Sheaffer vac/plunger filler - barrel threads no longer engage with inner capsule

[Keith_in_SF]

Hi all! I am just getting back into pens after a 4 year break... I recently have taken an interest in old Sheaffer plunger fillers and have purchased some tools to work on them...

So I have a Sheaffer vac filler here, of the type where there is an inner ink chamber which contains the plunger, etc... the outer barrel threads no longer engage with the inner ink capsule and tighten down like they are supposed to. What is the best method to address this (other than scotch tape!)...?

Thanks.

Photo:
[IMG] pen-issue.png[/IMG]