Hey, a blast from the past! We haven't had a good "can't fill" discussion in awhile now.
Unfortunately smittymike, this used to be an all-too-common occurence and you would have been in very good company.
You're actually lucky it's only one tank at this point! On my '71 both tanks gave me trouble in the beginning. Luckily I was young and laid back and never in a hurry, because my gas stops were twenty minutes minimum. With regular nozzles and then vapor recovery nozzles. Didn't make a difference.
Now my '68's rear tank (aftermarket, one tank only) is half-way good, but gives me fits every other fill-up.
If you've got a '70 or later you have tanks with vapor recovery vents going to the charcoal canister. Early ones did not.
Very early Broncos did not even have fill-vents on the tanks (at least the front aux tank anyway) and in my experience it doesn't seem to make a difference what year or type of system you have. Some just give fits.
With mine though, the "cure" if that's what it was, was simply to replace the rubber filler tube and fill-vent hose with new. The only other thing I did was to gently blow some air into the evap lines. But I never saw any clue that they were clogged. Just did it "because" I had them off.
I just replaced the hoses because they looked haggard and like they wanted to be changed. Not because I thought this was the issue.
But sure enough, the very next fill up went like a dream and I never had a problem at all after that.
So the moral of my story is, check your fill and vent hoses. And if they look even remotely old, change them out. Maybe you'll have the same good luck I did.
Paul
