Did the compressor die? if so, you can get a new one from these folks for under $200 http://www.nostalgicairparts.com/compressors.html ( the sanden 508 is a direct drop in, the 709 is a stouter compressor and willl fit in , but you will have to move the AMM bracket about an inch )

I'v converted my 84 sedan the cheap way here in Arkansas with the wal mart type conversion and it worked fine, I did the factory conversion with the new condensor and all( the same kit fcp groton is seling ) on my '90 wagon, and between that and the 709 compressor,you could hang meat in that thing , even in mid summer

You could replace all teh parts and take it to a shop for evacuation and filling, or if you own a good air compresor, you could get a air powered vacuum pump from Harbour freight for about $18 and a set of cheap gauges for about $30 and do the vacuum and fill yourself.
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-------Robert, '93 940t, '90 240 wagon, '84 240 diesel (she's sick) , '80 245 diesel, '82 Mercedes 300SD