i got this free AC check on my 93 pickup and the shop said i have some leaks and i would probably want to convert over to the r-134 i think it is. they wanted like $300 but i wanna try it myself if i can. what invovled in this. how do i check for the leaks. and as far as converting it over i've seen those kit in like peps boys and places like that. do they work at all? if so whats the best one to get?