Fuel Tank Leaks at Top/Sender

Jwawhite

Jwawhite

Well-known member
Smelled fuel after fill up, removed inspection lid (which is below the spare tire of a station wagon). This leak is very apparent in the cab and it must stop!

The lid is leaking fuel and I've ordered a new cork 6 point gasket.

Question: Which is the best way to install it? Dry, with cleaned surfaces? Use a fuel resistant glue with the cork gasket? Adhesive only with gobs over the screw heads?

What is the proper way in your experience to have a non leaking sending unit?
 
I went through this recently too, garage smelled of gas after a full up. I used a rubber gasket (actually an oring) on my 57 ford Tbird. No glue or sealant, just a little bit of pressure to make the seal.
 
If you did use a large O-ring, the material would need to be compatible with ethanol fuel or it will deteriorate very quickly. Also very important, the diameter of the O-ring would need to be such that it sits along the surface between the opening for the sending unit and the mounting screws. If the O-ring runs along the outer diameter of the mounting screws, gas will just squirt up out of the screwholes.
Notice how on the car gas tanks, the sender mounts down in a recess. It seems that the automatic stop on the nozzles at the gas station doesn't trigger until after gas has already overcome the sending unit. On the wagon models, the sending unit mounting surface is on a slanted pop-up, but the tank is tilted a little bit so you fill to the top at the front of the tank, while the level of gas at the back of the tank is much lower. So, you essentially have the same problem, not to mention the wagon tank has that ultra long filler neck which tends to fool the gas nozzle into thinking its not full yet.
I have a habit of just putting in about ten gallons at a time when the gas guage reads near empty. Yes, I agree, that is a little substandard, but you can get away with it while never running out of gas or leaking out the sender. It just takes more stops at the gas station for long trips.
Nother thing to look at is that little rubber vent hose where it connects to the gas tank to make sure it aint cracked and leaking gas.
 
Jwawhite............and the rest of the Barners (this may sound strange). I had the same thing going with my '50 Ford in my avatar. I fought a gas leak at the sending unit gasket area for 6 months. I got the leak down to a seep but not totally stopped. I put in a new sending unit, straight edged the tank, cork and fiber and rubber gaskets, every "fuel resistant" sealer I could find but no luck. A tractor rebuilder friend told me what he does with those is to use JB Waterweld epoxy putty. Gas will not soften or eat it up since it is an epoxy. I put some around the edge of the sending unit and on top of the 6 screws and let it set up. A chisel will knock this epoxy off if needed. Next morning filled the tank until it ran out the snout-no leak or seep. Been that way for a year now with no leaks. Worked for me!!!
 
JwaWhite, I do NOT recommend any of the tubes of gasoline resistant gasket sealers you can get at the chain auto parts stores. They WILL leak.
I'm not familiar with JB waterweld, but I will just tell you this; I mixed up some JB weld epoxy to seal up around a bypass tube I mig welded to my old gas tank and allowed it to dry and harden for several days. There couldn't have been more than a pin-hole or two to seal but I globbed it around the tube real good. It leaked the first time I drove the car.
 
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