1988 f150 GAS LEAK!

Good afternoon guys! I recently acquired an '88 f150 for a screamin deal (Traded a 99 neon i picked up for 300), but it does have a few nics and tics. Main one being the front tank has a wicked gas leak on the underside of it. My intention is to run off of the rear tank only. When i hit the switch for the rear tank the fuel gauge reads above and beyond full, however I am almost certain that it is still running off the front tank because it’ll still run out of gas even though there is gas in the rear.
What do you guys think a good remedy to this is? I am trying to get my hands dirty without busting the bank.

http://www.arfc.org/complaints/1988/ford/f150/fuel_system_gasoline/problem.aspx

Tester

If the tank itself is leaking and if the truck were mine I’d just spring for a new tank from AutoZone or wherever. A new tank could probably be had for 100-125 bucks.

Sounds like you got a deal on this so it would be well worth the cost of a new tank.

My goal was to figure out how to bypass that switchable valve, and swap the fuel pumps if finding out the rear pump is bad. But what explains that gauge reading beyond full in the rear tank? The truck gets 8 miles to the gallon plus that gas leak cost me a lot of money at the moment lol. I figured if i have one good tank and all the parts to make it work, i might as well make it work right ?

Thank you @Tester, apparently this was a common issue.