89 Dakota 2WD 3.9. I had local mechanic with a good rep change my upper bushings and ball joints. Turns out he "pressed" the ball joints instead of screwing them in and out. Now they move slightly. The truck was aligned and I don't want to remove the arms again. I'm thinking spot weld (never changing them again) or is there a nut I can screw on from the bottom side of the ball joint to tighten to the arm? And that's why I try to do repairs myself. That takes care of his rep!

Just put a couple spot welds on them and you are good to go . . . when need to change again, look for upper control arms . . . .

MIG or ARC?

If the area is clean enough (read that shinny metal on both surfaces at the spot weld) Mig spot welds will be good. If you can't get the area clean, then arc weld the spots. All those spot welds have to do is keep the ball joint from moving, won't take much to keep them from falling out of a pressed or threaded hole. I'm a welder by trade. Gene

Did 4 stick welds on each ball joint