More info. Were the original factory air springs on the car? Was the replacement an OEM air spring or an Arnott (or equivalent)? If one side is OEM and the other aftermarket, that's the problem. Replace air springs in pairs, do not mix and match OEM and aftermarket. If replacing a bad Arnott with another Arnott, it will take a bit more digging. Did you have the car sitting on its suspension prior to torquing the bolts? Assuming both rear air springs are identical manufacture, loosen the bolts on the air springs and shocks, ensure car is level, then torque the bolts to the proper value.