I'd turn a piece of barstock in the lathe big enough to drive it in the end that has become smaller, swelling it, restoring to become a tight fit again.
(of course it would need driven out of the tube before the tube is re inserted again in the block).
might need a couple tries to get the right expanded size.
For those that have no lathe or access to one, you might get lucky and find a socket just the right size to use as a tube expander.
----I'm not a big fan of JB plastic goop
We used to have to expand driven in oil dip sticks in the small block chevies in the late 50's long before they went to rocker cover fills.
Also the fill tubes were driven into the intake manifolds that at times needed
re- expanded that way also.
just my take, your ideas will vary.