A fix for the increasingly scarce 1533 differential bearing

[pacer 3,168]

If you're around the horses for very long you'll hear of the very scarce 1533 differential carriage bearing in the stick shift transmissions. The obvious reason for this is simple - they havent been made for many, many years and what few are around are dwindling at an alarming rate.

 

I had heard of guys "machining" a case to fit an oversize bearing but never knew any details, so being a fairly decent home shop machinist with a nice large Bridgeport type mill and lathe I thought I'd see what I could come up with. With member Groundhog44 having a couple sets of cases the 2 of us started looking.

 

The original 1533 bearing is/was 1-1/2 x 2-1/2 x 1/2" - the nearest thing to that (that I could find!) was a R24-2 rs or zz with its diminsions being 1-1/2 x 2-5/8 x 9/16". With only adding 1/8" diameter and 1/16" thickness the case appeared to have ample 'meat' to handle machining out this amount. This size bearing is very common and is relatively inexpensive, so I got 4 of them to see. The first puzzle was to get the case 'fixtured' on the mill to do the boring - this was stumping me til I called my "machinist by trade" buddy and with his years of experience quickly pointed me in the right direction. He was also able to furnish the 2 heavy steel bars needed to 'hang' the case off the mill table.

 

Let me pause here and state the rather obvious fact - this is not a repair that can be done in most of your shops, but I would think many of you know of, or have friends that have the necessary equipment - and its very possible in the not to far future that a visit to a machine shop may have to be done.

 

In order to get a grasp of what we did, I tried to get enough pics to see the set-up...

 

This is the 2 heavy bars mounted to the table with the mills head swiveled around in order to reach the case that will be mounted off the right front of the table to clear the mills knee.

 

 

This is the case mounted in the fixture where I am about to locate center of the existing bearing bore in preparation for the boring

 

 

Here I am starting enlarging the hole. The depth of the hole needed to be increased from the original 1/2" to the 9/16" which is only .0625, but has to be done. I finished this step before enlarging the hole the extra 1/8" (this is only 1/16" off each side)

 

 

And this is the new bearing sitting in its new home -  this is a R24 rs bearing meaning it is a sealed unit, its only necessary to 'pop' out the rubber seal to allow oil to flow through, which I have done here (this same bearing in  zz designation is a shielded bearing and doesnt require anything)

 

[meadowfield 2,570]

Awesome work! :thumbs:

[rmaynard 15,408]

So what you're saying is that I can't do this with my Dremel and my DeWalt drill?

Nice tutorial.

Sent from my Moto G using Tapatalk

[buckrancher 2,679]

I did it the other way

 

Brian

[daveoman1966 3,745]

Since the original 1533 bearing is 1-1/2 x 2-1/2 x 1/2"  and the nearest thing to that is a R24-2 rs or zz  1-1/2 x 2-5/8 x 9/16", wouldn't it be an easier process to SLIGHTLY grind down the R24 bearing to the size of the 1533 using a precision grinder of some sort. 

 

One would only need to grind 1/32" from each side to reduce by 1/16" to 1/2" thick.  Next, the OD would need ground by a mere 1/16" on each side to reduce the OD by 1/8" to 2 1/2".  It seems to me this would be a simpler way to the same end, IF the bearing structure isn't compromised.

 

Of course, this wouldn't be a good idea if these bearings were supporting a HIGH SPEED shaft of some sort.  The Wheelhorse axles aren't turning at a high speed...or at least shouldn't be.  These aren't race cars....   

 

As to the structural integrity of the 'ground down' R24 bearing: 

I don't know the thickness of the outer race (or wall) of the bearing and can't imagine that to reduce it by 1/16" would be detrimental.  After all, the cast iron case tube thickness is still there to support the outer wall.  By the same reasoning, how would reducing each side by 1/32" defeat the structure.  Certainly the ball bearings wouldn't be able to drop out just by grinding away 1/32" of their 'fence'.

 

I'm not an engineer....could you guess that? ?  Just a novice trying to find an acceptable and simpler way to find resolutions.  I do, however, have a bench grinder.... and a platform sander.     

Edited May 8, 2014 by daveoman1966

[rmaynard 15,408]

...I do, however, have a bench grinder.... and a platform sander.     

That, along with my Dremel and Dewalt are the makings of a fine machine shop.

[wrightorchid 261]

Any idea how hard would it be to have a run of bearings made?

[Coadster32 793]

Nice setup. Seems like it worked like a charm.

 

Never truly stuck when your a machinist. Just gotta think about things sometimes.

[bmsgaffer 2,043]

Any idea how hard would it be to have a run of bearings made?

 

THOUSANDS of dollars are required for this, so I doubt there is enough support from buyers to make this happen.

 

Is there any way to use a smaller bearing and machine an adapter/bushing that you could sell to people to fit in the standard case opening? Or would there not be enough weight handled on the smaller bearing?

[pacer 3,168]

Brians method of turning the differential hub is certainly a viable method of approaching this problem.

 

As for grinding the outer diameter of the bearing, that sounds much more difficult to do requiring a grinder set-up that I'm not even familiar with (I know its done but I dont know the machine) I assume you were jesting when you mentioned using a bench grinder?? And I would also question the integrity of the bearing on something like this. Brians lathe method and using a mill remove such a small amount of the already robust castings should mean there is little chance of weakening the drive train.

[daveoman1966 3,745]

F I N E ! ! !  Go ahead an laugh at my bearing-reduction grinder idea.  Some laughed at Orville and Wilbur, too. 

 

 

 

[AMC RULES 37,125]

           

F I N E ! ! !  Go ahead an laugh at my bearing-reduction grinder idea. 

 

 

 

[groundhog47 347]

I stood there and watched the whole operation and understand it thoroughly now. The set up is as straight forward as can be , just a bit time consuming. Told Bill "If I had one of those machines, I'd be out there all day long havin' fun. Course Bill made it look easy at findin' center and boring and all.  In the long run the strongest part, the case is less likely to shear than differential carrier hub, yes bought a used one with sheared hub, they will when bearings seize and under load an ear muffs on. Must've been literally howling.

[SousaKerry 501]

Grinding the OD of the bearing would require a center-less grinder and a lot of time as most are set up to only grind off a few thousands of an inch as a finishing operation.  Also the part is quite narrow so holding the bearing square between the wheels would be problematic.  I only ran a center-less for a few weeks and did not understand it well so I may be way off here.

[groundhog47 347]

Since the original 1533 bearing is 1-1/2 x 2-1/2 x 1/2"  and the nearest thing to that is a R24-2 rs or zz  1-1/2 x 2-5/8 x 9/16", wouldn't it be an easier process to SLIGHTLY grind down the R24 bearing to the size of the 1533 using a precision grinder of some sort. 

 

One would only need to grind 1/32" from each side to reduce by 1/16" to 1/2" thick.  Next, the OD would need ground by a mere 1/16" on each side to reduce the OD by 1/8" to 2 1/2".  It seems to me this would be a simpler way to the same end, IF the bearing structure isn't compromised.

 

Of course, this wouldn't be a good idea if these bearings were supporting a HIGH SPEED shaft of some sort.  The Wheelhorse axles aren't turning at a high speed...or at least shouldn't be.  These aren't race cars....   

 

As to the structural integrity of the 'ground down' R24 bearing: 

I don't know the thickness of the outer race (or wall) of the bearing and can't imagine that to reduce it by 1/16" would be detrimental.  After all, the cast iron case tube thickness is still there to support the outer wall.  By the same reasoning, how would reducing each side by 1/32" defeat the structure.  Certainly the ball bearings wouldn't be able to drop out just by grinding away 1/32" of their 'fence'.

 

I'm not an engineer....could you guess that? ?  Just a novice trying to find an acceptable and simpler way to find resolutions.  I do, however, have a bench grinder.... and a platform sander.     

Dave...66, Don't think anybody would really laugh at your idea. That barring a square and perpendicular set up would be simpler, heck think I've seen that suggested on here before and I even thought why not. Looking at thickness of od vs. id of just race, ain't a lot o meat. If someone could rig up a way to hold the outside stationary and lock up in a late, it sure would be a fun thing to try, but I don't know anything about how to cut/grind that super hardened material. But ya know we wouldn't have gotten out of the stone age without ideas and trial and error.

[daveoman1966 3,745]

At the risk of taking abuse from some (many)..... and others with a knee-slap...

 

All you tool-maker guys....think about this.  (1) Secure the bearing via mag base on a big flat grinder and whack 1/32" from each side, reducing thinkness to 1/2". (2) Epoxy the 1.5" ID bearing race to axle shaft of equal dia. (3) Hold axle & bearing in an x-y indexible device or tool similar to a drill bit sharpener (4) gradually move outer bearing race at a slight angle but flush into the side of a  high-speed grinding wheel (5) Outer race will spin (not too fast) and uniformly reduce the OD to 2 1/2" (6) Dissolve epoxy and remove bearing from shaft (7)press bearing into housing.

 

Once again, I don't know how much meat is in the outer race.  However, even if there is only 1/32" left after grinding, the INNER SURFACE of the race will be unchanged...that's the important part.  It will be supported / strengthened / reinforced by the cast iron housing.  It is, after all,  the INNER SURFACE of the race to be more concerned about...not the OUTER.  Bear in mind, also, that this is not about bearings in a race car..... 

 

BTW... I worked as a bean-counter for a local tool & die shop and I have a lot of respect for those guys.  To this day, I am in awe of the things a competent, experienced, and professional tool guy can do..design, build, repair.  Hats-off to them and to a trade that we all can't afford to lose.             

Edited May 11, 2014 by daveoman1966

[jdleach 525]

While the idea of grinding the bearing may sound good, the VAST majority of bearings, especially ball types, have little material to remove before compromising the structural integrity of the race. Consider this: while a ball bearing may appear to have material on the outer race, the center of the race can be much thinner where the ball track lies. Too, the race is quite hard, which also means it is brittle. The thinner the cross section, the greater the chance of breakage.

 

The boring of the casting is about the only option I see in this case, outside of finding an exact replacement bearing.

[wheeledhorseman 574]

Brilliant piece of work done here !!  

 

IMHO this thread needs to be moved to the 'Instructional' heading so that it doesn't get lost over time in the vastness of this forum.

 

Thanks for sharing.

 

Andy

[Fordiesel69 259]

Question, the case half that needs to be machined.........are they the same thru all the tranny models?  If so, would someone be insterested in a core program.  For example bore out 4 cases and set aside, somone could ship their half case, and receive someone elses case half already machined out?

[swarfeater 49]

a friend of mine had a similar problem, but I do not remember the name of the tractor, farm something. it was a cast iron 16hp briggs, auto, nice heavy duty thing.  I simply made a bronze bushing with oiling grooves in it.  he used that tractor like that for 15 years or so till he died and it got sold. they made em like that for a hundred years with bronze or other bearing metal and a lot are still running. still works today.

[smoreau 658]

I used a lathe several years ago to turn down 8 pinion diff to fit my 875 in my avatar. The original 4 pinion came apart and had metal chunks everywhere in the case. I was able to save most everything but the diff. I went through the entire hydro trans and all is good know. Know I have a 8 pinion sundstrand 875!