My Steering Column Lower Steering Shaft Is Too Short

[Jim S.]

The General Motors energy absorbing, collapsible steering columns (starting the 1967 model year) have a steering shaft that is assembled in two pieces and held together at a set design length with injected plastic. The plastic is designed to shear and the upper and lower shafts are designed to telescope on each other in a severe frontal collision. (This prevents the steering column shaft from becoming a spear and driving the steering wheel into the driver.) The two shafts are formed such that there is generous overlap between the two. There are no safety implications in terms of pressing the lower steering shaft into the steering column and returning it to its original design length.

This telescoping design can cause problems with respect to working on the steering column in your Vette.
1. As a means of replacing the flexible steering shaft coupling assembly, some people have been told to use a pry bar to force the flex coupling assembly away from the flange on the end of the steering column. This can cause the steering column shaft to be forced up into the steering column. You may not notice this problem at the time.

2. Some people remove the steering column from the car and accidently drop or hit the lower steering shaft while the column is out of the car.

You will also find that the two telescoping steering shaft parts collapse upon themselves a lot easier than they come back apart to their original length. It is this fact that prompts this thread.

The following is a listing of the various lower steering shaft lengths for C3 Steering Columns for your reference. It is the amount of shaft that "sticks out" from the face of the lower steering column bearing retainer face (or clamp) to the very end of the steering shaft.

C3 Standard (Non-Adjustable) Steering Columns
1968 2.7 inches from clamp to end of steering shaft (clamp is hard against plastic spacer)
1969 (Early) 3.2 inches from clamp to end of steering shaft (0.5 inch gap between clamp and lower bearing)
1969 (Late) - 1977 4.5 inches from bearing retainer face to end of steering shaft.
1978 - 79 4.8 inches from bearing retainer face to end of steering shaft.

C3 Telescoping Steering Column (1968) and C3 Tilt & Telescoping Steering Columns (1969-1982)
1968 2.2 inches from clamp to end of steering shaft
1969-76 4.7 inches
1977-78 4.9 inches
1979-82 5.0 inches

So if the length of lower steering shaft sticking into the engine compartment is less than the above dimensions you will need to extend the lower shaft to the dimensions given.

First of all, do not try to hammer or "shock" the lower steering shaft back to its design length. This type of procedure can damage the steering column bearings that support the steering shaft. You want some type of steady pull on the lower shaft to return it to its design length.

I all cases you will find that the cast flange on the lower steering shaft will provide you with a surface to grip in order to pull on the lower shaft. Also it is a good idea to place a piece of tape on the steering shaft so you can monitor the amount of movement.

Steering column still in the car
1. Use a large vise grips to pinch between the cast steering column flange and the cast bow tie flange that is part of the flexible coupling. Slowly squeeze them together a small bit at a time. (Make sure that you don't dislodge the flex coupling shoulder bolts.) Slowly pulling the steering shaft out. Once it is back out an inch or so you should be able to easily move it the remaining specified amount.
2. I am sure that people have probably found a point inside the engine compartment to somehow pry on the steering column flange (I just don't have a good description as to what and where.)

Steering column out of the car
1. Only if you are athletic. Securely bolt a two foot piece of lumber across the cast steering column flange. Attach it so that you have a handlebar on each side of the flange. Sit yourself and the steering column on a piece of carpeting (so you don't scratch the column.) Place your feet on either side of the welded bracket that holds the column up into the dash. Now with your back braced against a wall, pull back on the wooden handlebar with your arm strength. You should be able to move the steering shaft back out.
2. Secure the column to a bench and use a "come along" type of device for a steady pull on the lower shaft.

Any other techinques or ideas are appreciated.
Jim

[Rey S.]

Re: My Steering Column Lower Steering Shaft Is Too Short

Hi Jim.
Responding to your post of 12/09/14.
Taking note of the two drawings in the response to my collapsible column post I see that the upper drawing (my style) appears to be a round shaft (lower piece) in to a round hollow shaft (upper piece) Locked into place (?) with plastic inserts. My question is if I force the lower column beyond the plastic to shorten it ( Quoting you "there are no safety implications in terms of pressing the lower steering shaft into the steering column"). So that being said it would stand to reason that it is some what OK to do this, not desirable but OK versus cutting the column. My next question is once the column is collapsed, breaking the plastic loose, what then keeps the lower shaft from turning inside the upper column? Are there splines or square inside of square "tube" connection.
I find no information in the AIM or any of my other publications
Thanks for your input
Rey

[Jim S.]

Re: My Steering Column Lower Steering Shaft Is Too Short

Rey,
What year Corvette? Also, a standard (non-adjustable) or a tilt & telescoping typeof steering column? If you have a 1967 thru 1982 Vette your steering shaft should be the same as the lower picture (above). The upper steering shaft is a solid bar that is precision formed with long flats on each side. The lower steering shaft is tubular and is precision formed such that it also has flats on opposite sides that engage the flats on the upper shaft. So the two shafts can telescope over each other in a severe frontal collision. Since they have mating flats there is no danger that they can disengage and rotational integrity is insured.

BTW, the upper picture shows the shift tube.

I am now back.
Jim

[Rey S.]

Re: My Steering Column Lower Steering Shaft Is Too Short

Hi Jim
I have a 1972 with tilt and telescope (Steering wheel) column. In VERY near future I will attempt to send a photo of the under hood portion of my column.
Rey

[Jim S.]

Re: My Steering Column Lower Steering Shaft Is Too Short

You know, there is an awful lot of information in my first reply of a year ago. Your steering column should have 4.7 inches of steering shaft tube sticking out from the steering column lower bearing. It is usually somewhat difficult to extend the steering shaft back to its original 4.7 inch length.
Jim

[Rey S.]

Re: My Steering Column Lower Steering Shaft Is Too Short

Hi Again Jim:
Yeah I can see that it will be difficult. What I wish to do is to shorten the exposed part of the shaft (both pieces?) for the purpose of making enough room for the new Borgeson steering box. My fear is that I will have to cut the column. I have a good photo showing the end of the column. It is hollow and appears to be two pieces one inside of the other. The ends of the two pieces are flush with each other. I would like to post the photo I took but my ancient cranial mater is not up to speed on how to do it.

[Jim S.]

Re: My Steering Column Lower Steering Shaft Is Too Short

Rey,
The Borgeson power steering gear results in the gear input shaft being located further rearward (closer to the steering column steering shaft) than the Corvette manual gear. You will not have to do any cutting of the steering shaft to make things fit. You need to press the lower tubular shaft back into the steering column. Borgeson should be able to supply you with a dimension to accomplish this shortening of the shaft. If you have a lot of corrosion on the steering shaft you might want to use some sandpaper or Krocus cloth to polish the steering shaft and allow it to slide through the lower bearing more easily.

Since the steering shaft parts were designed with generous overlap between the upper and lower shafts where they come together inside the steering column, there are no safety issues when you telescope that lower shaft back into the column.

Try not to pound the shaft back into the column. This could damage the column bearings.

Jim

Jim