I contracted Stromberg and they no longer make or have any linkage. Looks like Lippert owns the step. The linkage is braking next to the ball threads. I did find one, but before I got it I decided to drill out the inside of the ball where the threaded part goes into. Looks like a slip joint. After drilling it out, I bought a one half inch Grade 8 bolt and locking nut. Slipped it through the ball and connected it into the step. Now if the bolt brakes again I can just replace the bolt. By the way, I found a new linkage for $30 on line.
Here is what the linkage looks like