thanks.when i phoned gas gas they said they couldnt supply me with a 16mm shaft as they only sell the 18mm now. Yeah i got the case re bored to take the bigger seal n shaft.well there was no spare washers, and when it was all put back together again, it seemed locked solid,the clutch moves freely aswell as the piston so its not seized as was another theory as it has been sat idle in a leaky container for a while, an exploded diagram of the assembly might be usefull, but i woulda thought as i had an experienced mechanic doing it with me that we would of put it all back correctly as he helped take it off to satrt with. any other ideas welcome