Steering Column Repair

 

I had to remove the steering column to remove the instrument cluster for repair.  1967 was the first year for the collapsible steering column.  When I pulled the column out, I discovered this column had been collapsed at one time or another and the expanded metal section had been (poorly) welded back together as a repair.  It was broken and loose and the steering shaft had been rubbing the jacket.  I also found there was no bolt in the clamp where the column goes through the firewall.  I later found that was because the shaft was bent and if the column was clamped down at the firewall, the shaft would not turn.


I pulled the column apart and found that in addition to the fact that the bottom bearing was bad, the "shear buttons" that shear and allow the column to collapse had been sheared.  There were two different columns used in the ’67 Corvette; an “early” column used until ~ February ’67 and a “late” column used after that.  All of the early columns were recalled in a replacement campaign but this car was never retrofitted.  The bottom bearing was completely worn out and the balls were missing, leading to the shaft rubbing on the jacket.


Lower bearings are available from the various Corvette suppliers so that was solved with an order to ZIP products.  The jacket was to be harder to fix.  There was no logical way to replace the expanded metal section so I finally decided to obtain a piece of 6061-T6 aircraft aluminum and machine a sleeve that would be a medium press fit into the outside jacket.  That would be secured with a small amount of JB weld.  JB Weld has a shear strength of about 1200 lbs. per square inch.  In the unlikely event of a crash, the JB Weld will shear allowing the aluminum section to telescope into the outer jacket, providing the safety of the original collapsible column.

I ordered a piece of aluminum tubing with a 1.5 inch OD and a 1.25 ID.  This was chucked in the lathe and the OD was turned to 1.416 so it was a slight interference fit into the steel outer jacket of the column.  The outer jacket was not perfectly round but this provided a good press fit into the jacket.  The JB Weld would lock it into place and provide the necessary sheer in case of an accident.  I also turned a plastic bushing which was pressed into the aluminum sleeve to support the steering shaft in case of any unexpected runout.

 

After pressing the entire jacket assembly together (to 26.25 inches end to end), I allowed the JB Weld to cure for 24 hours before reassembling the column.



The original covering over the collapsible section was taped back in place as suggested in the Chevrolet repair manual.  The shearable aluminum mounts were re-injected with hot melt glue which secured them very well.   From the outside, you can’t tell the column is not original.



After completing the assembly, I discovered the steering shaft was bent, thus the reason for no clamp at the firewall.  I pulled the shaft back out and tried to straighten it using my 12 ton shop press and although I made it better, I ended up "chasing" the high spot around the shaft.  Dick Zahnter mentioned there were places that straighten shafts so I did a search in the Houston area and found a company called "Pro Grind" located in the southeast part of Houston.  I took the shaft to them and they said they would give it a shot but no guarantees.  They said there was a chance it might break but if it did, I wouldn't be much worse off.  They kept the shaft about a week and $100.00 later, I had a straight shaft. 


Today (11/7/09) I finally put the steering column back in place.  This time, the bolt went in the clamp at the firewall as well as a new gasket so seal it.  Everything lined up the way it's supposed to including where the column goes through the instrument cluster which is a first in my ownership of this car.  The steering is nice and tight and I am sure that's because of the rebuilt steering box and the fact that they use grease in the box now instead of 90 weight oil as it originally had.