Originally Posted by nothermark
The problem with how you roll is the construction of the tank. At least the one's I have seen have a ring welded or formed into the tank wall where the plug goes. As you increase tap size you decrease the wall thickness of the ring that was put in to beef up the tank wall and get a flat section to tap. It you were talking a flat sheet of metal I would agree with you but When you reduce that wall thickness you are treading into another failure mode. That is the problem with helicoils to some degree and a larger pipe size to a larger degree.
There's no problem with 'how I roll'. "How I roll" is making an attempt at a proper repair before giving up.
I never said anything about increasing the hole size, you're getting posts confused or something. I don't know why you're so stuck on that.
All I recommended was to chase the threads
that already exist. There is no increase in hole size
if you use the same size tap.
With that said, it may or may not work depending on the damage of the sleeve in the tank. For 10 or 15 bucks, It would seem worth a try to me.
If it doesn't work, then
go to the rubber plug idea.
Remember, the goal here is to help the OP and give suggestions, not to become combative and argumentative, that is not the purpose of this forum and the end result really helps no one.