See Figure 1
Most Ford refrigerant line connections are joined by these type couplings. The coupling is held together by a garter spring inside a circular cage. When the coupling is connected, the flared end of the female fitting slips behind the garter spring inside the male fitting cage. The garter spring and cage prevent the female end from pulling out of the cage. There are 2 O-rings at each connection.
These O-rings are different than those used in conventional refrigerant connections. You cannot interchange the 2 types.
There is a special tool available to disconnect and connect these fittings.
When connecting the fittings, always check for broken, defective or missing springs.