The float in the tanks is a brass ball that is clam sleaved together with swet solder. The solder joint has failed and the float ball has filled up with gas and thus sunk which does not enable the gauge to work (always shows empty). Remove the gauge from the tank top, snap off the brass ball and re-solder the seam. CAUTION: THE BALL IS FILLED WITH GAS AND ANY SOLDERING HEAT OR FLAME WILL CAUSE IT TO BLOW UP AND CATCH FIRE. What I had done was to drill a hole in both ends of the ball float, drain the fuel, fill with water and blow the water out, then re-solder. Despite the water wash, the brass will still be impregnated with gasoline, so a small explosion, however manageable, will still occur.
58ht in MN
'58HT and '48 Dodge Panel in MN
Thunderbird Registry #3810 VTCI#7652