hey guys, ive got a kold locker by nor lake old walk in 8x8. old r12 system. compressor chatters on start up, not keeping temp (about -5 to 8*). appears to be low charge. i dont want to buy a tank of r12, or really deal with r12 at all. (this is my deer processors walk in). what would i need to replace the condensor, and evap so that it could be run on 404a or a similar refrigerant. model on the box is klf66-cl-26 serial is 91101798 ive never done a rebuild on a box, so i figured i had better ask you guys. thanks. KB