The rest of my story (i guess it's offtopic):
When i got all of the necessary A/C parts i've assembled the
whole system with new (green) preoiled O rings. I've been told
the compressors are sensitive to inactivity, therefore i don't
wanted the A/C system to be filled without leak check.
I have drained the old oil from the compressor to check the
presence of metal particles (it was clean). I knew the oil quantity
from the Sanden manual, so after flush, i have filled the compressor
with oil. Then the compressor was placed on the engine provisionally.
I have borrowed a tank of nitrogen, i used a dual gauge pressure regulator
from my argon welding tank (i know this wasn't the correct instrument...),
and connected a multimeter to the trinary switch on the drier filter.
During the nitrogen fill i have monitored the multimeter, when the trinary
switch changed it's state from open to closed i've aborted the filling
(the low pressure gauge showed around 10 bars @ that moment).
Then i used leak detector spray to check system for leaks, fingers crossed.
I don't have to look to much, bubbles appeared at the edge of the compressor's
, but no other leaks found.
Because i don't have the necessary parts for the compressor, i left this
part of the job to the A/C workshop, after the compressor was ready,
the assembled system was evacuated in the workshop (i don't have vacuum
pump), then filled with refigerant (1150 gramms [!] required for this model).
Since then (2008) it's working. (BTW i have a second leaky compressor also...)