Senior Tech Team
Join Date: Nov 2001
Location: Saginaw, Michigan U.S.A.
1964 through 1966 GM A-cars had a solid, one piece steering column shaft that extended down through the steering column all the way to the steering gear. Standard (non-adjustable) columns had a stamped flange on the end of the column shaft that attached to the flexible coupling on the gear. Tilt columns had a detachable bolt-on flange that attached to the flexible coupling.
In 1967 GM introduced the first generation energy absorbing steering column in all of their passenger cars. There was still a continuous shaft down through the steering column down to the flexible coupling on the gear. However, this shaft was made in two parts and was designed to telescope on itself in a severe frontal collision. Again the standard column had a stamped flange, the tilt column required a detachable flange.
Because there were problems with the long continuous steering shaft, GM introduced a separate, intermediate steering shaft (I-shaft)between the steering column and the steering gear. The I-shaft had a pivot joint (pot joint) at the column connection and a flange that attached to the flex coupling on the gear. (Big blocks required a detachable flange, all other engines used a stamped flange.)
I always thought that the I-shaft was introduced with the start of 1969 production. However, a recent post on this board now leads me to believe that the I-shaft was actually introduced either at the beginning of 1968 production or it was introduced as a rolling change during the 1968 model year.
My question is: If you have a 1968 A-car, do you have the one piece steering shaft, or do you have the column with the separate I-shaft. If you know the approximate build date, that would be helpful also.