Make the plug for a tight press fit
Could you give me a reference to say the diameter of the bearing. bigger, smaller, I can relate to a measurement. I do not know if you mean tight if I were tapping it in with a plastic mallet or so tight I should take it someplace with a small hydralic press and use like a socket to get it uniform pressure.
edit:
Probably would not need a sealer probably if it were a hydralic press tight diameter.