As long as this tread is on the subject of fuel lines, fuel filter (see diagram), and fuel pump (also in diagram), a big question is about the pressure in the lines between the tanks and, say, the fuel filter or fuel pump.
With the EFI system the fuel lines ae supposed to be pressurized, and in order to remove the tanks the lines will have to be disconnected. Given that there is a fuel pump inside each tank, that means the line going forward (toward the engine) will, or can (or whatever it is technically called), have pressure in it. However, when I've changed the fuel filter it hasn't been a problem, just unscrew and drop the can with the filter, pop a new filter on, then screw the can back up. Had a container to catch any spilled fuel but that was never a problem as there wasn't very much.
So, getting ready to remove the tanks:
If the filter is removed (see Edited diagram above), and with the battery disconnected, should one be able to safely disconnect the fuel line (that runs to the tank) where it attaches at the filter?
My understanding is that the tank pumps are not a high pressure type, so the pressurized line should then have only low pressure, and hopefully not squirt a lot of fuel at the connection joint.
I was thinking about starting a separate thread about this part but maybe it isn't necessary. Or is it?
At least for the tank aft of the rear axel, I know that it cannot be dropped without disconnecting and/or removal of the tank fuel pump assembly. The mid tank I haven't researched but assume would be similar.
The part about the fuel line being soft or mushy means that this is probably a good time to replace them. But, what an ordeal! But if not now, then the tanks would have to be dropped again, or the bed removed.
-= John =- 1985 F-150 EFI 302/5.0L dual tanks, long-wide bed, "heavy-half"