VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1916-1922 - Model 490 Drive shaft, ring and pinion gear, rear axle

In the end of July, 180 miles from home heading for a meet in the south of Sweden, the car suddenly lost driving.

The last week I have removed and disassembled the rear axle, the torque tube and the U-joint. I noticed this:

As I removed the torque tube, the pinion with bearing and a piece of the drive shaft stayed in the rear axle housing.



The drive shaft is broken at the place for the woodruff key for the pinion.

On next picture you can see the break on the other side of the drive shaft. The drive shaft lock nut (to the left of the thrust bearing) is not quite fixed. Although the drive shaft lock nut screw is fixed with two centre punch blows, it can be turned 5-6 mm (.02”).



The pinion is quite worn, with a couple of small fragments missing and also small cracks.



The ring gear seems to be more heavily worn, also with small fragments missing and a number of small cracks.



As I pressed on one of the axle shaft ends, the other end moved out 2 mm (.08”). I think there should be no play at all. The same play showed as I with a screwdriver through the oil filling hole pressed the differential and the axles from one side to the other. Adding to that I have noticed that the rear axle housing moves in the rear spring seats 1,5 mm (.06”) from side to side.

The U-joint is heavily worn.



The play is up to 3 mm (more than .1”). When I made a transmission overhaul five years ago I replaced the open bearings on the in- and outgoing axles with double sealed bearings, in order to minimize oil leakage from the transmission. I also made a hole in the U-joint ball retainer, in order to simplify manual lubrication of the U-joint. Maybe I haven’t lubricated enough.

I also noticed that the drive shaft bushing, in the front end of the torque tube, fell out without pulling as I held the torque tube vertically in order to take out the drive shaft. The play was approximately 0,15 mm (.006”). I thought that I should need a puller to get it out. Also the play between the drive shaft and the drive shaft bushing was approximately 0,15 mm (.006”).

Today I pulled the rear axle housing apart, in order to get a closer look at the ring.





I understand that I have quite a lot to, and I need good advice. This is the first time in my life (67 years) that I have disassembled a rear axle, differential and drive shaft.

I have good hope to get a used but OK drive shaft and U-joint. But I have a couple of questions, so far.

1. From the pictures and my description, do you have an idea of what started the wear that caused the drive shaft to break: The insufficient lubrication of the U-joint?The play in the axle shafts, by age? The drive shaft lock nut came loose? Other?
2. I understand that there is no reproduction of ring and pinion gear set for this model of Chevrolet (1922 490 and Superior series B and F, spiral bevel), and that it is almost impossible to find a set that is not heavily worn. What is the best option, considering that I want to drive the car as I’ve done so far, that is up to 3 000 miles a year, with day trips up to 500 miles. Use the originals, with their wear and tear? Use a ring that I have, in much better condition than the original, together with the original pinion, with its wear and tear? Buy a ring and pinion gear set for T-Ford from Snyder’s, as has Solan? Other?
3. If you have good experience of rebuilding with new reproduction ring and pinion gear set … what parts did you use and what is there to consider to make a good working rebuild?
4. Must I do something to handle the 1,5 mm (.06”) play of the rear axle housing in the rear spring seats?
5. And of course: Any interesting reflections and good tips are welcome!

The links to the pictures above goes to my website, Our fine old cars . There you can find a lot of text and pictures about my Chevrolet, but the text is only partly in English. I intend to translate the rest too, but that may take some time.

Hi Larson, sorry to hear about your damage to the rear axle.

I do not think that the model T gears will fit onto the spiral propellor shaft , as the two have different part numbers in the 1924 Parts book. So you may want to check with Snyders on diameters and bore sizes in the pinion gear before you lay out your money for those parts.
Maybe you should take your gears down to a differential place to see if they can repair the damaged tooth and lap it back in. Only my thoughts. Maybe they cannot repair them.

I think i would try to save the universal joint, maybe you can have it hard faced brazed , or welded and rebored to remove the play / wear.

You may also have to have a new propellor shaft machined from modern material, which is also going to be expensive.
I do not see an easy option ,except to swap to a complete straght cut rear axle assembly , and they are not easy to find.

Hi Jack
I am afraid you are right about the model T pinion gear will not fit propeller shaft for spiral tooth bevel ring gear, part # 24040, so I'll check.

Today I noticed what may be the reason that the axle slides in the axle housing. If you look at the picture above on the differential case I think you can see the edges of two differential end thrust washers, part # H-117. But shouldn't there be at least one differential thrust bearings, part # H-391, between those two washers? In my Repair Manual (1918-1924) there is a picture showing three "thrust washers", two of them with two small holes like H-177, and one in between without holes, like H-391. I think that makes sense. My Parts List (1924) states numbers of thrust bearings that I dont't really understand.

When i was looking at the Snyders online catalogue, i could not find any model T ford propeller shafts, so i could not work out if they have a long torque tube the same as the 490. All of the other model T parts differential parts will fit in the 490 including the axles. I also saw that they make a new ( and expensive) floating rear axle hubs, which prevent the loss of a wheel if you break an axle.

I found the T-ford Drive Shaft i Snyder's catalogue, but it has a square end for the U-Joint.

From a 490-owner in UK I have recieved this picture.



The axle end is damaged, it has twisted as you can se on the slot for the woodruff key. He had a shop to cut off approximately 300 mm av the shaft, make a new shaft end and weld it to the drive shaft. This was five years ago and he writes that he after that has driven several thousand miles.

I think it sounds like a good idea. Now I'm going to ask Gary Wallace if it is possible to use the ring and pininon gear set that he offers for Superior models 1925-29.

Contact Bill @ Billy Possum (aka CP Automotive) http://www.billypossum.com/C&P_Catalog/C&P_Catalog_rev_031225.htm. They make the later drive shafts (aka propeller shaft) so might be able to make a few for the earlier cars or modify a later one to work.

Billy possums website is listing the 1925 to 1928 driveshaft as temporarily out of stock. They may be producing them now so it would be a good time to give them a ring as they may be interested in an earlier sample to copy.

I have heard of a fellow near here who makes ring & pinion gears for various rigs. I think he made one for a brass era car last year. Probably not cheap, but I can try to get his phone number or e-mail after the weekend if you would like. We are on the West coast of the US.

What does the forward end of your pinion gear look like? Is the pinion only as thick as the gear, itself, or is there a cylindrical portion that protrudes farther forward?
Also, what is the gear ratio?

Mike

The forward end of the pinion gear has a "cylindrical portion" (collar? tube?) on wich the pinion bearing is pressed. The bearing width and the collar length is 21 mm (13/16"). The gear ratio is 1:3,67, with nine teeth on the pinion gear and 33 teeth on the ring gear.

I successfully installed the Ford Model T ring and pinion in my 1922 differential. I had to have a new drive shaft made to fit the taper of the Ford pinion. As the Ford gears are not beveled there was a certain amount of noise from the straight gears. I never drove the car much with this setup, so I can not attest to the durability of the setup. I then was able to find an intact 490 differential at an auction that I purchased for $10.00 and swapped out the Ford/Chevy rear.
I might add that there was no problem with clearance with the Ford gears in the differential case. I did find a outfit in Washington state of which I can not recall the name that would produce the 490 ring and pinion but at a cost of around $2500 and this has been a few years ago.
Good look with your project.

Hi GMong

Thank you! Do you remember how you fixed a seat for the pinion bearing? Just a steel bushing? Did you first press the bearing on the bushing and then the bushing (with bearing) on the drive shaft?

I noticed that this was your first post. If you are new on this forum I must say I am really happy that you have joined it now. In my opinion it is a gold mine.

Now I know that it is not possible to use the ring and pinion gears for 1925-1928 models on my 1922 490. Most of the measures differ from 1922-24 ring and pinion. Since it seems almost impossible to find a ring and pinion set for 1922-1924 models, I can see no other way than to make a new propeller shaft end and make it fit the Ford T pinion and ring.

Larsson , let us know how you get on with making the new drive shaft section or splicing a T model section (new or used) onto the 490 drive shaft front section. We can all learn lots from your experience.

Of course, but it may take some time.
And thank you again for measures of the 1925-1928 ring and pinion gears.

Now I have cleaned up most of the parts, and new questions comes up.

But first, a picture of the “Differential thrust bearing”.



This bearing is from a spare rear axle that I bought five years ago. I hope you can see all the cracks, especially at the edge.

In my car there was no such bearing at all. As I understand most of it was grinded to small fragments and followed the oil as I drained it. The oil was maybe a little more gray-tone than it use to be. The remaining fragments showed up as I now cleaned the roller bearings, the ball bearings and the differential case. The bottom of the can that I use for cleaning was covered with dark grey slug.

In the slug I could also see a lot of small steel fragments (magnetic; the thrust bearing stuff is not magnetic). The steel fragments comes from different places: The damages on the ring and pinion gears, as you can see on pictures above. And from the spacers situated between the inner roller bearings and the differential case.

The picture below shows the two spacers from my car, and one from the spare axle, to the right.



The edges has been heavily worn, on the left spacer about 3 millimetres (.118”) are gone, on the right spacer 1 mm (.039”).

I don’t know for how many miles these steel fragments has circulated. So here are my questions.

I guess I ought to buy new front and rear ball bearings for the drive shaft. Or?

How do I know if I ought to search for new inner roller bearings and new races? The races looks fine, but how do I know if they are heavily but evenly worn?

The left axle shaft seems to be worn where the inner roll bearing has raced.



There are visible pores. The diameter is 26,8 mmm (1.055”), that is 0,2 mm (.008”) less than the machined part of the axle on both sides. At the edge (crest?) to the right the diameter is 27,5 mm (1.083”)

Does any of you know recommendable tolerances? Does any of you know if the roller bearings and races for Ford T fits?

Should I consider new axle shafts? Does the axle shafts made for Ford T fits?

And what about the differential thrust ball bearing, fitted on the left side of the differential case: Shall I put it back, or is it safer to replace it with two steel axial thrust washers and one bronze thrust washer, as on the right side?

A friend of mine recommends that I shall give the worn and damaged pinion and my extra ring gear a chance, but I am not convinced. My wife has taken a couple of close up pictures of the ring and pinion gears. Anyone willing to give an opinion?

Pinion gear from my car (all teeth are more or less damaged)



Ring gear from my car (all teeth are more or less damaged)



Ring gear from the spare axle.



What do you think is the best option, considering that I want to drive the car as I’ve done so far, that is up to 3 000 miles a year, with day trips up to 500 miles.

I don't have any suggestions, but want to thank you for posting such detailed appends and pictures. They are fascinating!!

Cheers, Dean

Larsson, I would not try to use the ring gear and pinion shown in the pictures with the obvious cracks. As this metal heats up with use the pinion will come apart as mine did. I had a new set machined in a machine shop and it is working perfectly. Spend the money, repair it correctly, and you will be glad you did.
thutch7244 Texas

After considering advices from you and others I have decided to make an enquiry to try to find out if there is enough demand to place an order for a small series of new production of ring and gear sets. Among other steps I intend to open a new topic on this forum.

I understand that it may take some time, maybe years. Therefore, in the short run I will give my pinion gear another chance. If I can have it fit with the ring gear from my extra axle (shims, testing with preussian blue or like ...) I'll try that. If not I'll try with the original ring gear. And hope that it will last for one season or two without further damage.

Please wish me luck!

Is there anything you need besides the ring gear and pinion? I have a 1922 rolling chassis with radiator, motor, transmission, drive shaft, springs, axle assemblies,and wheels.I have been wanting to sell this as a unit for $1,000, but I would consider parting it out, if I can find a buyer for some of the other parts. Ed

Hi Ed
I can be interested. I'll send you a private message, so please check "My Stuff". Or you can send me an email, you'll find my adress if you click on "Larsson" to the left, and then "View profile".

Now I have a plan for repair of drive shaft, differential and rear axle. If you have any comments, please make a post.

I have studied “The Model T Ford Front and Rear Axles”, and found it most interesting. Not only the detailed description of the repairing and restoring, but also information on measures and tolerances. In the introduction the author states that the design was reliable, but had “one weakness, the Babbit thrust washers”.

Since the 490s had the same lousy thrust bearing, I hope that my thread will make other 490-drivers check their rear axle and … if needed … replace the original thrust washer with a new production bearing made of bronze.

After a new inspection of the rear axle housings I noticed excessive wear also in the bearing inner race, especially on the left side.



My plan is to ask a shop to grind the axle shafts where the inner roller bearings race … see picture above -, and to make new, over dimension races for the axle housings.

At the most worn area the axle diameter was 26,75 mm (1.053”). I guess it should be 26,97 mm (1.062”), the same as Ford T. Does anyone know for sure? According to the Ford manual “one or two thousands wear is acceptable”.

On my left axle I guess they must grind at least 0,4-0,5 mm (.016-.020”), probably more, to get rid of all pits.

As to the races, the left one is most worn … on the lower third. The upper half seems OK, but I do not know what the race should measure. Does anyone know?

And how long shall the “Rear Axle Shaft Bearing Spacer” be? (Part # H134). My spacers are badly worn, as you can see on a picture above. I have two extra, which measure 8,3 mm (.327”). Are these correct, or are they worn too?

Now to the plan for ring and pinion gear and drive shaft.

After a tip I found that Vintage Auto Parts offered pinion gear for “1916-1924 Chevrolet, 490, Superior, Passenger & 1/2 ton truck”. As I was aware of the differences between the earlier 490s and the 1922-1924 490s and Superiors I asked them to confirm that the pinion had the shoulder for the pinion ball bearing. There was in some way a misunderstanding, so I received two pinion gears with the correct spiral cut tooth (nine teeth) that fits my ring gear … but without the shoulder for the pinion ball bearing! Neither does the tapered hole fit the 1922 drive shaft end.



I guess that these pinion gears are part of a conversion set, in Parts List 1924 with number 24102, “Parts Necessary to Convert Old Type of Rear Axle to New Type Using Spiral Pinion and Ring Gear” (page 23). Or that they were made as replacement for those who were converted. Anyone who knows?

Anyway, my plan is to ask a shop to repair my broken drive shaft by making a new end that fits the pinion gear without shoulder. To replace the shoulder I plan to ask them to make a sleeve that can be pressed to the drive shaft and on which I can press the ball bearing. I guess it could be a good idea if the shop makes a notch in the sleeve to engage the pinion gear woodruff key, which I guess should end approximately 2-3 mm (.1”) in front of the pinion gear. Does I make myself clear? Does it seem a good idea?

Lots of questions yes. But is there a Chevrolet repair manual, an article in G&D or a thread in this forum that I have missed and that gives good advice and answers to my questions?

I was just reading back though these posts , and the picture you have posted of the Left hand axle with the wear in the bearing area (post # 263951) , looks to be a new machined replacement. I wonder if it was a previous issue with your rear axle, and the previous owner had a new one machined. Maybe the axle was never case hardnened, and they just installed it to "put the car back on the road" How does the LH axle compare physically with the RH axle.

Thanks for input, Jack.
The LH axle looks identical to the RH, except that it is less worn in the bearing area: the RH axle has pores/pittings the whole length of the roller bearing, while the RH is pitted only about one inch, the part near to the axle gear. The inner machined part is near 200 mm (8"). I don't know what original axle shafts looks like. There is a picture in the Chevrolet Repair Manual 1918-1924 that indicates a machined part of that length. So does a picture in the Ford T manual too.

Any comments on my plan? Do you think it could be a better idea to check if the new produced axle shafts for Ford T easily can be machined to fit the 490? These shafts are 36 mm (1.22") longer.

The information i recieved ( from Twin4) was that the all model T components fitted the 490 rear axle with straight cut gears . With the exception of the different driveshaft. I would suggest that you remove the bearings in the housing , and then compare the dimensions with those of the model t. from Snyders, to see if the they are compatible. I would assume that they would be a special case hardened inside surface also.

http://www.snydersantiqueauto.com/modeltparts/rearaxle

http://www.snydersantiqueauto.com/uploads/T2508AOT2508AI-10294.pdf