VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1937-1945 1941 ball to tapered roller bearing conversion

Has anyone done this conversion to their 1941 Chevy front end?? I'm in process with the kit that Chevsofthe40s sells. The races are pressed in, new bearings packed and now having issues with the seal installation. It's a bit frustrating and I'm in the process of measuring up all the stack-up heights to try and figure out why the seal doesn't ride where it should. The rubber seal edge comes right up against the first machined lip on the bearing vs. being centered in the .220" smooth area before the machined lip(where it's supposed to ride). Chevsofthe40s say they have sold 100's of these kits and never had any problems. It's a pretty simple thing to install wheel seals.......until they don't fit and ride where they should. Just wondering if anyone has any ideas!?? I'll take some pictures to illustrate and post them up later tonight. Thanks in advance for input to this seemingly simple problem!!

I can't answer your question but I'm curious, what is the advantage of tapered roller bearings over the original ball bearings? I have never had a problem with the ball bearings.

I agree with Ed. I have driven ball bearing cars many 100,000's of miles in the last 60 years and can recall replacing only one bearing.

Same here. I have never replaced a ball bearing in any of my cars in the last 48 years.

Yep, I am not exactly sure of the mileage on my 37 but it has been in the family since 1956 and I've owned it since 1967 and as far as I know it has never had a wheel bearing replaced. I think it has about 130,000 miles on it and used to do some pretty severe duty back in the 50s and 60s.

Well I might as well throw my rope in at this one also. Got my truck just about from the original owners and talked to the guy that maintained it. At 56,000 miles in 60 years when I rebuilt the brakes the Ball Bearing Wheel Bearings were still in perfect condition.
Here are a couple of quotes that say it much better than I can:
“The purpose of a ball bearing is to reduce rotational friction and support radial and axial loads. It achieves this by using at least two races to contain the balls and transmit the loads through the balls. Usually one of the races is held fixed. As one of the bearing races rotates it causes the balls to rotate as well. Because the balls are rolling they have a much lower coefficient of friction than if two flat surfaces were rotating on each other.
Ball bearings tend to have lower load capacity for their size than other kinds of rolling-element bearings due to the smaller contact area between the balls and races. However, they can tolerate some misalignment of the inner and outer races.
Compared to other bearing types, the ball bearing is the least expensive, primarily because of the low cost of producing the balls used in the bearing.”
“Tapered roller bearings use conical rollers that run on conical races. Most roller bearings only take radial loads, but tapered roller bearings support both radial and axial loads, and generally can carry higher loads than ball bearings due to greater contact area. Taper roller bearings are used, for example, as the wheel bearings of most cars, trucks, buses, and so on. The downsides to this bearing is that due to manufacturing complexities, tapered roller bearings are usually more expensive than ball bearings; and additionally under heavy loads the tapered roller is like a wedge and bearing loads tend to try to eject the roller; the force from the collar which keeps the roller in the bearing adds to bearing friction compared to ball bearings.”
So balls were used back in the day mainly because they were inexpensive (bean counter influence) yet in the same breath they were perfectly adequate for the job at hand. Today with the higher vehicle cornering speeds and the better bite today’s tires get on the super highways the axial loads have increased. Also the cost of the tapered bearings is a lot closer to that of the ball bearings, so the tapered bearing has taken over as the standard for wheel bearings.
If the geometry of your hubs was engineered for the ball bearings and you decide to fit a different part then you become the engineer and must solve the inherent problems with the fit. I think that falls under the category of hot rodding unless the ball bearings are no longer available then it's necessary and called retrofitting.
Denny Graham
Sandwich, IL

Thanks guys for all the varying inputs. I was hoping that someone out there in the cyber Chevy world had already done this conversion and would have some input as to what I'm dealing with. The reason for the conversion to roller bearings was because the small outer ball bearings were starting to pit and flake. The tapered roller bearing kit was available and seemed like it would be a positive upgrade in a purely mechanical sense. According to 'Chevsofthe40s' they have sold hundreds of these tapered roller bearing kits and have never had anyone have problems with the seals. Here is the kit I'm dealing with; http://www.chevsofthe40s.com/detail/16111/Chevrolet_COMPLETE_FRONT_ROLLER_BEARING_CONVERSION.html .

I need to find out what is different about the hubs on this 1941 Chevrolet business coupe that the seals don't locate where they should. I didn't get around to taking pictures last night as the death of a friend's mother has been consuming a fair amount of time.

I'll take some pictures now and get them posted up. After seeing the pictures maybe someone will have some positive insight/input as to why the seals don't seat where they should on the sealing surface of the bearing(s). IF the seals just had more O.D. shoulder height where they seat in the hub to raise up point where the rubber seal contacts the bearing they would work as intended. Pictures soon.....

Here is some photo-documentation of bearing/seal situation. I hope these help explain the problem I'm up against.

First make sure that you have the races and bearings in the correct position. Next drive the seal in until it's flush with the hub. Put the wheel on and see it it will turn. If it does, you're probably okay. If it doesn't turn freely, then knock the whole mess out, put a wire through all the parts and hang it up on your garage wall as a reminder that you should ask here (Chatter II) before you go off on half-cock trying to get modernized when there is no need to.

Ball bearings are just fine in that old 41 coupe, I've been running them in 41s since 53. Properly maintained, the only time they will fail is when you jam (run) the keeper nut up too tight or way too loose. And, it'll take a lot of ignoring something wrong for even that to happen.

Roller bearings? Why do you think every other mission for 8th "U.S. Army" Air Force during WWII was to bomb ball bearing factories? For instance in those old war movies you never heard, "Listen up, men. Today our mission is fly unescorted through all the flack, ME 109s and FW190s and everything else they can throw at us, in order to bomb the hell outa them roller bearing factories way down there in Stuttgart." Noo! It was always "Ball Bearing Factories." They were everywhere.

The above "U.S. Army" reference was just a reminder to our, bus driver, blue suited, fly-boy buddies that they have a rich heritage stemming from sound roots in the U.S. Army.

P.S. 4T1 Chevy Coupe, after you have strung that mess up on the garage wall, get you some ball bearings and go back to tried and true. And remember, next time ask here first. That's what we're here for. Grin.

Best wishes, Charlie

Thanks for your input Charlie! *grin*

I understand that the original ball bearings are adequate for the 4T1. I figured that if a large company like "Chevsofthe40s" had a conversion kit it would be a positive upgrade to go with that conversion.

Yes, the races are pressed in to the machined stops in the hubs with a couple of ton pressure to make sure they were fully seated. There are only two sizes of bearings/races in the kit so there's no confusion there.

The situation is why, in this particular vehicle, the seals that come with the 'Chevsofthe40s' conversion kit do not install correctly. I think the pictures show what I'm dealing with. Certainly someone out there has done this conversion and has hands on working knowledge on the seal location issue I'm faced with.........?? I'm not inclined to give up and hang $183 on a wire when it's worked for many other folks.

Okay. Heck fire, I didn't know the kit cost that much. We must, therefore, figure out how to make them work.

a. Were there any instructions with the kit?
b. Were the seals what the kit called for?
c. When you contacted C of F about the problem of the seals being too thick, what did they say other than others had had no problems? Did the verify you had the right seals? What was their recommendation for installing seals?
d. Have you tried pounding on in flush to see what happens?
e. Maybe the clearance is just enough so the bearing is not adversely affected by the seal.
e. I know you have made measurements but have you stacked the old bearings up with the new to see if there is a difference in overall height? That is, does the new bearings leave you with a negative or plus measurement to the old.
f. I'm with you in that it seems to that the new seal should fit just as the old one did or, else it should be noted on the instructions or invoice that the height is different and how to deal with it.
g. As you said, someone who has actually completed the conversion would be best to give you advice.

Sorry, but I have not done such a conversion. And, because, it seems, no one else on Chatter II has either, it makes my earlier statement about coming here for advice a little hollow. I apologize for that and my making too light of a relatively serious, owing in part to cost, situation.

As for me, I'd send the whole mess back and ask for a refund. Then buy some roller bearings, races and seals and go back to original. You are right. $183 is too much to hang on a wall.

Best wishes and I hope you get it all sorted out soon, Charlie

This does not surprise me at all. One of the parts I needed for doing my 3.55 gear ratio conversion in my '36 1/2 ton is a '37 Chevy drive shaft seal. The shaft size is 1 1/32" (1.031").

Chevies of the 40s advertizes a seal for this application. I contacted them to ask about the ID, OD and width of the seal. They were unable to answer that simple question.

Then I asked them for the seal number and looked it up myself in a seal catalog. That seal is for a 1 1/16" (1.062") shaft.

I called this to their attention and they were completely unconcerned. BUYER BEWARE!

I did the bearing conversion you are doing myself on a VW Bug nearly 40 years ago. It can be done successfully using a bearing catalog that list bearing dimensions, allowing a perfect match, not the mess that you have.

1941 Chevrolet front wheel bearings CR Brand Inner B52,Outer B01, Seal 18772.
B52-SKF brand G909052
B01-SKF brand G909001
This is for the original type ball bearings.
May be of interest, and may be not.

Hello Charlie! Thanks for your response and I'm going to respond in your e-mail below with green text.




Heck, that's too hard to read in the quote box.........soo here it is in bigger font!!

Okay. Heck fire, I didn't know the kit cost that much. We must, therefore, figure out how to make them work.

Yes, it was a bit on the pricey side however the stock ball bearing replacements aren't inexpensive either!!


a. Were there any instructions with the kit?


Negative, just a bag with the bearings, races and seals.


b. Were the seals what the kit called for?


As noted above there was no "called for" seals.......just what came in the package.


c. When you contacted C of F about the problem of the seals being too thick, what did they say other than others had had no problems?


Actually the seals were not "too thick". They just ended up being spaced at the wrong "deck height", if you will. I'm going off my past wheel seal installation protocol in that the top of the seal should seated down to the top of the hub that it's being seated into. What happened when installed that way is that the seal ended up being jammed against the raised up machined lip that is part of the one piece tapered roller bearing design(you can see that lip in the pictures. .

Did they verify you had the right seals?

I ask them about it and they cross-checked that the seals that came with the kit were the same ones that they sell for the stock inner ball bearing wheel bearings.


What was their recommendation for installing seals?


This is where I was disappointed. The person I was directed to at C of F(great guy) to talk about my problem had never installed this kit into any vehicle(apparently nobody there has!!???). So he'd never actually looked over the parts and how they interrelated/fit together in the conversion kit. He did go and pull parts and look over what I was telling him my problem was. He did not see the pictures so quite possibly didn't understand the problem since he didn't have a hub with races installed to reference the assembly. He didn't know about where the seal was interfering with the machined lip on the bearing or how to deal with it. The only "solution" he had was to clean up the bearings/races/seals and send them back for a refund. Well I didn't see the sense in doing that as everything pressed in fine and the only problem was the seal interference.

d. Have you tried pounding on in flush to see what happens?


I did not want to do that as I could see that the only thing that would happen is the seal would be majorly jammed against the machined lip on the bearing.

e. Maybe the clearance is just enough so the bearing is not adversely affected by the seal.

I think it would be the other way around. The seal would be adversely affected by the bearing/lip on the bearing. There is not enough clearance.


e. I know you have made measurements but have you stacked the old bearings up with the new to see if there is a difference in overall height? That is, does the new bearings leave you with a negative or plus measurement to the old.

I understand what your exploring here and it might be a taller stack up vs. the ball bearing assembly. I didn't anticipate a problem so had already pressed the new races into the hub. I wasn't inclined to drive them out to check what shouldn't have been a problem.

f. I'm with you in that it seems to that the new seal should fit just as the old one did or, else it should be noted on the instructions or invoice that the height is different and how to deal with it.


Yes, I am baffled at why there is this issue with this conversion kit. As you'll read next I have come across a fix and will be communicating that with the C of F folks!!

g. As you said, someone who has actually completed the conversion would be best to give you advice.

Here's how it's played out. No help off the internet forums.....have the problem listed in two other forums. I did call C of F and implore them to hook me up with someone who has done this conversion kit installation before. Kudos to them for hooking me up with a very sharp guy in their area who was actually doing the installation yesterday on his 1941 sedan!! He ran across the same interference problem that I did and figured out a viable solution and shared it with me. Basically it involves doing a light press on the seal, with the bearing, which cones the seal out and provides adequate clearance so the seal doesn't get loaded against the raised up machined lip on the tapered roller bearing. It just rides on the smooth part of the bearing where it's designed to do it's grease sealing job!!

I was very very happy to make this connection with a person who was so clever in figuring out a viable solution to the problem. He also shared that the steering was more precise feeling and no ballsy ball bearing noise coming from the front hubs.

Sorry, but I have not done such a conversion. And, because, it seems, no one else on Chatter II has either, it makes my earlier statement about coming here for advice a little hollow. I apologize for that and my making too light of a relatively serious, owing in part to cost, situation.

Thanks for your apology, no harm/no foul. I will do the tapered ball bearing conversion on any older vehicle that has ball bearings, IF the parts are available. With the higher speeds on roads today it's one less thing to have to worry about with an older vehicle.

As for me, I'd send the whole mess back and ask for a refund. Then buy some roller bearings, races and seals and go back to original. You are right. $183 is too much to hang on a wall.

I'm thinking that you meant to say "ball bearings" vs. "roller bearings" in the above paragraph??

Best wishes and I hope you get it all sorted out soon, Charlie

Thanks, Charlie, I'm pretty happy with the modified/coned seal approach and will post up pictures a bit later to illustrate what my new friend, Ron, helped me figure out as a solution!! Right now I'm going to take advantage of the aweome 70+ degree weather and go press the second seal and reassemble the hubs for installation!!

Yes, I'm not happy with the lack of knowledge/technical support that C of F has. However they did in a round about way help me out with hooking me up with Ron, who had a solution. The point is I feel that if I'm going to spend that kind of money for a "conversion kit" that it damn well better have everything figured out in advance of my assembly of the parts. I've wasted an inordinate amount of time and effort trying to figure this problem out when it SHOULD have been ready to assemble.

IF the 100's of kits that they have sold got installed with the seal jammed up against the machined lip I wonder when folks actually figure out that they have a problem!!????

All I have to go off of is the experience that I've had....and the input from Ron with the experience he had. We both happen to be pretty AR and have machinist backgrounds so we know about tolerance stack-up, "go / no-go" and deck height situations.

I can relate to the VW conversion..........I did that same conversion many years ago also!!! Memories!! :-)

4T1, I'm glad to know that you got it worked out. Seems, though, that if the seal was "bowed/pressed out" that it would have a tendency to rub the spindle when everything is all cinched up. I'm sure you have thought of that, though, and it presents no problem. Helps to be an engineer here, I suppose.

BTW: At one time I was interested in changing my 41s out to the roller bearings. Even with their superior load bearing and side load benefits, though, I've scarped the idea, at least for now.

Best wishes. Charlie

The "coning" of the seal basically moves the sealing lip out on the bearing. There is .220" of smooth surface on the bearing, before it hits the machined lip (seen in the previous pictures), where the seal can locate and do it's job of sealing against the grease.

The "coning" of the seal does decrease the seal I.D. diameter which will create a slight increase in the seal edge pressure on the bearing. I'd MUCH rather have the increase in seal edge pressure vs. the seal being jammed in to the machined steel lip on the bearing. The very end of the bearing is what contacts the spindle. The seal is inboard of the end of the bearing. I'll have pictures later to illustrate.

Hello. I am relatively new to this forum. It has occurred to me that it might be a service to the overall membership to inform everyone that Chevies of the 40s is selling parts that don't fit and are completely unconcerned when the problems are pointed out to them.

I have had bad experiences with vendors before so I knew to ask Chevies of the 40s for actual dimensions of a seal they are obviously misrepresenting for my application.

I am an engineering geologist, but not an automotive or materials engineer. Because of my technical training and experiece, I believe that each seal, for example your wheel bearing seal, is engineered and manufactured for a specific application.

Misapplication of a seal, for example using one on a shaft or in a bore that is too large or too small will affect the performance of the seal.

In my own application where a '37-'39 Chevy driveshaft seal is required, there is no currently manufactured seal with the correct ID and OD. The OEM seal used by Chevrolet in manufacturing their cars was a special part for GM only and has been out of production since 1978. A technical advisor in National Seal Company gave me the number of a double lip seal with the correct ID but wrong OD (too small) for my driveshaft application and recommended that I use that seal. I will make a sleeve for that seal to increase its OD to the correct size.

Greetings '36 1/2 ton' !!

Good deal on adapting a seal to fit using a sleeve adapter. I hope that works out well for you!!

Yes, it's a bummer when vendors can not provide accurate and concise information about parts you want to purchase.

Here are some pictures of the seal solution I came up with for the problem I was dealing with.

Here is a picture of the old ball bearing race I used for the pressing of the seal to cone it out for clearance.


Here is another view;


Here I taped the seal to the race to keep it centered during the pressing process.


The pressing process;


Here you can see a distinct ring where the outside of the tapered roller bearing race pressed into the rubber side of the seal to bend the steel part of the seal and cone it out.


Here is the end result;


I'd wanted to take a few pictures of the seals installed into the hub(s) however I got busy and didn't do it before I installed the front brake drum/hub assemblies.

Now I've got another problem that I'll be detailing in a new post.........it's always something with projects!! :-)