What you need to do is find a shop manual, and follow the proceedure for
adjusting the steering box. Your problem stems from the fact that far too
many people over the years have done exactly what you did, which is probably
the LAST STEP in the proceedure, not the only one. There are several steps
to adjusting the steering box, and the top adjustment is one of the last
ones, and it maily locks things in place,
John