Xantia V6 Rear Suspension Problems

[Zanderman90]

Hey, I hope someone can help me out here.
I have a Xantia V6 mk2 and I've started to have problems with my rear suspension. When I accelerate, go around a sweeping corner (left and right) and round-a-bouts the suspension at the back end goes hard until you ease off the pedal, or straighten up. It doesn't happen regularly though, although it's becoming more common. I really don't know where to start. I would really appreciate and help.
Regards,
Alexander

[andmcit]

The suspension electronics are designed to switch into a firmer state with the ECU
receiving feedback from the accelerator, steering angle, anti roll bar sensors etc
but as soon as the rear centre suspension sphere is switched out of the hydraulic
circuit the remaining x2 rear corner spheres aren't up to the task and could be flat.

[Mandrake]

I second this. If it goes really hard in the conditions you describe you know the rear suspension is switching into the firm mode as it should during hard cornering or acceleration etc, but that there is probably very little if any gas left in the rear strut spheres (the ones just inside the rear wheels pointing backwards) thus it goes much harder than it should.

At minimum you should replace those two spheres. I would also be inclined to replace the Hydractive regulator sphere, this is the one that provides most of the cushioning in the normal "soft" mode that is engaged while cruising, although it may not be in as bad condition as the other two its still likely to be poor, and the balance between that sphere and the other two is important for the overall ride/handling tuning and balance, so unless you know for sure the regulator sphere is ok or recently replaced I would replace them together as a set of three.

It's located on the Hydractive control block - looking from the rear with the spare wheel carrier removed its in front of the spare wheel carrier to the right, with two large pipes going into the block. (There is a cutout in the spare wheel carrier tray to clear the sphere in question when the tray is tilted down)

There's plenty of threads on the forum that cover the actual sphere changing process, and being in Australia where the underbelly of the car won't rust nearly as much as the UK you should find getting the old spheres off MUCH easier than described on the forum.

[Citroenmad]

I 3rd that, it will be the corner rear sphere which have little, if any, gas remaining. Replace those and you will have a totally different car.