hydractive ones and if in doubt, those are the ones you should change first. The accumulator sphere should be changed if the cut in/cut out clicking occurs at much less than (I suggest) 30 second intervals.

Derek

[Peter.N.]

The spheres won't have any affect on the rate that the suspension drops, that's mostly down to the general condition of the hydraulics. To check the spheres, bounce each corner of the car with the engine running, you should have at least 4"-5" of movement, much less and that particular sphere or pair of spheres will need changing.

The 'sport' mode switch will have no noticable effect if you have a Mk2 model, difficult to tell with a '94, could be either. If its after August it will probably be a Mk2, will have the chevron in the centre of the grill and a curved instrument binnacle, the Mk1 is flat. On the Mk1s it does stiffen the suspension by closing the electrovalves but on the Mk1 it just makes the system more sensitive so that it switches to 'hard' mode earlier.

Peter.N.

[Peter.N.]

Sorry Derek. Someone else that types faster than me!

[DerekW]

It doesn't matter Peter, we were in agreement!