Fixing a Fuel Tank Leak

[Ziggy]

I have a Moeller fuel tank, made of crosslinked polyethylene. There's a small leak where the aluminum pickup tube fitting penetrates the tank wall. I think the best way to fix it might be to weld it, but I don't have the right equipment. West System flexible epoxy (G-Flex) claims it will adhere to flame treated polyethylene so I could try that (I guess I should empty the tank before flame treating it!)

Any advice?

[Ike]

The simple answer is don't get anywhere near it with flame treatment. You may only have a leaky gasket. I have seen thousands of these tanks and the only leaks I ever saw were gaskets or someone accidentally put a hole in the tank. Those tanks have no seams to weld and they are not flame treated. Cross linked PE tanks are rotomolded, not welded together. That way they are seamless. What do you mean, "the tank wall" the pickup tube should come out of the top of the tank. If it's on a side wall the tank is on its side.

[Ziggy]

The fitting is on top. Only leaks when the tank is full and the boat is healing. There is no hole that I can see, so it's probably an o-ring. The pickup fitting is free to rotate (to make the installation easier?) and is held in place by a snap ring and sealed with o-rings. It almost seems designed to leak! I was thinking of putting a fillet of epoxy around the fitting, permanently fixing it to the tank.

[tallyhorob]

sounds like a o-ring leak to me. poly tanks flex a lot with temp so using a hard epoxy will more then likely crack anyways. So re ring it and lube the o-rings could have just been a bad placement to start with.

[Ike]

Like I said. Leaks at the gasket. Replace the o-ring. One thing to make sure you do is tighten all the screws that hold the fitting in place exactly the same amount and do not crush the o-ring.

[GordMay]

See the instructions
➥ Repair Procedure-Pickup/Vent Insert

➥ Moeller Marine Online - Technical Support

[Ziggy]

Gord,
Thanks, but I already went through their procedure once, without success. It's actually the "poplock" fitting (http://www.moellermarine.com/sites/m...3_pop_lock.doc) and it's very difficult to re-insert it and lock the snap ring. The fitting is free to rotate so it can't be tightened and the only seal is provided by the O-rings. I'll try it again according to their instructions, but I'm looking for a way to seal it permanently and not to have to worry about the O-rings leaking fuel.