Early this year I finally replaced the mechanical fuel pump & removed the electrical pump. Not long passed & it quit pumping so I put the electric fuel pump back on. The mechanical gets her started (pumps the gas to the carburetor) then the mechanical ( I have a toggle switch to turn it off/in) one keeps her going until I turn off the engine. I have to use the electric to get her cranked.
Yesterday I drove the the auto parts place to get a new alternator. It would not crank up (run). Had to put a new electric pump on it. It wouldn’t get the gas pumped up until I sucked on the gas tube from the tank. It was very difficult to get the gas to my mouth & I could blow into the tank either.
Usually I just start doing a project and find out later that I should have done something differently.
So I’m asking what or how to do it?
Remove the tank, clean it & replace the outlet? Can’t do anything with it in the truck?

I’m thinking the old rubber hose I see under the truck coming from the tank has collapsed.

1953 Chevy 153A 3/4-ton
Working on my project since 2015
Follow along in my DITY