Leaks from fuel tank selector valve
 

In the course of a recent crisis which turned out be a failed fuel pump, I discovered leaks from the selector valve. A PO had installed an electric pump just ahead of the valve so some of the lines had been modified with steel pipe and worm gear clamps. One such clamp needed tightening, but there is still a leak somewhere. There is no sign that the valve isn't working properly, so I am not inclined to replace it, but I am hesitant to fool around with the connections which have those special Ford fuel line clips. Recommendations ??

Is the valve itself leaking fuel? If so it needs to be replaced. I used worm gear style clamps and rubber hose when I installed a new FSV in my truck. In addition to ensuring that there are no fuel leaks you need to make sure there's no air intrusion. You can do this with a length of clear vinyl hose plumbed into the fuel line to look for air bubbles.

Hi, mine actually did leak from the gasket. I pulled the valve, opened it up and cleaned everything inside. The main gasket was swollen on one side and brittle on the other. I used RTV to create a new seal and four small M3 screws to hold everything togehter. Works perfectly now. While working on there I installed two inline filters before the valve to keep debris out, as well as new rubber fuel lines with fuel injection clamps instead of the worm clamps. They just clamp more even.

Update--I unbolted the valve from the frame rail, pulled it away so I could clean it as much as possible with a rag, and cleaned up all diesel-soaked debris on the frame. Started it up and crawled underneath to locate the leak. No leak evident, so I switched tanks, and still no leak. It appears that tightening the original clamp solved the problem, but it wasn't evident due to all the crud.

Glad you fixed the leak. :-X22