I have a 1972 Charger (B-body) with a fuel leak. First off, the charcoal canister was removed and blocked off (near the engine) long ago. Fuel cap is stock Stant #11806 which is a pressure relief cap. The leak seems to coming from just above the the 4 vent tubes on the passenger side of the tank. First I thought it was the hoses (original). I pulled hoses (they looked pretty good) and chopped off 2" of hose and reconnected, same leak. Then I installed new fuel hose with blocked ends, still same leak. Not sure if vent tube welds are leaking or from above tank but it seams like where vent tubes are welded to tank, yet they don't feel loose. Only way to tell is to drop tank. I want to repair tank and install vented cap for a 1966/1967 Charger, Stant #11646 because I don't need pressure building up in tank without the emission control charcoal system. I can tell the pressure builds up because often when I gas up I can her a big whoosh and even sometimes hear the tank kinda pop.

My questions-

1) Is 1966/1967 Charger fuel tank only vented thru gas cap or does it have an additional tank vent?

2) Is what I plan to do a good idea?

A little help? Someone must own a 1966 or 1967 Chager or FSM that can help answer where the vent is?

66/7 charger vents from the front of the tank, and runs up intothe 1/4. the 72 vents to a box over te axle, and yes sounds like the soldered joints went away in the 72 tank the gas cap change will work, necks are the same but the tanks are entirely different

So I think when I repair tank I am going to weld up the 4 vents and just vent thru the 1966/1967 vented cap. My 1962 has a vent from the tank with a non vented cap. Don't understand 1966/1967 would have the tank AND the cap vented but I assume as long as the cap vents I won't need another vent from the tank to atmosphere. It clearly says "vented" on cap.

Okay I think I know what my problem is. I don’t believe it is the soldered joints. I can actually feel fuel coming from the top of the tank above the 4 vent tubes. Didn’t make any sense to me until I searched the old posts. There is a rubber plug that goes into the thermal-expansion volume tank at the top of the gas tank. Didn’t even know I had one! I think that is where my leak is from.

These pics are from a 1970, believe my 1972 is similar. My 1972 FSM shows a diagram for vent tubes but not the extra tank.



***Anybody have or know where I can get one of these rubber plugs?***

I still don't understand how plug could leak yet I can still build pressure in tank. I can hear pressure escape from tank when I remove cap to fill up. But it is the only logical place for leak to be occurring.

I guess I either replace plug or just stop filling up tank...

I have a few 72B tanks out. I'll check but I don't think that the 71-3B tanks have that hole in the center of the tank.
71-5/72 has the vent tubes on the drivers side of the tank. 6/72-73 has them on the front.

I have seen tanks rust out on the top from dirt and mud sitting up there.

Yep I just checked and no top hole on the 71-3B's

All 66/67 vents through the fill tube with a vented filler cap. No other vents.

Thanks so much for all the input. I guess when I get the time I will just have to drop the tank and see what's up.

I would have a pro radiator shop that does fuel tank repairs weld it up.

Took out tank today. Getting it cleaned, dipped and coated vent tube welded up. There was surface rust inside tank where the vent tubes come out of the side of the tank. Fuel was leaking from the solder/weld joints