I have a 74 W100 with the fuel tank behind the seat. It always smells like gas, but i found it rather odd when my windshield scraper was melted to my floor board. Theres fuel leaking into my rocker panels and off the bottom of the cab. I looked at the seam that seals up the tank and didnt see any signs of leakage. Is there anywhere on the back of the tank it could be leaking from? I really dont want to pull the tank but i guess if it comes down to it...

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Drive it like its stolen, and be glad im not YOUR son...

Oh, wow! Not good. Hope you don't smoke.

Possible leak points are:

-Tank seam
-Tank itself (rust/damage)
-Tank-to-filler pipe junction
-Filler pipe itself
-Gauge sender seal
-Gauge sender itself
-Line(s) coming off tank

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

You need to deal with this right away. Take the vehicle outside (out of a garage), disconnect the battery, remove the tank, find your leak, and fix it.

Even if you don't end up on the evening news (truck explodes, film at 11), the constant breathing of gasoline vapors in an enclosed space is a bad thing.

-Mac

Yup, Slanted Opinion is right. This truck needs to be taken out of service now and not placed back in service until you've fixed it. It's just not safe.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

So i went and bought 5, 5 gal cans to drain my gas into( would have been about 70 bucks if i didnt work there), and disconnected my battery. I considered all the possible leak points listed but, all the plumbing for the tank comes out the top. The seam line hangs down on to a lower part of the floor board and is very visible, but i see no signs of leakage. So i assume that some how a hole got warn into the back of the tank. I had the idea that instead of having someone weld it, perhaps i could thread a sheet metal screw into the whole and seal it with like JB weld or a silicone type sealant. The only thing i could see wrong with doing this is if the hole is rusted. Any other ideas as to how it could be sealed besides welding?

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Drive it like its stolen, and be glad im not YOUR son...

Welding a gas tank, no matter how many precautions you take, is almost a surefire suicide method.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

From what i understand your supposed to fill it with water, but the again fuel is lighter than water( isnt it?) so all the fuel would be right on top where your welding...i think the sealant is a good idea, as long as the fuel wont eat through it, like my ice scraper

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Drive it like its stolen, and be glad im not YOUR son...

Call around to radiator repair shops. Some will still repair tanks. Get it done right.

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225

welding a tank has its risks, but filling it with water so that it over flows is the way its done. Over flow the tank in one area and weld it in a different area.

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67Cuda,FAST EZEFI,340cu,CR=10.25,RollerCam&Rocker (XR268HR,#20-810-9)(#1622-16)(EddyRPM#60779,#7576), (MSD6AL,#6425) A904, GearVendorsOD, 8 1/4,3.55:1, ClassicAir

Don't forget to replace that ice scraper......asap!

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Excuse me, does this smell like chloroform to you?

If the leak is from a rust-through, you may find that there are actually many areas almost as bad. Welding can be done as described, but I wouldn't want to do it. I'd rather see a new tank in there.

Another alternative is to use one of the cleaner/etcher/liner kits like THIS.

A good, new tank would be better and easier, but would cost more.

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"When you find a big kettle of crazy, it's best not to stir it." - Pointy-haired Boss

1964 Valiant V200, 225/Pushbutton 904
BBD, CAI, HEI, LBP, AC, AM/FM/USB, EIEIO

I got the tank out, took me about an hour. Turns out theres a foam pad about 1/4" thick, and about 5" wide thats adhered to the back of the tank, to go between the tank and the cab. SOMEHOW it got wet and the whole bottom part of the pad had rusted through the tank in a band about an inch wide that stretches about 3 feet across the tank. I poked at it with an awl and got about 10 or 11 punctures. I filled it with water and let it over flow for a few minutes, drained the water and went at the rust with a palm sander and a dremel. I plan on calling some shops tomorrow for price and availability.

Ill have to say, im rather butt hurt about the scraper...poor little thing

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Drive it like its stolen, and be glad im not YOUR son...

I think you'll do better with a replacement tank.

Better yet, how about putting in a tank that is under the bed of the truck?

The idea of the tank in the cab always made me nervous... I had an old Ford that was built that way.

-Mac