My 96 F150 started transferring fuel from the from tank to the back tank. The rear tank has not worked for a few years so pulling off that one is not an option. Since I cannot use the rear tank anyway is it possible to T the rear return in to the front tank? I really do not feel like changing both pumps, pressure regulator... Just an old work/hunting truck with almost 300,000 miles. Any help with this would be great. Thanks

 

The rear pump assembly is your issue - the valves are shot and letting fuel go where it shouldn't be going.

Quick fix? Pull the rubber lines off the back tank and plug them (just simple hardware store plumbing supplies will work - barb fittings and threaded caps)

 

Trying the plug deal, one of the braided lines has a lot of pressure on it. Can't seem to get it to stop dripping. Any suggestions?

 

Might try a small hose clamp to secure the barb fitting.