Hey there -
If you are constantly having to prime your pump then there is an air leak somewhere in the line that needs to be addressed. I had the same problem when I did the re-build. I am almost certain (if done correctly) it is not necessary to re-build again. To solve my problem I replaced the one way value on the intake hose and added a hose clamp at the bottom NPT on the pump itself. Worked like a charm.
It's all Good