doors sagging

is there any way to adjust front doors or any tricks to get them to quit sagging. my 93 p71 front doors sag, the pass not so bad but the drivers knicks the back door enough now to chip off paint. they close fine and everything, they dont need slammed to get em shut, but there saggin.

Body shops have a tool that adjusts the doors some to make them close. Look at the hinges to be sure they are not worn out or the bolts rusted where the nut is welded to body.