Suspension, no movement on one side - Citroen XM

[AndUK]

Hi there,
Can anyone help me with this one please?
I have a 1995 Citroen XM with Hydractive 2 suspension.
At times, the car bounces me about as if there is no suspension and then is OK again later.
I decided to investigate a little further and discovered that when this happens the front driver's side has no movement in it whatsoever, it's solid.
If I push down on the other three corners of the car, they react normally.
I tried raising and lowering the suspension in the hope that it would help cure the problen - didn't work.
This is the odd thing, if I turn the engine off and leave the car for a few minutes and then re-start, the suspension corrects itself.
Driver's side back to normal again.
Until the next time.
Any ideas?
Thanks in advance.
AndUK

[RichardW]

Sounds to me like the driver’s side strut sphere is shot, and when the car switches into hard mode and isolates the centre sphere that side goes hard. I would start with new front spheres. This may be masking a problem with the hydractive switching in and out of hard mode, but at least the new front spheres should stop your teeth falling out[:D]