I have recently purchased a compressor and a drier for my 83' 300SD. I know the old compressor is bad because I saw the previous owner had snipped the belt and also knocked the compressor housing off that was rattling. My question is what is the best way to attack putting a good used compressor and new drier on my vehicle. In other words do I do the entire nut and bolt work and then bring to a shop to have R-12 charged? I have done a lot on this car already and this is the last thing to make it perfect. Should I just go ahead give the parts to a person with more experience and pay for the labor? Advice is greatly appreciated!