may not be related; but i have a 1969 chevy ton and half; sometimes when it has been setting for a while (month or more) the clutch won't disengage; and what i have to do is put it in gear, which i am lucky the starter is strong enough, and start it with the clutch pedal to the floor, and while it is going i tap the breaks a couple of times and it breaks loose and works fine as long as i keep using it every few days;
like i say it's not a tractor, but it is a manual clutch which should be simular;
leon