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Discussion Starter #1
so in my quest to install a 100% (or as close to it) factory correct tilt column in my survivor 67 SS 350
I bought a 56998423 column off ebay which is a correct P/N for an early 67 car w/floor shift

I later found a 7803779 column allegedly taken from a low mile 68 which is a little better shape and has the correct original levers,,another piece that was eluding me.
I paid handsomely for it,,but that's the game I guess

7803779 is correct for a 67-68 as it supersedes the 56998423
yes I know as far as judging goes I would get dinged for the later P/N if they saw it
but visually they appear to be identical,,,,EXCEPT the 56998423 P/N column appears to be 1/2 in shorter? am I missing something?
I laid them both together and one is definitely shorter?? I don't understand why? maybe somone that is familiar with these could chime in?

the nicer column is in the back w/the orange sticker
any advice appreciated
 

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Perhaps the shorter one is partially collapsed? Happens all the time when guys are removing them.
 

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Discussion Starter #3
is that a bad thing? will it extend once its installed??
 

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Discussion Starter #5
I don't understand what compressed up in their I cant pull it out with my hand??
 

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I don't understand what compressed up in their I cant pull it out with my hand??
There is internal mesh that compresses along with the telescopic shaft. It can’t be easily pulled back as far as I know.

Don
 

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Discussion Starter #7
ok, that makes sense, Thanks for that!
 

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You can pull it back with a slide hammer rig
 
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There is internal mesh that compresses along with the telescopic shaft. It can’t be easily pulled back as far as I know.

Don
Exactly. The factory column sleeve is designed to collapse upon impact, it is similar to expanded steel. Those who have rebuilt a few would know. Rebuilding a column is easy. Aftermarket columns I have dealt with do not collapse.
 

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It is not mesh. It is slip tube held in place with plastic injected. On front impact the plastic sheers and the tubes slip.

Often when guys are separating the columns at the rag joint with a pry bar or screw driver they partially collapse the tubes.
 
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Are tilt columns different with regard to collapsing than non-tilt. My 67 non-tilt has a slip joint for the steering shaft, shaft on top, heavier wall tubing on the bottom, a tube on tube section with plastic shear joints that i took to be inert in my column but part of a column shift system if so equipped, and an expanded metal (mesh) section in the lower part of the outer column.
I had to wonder when I had it apart how they made the outer section because it looked like DOM tube and if they poured the plastic into the center shear tube assembled sections to make that piece.
 

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It is not mesh. It is slip tube held in place with plastic injected. On front impact the plastic sheers and the tubes slip.

Often when guys are separating the columns at the rag joint with a pry bar or screw driver they partially collapse the tubes.
A portion of the column tube is mesh(under the plastic sleeve);combined with the slip shaft, both provide protection. Note that Don wrote "along with".
 

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A portion of the column tube is mesh(under the plastic sleeve);combined with the slip shaft, both provide protection. Note that Don wrote "along with".


http://www.crankshaftcoalition.com/wiki/images/d/d6/Jazzman_Steering_Rack_Rebuild.pdf

Page 18 describes how the shaft collapses

One of the main safety features of the steering column is that this shaft assembly is collapsible. This is done by
using a telescoping tube design with an injection-molded plastic key to lock the tube and shaft together:
This plastic key will shear when the torso hits the steering wheel during a severe collision, allowing the shaft to
collapse into the tube instead of punching your heart out through your spine. When a column is dropped on its
end or a hammer is used to knock the steering wheel loose this is the part that is typically damaged, causing the
column to rattle over bumps and sometimes feel like it has slack with a "click" feeling. Once this happens the
shaft is considered non-repairable.
The column itself is designed to collapse into the instrument cluster, The shaft itself can collapse without the column collapsing.

I don't believe there is any mesh used the the shaft assembly.

Even a slight blow to the bottom can break the plastic fasteners. Also happens when a guy decides to use a hammer to help install a rag joint.

Looking at Tim's pictures it appears that is was has happened to the column that is shorter. You can see the lower shaft has been pushed into the column
 

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It is not mesh. It is slip tube held in place with plastic injected. On front impact the plastic sheers and the tubes slip.

Often when guys are separating the columns at the rag joint with a pry bar or screw driver they partially collapse the tubes.
A quick search found the following:

But collapsible steering columns did not enter production until 1967, when General Motors began installing two-piece columns with steel mesh that crumpled under pressure as the column telescoped. The mesh slowed impact by absorbing energy.

Don
 

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A quick search found the following:

But collapsible steering columns did not enter production until 1967, when General Motors began installing two-piece columns with steel mesh that crumpled under pressure as the column telescoped. The mesh slowed impact by absorbing energy.

Don
Don, I agree that is the way the "column" collapses.

I'm referring to how the shaft assembly is designed to telescope and is held in place with plastic.

On impact both the column and shaft collapse. The shaft can collapse slightly (and inch or so) without the column collapsing.

I appears that is what happened based on Tim's Pics
 

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From Jim Shea's Paper on Steering Columns

All General Motors 1967 and 1968 passenger cars came equipped with the first generation Saginaw energy absorbing steering columns. All steering columns were of this design (including tilt and the telescoping types). In a severe frontal collision these steering columns were designed to collapse forward into the instrument cluster with a controlled force. The steering shafts and transmission shift tubes inside these steering columns were also designed to collapse as well.

Refer to the parts picture on page 4 of the Jazzman Doc I posted the link to. It shows the column assembly as a tube within a tube that will collapse via mesh and also the collapsable shaft assembly.
 
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