The mystery of the collapsing gas tank.

[thehueypilot]

Here is a new one on me. I am having fuel delivery problems and crawled under the car and the (brand new) fuel tank has sucked in slightly on the bottom. The only vent on this tank (1968) is at the filler cap in which it is a little indentation on the rim of the filler tube and the gasket on the cap is cut out to allow the tank to vent. The size of the indentation and the size of the fuel line do not match. It would reason that if I am using 160 gallons per hour of fuel (just an estimate)than the vent should flow the same amount of air otherwise the tank will start to implode? Has anyone experienced this problem? What did you do to correct it. I do not want to vent the tank into the trunk for explosive reasons. What is a good, safe, reliable fix?

 

[TOM B]

It will get enough air. sounds like the cap isnt working at all, If its a repo you better check it. Take the fill tube out then screw the cap on, taper down the other end with a hose and duct tape then suck on it, you should NOT get a vacuum and you should hear it sucking air through the cap.
Yea it sounds funny but it works for early stangs.

 

[thehueypilot]

I have a "pop-open" factory original gas cap. Does anyone know if it is supposed to have a rubber gasket in it or does it have a metal to metal seal?

 

[67GTA-FB429]

There should be a seal. But it should still vent through there as the pop-opens don't seal all that well.

Some will tell you to replace it, so you don't vent gasoline fumes to the environment.

 

[Cantedvalve]

I have a "pop-open" factory original gas cap. Does anyone know if it is supposed to have a rubber gasket in it or does it have a metal to metal seal?

Originals had a leather seal right?

 

[crushnut]

Originals had a leather seal right?

I dont think so, but i could be wrong.

 

[WORTH]

the mustang tanks do not have a vent, they vent threw a checkvalve in the cap, if it is sucking the tank then the cap is bad. You can try cleaning it with carb cleaner, but if it doesn't vent properly you will have to replace it.

PS. it is designed to vent into the atmosphere, it does not use a recovery system like the newer vehicals.

 

[skywalker]

Here is a new one on me. I am having fuel delivery problems and crawled under the car and the (brand new) fuel tank has sucked in slightly on the bottom. The only vent on this tank (1968) is at the filler cap in which it is a little indentation on the rim of the filler tube and the gasket on the cap is cut out to allow the tank to vent. The size of the indentation and the size of the fuel line do not match. It would reason that if I am using 160 gallons per hour of fuel (just an estimate)than the vent should flow the same amount of air otherwise the tank will start to implode? Has anyone experienced this problem? What did you do to correct it. I do not want to vent the tank into the trunk for explosive reasons. What is a good, safe, reliable fix?

Everytime you ask a technical question on here I ask myself why we have you guys out doing pre-flights on our birds. J/K

 

[Pakrat]

I dont think so, but i could be wrong.

Actually it is a cork and ground leather pressed composite originally. The best replacment is to use sheet stock cork cut to fit. I don't know what the repro ones have on them, but they say for show not street use for some reason. Mine is an original.