Disconnect the machine by closing the valves on the service hoses and removing them from the service ports on the vehicle. Early machines designed to handle R-12 (Freon) refrigerant are required to have shut off valves on the hose. read more
Freon has to be in a vacuum and to do this you need a evacuating pump. My advice here is have it done at a shop where it will capture the freon, make the repair and then evacuate the system and reinstall your freon. read more