How to fix/prevent gas tank leaks on Cub 70?

[cuballis]

I've got a 70 that is 99% restored, everything has been disassembled, blasted, repainted, rebuilt, etc. the only thing keeping it from being 100% is a very small leak/seep from the square plug in the gas tank. It doesn't leak much, but if it got worse I'm afraid it will drip and ruin the PPG paint job. I have tried two different tanks and both have the same issue. Both are leaking at the square plug. Is there a way to seal the tank from the inside?
Thanks

[J-Mech]

Strip the paint off and resolder the plug back on. Yes, solder, not braize or weld.

[ol'George]

To add to that correct advice, do check that it is not your fitting, but is really the square soldered connection that is leaking.
Gas will wick quickly and fool you, so look closely
FWIW when a connection is previously soldered,
any attempt to braze or weld later will be unsuccessful no matter how clean the area is made.
And a GOOD sweat soldered connection will work fine.
Mudded ,globbed goobered, JB weld, epoxy are fruitless.

[cuballis]

Thanks for the information on this. I'll give it a try.

[Yosemite Sam]

I have soldered a number of tanks with the exact problem you describe.

I like to screw a long pipe nipple into the square plug to use as a "handle" if you get it too hot the square plug will fall into the tank and is a pain to get back into position.

Several repairs that I have made to these tanks required no additional solder, clean it good with liquid flux before and early in the heating process, you will see the solder flow out and puddle, remove heat and hold onto the "handle" a little while longer and you should be good.

Good luck.

[Rescue11]

"Squelching" is common practice when soldering pipe. Actually makes the joint stronger. Do thd same rules apply here?

[ol'George]

Not familiar with the term "Squelching" so I "googled" it.
OH MY
It said among several definitions, the sound of sloppy sex.
----So ya the joint needs to be "prepaired" brought "up" to proper temp, well lubricated with soldering paste, turned while inserting , withdrawn just a bit and re inserted,
allowing for a fully tinned/coated "pipe" joint

In this case, I'm thinking a good clean area around the square insert will allow
for a complete leak free joint.
There is not a "receiver" in this case like a "nipple" in an elbow, "T", or coupling.
(Dam it is difficult to type while laughing, not to mention drinking coffee.)

[DoubleO7]

And filling tank with water to find the leak might not work either because gasoline will leak out of a hole or crack where water will not.

[Rescue11]

Originally Posted by ol'George

Not familiar with the term "Squelching" so I "googled" it.
OH MY
It said among several definitions, the sound of sloppy sex.

That has to be the funniest damn thing ive heard all day. I ment to say quenching, but your way is much more entertaining!

I can see it now... well thats where im leaving it... too graphic.

[J-Mech]

Originally Posted by ol'George

Not familiar with the term "Squelching" so I "googled" it.
OH MY
It said among several definitions, the sound of sloppy sex.
----So ya the joint needs to be "prepaired" brought "up" to proper temp, well lubricated with soldering paste, turned while inserting , withdrawn just a bit and re inserted,
allowing for a fully tinned/coated "pipe" joint

In this case, I'm thinking a good clean area around the square insert will allow
for a complete leak free joint.
There is not a "receiver" in this case like a "nipple" in an elbow, "T", or coupling.
(Dam it is difficult to type while laughing, not to mention drinking coffee.)

OMG.

That's funny.
I googled it because I wanted to get the "full effect" of what you read....
I can see you now, eyes fixed to the screen, then suddenly covering your mouth to prevent the spray of coffee from hitting the screen.

TOO FUNNY GEORGE! Too funny!