I have been having an air leak into the fuel line, so far I have replaced all old hoses, and vacuum tested the lines and fixtures. I took out the rear tank and it seems it has been tampered with before, I have found rust and a damaged sender, the intake is missing, the hose they put on is loose, and the aluminum valve seems to be opening under very light suction. #ad
I have not been able to find a new sender for diesel, it seems everyone is selling gas senders as "correct" however, they do not have the bypass feature for gelled fuel. Is this what others have been using? I don't want to buy a new tank if I can't get a proper sender. Another option I have is a '96 tank from another truck I have, however it's listed as being a little smaller.
Also, I cannot find a spec for testing the bypass valve (is that the correct term?), it seems to open too easily, how much vacuum should be required before it opens?

 

1983/84 F250/350 6.9L Diesel

E3TZ-9275-E .. Aft Axle Fuel Tank Sending Unit - Use with 133" - 155" - 159" wheelbases / Obsolete

E3TZ-9275-F .. Aft Axle Fuel Tank Sending Unit - Use with 137" wheelbase / Obsolete

No Ford dealer or obsolete parts vendor has either sending unit.

 

I have found these charts to be very helpful. I believe they have a large listing of available charts

 

Thanks Bill, mine is the 133, Reg. cab. Every listing I have found traces back to E0TZ, before Diesel Fords were even released.

I examined the tank out of my '96, and it is spotless, so that is what I'm going with. Same basic tank, but a larger sender, I will have to change the wiring end and use the later type Quick connect fuel lines, but I can make it work. The bypass seems to open at a higher vacuum, and I expect that was behind the original problem I was trying to fix.