There's yet another trick.  Get a 5 or 6 inch 1/4 inch bolt.  From the
bottom of the armrest, insert the bolt and use it to align the holes in the
mount and the armrest.  THEN, with it nicely aligned tap in the Mills pin,
chamfered end first and it will gradually drive out the 1/4 inch bolt.  A
second bolt reversed so the head is on the end of the Mills pin can be used
to make the tapping into place a little easier.

pensioner