Yeah, that little adjuster rod and it's threaded "head" are subject to stripping the threads. It has left-hand threads (my '91 does anyway) and the more you tighten it, the more the rod moves out the bottom of the threaded head.
When it get down to 3-4 threads then it can strip.
What I did, I saved my old stripped "head" and use it as a comparison to see how many threads I have still engaged on the new one. Just stick a small screwdriver in the one on the car, and compare the depth of the rod to the old one on the bench. Seems we all have the same issues when working on these.

DG