tank vent leaks

[Clyde K.]

It is me again. This time my problem is fuel leaking from the over flow or vent hose on my 78 E gas tank. The tank is only half full so and it hasn't moved all day. So, what is going on? Ideas please. TIA, Clyde

[TopCatGr58]

The overflow vent hose runs THRU the inside of the tank, and may have rusted THRU causing it to leak, vs. a poor gas cap rubber seal, and then heat expansion pushing fuel out past the cap into the surround and down the hose!? You could attach a hose to the drain, and blow into it and see/hear if you get bubbles in the tank to confirm the leak??

T.C.

[Clyde K.]

Roger that! I can barely hear hear them, but I am blowing bubbles. Can I tee into one of my fuel lines to recycle the gas?

[TopCatGr58]

Probably can, but just make sure that it's ABOVE/before a fuel filter...rust particles and such not good! Also, you may want to look into possibly sealing the top port in the recess, because rain/wash water can also get in there and contaminate your fuel???

T.C.

[Clyde K.]

Thanks TC, your idea is better. A dab of RTV will resolve the problem. Now I must pull the 750 FD back off and insert the 1100 spring. Maybe I should work the 750 spring through one of my ears so I have something in the void up there. Thanks again. Clyde

[Clyde K.]

TC, you wouldn't pull an old Gunny's leg, would you? LOL Seriously, I put a dab of RVT in the top of the vent to keep water from contaminating the fuel (as you suggested), then I raised the back of the tank until the fuel quit leaking. I figure that since there is no way to fix the leak I will just JB Weld the stinker shut and put the hose back on to protect the seat. Thanks again for the help. R/S Clyde

[DGXSER]

Another local XSive here also had an issue with that line leaking, his was where it penetrates the back of the tank. He used JB-Weld and I think PLastex on it. Nothing held up for more than a year or so though. The fuel will eat through those materials over time. If it were me, I think I would take a small screw, put a nitrile o-ring on it, and screw it up tight in there to plug it. Just a thought.

[skids]

And of course you from then on be careful not to fill it with gas to the bottom of the filler neck, unless you want a bad rash!!!

[TopCatGr58]

Hey Clyde,

I didn't necessarily say to use RTV, but "something" to plug the top port. Might even just get a nitrile/neoprene rubber type plug similar to the ones for the later carbs pilot jet tower plugs, might fit??

Also from what I've read/seen REAL JB Weld, not the JB "quick" stuff is more fuel "resistant", and since it's on the top, it's not SUBMERGED in fuel like it would be for a float post repair, and should seal and keep sealed fairly well.

I've used another product called "quick Aluminum", related to Quick Steel, that is a dual compound that you knead together to activate it, and it had real aluminum particles in it, sets rock hard, and IS impervious to gas. I've had it on my #2 carb float post for many years now, no sign of softening like the JBquick did!

T.C.

[Clyde K.]

The leak seems to be some place near where the tube exits the tank. The tank is about half full and when I lift the rear of the tank about 3" the leak stops. So, my plan is to leave the top of the tube unplugged then, theoretically, if I slosh fuel it will go down the tube and eventually reenter the tank at the point of the leak. I will do the screw/washer plug thing where the hose connects. How does that sound?

[cywelchjr]

Not a good idea. Any water, from rain or whatever will also go into the tank. You do NOT want to leave that open, too much bad stuff can get in to the tank that way.

[Clyde K.]

Thanks Cy, and everyone else. It is so nice to have people around whose brains actually work. Don't know what I'd do without this site. Clyde

[DGXSER]

Clyde,

I was thinking, dangerous I know, that perhaps the best solution for you would be to find a small tube with its OD the smae size or just a hair under the ID of that drain tube. (I have never owned a Standard, so I do not know the size we are dealing with). Anyway, take that smaller tube and insert it up through the existing tube. Then swage the end at the top open so it can seal against the orignal tube with some JB weld or what ever other compound of your choice. At the bottom end, I seem to recall the tube extends long enough you could try to braze or at least solder the two tubes together.

JAT

[natemoen]

That would be a smmmmmmaaaallll tube! The stock one is maybe a bit under 1/4 inch id.

[crazy steve]

That tube is way too small to put another tube through it; it's also not straight and is spot-welded to an internal brace...

You really need to look for another tank. As has been stated, anything you do with the upper end of the vent is just going to make it very likely you'll end up with water in your fuel. It may be possible to replace the tube, but that would be a very tough fix. If you try that, go with a larger diameter so it can be unsupported inside the tank.

Something like this is probably the best solution for salvaging that tank...

[IMG][/IMG]

This is a vented cap/neck assembly cut off another tank and trimmed to fit into the existing recess. Not shown, but the stock recess/neck below has been cut out. Braze/solder the lower exit closed, and weld/braze this new neck in.... still a lot of work, and you have to get all the gas flushed out of the tank before doing this so you don't blow yourself up!