I gave a cleaning to the clutch plate
and a second washer got freed
placing both washers on the compressor threaded axle
then refit the clutch plate
a few light hits with a hammer and a socket, to get the threaded part visible
the special tool needed to push the plate on the axle :, by turning the big nut
(the screw on the right needs to be removed to screw the tool on the thread of the axle)
first, screw the centre axle on the threaded part of the compressor, until it blocks, then turn the but nut while holding the central part
the plate get pushed on, the axle, until the correct air gap is reached (0.4 to 0.8mm)
if the gap is ok, reft the central nut