The Stovebolt Site Forums The Shop Area General Truck Talk Fuel leak at tank

I’m a big fan of Teflon tape, since you are having a issue clean everything with brake clean/alcohol or similar, a small amount of pipe dope (sealant of choice) worked into the root of the male threads, wrap Teflon tape in the correct overlap direction, on a small pipe size no more than 2 tight stretched wraps, a slight layer of sealant over the Teflon which works into the cleaned female threads and assemble. Slight amount means more is not better. No need to crank it excessively, to tight can ruin the tank threads.
As a side note when working we had storage tanks out of Germany that came with straight threads and IPS adapters, we were provided hemp (like dry oakum) to wrap onto the threads for assembly. (PITA? Yes).
Ps: on my tank which I just redid I used an actual pumbing IPS ball valve

Chuck