fuel tank leak after filling

[mx racer 904]

After I fill the tank it leaks almost like an over flow...but then continues for a little while I am guess until the tank level goes down a little...any idea...its not from the part of filler hoses I can see but not sure whats on the tank side....

 

[unclebill]

under the seat tank?
mine does it too.
i just dont fill it all the way.

 

[Saddle Tramp]

If it's a 76 the tank is centered under the back seat, fills on the passenger side under the turn signal light. Where do you see the gas hit the ground? How quickly does this happen? I have had problems like this over the years when I fill the tank to the top with cold gas out of an underground tank when the weather is warm. The gas expands and has no where to go but out. I built a restaurant in Shepherdsville, KY years ago; got there on Derby weekend and remember it was already hot. Well, hot to someone from the rainy Northwest anyway.

 

[mx racer 904]

It hits the ground quick from almost dead center....then keeps on for a little bit over on the passenger side...what you are saying makes sense....it has been very hot here....thanks guys

 

[mx racer 904]

shepardville is about 2 hrs from here we are up here by KY speedway halfway between Cincy and L'ville....

 

[Saddle Tramp]

The 1976 CJ has one of two fuel tank versions, California and 49 States. You say the gas shows up in the center (I assume you mean right to left center at the back of the jeep) and then moves to the passenger side.

It sounds to me like you may have a California fuel system because the center seems to be where the gas shows up first. The California tank has the fuel gage/fuel outlet line to the fuel pump centered on top of the tank and the filler hose and filler hose vent hose both coming out of the center of the back of the tank. The hose connections may need to be tightened and/or the hoses are cracked and need to be replaced, or the fuel tank gage/fuel outlet line seal and/or hose connection is in need of repair or the hose to the fuel pump is cracked. Also the hoses could need to be tightened or replaced where it attaches to the filler inlet at the gas cap area of the body; gas could be leaking out at the body connection and running down the outside of the hose, dropping to the ground when it hits the tank. The fuel tank vapor vent lines (2) connect on the right and left sides of the back of the tank.

On the 49 State versions all connections are on the sides of the tank except for the fuel gage/fuel line outlet which is on top of the tank towards the driver side. If you have a 49 State tank then the gas must be running alone the tank or some other avenue until it drops to the ground at the center.

Having said that, I don't know if the vapor canister and/or liquid check valve are having any influence on your problem but I would start by checking all of the hoses and connections I described above first.

 

[SteelHeadz]

X2 from Saddle tramp. Check all the hoses connected to the top of the tank. The best time to isolate it is when the leak is evident so you can pinpoint the problem.

 

[1983CJ7]

I have a similar issue with my 83 CJ7. The gas gauge doesn't work, so I filled the tank, with a plan to drive it a while in order to calculate MPG. I parked it in the garage for the night, and woke to a strong gas smell coming from the garage. There are no leak spots on the floor, and nothing fresh around the tank. I did notice that a number of hoses under the hood are missing. Also, there is a tube coming from the exhaust manafold area that drops straight down under the engine. At that point it was cut off and bent back. Where to start looking for the source of this smell?