You didn't say if you had the steering box apart but I can say that it is possible to assemble the ball nut and sector shaft one tooth out which will cause these symptoms. Here's the specific page in the overhaul booklet (index at page bottom):

http://chevy.oldcarmanualproject.com/booklets/5220mts28.htm



1952 1300 Canadian 1/2 ton restomod
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