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.

So one aspect that bothers me is the situation where after installing an Oakie, the original rearmost bushing is running dry. You would think that would cause a problem

Here is my theory which I hope others will challenge.

The original rear bushing is irrelevant after the Oakie is installed. There is a rear bushing in the Oakie which supports the drive shaft. It is a new bushing running on an unworn part of the shaft so it has less clearance than between the old bushing and driveshaft. So having no lubricant to the original rear bushing does not create any problems.

Agreed. Plus I figure no seal is perfect and some lube will inevitably migrate from either end along with any lube already in the tube from it's first 70+ years of service...

OK, I finally attacked my torque tube. Almost didn't want to take it apart as the propeller shaft turned so smoothly with no play or roughness but I will rebuild this with a 3.73 since my original is 4.22. Plus we ALL want to see what is inside these darn things!

I will be posting a series of photos. Maybe wait until I get these ALL posted before commenting so they are all in sequence.

This series of pictures shows the torque tube by itself on axle stands and "Special Tool A" - some local brew. I simply removed the axle by removing the perimeter bolts and wiggling and the ring/axle assemble pulled free from the pinion and torque tube.

I was mistaken that there was no taper in any of my three torque tubes (ya I collect stuff lol). There is a taper but I had each wrapped in garbage bags and taped so the taper was not obvious. daaaa....

These photos show the shaft, tube and the bushing removal tool. the tool is cheaply made but works with care. It is shaped like a penis and is driven in past the bushing, then the metal tab is pounded in to expand the end so the bushing can be pulled. Tightening the bolt pushes the tool away from the splined shaft bringing the bushing with it.

The dowel is very short and stubby. I centre punched it and then drilled with a couple sized bits until it spun then dug it out with a small screwdriver and pliers. It would really suck to try and remove this dowel pin while this assembly was in a car, What took me 5 minutes I could see taking hours and much blood (and beer) to accomplish.

You can clearly see the both the front and rear dowels and how they are staked.

More pictures coming

Hard working with thumbnails and oldish eyes. Will post the pictures and then go back and add comments so bear with me!

Here you can see me pulling the front bushing out. It has a hollow in it for the dowel. The replacement bushing does not have this hollow. There is only a bushing. There is no seal of any kind. This is the original bushing.

I slid one of my Oakie bushings inside just for fun. It fit fine up until the last 3/8" section that was thicker, but would certainly pound into place. The genuine Oakie will pound inside the tube and be approximately 1/4" from the rear bushing, leaving the rear bushing untouched. The front bushing MUST be removed before an Oakie is installed as the original front bushing and Oakie are longer than the distance to the rear bushing and the rear bushing is held with a staked dowel.

My pictures then shift to the differential end of the torque tube. I remove the 3 set screw/bolts and then simply hammered the shaft from the front side and the whole assembly (propeller shaft and pinion gear/bearings/shims) came free and could be pulled out.

The service manual mentioned drilling a rivet out before removing the pinion but I did not see a need. There are 4 rivets holding the torque tube to the differential case. They are staggered and each protrudes inside the tube but do not contact the propeller shaft or bearings so not sure what rivet the manual is referring to. Edit: Later realized the rivet mentioned is the one holding the pinion shaft onto the propeller shaft.

Last batch of pictures. Give me a bit to type details.

Had to include an ugly mugshot of the photographer. Beard is still dyed purple at the request of my 18yo daughter who finished her cancer treatment yesterday. 6 months ago she was a full paraplegic with a stage 4 diagnosis and 5 tumors. Several surgeries including opening her spine to scrape tumor off the nerves, Chemo and lots of medical attention and she is almost back to 100% besides having less hair then me lol. Been a long year with Covid too so there's a reason this car project has been sitting still since April. This site and the people on it have kept me sane.

I compared the positions of the original style bushings beside the Oakie. The rear bushing can indeed be left in place as the Oakie is about 1/4" shorter. Strangely the replacement rear bushing is a smaller diameter than the Oakie rear bushing. The Oakie rear bushing is way bigger than the shaft so may be meant to cover various years. It was too hard to measure the original rear bushing (the original LOOKS smaller diameter than the Oakie) which I left in place as I haven't decided whether to replace it as I don't want a leak from the dowel hole.

Edit: It was later determined that there is a rubber spring backed seal rearward of the rear bushing. Will remove and post pictures later.

There was zero fluid inside my torque tube and the propeller shaft had some minor rust so my bushings have done their job for the 63,000 miles on the car. The car is a 1938 Canadian Coupe.

The Oakie seal is labelled "M101" so hoping a modern one is available. I have 3 Oakies and they all use the same seal, They are quite old. I was very surprised that there was no seal originally within the torque tube, The propeller shaft was dry as I mentioned above so the bushings were obviously enough to hold back fluid. The splined shaft does have some ridges visible in some pictures. Enough to snag with a fingernail. I assume this is wear from rubbing on the bushing.

I also showed a picturred of my 3.73 pinion so we could all see where the dowel pin? holds the propeller shaft to the actual pinion.

Let me know if you would like any particular pictures.

Finally think I've got all relevant pictures posted.

Still surprised there was no original seal in the torque tube, only the front and rear bushings. Have to check the parts manual sometime but there really isn't room at the end of the splined shaft closest to the ujoint and you can see in the pictures that the original bushing is almost flush with the torque tube so the only place for a seal would be between the front and rear bushings and there is nothing in my tube. Edit: found a rubber spring backed seal rearward of the rear bushing. Will post pictures later.

Added one final picture showing the side by side of the torque tube with dowel holes, propeller shaft, original bushings and the Oakie bushing.

Tim, great set of photos. Couple notes... there should have been a seal just rearward of the rear bushing. They were cork, so prone to disintegrating. Their purpose was to keep the transmission fluid from migrating to the rear end. My '53 Bel Air (Powerglide) had that seal disintegrate some time in the distant past. Not good to have ATF in the rear axle assembly, but when I took it apart, it was the cleanest differential I think I've ever seen. LOL.

You might want to consider going to 3.55:1 gears. My '53 cruises very nicely with that ratio, which was OE in the '50-'54 PG cars with torque tube drivetrain.

Cheers!

Doug

You made me look again Doug!!

I have seen the cork seals that go behind the rear bushing though I thought they went on trucks (at least around 1938 years). I suspect there are variations over the years and models...

My torque tube was clean inside so I dug out the Amazon inspection camera and low and behold, there is a rubber seal/spring on the backside of the rear bushing. Drat, I was hoping to not have to take that bushing out but now I have to get it into my hands.

Attached a picture I just found in the service manual (after I finished ripping things apart of course).

The 3.73 is a direct bolt-in for 1937-1939 cars as it was available in the USA built Masters. The 3.55 needs a fair amount of machine work for a 5% improvement as the later model car torque tubes are longer and the gear design is completely different. If I can fit a taller tire I can gain close to the 5% back if I need. If I couldn't go to a bolt-in 3.73, I would likely look at the 3.55. An overdrive would be nice to find as some guys really like the original 4.22 around town as it feels like a hotrod. But alas the 3.73 is soooo easy lol.

Found the rear seal with some searching. Has the small spring along the edge like I saw with my cheapo camera.

Attached a pic I found online. It cross references to National 50606 Seal

Gonna have to tear this out now that I've disturbed it. At least I finally know what's inside this pesky torque tube.

Great pictures and write up, thanks for posting. Check out National 471270 for a replacement for M101 and post what you think. I have this job ahead of me and your write up helps!

Prayers for your daughters full recovery.

Dave

I will pull the rear bushing and seal today so I have pictures of everything done. I'm tempted to make a new post eventually that is more organized and after I get other questions or question things myself - like where to get new new dowel pins. The usual vendors sell them but they are miles too long. Like to test replacement seals for fit and then post what works.

I have ordered the National 471270 seal Dave for replacement of the M101 on the Oakies, as well as a SKF 10632 for replacement of the rear bushing seal. Will see what they look like.

Attached is the service manual picture showing the line drawing of the pieces.

2nd picture are the actual pieces, including the rear bushing and rear seal. The seal is leather..

Pictures of the Oakie Bushing.

In placing it side by side with the original bushings, it offers more bearing surface than both the front and rear bushings and obviously has a seal. The rear bushing and seal appear to essentially replace the functionality of the original rear seal and bushing (even though they are normally left in place when installing an Oakie). The Oakie then provides a new bushing surface for the u-joint.

This one is dirty but shows enough detail to be useful. I positioned the Oakie in it's intended position in some previous photos so you can see the position relative to the original bushings and seal.

Tim,
That is good news about your daughter. I bought my 38 to celebrate surviving esophageal cancer in 2015.

What instructions do you have to shim your new assembly?

Great information and photos. Many thanks for sharing this level of detail.

Based on my first pass through the pictures it does look like what I expected. But it really helps to see the actual parts!

I agree that if you have the 3.73 it is it not worth all the effort to adapt the 3.55.

Not sure what you are referring to Fred. I suspect setting up the Ring and Pinion - that is much later! I just tore the torque tube apart since so many of us were questioning what was in there. The differential setup is a whole 'nother battle much later...

Sorry I didn’t mean to get ahead of you. Myself I tend to think through scenarios months ahead of time and go through all the steps in my mind. Anyways it sounds like you have a lot of spare parts! And thank you for showing us all the details up close!

Tim,
I have a copy of the Chevrolet Mechanics Repair Manual for 1937 38. It describes the use of a gear setting tool that measures the actual depth of the pinion. It appears that they didn’t document this procedure in future manuals. If you would like I can send you a copy of the article.

A friend of mine who is a mechanic and a machinist used this procedure on his early Ford. He initially used the standard process of going by the pattern but it resulted in a noisy rear end. He ended up measuring the pinion depth and corrected the problem.