Have you addressed any of the other parts of your steering? Maybe the trouble is also there -- steering box (has adjustments), tie rod ends, pitman arm,etc -- all have parts that wear and add play to the steering. Maybe someone else will have a specific answer, but I found in my '49 rebuild that I couldn't just do one thing in the steering, I pretty much had to do it all. And then the difference was amazing.
Good luck!
John
