The return line had a half-moon worn in it from where it'd been lying on the front driveshaft (Another note to previous idiot owners: Ford doesn't put all those clips/brackets/supports in because they like spending money). I ran new line all the way back to the tee on the rear of the engine.
I couldn't find one-piece barbed 3/8 to 5/16 adapters so I did the next best thing - screwed two barb/NPT fittings together
Connected all the lines, printed out a copy of the selector valve wiring and hooked up the pigtail. When flipping the dash switch, the front tank went to beyond-full (as it should, since it wasn't there so infinite resistance), and the rear tank showed 1/3 which is about what I'd siphoned back into it. So far so good. By the way, the bolt spacing on the Standard valve is
just a bit smaller than the stock valve, so some rat-tail file work was needed on one frame bolt hole.
Next, I mounted the new front tank, hooked up the final two hoses, and siphoned a couple gallons of diesel into it. After looking at the 7 gal. of very old fuel that came out of the rear tank, I decided not to reuse it. Not only is it reddish (likely dyed), it really smells more like stale
gas than anything. Any ideas what I should do with it? I'm not putting it in my JD 70 Diesel tractor either...
I ran the electric lift pump (from the rear tank) for about 20 seconds, then started the engine... but after 5 seconds it died and wouldn't restart. Then it occurred to me that I should have bled the air from the Schrader valve first! Oh well, at least that was easy to do (jumper the pump relay to the battery and depress the valve stem). Got the air out and after some cranking and stumbling as the remaining air worked through the injector lines, it fired up. No leaks!
So I put all my tools away... walked around the truck and realized I hadn't put the front tank skid plate back on
but it wasn't too hard once I lay down under it and lifted it up, although another pair of hands would have helped!
Now if my friend with the backhoe will help me put the bed back on... except he got a flat on one of the (very old) rear tires and is busy getting that replaced. And it's supposed to rain every day at least part-time for the next week.