I'm wondering if there is either a check-ball in the filler neck (which I'm not sure there is) or if possibly the vent valve in the tank can prevent me from filling up normally. As it is right now, I have to very slowly add fuel from the tank or the pump keeps shutting off. I know on newer vehicles, vent valve solenoids can prevent gas from entering the tank normally.

 

Check this out: https://www.ford-trucks.com/forums/1...e-problem.html

 

I've really got to start searching the forum first before I post!! LOL

So is something jammed down the neck or a broken vent tube pretty much the only thing that will cause this problem? The vent valve on top of the tank has nothing to do with this I'm assuming?

 

In the pictures below you will see the plastic vent tubes sticking out of the rubber fill tube. From was I remember when I pulled all the tanks only 2 have the vent tubes and they have a hole top & bottom that the plastic tube fits into to hold them in place. Should be fun to get that all back the way it should!


I will have to check the top fill part but I don’t remember a “flapper door” but could be wrong as I was not looking for them.


Dave ----

 

The vent valve on top of the tank is very small. It lets the tank breath when the engine is using fuel from the tank, and when the fuel gets warm and expands. Its a very small vent.

Your problem is during filling. You are pouring a lot of fuel into the tank, so a lot of air has to come out of the tank to make room for the fuel. All that air comes up the filler tube and interferes with the fuel going in, making it gulp and splash, and that is what keeps turning the station nozzle off.

Those pipes in the pictures above are to keep the air going out of the tank away from the fuel going in. They are very important for fast filling of the tank, and there is a clip that holds them in place inside the large metal pipe, and they do tend to fall out of the clip and cause problems.

 

Is the solution to replace the entire filler neck or is it repairable?

 

I would not worry about the neck not having a small opening or flapper. That was in place when there was leaded fuel and they had a bigger round pipe on the fill spout gun so you could not put leaded fuel in a unleaded tank.

What you might want to do if you cant look down the fill tube and see that vent pipe you may need to pull it apart to see if it fell off the clip up top.
Dave ----

 

When mine fell out I took the large clamps loose and the 3 bolts that hold it to the bed, and took the filler out. I was then able to fiddle around with the little pipe and get it back into the clip.

If you wanted, you could look in the junkyard for a later model filler neck, one like yours, up to 1996. I don't know what year they changed it, but on the older ones like the picture above, the fuel flows down the large metal pipe and the air comes up the small plastic pipe. Sometime later they changed it around so the fuel goes down a smaller pipe in the middle and the air comes up around it in the large metal pipe.

It's suspicious to me that Ford changed it around, like it was a solution to a problem.

 

I checked the 2 filler spouts off my 81 parts truck and they both have the flapper in them at the top. It is also the ones I took the pictures of the plastic vent tubes from.


I did not have time to look for the filler neck that came off my project truck but I do know it did not have the vent tube inside the main tube.
Dave ----

 

I have read about people swapping the later (bricknose) filler hoses, where the fuel goes down the center and the vent is concentric.

The neck that's inside the fuel door sits at a different angle but it seems to be a non issue.

 

I thought of doing the swap but wasn't sure if that brick nose filler neck swap would work on a flare side truck. Cant even buy filler neck hoses for the flare side truck of 80-86 vintage.

Besides that, I think some cases the pumps put way too much fuel out even for the plastic vents to handle. You can see mine is up near the top of the filler neck itself even if I place the pump nozzle past and to the side of the vent full on pumping of fuel results in burping back and shutting the pump off constantly. Run the pump around 1/4 speed which seems about full speed on pumps from 10 years ago and there is no problem. So I tend to think there is a limit on the vent capability of this set up when it comes to volume of fuel being put in.

Big reason why I contemplating swapping the filler neck from a brick nose onto mine. Reuse my OEM hose, reuse my OEM plastic filler neck mount behind the fuel door and just stuff the center fill tube down into the tank. Not sure how long it is or if that is even flexible plastic/rubber or not how ever.

 

Just wanted to give you all an update. I dropped the midship tank (the one I primarily use) because I need to swap the sending units out and found the problem - the vent tube broke off at the tank. Someone had dropped this tank before (non-factory sender in place) and they must have broken it off during the process. Luckily I was able to source an NOS one from a seller on eBay (they also had the aft tank one too, so I bought that for when I do that tank)