If its in there good and tight and flush but it just keeps spinning. I would tack weld it in too.
If its spinning kind of loose, I would look for a crack in the control arm surrounding the ball joint. Then Id make a decision as whether I would weld that too along with tacking in the ball joint or replacing the control arm.
Knowing me Id probably weld it anyways. If tack weld it in try not to get it to hot. Jump from one side to the other.
Since the ball joint will last another 50,000 miles easy. I dont think you will ever have to worry about changing it out again. mike
