VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1937-1945 Torque Tube, Okie Bushing

Hi Guys, I have a 1940 Special deluxe that I'm in the process of replacing the propeller shaft front bushing. I've purchased an Okie bushing from Chevs of the 40s'. When I go to install the Okie I noticed this is an extremely tight fit over the splined section of the shat, this is even before it reaches the Torque tube. Is this normal? It is so tight I would need to drive it on with a hammer. I dont want to drive it on and then find I've screwed up the Okie and the shaft somehow. How far in do the splined section of the shaft reach?, Is it possible that the shaft is a tiny bit smaller after the splined section?. Hope I'm clear on this. Thanks

Never heard of the inside being too tight. Have heard of the outside being too tight several times. Watch this and you will see.

That is a good video.

Okay I ended up taking a file and lightly filed the splines on the shaft. After that the bushing slid in. From there I had another problem. The bushing would only go in for about 1.5" into the torque tube. After trying to hammer it in I noticed the knurled part of the Okie seemed to be to large. I filed the knurled part down a bit and got it to go in. So all well in the end. Thanks for the input guys.

That is a good video. I was glad to see his work to analyze the sizing issues. There have been numerous posts about how hard it is to install the Oakie bushing.

There are a few questions I have after watching it.

I did not see him remove the dowel pin before he pulled the original bushing. Did I miss that step or is that not necessary?

Can you use that puller to remove the original bushing and seal? He called it an Oakie bushing puller.

There have been other posts in Chat that state you simply drive the new Oakie bushing into the tube and it pushes the old bushing and seal out of the way further down the tube. Are there problems with that method?

The tool should work for both though often the original is simply shoved deeper by the Oakie being pounded in. I got a tool by accident and have played with it a bit and looks like it will remove the original.

I believe there is only one dowel pin and it is closer to the rear bushing near the pinion on the earlier years like our 1937/8. At some point there IS indeed a front dowel pin as well - maybe around 1940/1 and newer?

I plan on stripping mine completely while everything is apart so will try to document with pictures as the torque tube is at least a partial mystery to most people. I NEED to see this whole darn thing apart to know exactly what is in there and where it is. The different years and posts get tangled up in my mind.

Hi Tim,

I agree that this one of those areas that after you see it once it is obvious. Based on what I see and read in the parts book and shop manual the original design uses a separate bushing and seal. I can see how the Oakie makes that repair a lot easier

I assume that you need to drill out the dowel pin. Which looks like it is an awkward position when the axle is in the vehicle.

I found instructions for the Oakie bushing and checked the service manual. Indeed there is a dowel pin staked in place that secures the front bushing. The instructions state to remove the dowel pin, punch out the old bushing, lube up the new oakie bushing and drive it in.

I know I have seen many recommendations that if you cannot, or choose not to remove the old bushing, to just pound the old bushing further down inside once the oakie bottoms on the old bushing.

The new oakie may or may not need the dowel pin. If it's a tight fit then no dowel pin needed. If the oakie is loose. then the dowel pin is reused and staked.

I have gathered some NOS front and rear bushings with seals since the seal is easily found new. I have some Oakies too but the seals are old and I don't trust them due to the difficult location but from what I've read, the seals for the oakies are an odd size though I have not tried to source them yet

Mine had the original bushings in the tube. I had to drill out the dowel on the front bushing, from there (used a 5/16"drillbit) I used a small punch to drive the bushing out a bit, took awhile, but I got it out enough where I could grab it with pliers and get it out. The dowel for the back bushing was about an inch past the length of the Oakie, so I didn't touch it. I had the same problem as the guy in the video. Goes in a certain amount then stops. He had access to a lathe, made things easier. I just used a file and managed to remove enough of the knurled part that I could drive it in. Once in, it sits in front of the original rear bushing and seal. I was stressing for awhile but its in good and tight. I'm happy with it.

Great thread! It is helping me better understand what at first glance looks simple. I may need to deal with this over the winter when I replace the clutch in my ”˜37. Right now there are no indications that the seal is leaking and no vibration from the u-joint.

Here go some more questions and comments.

In the video, is he removing an old Oakie bushing or the original front bushing?

Based on what I read in the shop manual about the only way to remove the rear seal and bushing is to remove the complete differential. Then use a really long punch to drive them out from the rear. There is apparently a seat or stop in the tube that controls the depth of the seal and bushing. That would explain why it is so difficult to drive them further to the rear when an Oakie is installed.

I cannot find a part number for the rear bushing in the 1941 Master Parts list. Did they not offer it as a service part?

I assume that the inside diameter of the front bushing fits over the outside diameter of the rear yoke of the u-joint. So it is a thinner wall bushing than the rear one. The rear bushing runs on the outside diameter of the shaft so it is a thicker wall bushing. This means that the dowel pins have to be fairly short. You do not want to drill through the bushings when making the hole in them. In the shop manual they tell you to install an arbor or u-joint yoke so you do not collapse the front bushing when peening the dowel pin in place. That also means the dowel pin has to be soft material, not a hardened dowel pin.

My analysis is that the Oakie bushing does not appear to be as long as the distance to the original rear bushing and seal. So the rear bushing and new seal in the Oakie are running on a different part of the shaft. That is probably good in case the old seal has cut a groove in the shaft.

Wilson’s use of a file to help reduce the OD at the rear should work as long as you remove material uniformly. It should center well enough to seal.

In the video he already had an Oakie installed. The original factory bushing is not that big - maybe just over 1-1.5" long.

The rear bushing is shown further back - much closer to the pinion end of the shaft so a whole lot of work. People do pound the original bushing back further with the Oakie without removing it. I asked Gene whether I should replace the original and then also add an Oakie for double seal protection and he sad no, just use one. I'm sure my bushings are GM but couldn't find my pictures of them. Got them on Ebay.

I'm changing my 4.22 to 3.73 so will get to witness where this is eventually as my complete 3rd member is in the middle of my garage but only partially disassembled and the thick layer of gunge makes it hard to picture things. Might finish disassembly in the next couple months. Maybe sooner now that equiring minds want to know lol...

I suspect you are correct about the seal dimensions and how they compare. I'll have to look and compare sometime.

I'd be tempted to have a machine shop turn the diameter of the Oakie down if needed to ensure no leak around it. I suppose if really close but tight, a belt sander mounted in a vice could allow you to manually spin the Oakie against the belt sander and reduce the diameter evenly or just chamfer it a bit more.

Good to hear that you will be installing a 3.73 gear set. I really like the way my car runs with them. 60 to 65 mph is ok, 55 to 60 is very comfortable.

I agree that I would have the Oakie turned if size was a concern and I had time to get it done.

I still wonder how the rear bushing gets pushed further to the rear if there is a step or stop machined into the ID of the tube. It seems like that would collapse the rear bushing and make it bind on the shaft.

Your exploration will be interesting.

My understanding is that the rear bushing is at the very rear end of the driveshaft so several feet from the front bushing so an oakie should be nowhere near it. Now it's bugging me lol so I'll have to tear into it this week!!!

Ya 4.22 gears would be fantastic around town but we go everywhere here by highway and even 60 is obstructing traffic...

Hey, Tim. Actually the two OE bushings are both at the front of the torque tube. The forward OE bushing supports the u-joint rear yoke. The "rear" bushing supports the front of the driveshaft. To insert an Okie busing, the forward stock bushing is pulled, and then when inserted, the Okie bushing pushes the "rear" bushing and OE seal back into the torque tube a bit, and the Okie bushing's rearward bushing and seal ride on a "fresh" section of the driveshaft that is forward of the old bushing. Borrowed this image from Chev's of the 40s, who borrowed this from the original National instructions for the Okie bushing.

Doug

Thanks for the pic!

Interesting as it's still hard to tell from this and other pictures as they are not to scale and show both ends of the shaft making the shaft look only a foot long lol...
Gonna rip mine apart shortly as it's bugging me but suspect you are correct. It's odd that it's called the rear bushing and they take the time in pictures to shorten the shaft and show it at the rear. Just odd proportions I suppose...

Tim, what is shown in the instruction sheet and other pictures is only the front 8/9 or so inches of the propeller shaft housing that is stepped down in size. Inside that stepped down part is where the front bushing and a few inches back of that is the rear bushing/seal. Both/all in the first 8/9 or so inches of the shaft before it enlarges in diameter and continues to the rear end.

"I have gathered some NOS front and rear bushings with seals since the seal is easily found new. I have some Oakies too but the seals are old and I don't trust them due to the difficult location but from what I've read, the seals for the oakies are an odd size though I have not tried to source them yet[/quote]"


I was thinking the same thing about my nors Oakie seal. I came up with SKF 9894 and then decided National 471270 was closer. Mine is a 39 but my Oakie says 37-39 so they may be the same. Anyway it may save some time if it is the same. Let me know if you come up with a different part number. I haven't pulled the old seal to try the new one.

Dave

The Oakie seal is not as far back as the original and thus rides on an unused area of the drive shaft. The second bushing is around the driveshaft and the front bushing supports the yoke for the universal. They are different diameters. I had to use a lot of force to install mine. I used an old yoke to drive it in. The pounding damaged the old gasket between my torque tube and the rearend case. So now I have a leak there.

Great info ending up on this post like Rusty said!

My entire rear end is in my way in the middle of my garage floor so will dismantle it shortly and post pictures. Will dig out and compare original front, rear and Oakie bushings and post those too. I had planned on posting when I rebuild/reassemble it but details now would be nice...

Ruscar: All 3 torque tubes I have do not have a taper - they are straight with the same diameter from the threaded ball coupling to the "pumpkin" so maybe pictures are "generic" to cover a few years. But ya, that taper in the pictures is what makes the location of the rear seal look further back...

This is really helping me understand the design. I wondered how the original bushing and seal could be driven to the rear if there is a step or stop in the tube. Now it makes sense knowing that the Oakie bushing is slight shorter. It really makes sense to have the new bushing and seal run on a different unused portion of the shaft.

The driveshaft tube in my ”˜37 is the same shape as the one in Russell’s picture. The smaller portion is at the front. One difference is that the breather vent is on top of the tube about half way between the front end and where it fits into the differential housing.

The rear end of the drive shaft has a splined coupling which fits over the spline on the front of the pinion shaft. So the rear of the drive shaft is actually supported by the front bearing for the pinion shaft. Those 2 bushings we are calling front and rear are really pretty close together.

Everyone, I was able to drill out the dowel (It is only for the front bushing) and believe it or not, I was able to just push it forward with a small pick. I couldn't believe how easy it was. It was the original bushing. The Okie I got had the same issue from the video and I was able to grind the treaded part that is higher than the rest of the bushing and do the finish work by hand. I couldn't find a machine shop who would adjust it for me. Yes as most of you said, you just push the Okie in and I used a deep socket and drove it in. Worked great. It's tight so no need for a dowel.

Thanks for the follow-up post. It really helps to know the results.

Tim,
If you are going to install conventional bushings, I believe it is challenging find a modern seal with the proper ID and OD. I think some folks made up a small bushing to make a modern seal work.

The modern seals are easy to find at the usual suppliers for the original bushing but harder to find for the Oakie sized bushings.

I think you are correct that there has been a sizing problem with one or both of the new size seals that people have found though likely details a few years old so suppliers may have changed.

I think I would prefer an Oakie as it positions the seal on a virgin portion of the shaft. I have NOS Oakies like you have in your parts stash and my concern is that the seals are very old - likely 50-60+ years. I would prefer a brand new (north american) seal than a decades old one. But maybe an old seal is just fine too.

Have to see when I get there. I just like to compare the original to the replacements more for curiosity. I am off work for a few days so really hoping to rip apart my torque tube and give us all some pictures to discuss lol...

I agree with the preference to run a new seal rather than a “shelf-cured” 50+ year old one.

We know from experience that is a questionable practice with brake cylinders and hoses.