[96bliss]

Looks like it's coming from the vent hose but there's no obvious cut or tears in the hose. The leak appears after filling the tank to full. Any ideas?

 

[1slow96]

Soon as gas nozzle clicks off... STOP PUTTING MORE GAS IN....

 

[5SSix1caprice]

Have you replaced fuel pump or sending unit recently? I’ve had that same problem more then once. 1st was the o ring between the fuel sender and gas tank was bad and the other was the flat surface the sending unit rests on was not flat (mine was wavy and bent a little) that caused it not to seal properly.

 

[bluedart]

Had the same problem on my 91 Caprice wagon. Mine was a old hard vapor return hose. The only way I found to fix it was to drop the tank and replace. Did the sending unit and fuel pump as well as the filler and vapor hoses since the tank was out. Fixed it nicely.

 

[RMS-Sullivan]

I will also second the vapor return hose. Recently dropped the tank to replace a fuel pump that went bad. My vent hose was pretty well cracked and have had fuel fumes on full tank near the rear.
While I had the tank dropped I went to the junkyard and pulled a fuel sending unit and refurbished it as per Sherlock's? (I believe), procedure and put it in place of mine as it had been reading wayyy over full on the gauge for a bit. Definitely worth cleaning the contacts on the sender while you have the tank dropped and may correct/prevent any gas gauge discrepancies.

 

[sherlock9c1]

All the vent hoses I've seen on B-bodies tend to crack over the rear axle.

 

[jayoldschool]

I've had a rusted out sender top cause this as well. Tank was fine, pump was fine. Sheetmetal was not. Drop tank, you'll find the cause quick. Others have reported cracked tank up there, too.

 

[storm9c1]

Follow the advice of everyone else here so far.

But one more thing I ran into that nobody mentioned... rare but possible.

I worked on a Caprice where someone must have used the smaller hose going to the filler neck (vapor relief hose?) as a handle when dropping or lifting the tank. This cracked the plastic and a leak developed here that only revealed itself on fillup. The crack was not obvious at first and was on the bottom of the nipple where it entered the tank.

So when you drop the tank, add that to the list of things to check along with the other items mentioned above. Tilt the tank at all angles with some gas in it and look for leaks, smell for fumes, look for wetness.

 

[96 Black]

It sounds from the replies everything's pretty much covered and nothing really to add. Except that's one damn fine stable you got there, storm9c1. You ought to throw up some vids of the rest of your old iron, especially those MOPARs.

 

[storm9c1]

It sounds from the replies everything's pretty much covered and nothing really to add. Except that's one damn fine stable you got there, storm9c1. You ought to throw up some vids of the rest of your old iron, especially those MOPARs.

Thanks! I'm in the process of editing a video on my '69 C30. Mice got into the cab light wiring. And I had to serve them an eviction notice. The truck also has a cameo in my "National Pike Steam Show" video from this year.

My channel was not supposed to be a MOPAR channel, there are plenty of those on YT. I couldn't do those channels justice. That said, next time I do some work on one of them, I'll try to record it. Maybe I'll do a backroad cruise video with the Charger one day next spring. It's nice taking that car on windy back roads, relaxing to the music of a MOPAR big block.