if it still has some pressure in it , you can put a can of freon in it
,directions usually come with the kit . if you want to fix a leak,youll
have to open the system ,so youll have to have a vacume run on it before
new freon and oil goes back in ,so may be best to hire that done if you
dont have vacume pump,guages and know how. lucas

http://www.minibite.com/america/malone.htm