Robin, this sounds like the height corrector is not a happy bunny. Is the white plastic link between the ARB and the HC linkage in place?citroen7 wrote:no actually what i meant was moving the suspension from low to high the front goes up and down nicely but the back stays put ,except once when having a play around the back went all the way down and back up to normal height but would not go up to max.
Otherwise, you have the old problem of the mechanism in the HC cradle being seized up. The rear height corrector on a Xantia is a bit different to the BX.
Generally, a cleanup and lube works well but not always. Corrosion can be so bad that the only solution is to replace it. Very rarely is the hydraulic bit of the HC duff.