56 F-100 and bigger
 

I attempted to start my rescued Ford F-250 (gas tank in cab) and no gas to the fuel pump. I disconnected the flex line between the fuel pump and the stock hard tube that runs along the frame back to the drop tube from the tank where there is another flex hose. Both hoses had holes in them. I am assuming if I replace these two flex lines I can draw gas thru the line to the fuel pump if the pump is working properly. My question is the tube that drops from the top of the tank down into the tank......is it just a straight open tube that goes to the bottom of the tank or does it have fittings or some kind of diaphram that could be plugged up and not working?

I had mine out of MG a couple years ago. Since I've had five truck tanks down, cleaned in the past five years, I may not be accurate on MG. If memory serves me right, she had a straight drop down pipe, no sock on the end. Any way, it is an easy job to pull the pipe assembly out and a great idea to make and replace the gasket. A new gasket may just prevent gas smell in the cab.

I would take the view that all the lines are either crud-filled or compromised and replace / clean the entire fuel flow. Ray's suggestion will also allow you to install a fuel shut-off valve since the tank connection will be affected.

DW

Don't forget a fuel filter somewhere in the line as well.

I popped the gas tank sender guage off the top of the tank and looked inside. It was a thick coating of green slime on the bottom of the tank. Looking in the hole where the fuel guage was removed let me see the fuel drop line tube which ended right at the bottom of the tank. That area did not have the green slime build up, but rather a thicker black crusty deposit that resembled cold tar. I put half a gallon of acetone in the tank it it removed all the slime. It did appear to soften the black residue, but did not quite disolve it as well as the green slime. I used a brush attached to a threaded rod and cleaned it up pretty good. Then I took it outside and flushed it with water and immediately returned it to the shop and put a heat gun blowing on low heat into the filler guage hole. I checked after about five minutes. At the bottom of the fuel pick up tube there was a nasty puddle of black tar in a liquid state (melted by the heat gun). I think part of the original problem may have been the fuel pick up line inside the tank was plugged by the black tar like substance. The heat gun was never on high heat, only warm and by warm I mean easily able to hold your hand up against it without getting burned. But yes this "melted" the reisdue inside the tube.