sounds like your spheres have lost all the gas, relatively easy to replace they generally only last about 5yrs, front ones easier to replace than rear, i have done many myself, gsf car parts can supply approx £50 pair front and rear would also recommend replacing accumulator and anti sink sphere approx £30/40 each, brought my 96 xantia for £50 6yrs ago cos the guy thought suspension was knackered replaced all of the above for under £200 then had the magic carpet ride back front stil ok but rear wil need replacing again shortly, u will find yr high/low wil stil work even if gas is gone, if u have been drivin the car with no gas in the spheres it can cause the rear arm bushes to wear excessively worth checking these too again relatively easy to replace/repair, any repairs to suspension/hydraulics should be approached with extreme caution as it operates at extreme pressure, consult an expert or haynes manual first. good luck.
cliff, January 2010
