AC Clutch Question ???

[Vikram Mittal <vikram_mittal@notes.pw.com>]

I have removed the AC compressor from my car (after having the
system evacuated). The problem was that although the system was holding
pressure, the clutch seemed to be constantly engaged.

Well, I removed the clutch (free puller rental made this real easy)
and I checked out the coil and it seems to maintain continuity so I
guess the electromagnet is ok !?

Here's my question:

When I put the pulley back on and then the face and tighten the nut
that secures this face in front of the pulley, the clutch is always 
engaged.  If the nut is left loose, then it is ok !!? What's going
on ? Do I just leave the face plate to the pulley loosely attached 
by not tightening the nut properly (and risk it flying off the car)
or is something missing.  There are three washers behind the face 
plate which is used for correct spacing and I am using those.

MAybe some one can help with this by personal experience or looking
in the Bentley.  The car is an Audi 80 but this is the 
Nippondenso 10P17C compressor found on all Audi's after I think 1988/87.

Best Regards,
Vikram.