Vent tube on Gas Tank Sending Unit?

[scottylack]

I’ve got a 65 Barracuda. Turns out when we put the sending unit in we never put anything on the nipple which I believe is some sort of vent? How do I set this up? Is it a rubber hose or is it a metal tube and where does it go? And how do I get one?

 

[kiss]

That's an additional fitting to run a fuel return line. It is not a vent. If it's not used plug it.

They didn't have these on stock sending units, strictly aftermarket, so unless you have a fuel return line plug it.

 

[694spd]

I believe that you have a sending unit that has the nipple for a fuel return line. They were used in later years. You will have to plug it with a cap. The tank vents were found mounted high at the top of the filler neck.
Correct me if I'm wrong.....

 

[67Dart273]

I believe that you have a sending unit that has the nipple for a fuel return line. They were used in later years. You will have to plug it with a cap. The tank vents were found mounted high at the top of the filler neck.
Correct me if I'm wrong.....

Correct!!

 

[scottylack]

Ok cool. Is it usually 1/4”?

 

[MoparMike1974]

That is your tank vent. Not sure where it goes on a 65 but on the later cars it connects to a line that goes to the charcoal cannister in the engine compartment.
Some cars had the vent on the sender and some have a nipple on the tank. Your tank needs a vent somewhere, whether its a tank vent or a vented fuel cap.

 

[kiss]

That is your tank vent. Not sure where it goes on a 65 but on the later cars it connects to a line that goes to the charcoal cannister in the engine compartment.
Some cars had the vent on the sender and some have a nipple on the tank. Your tank needs a vent somewhere, whether its a tank vent or a vented fuel cap.

This is incorrect. The tank vents on early years had a line that went up the filler neck and then down underneath the car
'70 CA and '71 Federal had the 4-fitting vapor canister thing in the trunk of the car leaning up near the driver's side wheel well. From there a line ran to the front of the car into a fitting on the breather
'72+ had a single fitting on the top-middle of the gas tank, built into the gas tank (not the sending unit) which ran to a charcoal canister in the engine bay.

 

[67Dart273]

That is your tank vent. .

NOPE NO FACTORY CAR in those years had a 2nd fitting on the sender

OP: Go to MyMopar and download yourself a free factory manual. Page 14-75, an example:

This basic system was in place up until the "some of" 70 cars with the CA evap emissions controls/ carbon can setup, and Federally thereafter, which used a separate "vapor separator" can for a time, and later, a tank with the evap separator built into the tank, and multiple upper tank fittings.

 

[Killer6]

Ok cool. Is it usually 1/4”?

That is for later models w/a vapor management return style system. You could run the three fitting style inline mopar filter if You wanted to run a 1/4" line back to the tank.
Proper placement and vertical orientation for the filter needed tho'. As is, You can just cap it off and forget it. As posted above, Your vent goes up to the top of the filler neck,
and down through the trunk floor boot for the filler pipe. The top end of that vent tube is rounded where it is inserted into the short hose, and closed off to a very small dia.
pinhole. If You are having fuel delivery issues, and loosening the cap helps/eliminates them, there may be an obstruction such as an insect, debris, or spider webbing.