5000S Air Conditioning System Problems

["Rossato" <rossato@erols.com>]

I have had some real bad luck with my A/C system in a 1987 5000S wagon
(2.2L non turbo).  I've sold the car, but on the condition that the A/C run
and it's starting to eat up my wallet!

The A/C did not run.  I was told there was plenty of Freon, but the
compressor was seized.  I had a junkyard compressor installed.  The shop
was low on freon, but the compressor  was running.  I could see the clutch
engaging and disengaging after a few seconds.  This would repeat after a
minute or so.  I was advised that this behavior was related to low freon so
I brought it to the shop to top off the refrigerant.  After adding a pound
and a half of R12.  The compressor clutch burned out.  I was told the
clutch was probably bad in the junkyard compressor.  

Well this left me with some choices, none really good, but more importatnly
I am concerned that I ahven't really found the root cause here.  I started
calling all sorts of sources for a rebuilt compressor preapared to pay for
a new installation.  One call led to a shop that could sell me just the
clutch ($120 Hancock Industries 800-289-8282 if anyone is interested).  

Further conversation led me to believe the clutch wasn't bad in the
junkyard compressor, but that it burned once the pressure came up with the
full Freon charge.  I was told that the clutches rarely fail on their own,
being rather simple elecro-magnetic devices.  The casue of the problem is
more likely a restriction in the system, I was told.

So, who has any suggestions?  I would gladly put in a compressor, if I knew
it wasn't going to burn up the clutch immediately upon reinstalation.  I
believe I can replace the clutch, but the same logic applies.  Is a
restriction likely to cause this problem?  If so, where?  How can I
determine this?

BTW, the air distribution system is stuck on defrost and floor vent
position, typical of a failed controller/vacuum system.  Could a failed
controller be killing my compressor?

TIA