I read an A/C service manual that said essentially to detach the compressor,
take out the plug/bolt, turn it upside down, rotate the shaft several times
and let it drain. After it appears to be done, rotate the shaft again and
see if anything else comes out; if it doesn't you can consider it drained,
and then you add the correct amount of oil (just for the compressor) that
the specs call for. I haven't tried it myself, yoyo/ymmv.

Cya,
Robert

On 5/20/08, Roger Sisler <rogersisler2000@yahoo.com> wrote:
>
> You have to kinda gustimate how much oil to put into your old
> compressor.Got
> oil stains and accumulated dirt around the compressor(leaking oil attracts
> this dust)??  Same for the hose connections? Unknown history??Was your
> system ever so low the low pressue cut off switch shut the system down??
> More than once, you say! Stick about 2 ounces in for good measure, anyway.
> Won't hurt nothin'. The oil that leaves the compressor seems to wind up in
> the evaperator. If the compressor is making a racket and, a shot of oil
> quiets it down maybe add a bit more.
>
> In early Vanagons, VW satisfied the lack of a low pressure cut off switch
> by
> adding a sentence to the owners manuel- "Be sure to take your Vanagon to
> the
> dealer and have the A/C system checked out before each cooling season". It
> is the loss of refrigerant pressures that cause the oil to leave the
> compressor. I guess this didn't work,so they added the switch in '86.
>
> The Sanden web site shows how to make a dip stick to measure, but got to
> discharge your system and remove the compressor from its mounts--first. If
> you want to do it right.  Maybe  www.sanden.com
>
> Once , I went to an A/C speciality shop and picked the owners brain. When I
> asked which tools (and how hard) were needed for changing out the clutch
> /pulley, he answered that he had never done it before. He said that he
> changes the compressor. Nobody he was aware of changed the clutch pulley. I
> think it was a $$$$$ issue, and when it is 98 degrees and humid, few would
> complain.
>
> I say to get the Bus Depot compressor because their supplier is the best.
> New compressors have a shelf life of 18 months. If they are not installed,
> they are junk. The shaft seal has shrunk up and will leak. This supplier
> knows that and stands behind all his compressors. He calls them back and
> will ( he changes clutch/pulleys)put in a new seal.
>