I just replaced my fuel tank in an 83 Bronco. Anyone know if there is a certain procedure when adding fuel and then starting it up? I could swear I read something about it, yet cant remember where. Also there is a line coming off the the fuel sending unit, that looks like a vacuum or vent line. I followed the line up to the motor, and it was not even hooked up to anything. I guess I may just attach a vacuum line to it, and hook up to the intake. Any thoughts?

 

Welcome new user.
I just replaced the fuel tank on my 92 Bronco. I was able to start mine after cranking on the starter far more than I anticipated and I also bled air from the fuel lines at the valve on the fuel rail. I have EFI so this may not apply to your model year.

As far as the line from the tank to the front of the truck is concerned I think there will be two lines running from the tank to the engine on the driver side. One is fuel delivery and it passes through the fuel filter mounted on the inside frame of the driver side near the transfer case crossmember.

The other is the fuel return line to the fuel delivery module in the tank.

The third line that you probably will find runs from the fuel tank along the frame rail on the passenger side to the front of the vehicle below the battery where it should connect to the charcoal canister. It is a fuel vapor line meant to return fuel vapors to the tank. There should be a canister purge valve and/or solenoid there somewhere between the carburetor spacer nipple and the carburetor bowl vent hose that uses a vacuum line to control the flow of vapors from the carburetor to the canister and back to the fuel tank.

I don't have a diagram for your model year so I can only hope this helps you figure out what you're dealing with. I know there are some users here who can offer more help than this and I hope they'll jump in to clarify anything that I've muddied.