Hi, My AC system was working fine but unfortunately I had to vacuum the R12 out while cleaning out my evaporator box. A friend of mine is letting me use his 30lb tank of R12 to refill the system next week. Before I re-charge it, what parts in the system should I replace? Last time it was charged I had it leak tested and none were found so hopefully it hasn't changed. I would really appreciate any info on what I should replace and where I can get the parts. Thank You Dave