Not on a Bronco, but when we bought a 1929 Ford Model A Tudor Sedan it would drip gas constantly from the carb when the engine wasn't running unless the fuel line was shut off (gravity feed with no fuel pump).
We pulled the carb apart and found a damaged gasket and a bent float, so the needle valve never shut off and then it would leak out the damaged gasket.
Simple enough fix, but then the engine wouldn't start. We figured it had to be fuel related (always check the last fools work) so we chased the fuel path through the carb. Found out there was a fuel passage that had never been drilled out! Some clever PO had figured out that making the carb overflow in just the right place would let it run! Had to be that way since the carb was new (but no idea when that carb was installed, I'm hoping it wasn't in 1929!).
So we did our own Bubba fix and drilled through the side of the carb to drill out the missing passage. Then we hammered a lead fishing sinker into the side of the carb so it wouldn't leak there. Perfect!