I have a '96 F350. The driver's door is sagging a little and I noticed that the pin in the lower hinge is worn. My question: Do I have to replace the whole hinge, or can I drive the pin out and put a new pin and or bushings in.

 

replace the pin and bushings

you can get them at any automotive store in the "Help!" (autozone) section

do both the upper and lower while you are at it

 

This.

The pin has a little bushing that has to be drilled out. Once that's done, you can drive the pin out, and swap in the new ones.

Do them one at a time and it'll go a lot smoother.

 

Appreciate the help.