"... the designers at Ford decided to really cheap out on the Wagons and Ranchero's by using a Falcon tank. As we know a Falcon fills from the rear of the car. A wagon and Ranchero can not be filled from the rear, they have to be filled from the side. So Ford simply flipped a factory Falcon tank upside down, punched a fill neck into the side of the tank and created the Ranchero / Station Wagon tank.
... the vent on the Ranchero Wagon tank is on the driver side & I think that the vent extends into the tank about 1/8th of an inch. I also noticed that the fill neck does not pour into the top of the tank like a Falcon but it pours in from the side. So when your tank is FULL so is your filler neck...AND your rubber Union!! Makes you want to inspect your rubber union now doesn't it!!
... I was able to locate a generic hose at the local parts house which did the trick nicely.
Part Number: GATES-24712
Part Number: GATES-24712
To better understand the problem I whipped up these graphics to help illustrate what is going on inside our fuel tanks.
1. Full tank. All is good. The tank vents from both the fill neck and the vent tube. I suppose that the vent tube could be below the fuel level when the tank is full. If this is true than the vent would not really be venting anything. The fill neck will be the path of least resistance.
2. When parking at any angle with the filler neck aiming down hill, I believe that both the vent and the filler neck are covered by fuel. An air gap pocket is trapped on the passengers side of the tank with no vent provided for the expanding gasses.
3. As the fuel evaporates the gasses increase in volume creating pressure, like filling a balloon with air. Problem with this balloon is that it is made of metal. The point of least resistance is the large filler neck tube. Because there is fuel in the neck and the pressure in the tank is rising, the pressure actually pushes a column of fuel up and out.
I believe that this is what is happening in my case. When I visit my car, with a full tank, on a warm day, I'll twist my fuel cap off and it is like someone is pouring fuel from a beer pitcher. Once that has poured out I can see a flat pond of fuel in my filler neck, right up to the brim. And if I shake the car a bit, I'll get burps and bubbles from the tank.
It seems obvious to me that this tank is not well venerated.
So what is the solution?
... the real solution would be to install a tank that had vents in three special places. One vent at the forward left hand corner, one vent in the center of the tank and one vent at the back right hand corner. This would allow the tank to vent like modern cars no matter how full or at what angle."
1. Full tank. All is good. The tank vents from both the fill neck and the vent tube. I suppose that the vent tube could be below the fuel level when the tank is full. If this is true than the vent would not really be venting anything. The fill neck will be the path of least resistance.
2. When parking at any angle with the filler neck aiming down hill, I believe that both the vent and the filler neck are covered by fuel. An air gap pocket is trapped on the passengers side of the tank with no vent provided for the expanding gasses.
3. As the fuel evaporates the gasses increase in volume creating pressure, like filling a balloon with air. Problem with this balloon is that it is made of metal. The point of least resistance is the large filler neck tube. Because there is fuel in the neck and the pressure in the tank is rising, the pressure actually pushes a column of fuel up and out.
I believe that this is what is happening in my case. When I visit my car, with a full tank, on a warm day, I'll twist my fuel cap off and it is like someone is pouring fuel from a beer pitcher. Once that has poured out I can see a flat pond of fuel in my filler neck, right up to the brim. And if I shake the car a bit, I'll get burps and bubbles from the tank.
It seems obvious to me that this tank is not well venerated.
So what is the solution?
... the real solution would be to install a tank that had vents in three special places. One vent at the forward left hand corner, one vent in the center of the tank and one vent at the back right hand corner. This would allow the tank to vent like modern cars no matter how full or at what angle."
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