Just did mine today - the Dunlop bags.
the air fitting is a push in type and the instructions provided are clear. Simply cut off the olive from the screw in fitting making sure you have a clean square end. Push the tube into the new fitting and it's done.
One interesting thing I had. Once everything was back together but still on the stands and jacks I closed all the doors and started the engine and... nothing!!!
Compressor wouldn't run. Checked fuses, all ok. Finally wondered whether the system wasn't getting a signal to level the car so jacked up one of the wheels a couple of pumps and the compressor instantly kicked in and pumped up both bags. Phew.
2002 Td5 ES SLS and now new air springs.

