I have an '83 f-150, short bed, single tank. since I got the truck, it's had a problem or more of a quirk when you try and fill it up:

If you use the nozzle like normal then the pressure builds up a little and the pump clicks off after about two gallons. A little bit of gas'll come back out of the tank and run onto the ground. Not good.
If I just keep light pressure on the pump handle, then it will fill a little slower but it will fill the tank completely before clicking off, and it won't spit the gas back at me.
A friend told me to check out the gas tank vent. I looked underneath the bed and I couldn't find any vent tubing; only the filler tube.
If it counts for anything, the gas gauge seems to work fine and the engine runs well. So I don't think this problem is related to the rest of the fuel system.

Anyways, I don't know exactly how this is happening or how I should go about fixing it. But I do know it's not supposed to be like this. Anyone have experience or knowledge on this?

 

The vent tube is actually in the filler neck, there's a little metal hoop that holds the plastic vent tube in the filler neck. I guess the idea Ford was going for was that the gas will not go down the plastic vent tube, and the pressure building in the tank from adding more gas to it would hopefully escape around the incoming gas and go out the vent. Mine has always done it, so I just go really slow. Something to just get used to I guess.

On a side note, I tried reattaching the vent tube inside the filler neck when I replaced my tank with a Jeff's Bronco Graveyard plastic tank (great tank btw) and it didn't want to stay, so I just left it out. I found that it just takes longer to fill, but doesn't cause anything to blow up because of too much pressure in the tank.

 

On the older trucks like yours, the large round pipe/hose is the filler, and like was said the smaller thin plastic hose inside the large hose is the vent, directing air out of the filler neck while filling, trying to keep the air from mixing with the fuel going in from the station nozzle.

My old 80 would do this, and I found the smaller hose inside the larger hose had fallen out of the clip inside. I put the hose back into the clip, no more problems.

Sometime later on the late 80's trucks, they re-designed this filler system. They have a more substantial small rubber hose that mounts to the fill neck, and it's what the nozzle uses to add fuel to the tank. The larger hose now is just for the air. So they sort of swapped duties for the hoses, the smaller hose now guides the fuel down into the tank, the larger hose is the vent. This system seems to work a little better than the older system, and I believe some people have retro-fitted this to their older trucks.

 

Both the 84 and 85 I've had have always been slow to fill. The odd station won't let it fill at all, and the truck needs to be turned around so its going downhill onto the tank...

 

I'm not quite sure what you all are referring to exactly with the two hoses. I looked at it again, and past the little flap at the top of the filler hose I couldn't see anything. However there was a second opening above the big filler opening, which was also covered by the flap. Sorry if it's hard to picture... I could get a photo of it if that will help.

 

My '84 has been like that with both tanks for as long as I've owned it.

My workaround has been to not insert the nozzle fully into the filler neck. I only put the end of the nozzle about an inch past that baffle near the top of the filler neck. Most nozzles levers have a hold-open with three positions. The first position (lowest flow) works best. Is this a perfect solution? No, but it's thoroughly adequate and appeals to my lazy nature.

Do gas stations in your area have those accordion bellows on the nozzle for vapor recovery? My truck doesn't like some of them. My preferred gas station doesn't have these bellows, so no problem there. For the places that do, it usually works to hold the nozzle back, so the bellows don't touch the filler neck. I noticed when the bellows style first appeared around here (People's Republic of Oregon), they were very sensitive and would kick off right away if the bellows wasn't touching. But now they seem much less finicky, and so I'm able to still get away with not fully seating the nozzle.

 

So everyone know of this plastic hose with in a hose we talk of, here is a picture.

I hope mine work half way good!
Dave ----

 

It's a common quirk with these trucks. I am sure Ford did not build these trucks so they were hard to fill new. It's just a poor design that had a tendency to fail. It's too easy for that small hose inside the large hose to come loose.

Another poor design was the diesel trucks of this era. Diesel foams terribly during filling. They used the same iffy gas design for the diesels, and it's not good enough. I do believe the diesels were probably hard to fill when new. People have lots of solutions, some work better than others. The one I used, I pulled the tanks, took the complete vent/roll-over valve out of the top of the tank and put a large copper elbow into the grommet. I then bought a large rubber hose to attach to the copper elbow and ran this hose over near the fill pipe area, way up in the cavity of the bedside, and then back down forming a upward loop. This lets the tank breath nicely when filling the diesel fuel. The only problem I have is it burps foam out onto the ground when I top the tank off at the station.

 

The plastic hose can fall off or kink. The best solution is to eliminate it entirely, cut the various restrictions adn such out of the metal filler neck, drill out your rollover valve, and add an external vent (5/8" works well) to the top of the filler neck, put a small 1/4" vent hose teed out of the larger external vent.

I did this on both tanks and can take on 55+ gallons pretty quick. Pump sometimes clicks off in the last couple gallons if it's a fast pump, just pump slower for the last bit. This is more a problem with diesel foaming up the filler neck and external vent hose when almost full.

 

Could you take a picture of that? Sounds like something I should do on mine.