I may sound like an idiot but thought I would save my self a little trouble. I just bought a 1998 supercab f150 and was wondering where the jack is supposed to be. I don't have an owner's manual.

 

under passenger front seat along with tool, handle is under hood.

 

The jack,instructions & lug wrench are under the passenger seat and that long bar clamped above the fan shroud in the engine compartment is what you use to lower the spare tire.

You put that bar through the hole in your rear bumper and turn in to lower the spare tire.

It's a very good idea to get out there and lower your spare to check the pressure and see how much damage it's suffered from being pressed against the frame of your truck.

You can simply put some rags between the frame and tire contact points to save it from harm.