This may be of some use to someone looking to find a replacement (used) A/C 
compressor...

The compressor that came with my 84 GL when I bought it three years ago seized 
in the first week (always a good sign).  The shop I went to at the time was 
unable to get a replacement from another VW, so after I tired of them running 
me around I went to a large local salvage yard and took the old compressor up 
and down the racks of VW units...and couldn't find a match.  So I started 
looking in other makes (imports) and finally found the exact same unit, which 
had a label stating it had come out of an 87 Peugeot 505.  Once a different 
shop got the sucker in it worked like a charm and is still going strong.

I suppose the real question is whether the compressor I got was mislabeled, but 
I'd suggest trying other import models if going the secondhand route for 
compressors, 'cause I remember noticing that many makes used the same Bosch(?) 
unit; just the inlets/outlets and the flywheels were different.

I think they charged $125 and gave me thirty days to return it if it died.

Pete
84 GL "The Land Ark"