Hi Syd,
Preference is for it not to move up and down. I can't remember what holds the shaft at the bottom, I'm guessing a split pin but It is probably 10 years ago that I rebuilt the one on my mates Greenie. That is another one of those jobs for lifting it up with a chain block or tipping it on its side so you can get at things. I can't remember but if you loosen the bolt on the quadrant you may be able to slide the shaft up through the quadrant. I know I made a new quadrant so not sure what goes on there. I do have an old greenie sitting here so if you strike trouble I could pull it out and have a look.
