First check for loose tie rod ends, and idler arm. Once satisfied with the tightness of those components, use an allen wrench and box end at the adjustment atop the steering box. Hold the allen in place and loosen the nut. Back out the allen with your fingers until you feel resistance. Lock the nut without allowing the allen bolt to move from that position, you may have to loosen the locknut and retighten a few times before achieving this.
If this doesn't work, you will probably end up having to live with it.