the drivers door on my 88 camaro clunks at about 3/4 the way open. i'm pretty sure it needs the bottom hinge but it looks like the hinge is welded to the door. what do i have to do to fix it?

 

Buy the replacment hinge which you need to drill out spot welds and bolt new ones on. Yuck
If your hinge is not worn you can replace the pins and bushings on the lower.
I bought some shoulder bolts and bushings to repair the upper from a guy that makes them for repairing the Camaro hinges. He also sells them with the lower pins and bushings in his kit. If you like I will look for his contact info.