If the lines are free of air, the tanks will equalize. The lines will eventually free themselves of air while the truck is running. If you run it out of fuel, simply cranking it will purge the air. Some models have primer pumps, and you can use that to get fuel up to the engine and avoid excessive cranking.\Assuming that is correct, this brings what is probably a final question. The fuel lines (both pick up and return) enter the tank at the top. I understand what your saying about the system siphoning from tank to tank and the "Initial air purge" is necessary to make the siphon deal work. So what happens if you run the truck out of fuel? How does it "Re-purge" the air? And just as important... Once I tee into the current lines, how do I purge the air in order to get it all to work again/now? Or will adding fuel to the full tank level take care of purging enough air that it will pull enough suction to get passed the small amount of remaining air and just keep working?
Thanks again!!
If you run all the tanks very low, you may have to add fuel to all of them or it'll suck air from the empty ones.
What are you carrying that allows you to give up that much cargo capacity in exchange for fuel weight?
Oh, get aluminum tanks, if possible. Trucks of that area are starting to rust the tanks out in the corners, and the rust flakes easily clog the lines.