Had the same problem with a Zippo a while ago. Tried to just swap innards with one that worked fine, but there was a slight difference in size, so it didn't work.

I eventually gave up on Zippos. When you find one after a month, all the fluid has evaporated. Buy a package of Bics, and leave them around randomly, and you can always pick one up and get a light. The pink one in the package, I'll leave laying around at a bar or a party, so I can call whoever loots it a fag and/or thief.