To remove the tube, - Put either a 5/16,, or 3/8 bolt,, (which-ever is the best fit,, I've forgotten) into the top of the tube,, (to stop it collapsing),, and firmly clamp vice-grips or similar onto top of tube ..,, twist and pull...
To re-install,, slip a 3/8 or 7/16 box end over the tube ( again, - forgetten which),, slide it down to bulge,, gently tap on the wrench next to the tub till it seats,, at times I've used the open end as well..
If tube is loose,, lightly tin it with solder, if nec, sand to fit..
To remove a broken tube,, use a large self tapping screw/lag bolt, in a slide hammer.. without s/hammer, just keep tightening till it stops threading and turns the tube,, then twist and pull with vice-grip, or similar...
hope it helps