SMTA Front Gas Tank Support

Bud W · Feb 7, 2011

I may have a very slow leak at the rear gas tank support on my SMTA. The parts manual doesn't seem to show how the tank is attached to the support ( 358454R1 ).Is there a stud welded to the tank bottom that then is attached to the support? Maybe I'm just not finding the correct page in the book? Thanks

sflem849 · Feb 7, 2011

Yes, there are studs in the bottom of the tank. I don't remember if they are true studs with female holes on each side or if they are welded to the tank.

D Slater · Feb 7, 2011

7/16 dia. stud screwed in the tank. Fine threads both ends. Supposed to be a blind hole where it goes in the tank. Stud housing inside the tank may be separating from the tank.

Bud W · Feb 7, 2011

Interesting , so the fine threads are supposed to be sufficient to keep the tank from leaking???

rustyfarmall · Feb 7, 2011

(quoted from post at 17:58:44 02/07/11) Interesting , so the fine threads are supposed to be sufficient to keep the tank from leaking???

No, there is a threaded insert welded into the tank. The threaded stud screws into that insert. You can completely remove the stud and the tank should not leak.

D Slater · Feb 7, 2011

No, no fuel is supposed to get to the threads.
Bosses for the studs to screw in are fastened to the tank on the inside. Not sure if there solder to the tank, brazed, or riveted and soldered. Looks like rivet bumps under the rubber tank pads. Never investigated to know for sure. You can see the front stud bosses inside by looking in the fill hole.

Bud W · Feb 7, 2011

I finally " get it " so thanks. Would appear that if gas is getting to the threads about the only fix is to solder the stud to the tank on the outside or maybe JB WELD?? Any thoughts?
Thanks

rustyfarmall · Feb 7, 2011

(quoted from post at 18:22:06 02/07/11) I finally " get it " so thanks. Would appear that if gas is getting to the threads about the only fix is to solder the stud to the tank on the outside or maybe JB WELD?? Any thoughts?
Thanks

JB Weld will hold it for awhile. Might last longer than I think. I don't think I would consider the JB weld a permanent cure though.

Wardner · Feb 7, 2011

Chances are that the blind threaded insert is good. The leak is probably coming from the joint between the insert and the tank sheet metal.

Another possibility is that the tank sheet metal has stress fractures. If the rubber washers and springs were not installed properly, vibrations might have weakened the area around the insert.

The leak can be fixed but you might give some thought to getting another tank. That's what I would do. Do you want to live with a leaky tank, or worse, apply heat to repair it.

Bud W · Feb 7, 2011

The problem with another tank is that there is no way to predict how long it will last. Unless someone is making them new there all 50-60 yrs old

sflem849 · Feb 7, 2011

I wouldn't be afraid to weld it up. I wouldn't do it myself, but the professionals do this stuff everyday.

SMTA Front Gas Tank Support

Bud W

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sflem849

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D Slater

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Bud W

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rustyfarmall

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D Slater

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Bud W

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rustyfarmall

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Wardner

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Bud W

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sflem849

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