Yup, David's right - the repair was likely done in Europe during the war and this kind of retrofitting was not only quite common on otherwise non-repairable pens (shortage of parts) but actually worked quite well. I've even seen a few Eversharp Doric vac-fil pens converted to button fillers that were so cleverly done that one (not being a pen expert) wouldn't even suspect that the pen was never made this way. In the case of Parker Vacumatics and Eversharp (and Sheaffer) plunger fillers the transparent barrel can be a dead give-away though. But the good news is that you can stick a silicone sac in the pen and that way you will still be able to see the ink level. Otherwise it's just what the Doc ordered - the replacement parts would (likely) cost more than the pen and in addition to the lock-down vac filler unit and the bands you would also need to source a different section: in order to convert a Vac to a button filler (BF) pen it needed to be replaced with a section with a nipple for BF to work well. So do keep it as it is, this repair actually makes this vac pretty cool and it can still be a great everyday writer.
Edited by ihimlen, 27 May 2015 - 01:42 AM.