anti clock is the way to go.
now how to undo it easy:-
hit the nut with 3 firm blows of the hammer to break the loctite in the threads.now put a bar through the pulley in to the plastic tub to stop the pulley rotating.put the allen key in the nut head and undo it.a standard allen key will need a bigger lever bar or get an allen key that fits in to a socket and use that
ck, September 2011