Is there supposed to be some sort of pick-up screen on the sending unit or extension. cause i pulled my sending units out today and there was nothin at the end. when i get a little past half empty both tanks start sucking air. I checked all over inside the tanks and there is nothing inside there.
thanks in advance

 

That depends on the year. Some pick-up tubes have nothing on the end and some have a screen.

 

There is in most cases on diesel Fseries an upside down funnel with a filter screen and a bypass valve. There are numerous cases where the filter assy has fallen or broken off. Yours may have and the PO may have just removed it...... it will then run out of fuel at about the 1/4 tank mark...... new sender assy are available from some aftermarket sources and the odd ford dealer.If you want pictures click on my name and email me.

 

sorry to rip your thread, but my truck runs out of fuel at the .25 mark! 93 f350 c/c idi, maybe I need to get into the tanks and check it out!

 

85 and newer used the mentioned upside down funnel, and they sometimes disintegrate, and are now freely sloshing around in the tank.. 84 used a simple rubber hose run to the bottom of the tank, so that's my fix. I try to use neoprene hose to be able to take bio for when it may come into more use. You can get vinyl hose from Lowe's and the like, or if there is a local ag store, use anhydrous hose.