Steering Column Bearings
 

I'm rebuilding my 68 steering column and I see it needs a new lower bearing for sure. Also see that no one seems to produce that part.

Ames does sell a "conversion" kit to use a 69 lower bearing on a 68 column. Is it just a 69 bearing? Or does it have something special included to adapt it?

On both the columns I have I noticed the upper bearing is in decent condition ... but the shaft just spins inside of it unless it's lubed up and worked loose. Surprising since both columns look pretty good from the outside.

Any advice on steering column rebuilding is welcome.

It took me quite a while to find a ‘68 lower bearing. If I had to guess, I suspect the difference has to do with the locking column. Looks like the plastic housing is different which I assume means the bearing is different too. Probably not super noticeable once installed.

I wouldn't be concerned about originality on a part like that, so the conversion kit would be suitable .. just wanted to find out if there were other options before I dropped $85 on that kit with shipping.

I've got one sacrificial column to work with, was wondering about trying to locate the actual bearing that was used to see if I could just buy an off the shelf bearing and put it in the plastic carrier.

I have a thing about bearings ... I love finding the actual bearing an OEM supplier used and replace them with high quality off the shelf stuff :)

Original part number is 7804200

Here's an NOS

https://www.ebay.com/p/21019689046

Search of the web:
https://gmtiltcolumns.com/product/67...-and-clip-new/

Upper bearing:
https://www.ebay.com/itm/39394466157...IAAOSwLd9iD8K6

I restored my column a few years ago. Using the service manual its relatively straight forward and after cleaning, I knocked it out in an afternoon.
In the SM, just ignore all the info about the column shift mechanism. Take lots of pictures during disassembly.

Is that a conversion lower bearing you are using, or all 68 stuff? Mine has white carriers for the lower bearing.

Luckily I have two identical columns so one to practice on.

After seeing those NOS prices I guess the Ames kit isn't that bad a deal.

Quick question ... is the rectangular section of the steering shaft inside the column supposed to slide up and down inside the upper portion? Seems like it did when I pulled it apart but now it's not moving, but I could be imagining things.

This??

Yes, the bearing I have was a conversion piece. Waited about 6 months for an NOS piece to show up that wasn't $$$. So I went with the one you see from a Camaro vendor. Can't remember who though. About $80 if I remember right. Receipt is in one of my "boxes".

I also used this to glue the plastic piece back on.

I was asking about the lower bearing, the conversion kit so a 68 can use a 69 once piece lower bearing.

This is from the Ames site .. although they say it's not an actual photo of the part.

You know those three screws that go through the turn signal mechanism, then through the springs etc? How do you know how much to tighten those down? I assume you don't totally compress the springs.

Screws tighten down to 35 inch - pounds

I assume that's in the service manual if I'd read it instead of looking at the pictures. :)
Thank you.

When following the service manual, there is numerous references to the shift linkage. With the floor shift you can just ignore all of that. (67-68 only)
There are a few parts that require a little thinking and ingenuity when installing but nothing thats beyond the skill of most people.
I couldn't seat the upper bowl bushing. After struggling with it I noticed it had a keyway. duh... This bushing btw, does not wear with a floor shift. It supports the rotation of the column shift bowl.

Another thing to remember is the outer tube and shaft can be easily damaged if dropped on end. Once the C clip and lower bearing are removed the shaft is free to fall out of the tube.
And use the mounting tabs when placing in a vise.

Great idea on the vice ... mine's been flopping all over the bench.

I've got the top end figured out pretty well now. Working my way down.

Measured up the lower bearing, appears to be nothing close off the shelf, what a cheap little bearing, looks like a flanged pedal crank bearing from a cheap bicycle. Was hoping to find a sealed high quality replacement. Waiting to hear from Ames when their lower bearing kits will be in stock.

I don't see anything that appears to be an external seal protecting the lower bearing, degraded over time?

In the diagram below ... is "part 1" supposed to slide in and out of "part 2" or is fixed into place?

No, it is fixed. Upon frontal impact, both the column inner and outer tubes and the steering shaft collapse.
If you look carefully at the shaft and the inner tube, you can see the plastic (?) retainers that keep it as a solid piece. On impact the plastic retainers are sheared allowing the shaft to collapse along with the tubes.
Which is why you don't want to drop these on end.

There was a tape type of insulation wrapped around the inner tube near the lower bearing. It was severely degraded and I just left it off. I may put a wide black tape over the opening where the shift fork/forks would normally go to keep dirt out

Having a heck of time finding the lower bearing that is not either an extremely overpriced NOS part, or someone gouging on the price of the reproduction because everyone is out of stock.

Read tons of forum posts on the subject ... one guys solution, pressing a 2" OD, 1" ID sealed ball bearing into the column, had to leave some parts out I think. Just so happens in the ID of the column tube is 2".

I'm getting to the point where I might just get on the lathe and build a carrier that holds a high quality sealed roller bearing on the end of the tube. The OEM bearing really appears to be an extremely cheap bicycle head stock bearing (even heard one poster saying he knew someone that found a suitable bearing at a bike shop).

Pretty sure I could turn up an aluminum 2" OD flanged carrier that would fit into the tube like the original plastic carrier, Could probably even groove it to take the original clip. After looking at it, there is no magic down there ... just a plastic thing that holds the bearing (and not every well), big spring on the inside, little spring on the outside.

The way things are going supply wise lately ... could probably sell a bunch of them. Quality sealed ball bearing in that location would last probably 100 years of daily use.

Did some research ... I'm up for this project. Going to use either a Delrin, or Oil-lite Bronze bushing for the 1" steering shaft. Will make a carrier that holds it similar to the OEM piece. Will work better than the OEM piece and cost less (already have all these materials).

Noticed that aftermarket hot-rod, drag car etc. steering systems use Delrin bushings. Shouldn't a problem to get the total thickness the same so the inner and outer spring function as OEM.

On both my columns with the OEM bearing it was a filthy mess full of grit that totally destroys those cheap bearings. Perhaps I'll even machine a provision for a seal of some sort, and an oil hole on top for an occasional drop of oil or graphite lubricant. Should have way less slop than even a new OEM piece.

For some reason I find myself afraid to make parts for this GTO, I've made parts for racing motorcycles for 20 years, stuff that operates way more on the edge and requiring way more precision than a passenger car. I've been paying way too much for NOS or reproduction parts that are often pretty low quality when I could have made functional replacements myself. I could have literally fabricated a working replacement myself in less time than I have spent searching for a suitable factory style replacement.
Game On :)

I went through this with the '68 tilt column in my '64. At first I thought the bottom bearing was bad. After cleaning it in the parts washer it felt fine. I packed it with marine grease. It appears that a spring keeps the clearance out of the bearing. I'm not sure I have the correct spring though. Will post some pics later. I should do like you said. I should find a sealed bearing and machine an adapter. I think mine is fine if I can verify that I have the correct spring for it.

You know .... when I looked at the OEM bearings I had a feeling that is what the forward spring is for, between the lower column and connection to the intermediate shaft. Much like a bicycle steering neck bearing it needs pressure on it to maintain proper clearance.

When I was checking slop one column did not have the lower spring installed, the other column had it installed and held in place with a zip tie ... BUT, the zip tie was not compressing the spring nearly as much as it would be installed.

So, before I make the final call I will clean up the old bearings, grease well AND compress that spring and see what it does to the slop in the lower column.

Still ... I'd be excited about having a beefy sealed bearing down there. People that have done the modification have said it really improves the smoothness and feel of the steering.

The original bearings I have, failed the test. Cleaned them, greased them, compressed the spring, still the way too much slop, probably 1/8" total.

Did some very close examination, these columns are an odd piece. First .. they are in the majority .. Metric. The lower tube I kept getting a 2.045" ID for ... well that's 52mm, the lower tube OD (2.16") is ... 55mm. The lower bearing small OD is 37mm, the lower bearing large OD is 42mm ... the only thing Imperial on that bearing is the 1" ID for the shaft.

Now the lower end of the inner column tube is Imperial ... ID 1.25" OD 1.365"

Shame the large column tube is metric .. 2" OD stock is too sloppy to use. I did find the materials below in my stock. Some 2.25" OD 1.25" ID super high pressure aluminum pipe, and some 1.5" OD Delrin (or perhaps PTFE, or maybe UHMW polyethylene) that should work fine. Or I may go with a bronze bushing ... I'll do the drawings and see how things work out.

https://forums.maxperformanceinc.com...0&d=1645523845

I also considered making a bushing to replace the lower bearing. Nylatron would work well and it's charcoal gray. So it would be inconspicuous. Will likely stay with the factory stuff since it appears to be in good shape. It's is a poor design I think. Another idea is using a split collar to adjust the preload instead of the spring. Dunno if there's room for that though.

I'm still going to re-assemble my spare column, put it all back together with the bearing greased and the springs all in place to check it before I commit to making anything.

I have a feeling all the kind of "delicate" construction down there is purposeful and has something to do with the way the column is kind of supposed to self destruct on impact ... a big strong ball bearing down there wouldn't be conducive to that :)

That's a good point that I hadn't considered. Good thinking! Thanks for pointing that out.

Have the basic components laid out for a bushing type bearing.

More measurements need to be taken. Gives me a lot of exercise going up and down the stairs to the shop :)

https://forums.maxperformanceinc.com...7&d=1645575935

Wouldn't it be nice if it was this easy.

But .. it's not :)

https://forums.maxperformanceinc.com...6&d=1645612998

Nice work there! I wish I had those skills.

Make two and let me know what I owe ya. :)

Replicating the OEM plastic bearing carrier ... then I'll decide just how much I can simplify it to reproduce it in metal, suitable for holding a bushing.

https://forums.maxperformanceinc.com...9&d=1645617288

I absolutely love doing this kind of work, would have been nice if I made a lucrative career from it rather than dicking around in my little shop for pennies. No one ever accused me of being a good businessman, or of running away from meaningless work that I created out of thin air :)

Of course Ames just posted that they will have the 68 lower bearing conversion kits back in stock at the end of the week ... dohhh

You can't put a price on happiness they say. I can make the parts. Just never learned the CAD skills.

I came at it from the other direction, could do the CAD before I ever had a single machine tool. Not the best direction to go ... you need to know what CAN be made before you design something. So now I have to spend a lot of time simplifying designs so they can be made with my simple machines, or more accurately .. my simple tooling.

In the design above you can probably tell the grooves are way too deep to be easily machined ... I guess I could spend a lot of time with a small diameter mill and turning the rotary table. Too deep and narrow to do on a lathe. So next step is to see how much I can shorten it and still hold everything were it needs to go. I think the plastic pieces had that extra depth because the material isn't very strong.

Last step is to throw the ruined part across the shop after four hours of work and order the part from Ames :)

Duhhh..... was brushing my teeth before nap time and it came to me ... jeez, if I'm going to use a bushing ... all I have to do is turn up a bushing that fits and stick it in. No carrier, no modifications ... just a simple bronze or Delrin bushing the same dimensions as the OEM bearing.

Part of me is disappointed it's that simple :)

It's a done deal now. Took an hour or so with the test fitting. Fit is excellent, gave it about 0.002" clearance to the shaft. Made it a snug fit in the carrier but easily inserted by hand.

Tested it all out on the spare column, can't for the life of me see why this isn't a better solution than the OEM bearing, and it preserves the collapsible nature of the column. Saved myself $75 too.

I need to try to find out what material I used. I ran a few quick tests on this and what I think was UHMW polyethylene and this gray product seemed considerably tougher, not harder, not really slipperier .. but definitely tougher.

I'll have to check my records and see if I can find out what it is, just in case it's real sensitive to moisture or heat.

https://forums.maxperformanceinc.com...9&d=1645698053

https://forums.maxperformanceinc.com...0&d=1645698057

https://forums.maxperformanceinc.com...1&d=1645698063

That looks like Nylatron. Great stuff! It is a little challenging to turn. Damn plastics wrapping around the chuck!!!

I hear ya about making it simple. Curious why you didn't just eliminate the factory carrier since you were making a bushing anyway. Closer to stock appearance? Good solution regardless.

Jeez, I was going to mention what a pain it was to turn ... but I thought it would make me look amateur :) Tried HSS bits first ... ehhh, then bored it with insert tooling and did pretty good at about 1800 rpm .. but man, plastic going all over the place, looked like a cotton candy machine. Does look like the product you described .. I probably purchased it to make bushings for vintage motorcycles, or for sacrificial "sliders" on the frames/body.

Two reasons ... didn't have that stuff in large enough diameter ... and man, that carrier, all those grooves are different widths, different heights, and different depths. Would definitely been a challenge to machine.

BTW .. that's my "junk" carrier ... the column I'll be using is way nicer, but still sloppy.

No shame there. Those materials are a challenge.

That'll work perfectly. Good luck!

I just found the product you described ... ordered some of that. I noticed that the material I used has a temp limit of 180 degrees ... seems a tad low for engine compartment use. The material you mentioned has a temp limit of 230 degrees, seems more suitable, and is called out specifically for use in bushings. I'll just remake the bushing in that.

Will be a week or so before I put in the column so plenty of time. Thanks for the recommendation.

Very cool! Always fun yo see your ideas and work.

Good catch on the temp ratings.

Suggest you also check material for chemical compatibility too. Oils, greases, solvents, etc. may get in there.

Nylon absorbs moisture, but shouldn't matter in this application. I don't know about hydrocarbons but would look it up. I don't know Nylatron.

Delrin/acetal/POM family may be an option and easy to find.

Polysulfones are more expensive but may also be a good option.

Hard to know why a ball bearing was used there but probably about low clearance/ability to preload and wear resistance. Engineering plastics then were nowhere near what they are today. Dirt/dust is mostly silica. Will grind soft material. May have been a concern for a car used daily in bad places for 10 years but you don't need that. Plus you provide your own warranty!

You raise a good point about contamination. That could be bad for a bushing in the engine compartment.

Looks like the nylon is good for petroleum products, but I'd probably give it another couple thou clearance for moisture swelling. The Delrin is down around 180 degrees like the Polyethylene I used, but is really tough ... didn't realize Turcite is basically the same thing ... that stuff is now used on the wear surfaces of machine tools.

I can see there is a lot to know when it comes to plastic material selection. Wonder if anyone makes an app to plug in requirements and show material options. Not for this project really, but would come in handy.

What surprises me about the OEM solution is not so much the use of a bearing, but the use of such a low quality bearing in what you would think is a critical component, in a very hostile environment. I've never looked at a 69 bearing, but they did make a change in 69 that continued right into the 80's. From the pictures I've seen the 69 and later style is all sealed up much better than the 68 bearing, but evidently not the same dimensions.

It's obvious the spring is there to preload the bearing, but the necessity for pre-load seems to only be a function of the type of bearing they used, not something necessary for the overall design ... doesn't look like the 69 and later bearing requires it.

Always interesting trying to reverse engineer the OEM designs, in this case it baffles me why they didn't just use a standard sealed ball bearing (other than they are almost impossible to find with a 1" bore and less than 2" OD), or a needle bearing with an inner race sleeve on the shaft, and a seal. I CAN see that their solution was affordable, a bearing and spring that cost pennies. But jeez, no seal to speak of? They did use some kind of rubberized goo that appears to have degraded in short order to cover the outside of the bearing.

And, from what I've seen of these old columns ... I'd bet in 90% of them the steering shaft is just spinning inside the inner race on both upper and lower bearings ... making it effectively a bushing. It was doing that on both upper and lower bearings on both my columns ... and they felt just fine from the steering wheel.

I enjoy this stuff ... I realize that vast majority of people don't care, but I'd sit in a bar and discuss something like this for an hour :)

I agree it's interesting to guess at material and design decisions made decades ago. Sadly, I was helping make those kinds of decisions starting in 1976 so maybe I can sprinkle some distorted memories onto my guesses. I never worked in automotive nor any other "outdoor" equipment so assume my guesses came from that barstool.

I have never seen an automated polymer selector, but I expect some of the major suppliers will come close on their web sites. Here's a 2-second Bing search blurby overview link that might point to sources of real info:

http://www.tpacomponents.com/uploads/pdf/en/0205_EN.pdf

You can probably find many more like this.

Material selection in most commercial products is about cost, then cost, and finally cost. For any part, the "engineering requirements" are set first and then it's easy to compare prices for design, material, fabrication, shipping, and assembly options. Design engineers can quantify required stress and strain. Lowest cost to meet requirements wins until there is uncertainty. Reliability requirements are usually more uncertain than any so the focus turns to consequences of failure. How would you life-test a steering column without really knowing the contaminants? The consequences of failure under warranty and/or safety implications would probably over-rule total cheap and justify spending a little more to avoid failures. A 20-year history of field success with ball bearings in this application would probably sway decisions in 1968.

This application is not demanding as you have commented. There is really nothing for the bearing to do but allow the shaft to spin. The loads are small, the tolerances are crude, and even the friction requirements are not demanding. The rpm is near zero so there is no real care about "typical" bearing design criteria like friction, runout, fatique, lubricant loss, noise, etc. You might argue squeaking or grinding could be bad.

I'll stick with a cheap ball bearing being chosen because it was perceived low risk for failure, was easy to source and assemble, and would tolerate a lot of unknown and unpredictable abuse. It might not continue to roll smooth over its "design life" but it was unlikely to bind up, would not dissolve, would not get brittle or fall apart. Even if the bearing dried up, got looser, or locked up from corrosion, the column would probably still function and nobody gets hurt.



Note: if the bushing swells from absorbing water or oil, the ID will expand so you don't need more clearance to tolerate this. This used to be a common "interview question" for new hires. It's not intuitively obvious so takes some thinking!

You know, no matter how many times I heat something up to increase the ID I still instinctively think a donut hole will get smaller if the donut gets bigger :)

And many years ago we covered that in class quite thoroughly, unfold the donut, calculate the linear expansion of length and cross section ... put it back together ... the hole is larger.

Thanks for the insights into product design ... in my world everything would have been every expensive but worked very well :)

BTW ... how close do you think I could come to identifying a type of plastic based on density? I know some might have fillers etc. but this would be more of a go, no-go test for UHMW polyethylene, PTFE, Delrin, Nylon etc.

Density worked. Took some measurements, did some weighing .. all my materials came out to the expected products within about 1% error.

Lots of UHMW as expected, some PTFE, and couple of 1/2" thick 4" wide, 18" long sheets of Delrin, and one nice 12" x 6" x 1/2" sheet of Ketron Peek. Surprised, about $1000 worth of exotic plastics (at McMaster prices) .... most of that stuff came from people that donated it cause they know I make a lot of projects, or scrap that I picked up at auctions.

Already laminated the density chart to go in my shop info binder :)

Shame the Delrin is in 1/2" sheets, would be a pain to machine into bushing.

Good work! Glad it helped you sort your stuff.

Which way are you leaning?

IMO, any of those would probably work fine but I'd go with stronger/tougher because of the probable dirt and dust.

Delrin is a standard "go-to" for bearing surfaces but you were concerned about temperature. I think it would be OK personally but the PTFE and PEEK will definitely be more heat-proof. The PTFE is super slippery, inert, and temp-stable but I'm not sure how it would behave coated with sand.

The PEEK is high-tech. I'll bet it was expensive! It probably would be best for a bearing if carbon- or even PTFE-filled but even unfilled PEEK should be "slippery enough" for your bushing. PEEK may "out-wear" the other options if dirt is present as it is super tough. PPS is a similar material and I remember it being VERY wear resistant.

Thanks for sharing this latest project.

Mike

I think I'm going to try the Delrin ... I'm thinking with the 1" steel shaft it in it's unlikely to hit 180 degrees .. if it did it probably means something is on fire :)

Looking forward to machining it, ordered a 1 5/8 OD rod. Still might try to come up with some kind of seal for it, there are thousands of 1" seals out there.

Thanks again for the suggestions.

I am a little late seeing this thread.

Johnny, I have a few pieces of varied types of plastic pieces some rounds and some bars left over from past and repeat jobs that may work well for your project. If any of these pieces will work better than the materials you have on hand I will contribute to the effort.

Attachment 584877

IRT Heat and Delrin.
Quite a few aftermarket upper A Arms using Delrin bushings located adjacent to the exhaust manifolds.
Just sayin'

Dmorg ... hold on to that large OD stuff, it's got to be close to the cost of silver by weight. Appreciate the offer but I think I'm all set.

OG, I think you are correct, I don't think I've ever reached into an engine compartment and had any piece of metal except the engine and the radiator burn me.

Got in some Nylon 6/6 MDS filled today ... jeez that stuff is hard. I'm going to have a nice collection of materials to make ... you know ... whatever :)

Final product on the far right. Jeez, this Delrin is like machining metal that isn't metal, like if your most cutest and nicest little sister was metal, that's the way it treats you.

Makes pretty manageable swarf compared to most plastics, easily machines with carbide inserts, starting with large OD drills no problem with pecking and some WD40, surface finish is super nice, and I could easily take off 0.001" at a time unlike some plastics that want you to take more of a bite if using anything other than razor sharp HSS.

Also more dimensionally stable, doesn't distort while machining, chuck doesn't distort it much (assuming you don't over tighten). I perused a few forums for tips on machining it, and more than one person said it's their favorite material to machine and if at all possible to make something out of Delrin instead of metal that's what they'll do.

Below ... OEM bearing, UHMW Polyethylene and Delrin on the right.

https://forums.maxperformanceinc.com...8&d=1646128819

Interesting. I thought Delrin was always white. Machining is just part of my job though. I'm not a journeyman. We mainly use UHMW and Nylatron here. See Delrin sometimes. Looks good though!

According to McMaster the only difference is that white is FDA approved and meets ANSI 61 (no lead) specs. I assume they offer it in black as solely an aesthetics consideration.

Did some more reading up on it and it comes highly recommend for industrial environments, oils etc. with temp limits being it's only drawback.

Can't wait to come up with something else to make with it. Look forward to trying it out on the milling machine.

Johnny,

Another task completed and well done. Thanks for sharing.

Delrin is a trade name of DuPont "likely the largest manufacturer" and is an Acetal Copolymer.

Natural and Black colors are the most common but there are a few other colors available.


Dave