Seat tank question

Air pressure won't work for that, the steel is just too heavy and the shape is not meant for pressure. something bad would happen before you could pressurize the tank enough to reform.
The most sucessfull way is to very neatly cut out out the whole back of the tank, straighten the bent piece or even better have a new piece cut and bent to the right shape and reweld into tank.

I have seen a Couple where folk have simply Folded and Rolled a Sheet and welded straight on to Tank , Good neat Welding and a Coat of Paint and they Look fine and no one would notice. Take all safety Measures of Course LJ

I have seen a Couple where folk have simply Folded and Rolled a Sheet and welded straight on to Tank , Good neat Welding and a Coat of Paint and they Look fine and no one would notice. Take all safety Measures of Course LJ

Lance. That sounds like the easiest way to go and the least invasive option

Any chance you could slip a scissors type jack in through the fill opening and jack the dent out enough to use body filler on it. Some of them that come in compact cars are pretty skinny and you could cut down the "foot" to get it to fit better. Of course you might just create a corresponding dent outward in the front surface!

Very bad idea, good way to get hurt or worse if the tank splits....WA7OPY