EFI Fuel Leak - lines?

I have a 2011 (completion date) Factory Five Roadster Mk 3.1 with a 351 Windsor engine. The Mass Flo Fuel Injection includes a pump inside the gas tank. Recently, I noticed a fuel leak behind the passenger seat. I've removed the tank and unconnected the fuel lines. I don't see any evidence of a leaking connection or other obvious source. Could the rubber fuel lines, housed in braided SS wire, be deteriorated, cracked and leaking?

Anyone else have similar problems? I'm looking for a solution without randomly changing the fuel lines. I'm prepared to do that, but I'd rather have more confidence that the lines are the problem. This weekend, I'll finish my trunk box installation (yeah ten year late), and re-assemble. That'll give me an opportunity to "see" the leak better.

Thanks in advance,
Gary Patterson
Allen, TX

if you have rubber lines wrapped in SS, then it is definitely a consideration that the lines are leaking under the metal. replace the soft lines going to the hard lines or replace w/ PTFE lines and never worry about it again.

I second switching to PTFE. Your leak might actually be the lines sweating due to the ethanal content in the fuel. Because of the high gas prices our government allowed winter fuel level of ethanol be used in the summer this year. Winter fuel is usually ~15% ethanal and summer is usually ~10% or less. Unless your fuel lines are rated for the higher ethanal content you'll get this issue.

I agree with the previous posts. Better replace those lines before it gets worse.

Regarding hard lines: If you're interested, but don't have the tools to flare the lines (or don't want to), Mike Forte sells Swagelok fittings that can attach to hard line without the need for flaring, and are rated to exceed the pressure of EFI many times over. I used some of these on my fuel system (hard stainless under the car to PTFE lines on either end), no issues since being installed in 2015.