Are you talking shocks? Or air bags?
After two days sitting un-used, my Envoy would be sitting on the bump stops. There is a repair kit available from the dealer (Rock Auto might have it too).
It has a new spring, cover plate, Allen screws, gasket, and rubber part. Part # 15183676 compressor repair kit. I paid about $35 for mine from a dealer, but it was a special order.
When I took the compressor apart, the spring was rusted and in three pieces. The hardest part was getting the old Allen screws out.