Hi there is a pretty good chance that this question has already been answered but as a new member trying to find my way the system I did't see it.
I have just tried to put my 1958 Golden flesh back on the road after a 2 year total rebuild and have hit a snag, a large oil leak from the back of the clutch. When I took the primary apart and removed the clutch assembly I found that the collar, which acts as a screw seal in the sliding plate had become displaced from the center boss and was hanging from the gearbox shaft doing nothing. On further inspection I can't see what is supposed to hold the collar in place and stop it just sliding off of the center boss.
Any suggestions on how the collar should be retained?

Saluki42