Draining Old Gas

[RSWiser]

Because my car sat for about 4 years before I purchased it. I would like to drain the bottom of the gas tank. I looked under there yesterday and it is a large hex head.

Anyone know what size that is?

Thanks,

[Formerly Steve Wilkinson]

Don't remember the exact size, but the easiest and cheapest way to get it out is not to buy an expensive--in that unusual size--Allen wrench but to measure across the flats with calipers and buy a cheap bolt with a head of that size and two nuts to fit the bolt. Thread both nuts on the bolt, jam them tightly against each other and use the proper size box wrench to turn the bottommost of the two nuts counterclockwise. You can even use an inch-size bolt rather than the exactly right metric bolt, since it's a large and coarse hex socket.

Actually just went down and looked in my tool drawers and it's a bolt with a head 21mm across the flats.

[RSWiser]

Awesome idea. Thanks for the measurement and cheap tool idea.