What series wagon do you have. Are you saying that you can only push the car down 2 inches, then it feels like it's hitting something? Also is the car running. I own a '83 TD and am not aware of a firmness setting that you can adjust. If the back end is bouncy then the problem is the accumulators.
1994 MB E320 Coupe (199,500 mi)
1992 MB 190E 2.6 (173,000 mi)
1983 Porsche 911SC (148,000 mi)
2004 Volvo V70 2.5T (198,000 mi)
President of CT/Westchester Section