Ever wondered how to find pin hole leaks in a gas tank? Here's how: spend a week lovingly cleaning it with vinegar looking for any leaks whenever you handle it, spend all morning flushing it with baking soda, soap and water, coat it in Marvel to prevent flash rust, install it and then dump a couple of gallons of gas into it. THEN and only then will that pin hole leak make itself readily apparent!
Dammit!