is about 4 inches on my L2850DT, vintage 1984. The adjusting bolt is screwed all the way down, naturally tight against the locknut. The linkage doesn't seem worn at all. What's next? Rebuild of the steering box possible?
Parts to rebuild it should be available but they are pricey.
These type of steering boxes normally don't wear.
4" of play sounds extreme, have you checked all the linkage that feeds it from the steering wheel?