I'm gonna sound like a parrot on this thing. Haynes manual will detail this operation fairly well with the procedures.
In a nut shell? Changing out a fuel tank is not to bad--normally. It's pretty much:
Drain ALL the fuel from the tank.
Unhook any electrical leads going to the pump/sender. (sometimes best done when you start to lower the tank)
Unhook any and all hoses: Filler/Vapor/pressure/return/other smaller rubber hoses used for emissions. If unsure what went where if several are in the same area? Label things to make it easier. (also getting to a few might be hard, and done when you start to lower the tank)
Use a jack and a block of wood under the tank to support it. Start lowering the tank down with the strap bolts (if used...in general some will use just a set of straps...some use a strap and a few insulated (rubber washers used) bolts to the body..it varies depending on make/model) And once all the mounts are removed and out of the way? You'll wind up probably adjusting angles of the tank and it's position so it comes all the way out. (this is how we did the one on our former car we used to drive...general instructions ya know.)
Once the tank is out, it's decision time. Some salvage yard tanks will still have the old sender/pump unit left in place. You can use the existing one if it's a match for what you've just removed. (meaning...if your truck has the pressure pump as part of the sending unit...and the replacement tank has the same pump..I'm unsure as to when Ford went from using the two pump system (lift pump intank...pressure pump on the rail)
Might be a good idea to just re-use your own if it's working. New sending unit seal is required, and I'd replace the fuel pickup sock if I have to remove the sending unit/pump.
Other pitfalls would be having the fuel lines crap out when disturbed. (normally happens at areas where the line has a tight bend, or body clamp/clip to secure the steel line). And other areas that can be a pain. It'll take a couple of hours to complete from start to finish. Plus remember that no matter how well you think you have the fuel drained from the old tank? There will always be some left in.
These are just some general installing tips and such. The last tank I had to change out was on our '89 probe gt...that stinker had 2 hoses for the filler neck, 3 hoses going to the engine area (pressure/return/vapor) and 3 small vacuum lines at the top of the tank for emissions control. (all of the smaller lines where rusted off the tank at the top...not fun) Plus we reused the existing sending unit/pump...and the gauge failed within a week. So we had to remove it via the panel under the rear seat...and it was a bit of a pain.
S-
