Depending on how bad this problem is here are a couple of suggestions. I had to do this repair on a 93 two door that was bought with a torn out hinge that had been badly welded once. I did it pretty neatly one time, and thought it was fixed, but ended up having to do it again.
It's almost impossible to do well with either the door or the fender attached. Take the time and effort, or you'll just have to do it over again. Every time you have to redo it it's more of a mess and more difficult to get right.
First, if it's only beginning to tear out at the back, and still fairly firmly attached, the main thing you need to do is to hammer the rear edge of the hinge back in, and reweld it, but make sure it's seated properly. If it's begun to separate badly, or already fallen off, you will probably need to clean up the torn edges and tack it back together before you try welding it all the way.
If you use the repair kit, I think it should pull the hinge back in pretty well by itself, but I've never tried it. My observations apply only to welding.
It's really important on any pair of hinges to make sure that the two pins are on the same axis. For this reason, you must make sure that when you tack down the hinge, it is not tilted out at the top or the bottom, and that the rear edge is in as far as it needs to be. If you don't do this it will stress the hinge and the door.
The part of the door frame the hinge attaches to is double layered, and if you don't penetrate to the underlying level it will be weak.
As originally done, the hinge is not welded at all along the rear edge. There is no functional reason for this, and if you want a really strong attachment, one option is to weld that edge down. Because the hinge itself is curved and there's a big gap, it helps to put some kind of filler in, and then weld a big fillet over it. I cut a piece of 1/4 inch rod, stuck it in, and welded over it.
Once the hinge is back together, you can rehang the door. You may need to modify the shims under the hinge. If the door sags a lot, you can take the shim from the top out and add it to the bottom, but make sure the door does not end up too far forward. You may need to make another shim or two.
Finally, you must address the reason these hinges tear out. The door is too heavy for the check mechanism, and the check mechanism itself is a little too long. When the door is flung open, the check mechanism doesn't stop the door before the hinge hits its own built-in stop. At this point, it pulls the back of the hinge outward. If you don't address this, you will end up having to repair it again and again. Make sure first that the frame of the door, where the check bolts in, is not pulled out, cracked or weakened. You may need a new check, and may need to reinforce the door. Length is critical here. On my stepson's 93 I took the check out, welded the hole in the end shut, and redrilled the hole a little further in to produce a shorter check length. You might also consider getting a little file or cutoff wheel and cutting back the stops in the hinge itself, so that the door can swing a little further out before it hits. What you must end up with is the ability to open the door with normal force and not have it flex the hinge outward every time. Study it when you open the door, and keep at it until this is fixed, otherwise it's a losing battle.
