SEarch on nitrogen spheres this forum
Do a search on nitrogen spheres on this forum and go to jere(about to expire). s500 94 rear suspension. It has the best description on replacing the spheres. They are an integral part of the suspension coupled with the rear shocks. Those shocks are 500 bucks a piece. I don't think you can use the non-self adjusting shocks on the car, but I could be wrong. It's the accumulators coupled with the shocks that level the car. I've been told the the springs alone can not hold up the car without the accumulators working.
How did you close off the valves that normally go into the rear shocks?