Find someone with a set of gauges and a vacum pump. When you change out the parts do yourself a favor and pull a vacum on it. This does a couple things...checks for leaks and gets the trash out of the sytem. Dont keep running it till you fix it or your gonna tras the compressor.
Im sure someone is gonna say you dont need to it will work without it, will it work probably so. It will make a difference in cold air and freeze you ass out cold air or if you have a leak, howlong it will stay cold for