A-100 Gastank Venting Problem

[69a100]

Dealing with a 69 A100. I currently have 3/4's of a tank and in hot weather I get gas dripping out the filler neck. Upon removing the cap, the system vents air like the system's pressurized. From everything that I can tell, all is good, but not so. Anybody have any ideas what the cause is and/or repair? Thanks

[soopernaut]

Perhaps you need a vented cap.

[Oldguy]

I concur. A vented cap should cure the problem. Good luck! Mike

[paizao99]

Some kids messed around with my truck and wiggled the gas cap loose. While driving down the road I heard something fall and roll. Not knowing what it was I kept on going. Searched and hunted for it with no luck. Purchased one from NAPA (part #7031110) but for the life of me could not get it to lock on. Went with a different one (part #7031167) but am finding that gas is leaking down the side. Anyone have a part number or suggestion? Really want to get a locking cap, but anything to keep the fuel from spilling would be best.

Thanks,
Brett

[JimE]

Brett, been there, done that. What the kids did was wreck the inside of your filler tube and no matter how hard you try to fit a cap on, it won't work. The answer is to find a fuel tank shop and have them weld in a new filler piece, problem solved. Jim

[soopernaut]

If the filler tube is damaged and you have access to salvage sweptlines you can just remove the filler from the tank and replace. The gasket could fall apart though.

[nfury8]

A new cap may not help. I put a new vented cap on my 70 crew, which was also pressurizing the tank.
The vent is one way, it will allow air in, so you don't crush your tank, but it doesn't let air out. So it
was still pressurizing the tank. Allowing the cap to vent out will most likely allow fuel to seep out at
the cap.

In 1971 Dodge added vents to the trucks for emissions, California got them sooner.
The factory vent system has 2 vents, one in each corner of the tank. The vents run up to a
canister in the passenger rear pillar, a single line comes out of the canister and runs down
along the frame rail and up to the crank case breather on the motor.

To fix the problem on my 70, I took the tank to a local radiator shop and they boiled it out
and added a vent. A brass barb can easily be soldered to the tank to add a vent. Just make sure
it is boiled out or full of water first, they can hold fumes in them for years! I don't have one of the
canisters, but I am running a big loop of tubing up into the pillar to act as a trap. Rather than run
the vent up to the motor, I am just going to run it back and dump it under the bed, near the rear
axle. This might not be the most environmental way to do it, but it is the way the passenger cars
did it up till 69-70.

[paizao99]

This may be a no-brainer, but does anyone know where to purchase a gasket for around the filler tube? Other than a junkyard?

Correction (no link to delete posting): I found the website http://www.restorationspecialties.com/dodgetruck.htm