Ok all, working on a 55 f100. When I replaced the gas tank last year, I couldn't get the pick up fitting to stop leaking.... after getting a little frustrated, I put a little gasket sealant on the threads, and it seemed to solve the problem.

Now I have the cab off, and re-doing many things, I bought new fuel line, and a new pick up fitting. Trying to do it right this time.

As I tighten the pickup fitting, it starts to get fairly tight, while still facing down.

I figure it'll just leak if I back off, so I tried to carefully tighten it another half turn so I can get the line in. Trying to focus on not damaging the tank, I placed my wrench at an angle so that the pressure of trying to tighten kind of caved in the top of one of the thin brass walls on the fitting.

No big deal, the fittings are cheap, and I didn't mess up the tank, but I just don't know how I'm going get it to seal. Am I supposed to use something on the threads?

 

If it has pipe threads I would use "blue" brush on sealant that is impervious to fuels, I have gotten it at home depot for use the threads on heating oil fuel tank fill pipes.
Teflon tape will not last in gas.

 

Thanks, DrpTop, I'll give that a go.