Rear axle bearing cups / end play

[Ward Duffield]

OK, so if you need a puller to extract the rear axle shaft & bearing from the axle housing, the OD of the bearing race must be a press fit into the axle tube bore, right?

If that is the case, how are you supposed to check the axle end play by simply tugging and pushing on the end of the axle? The free play is the distance the bearing race moves outboard until it contacts the back of the brake backing plate; this gap is controlled by the shims behind the brake backing plate. All perfectly obvious to me except my bearing race is too tight in the axle housing to allow the axle & bearing cone to move outboard at all.

P.S. Do we have a new figure for high speed end play as referenced in some Service Bulletin from the 1950s?

Clarification, please!

[keithb7]

 

I may not be right. But...I'll try.

It is my understanding that the bearing cone, that is pressed on the axle shaft, moves outward, as one with the axle shaft, when you tug on the axle. The amount of free play is set by how far in your drive, or press, the cup in place. The cup should not be pressed in all the way flush with the end of the axle housing. You leave some free play, then when you choose the right thickness of shims, and re-install the brake backing plate, and torque the mounting bolts in place, the backing plate pushes the cup in toward the cone. This distance the cup travels, is determined by the thickness of shims, stopping the backing plate from pushing the cup in deeper toward the cone. This free play between the cone and cup is what is desired.  I think that when you tug the axle out, this is what you are measuring. The free play between the cone and cup. 

 

Am I understanding this right? Open to corrections and clarity. Thx. Keith

[Merle Coggins]

Keith is right. However, before measuring the axle bearing end play you MUST have both axle shafts installed. The other end of the axle shaft presses against a thrust block in the center of the differential. If you try to measure one side without the other side assembled you will get a false measurement. You are actually measuring total clearance of both sides together. 

[Dodgeb4ya]

After both backing plates are installed and tightened up each axle needs to be "wacked" with a dead blow hammer or regular hammer and a block of wood

.Do this at the end of each axle.

This makes sure the axles and races are set/relaxed  and will not change.

After doing that you should be able to grab the end of an axle and firmly push in on it and pull it out feeling a very slight movement and a very weak clunk. 

That means you have some end play.....that's good. Now check that end play with a dial dial indicator for the actual end play measurement. .003"-.008"

If there is no in/out end play movement of the axles...then shims need to be added behind each backing plate. Sizes of.005/.010"/.012"/.020" etc were available to adjust axle end play.

These shims are not easily available today.

If you take them apart/out  put them right back as they were on... balance them equal side to side. This applies to the old original bearings and shims. 

If you are replacing the axle bearings or changing the pumpkin ....you might be hunting for new different thickness shims to get the correct axle end play!

[Andydodge]

As far as I know "shim stock", ie, a thin sheet of brass in the relevant thickness is still available from bearing supply shops here in Oz and a sharp pair of scissors and you'll have the required shim .......at least thats what I did a few years ago when playing with the Oz 1962 Chrysler Royal( essentially a US 1956 Plymouth rear end) rear end that I'd converted to vented discs and cracked then spun a bearing cup, ever so gently "machining" the axle a few thou or so........lol.........ended up getting the cup metal sprayed to take up the slack, so to speak......needed to be done twice but ended up working o/k and lasting another 20 yrs or so..............other issues eventually made a rear axle replacement from a late model Oz Falcon needing to be done...........but back to the thread...shim stock is still available.............andyd 

[Ward Duffield]

OK- I will not seat the cups flush w/ the end of the axle housing. To extract the side I have already done, will compromise the new bearings, but so what. 

Once I have both axles out, why not pull out the differential, and rebuild that, too? Peace of mind.

Thanks.

Ward

[Ward Duffield]

OK and what is the approved, currently available gear oil for our cars?

 

 

 

[keithb7]

Yup. Pull axles. Drive shaft then the diff. I should have when I put in new axle bearings. I’ll be back in there soon enough. 

[Ward Duffield]

Diff looks great, but I have been mining some ugly gunk out of the axle housing.

IF I had only realized I was going to do all this, I would have removed the pinion input shaft nut (TIGHT!) while the tires were still on the ground...

 

[BHondle'40]

Gentlemen, please permit me to ask an additional question on this thread that was started in 2019 by Mr. Duffield, rather than starting an additional thread.  I apologize if that would be more appropriate.  In any event, I believe that I have read just about every thread with regard to extracting and replacing the inner oil seals to the axles in my stock 1940 Plymouth P-9.  The bearings for each axle looked good and the axle shafts appeared to be in good shape as well (no scoring to my observation, but there was some scuffing that was smoothed out with steel wool).  I replaced the driver's side oil seal with NOS #651678 (I believe it has the leather seal).  However, I replaced the passenger side with NAPA #13797 with a nitrile seal.  I used the modern (NAPA) seal on the passenger side because the NOS seal that was used for the driver's side was 1/2" in width, and after inserting it as far as it would go into the axle it still obscured about half of the hole for the plug that I would remove in the future to thumb-in grease for the bearing.  However, since the NAPA seal was only 1/4" in width it did not obscure the grease plug hole after it was installed on the passenger side. 

 

I recite this information for background information to tell you what I have done.  I am now attempting to adjust the end play to the axles, and I have applied the information on this thread (i.e., reinstalling the two steel shims that were existing on each side of the axle housing (they are very thin, so I am thinking .005" or .01"); then tightening each backing plate against those shims and the bearing race; then "whacking" the end of each axle with a regular hammer and a block of wood). 

 

Now, this is my quandary:  While I don't have any type of gauge to determine the axle end play of .003" to .008", I nevertheless believe that the axle end play on the driver's side might be within that parameter; however, the end play on the passenger's side is more than that of the driver's side.  "Dodgeb4ya" stated above in this thread:  "If you take them apart/out  put them right back as they were on... balance them equal side to side. This applies to the old original bearings and shims."  But, in my case, putting the shims back as they were, and balancing them (the shims) equal side to side, has not resulted in equal end play for each axle.   Now, I must candidly admit that I did not pay particular attention to the end play before I took things apart and replaced the inner oil seals because only the driver's side was slightly leaking.  So only the driver's side was my initial concern.  However, the vehicle has been sitting in the garage (in parts) since the early '60's and it is only recently that it has been put together.  I had previously repacked the front bearings but "dummy me" thought that the rear axle bearings (that I did not know how to get to) must have been lubricated by the differential.  Naturally I have discovered that is not the case, and since there was a slight leak on the rear of the driver's side backing plate I therefore felt I should inspect the bearings before I drive it too much.  Upon disassembly of the driver's side I discovered that there was hardly any grease at all in the bearing.  If there wasn't grease in the driver's side then there probably wasn't any in the passenger side either, so I then set out to repack the passenger side bearing was well.  As it turned out, there was even less grease on the passenger side bearing, so it was a good thing I checked.  As a result, the end play was not on my radar at that point, so I don't know whether the greater end play on the passenger side (which I believe is more than the allowable .008") existed before I removed that axle.

 

Am I misunderstanding something here?  Is it going to matter whether there is slightly more shim material on one side than the other, in order to obtain the proper end play for each axle?  Wouldn't getting the same end play be the main goal, in order to center the axles in the housing, even though it may require more shims on one side than the other?

 

I thank you in advance, Zen Masters and other mentors, for your continued courtesy and consideration!  ?

 

Bruce

[desoto1939]

Here is the Miller C-413 tool and I have one of these. It is used to drive inthe outer bearing cup on the rear axle housing. This centers the bearing cup race inthe housing and pushes it into the proper depth. Also attached is a picture of the actual tool

 

Rich Hartung

 

 

 

 

 

Rich Hartung

Desoto1939@aol.com

[Dodgeb4ya]

OK...A long read...

That Miller tool does not set the race to the proper spec. It is only a race driver tool...not really necessary to install the bearing race....though I use one most of the time if not a large brass drift.

As for axle shaft bearing end play yeah it should be roughly checked for end play before axle shaft removal..

I should have stated that and I do generally check it on jobs.

The rear end must be up on stands before checking any axle end play job..

The drums can still be installed if doing a quick end play hand check before pulling axle shafts for more service repairs. Use a dial indicator.

Axle shafts readings on the dial indicator should and must read equal either side.

Push and pull hard on the axle shaft and or drum and read the amount of end play.

Do exactly the same on the other side...

 it must read the same end play as the first side and normally always will on a properly operating rear end axle assembly.

 **On a rear axle that has had new seals, bearings etc it is critical to make that approximately the same thickness of shims are installed on both sides or the differential centering block will bottom out...

**It's also important to use the original factory width inner seal and drive it in fully to the machined housing stop depth. If this inner seal is too wide or not driven in fully the axle shaft step will rub against the inner oil seal (seals) causing erractic end play reading issues.

As for installing the axles and races/cups...

..Don't drive the bearing cups into the housing flush..drive them to with in a 1/16" of the housing mount surface. 

Then install the original shims both sides. Install both the backing plates semi tightened.

Now fully tighten up either backing plate which will push the bearing race in as far as the shim will permit.

Go to the other side and gradually tighten up the backing plate while "hand checking" for some axle shaft end play movement. Usually you will have correct or close to it if re-installing good original axles shafts and bearings.

If you don't have any end play before the second backing plate is fully tightened up you will need to add more shims (.005", .010", .015") etc and will need to be evenly added to both sides with in reason.

This till an .008" max end play dial indicator reading is achieved at both sides.

You will need to set up a dial indicator to properly do the final accurate end play check and adjustments.

Always double check for even side to side end play readings by firmly wacking the ends of both axles to be sure the opposite side bearing races are forced tight to opposite side backing plates.

Re-check axle end play a couple times to be sure it's set right.

Uneven uncommon side to side end axle play truble could be caused by

***Wrong or not fully seated inner seals.

***Wrong new axle shaft bearings or not fully seated on axle shaft

***Worn end of axle shaft

***Damaged centering block

***Wrong outer seals and seal plates (up to 1942).

 And that's enough for me to type out for tonight!?

 

 

.

 

[BHondle'40]

Thank you all for your courteous responses, and a special THANK YOU to Dodgeb4ya.  I truly appreciate your patience with me and your perseverance in writing your detailed instructions in this matter.  ?

I have used an NOS inner seal on the driver's side, and a NAPA interchange seal on the passenger side.  Neither seal is wider than factory specifications and both have been driven fully into to the axle housing to the machined housing stop depth.  

 

I have installed the axles and races/cups and have driven them to within a 1/16" of being flush with the end of the axle housing (i.e., the backing plate mounting surface).  Both backing plates and axle housing ends have been cleaned of debris. 

I will now apply the remainder of your instructions and let you know the results accordingly.  ?

Thanks again,

Bruce

[BHondle'40]

I once again express my appreciation to all of you.  I was able to work on the axle end-play today.  I purchased a dial indicator and now fully understand the need for that precision instrument in this matter.  In fact, I now see that it cannot be properly done without it.  But, I never really could figure out the proper way to adjust the goose neck, so I ended up attaching it to a jack stand and then moving the jack stand closer until the tip of the indicator came in contact with the axle, and then I adjusted the face of the indicator to zero.   Attached as the first picture is how I set it up, and the dial indicator is at zero.  Then I firmly pushed in the axle (and it went in about .002") and then firmly pulled on it and the second picture shows end play of slightly over the .003" after I pulled on it.  So I guess that the .002" should be added to the .003", to get total end play of .005.....is that right?

 

Then I pulled harder (like....really hard.....since I don't really know how hard I should be pulling in the first place) and the end play increased to about .005", so perhaps the end play is actually at the .008" maximum?

 

This result was essentially the same on each side.  I thereafter whacked each axle to ensure that the bearing cup was firmly against the backing plate, and rechecked the axle end play, and it had stayed the same. 

 

However, I actually had to remove one of the two thin shims from each side in order to effectuate the proper end play.  I don't have a micrometer so I don't know the the actual width of each shim that I removed, but I am guessing that each was .005" based on the initial end-play results I received when I simply reinstalled what had previously been used.  Just so that you don't need to re-read my lengthy initial post, I will simply say that I merely replaced the inner oil seals on both axles and greased the bearings, and that is all I did, so I am thinking that the axle end-play was way beyond the maximum to begin with (since I had to remove one shim from each side).

 

But I now have an additional question.  I could not hear any "clunk" (let alone any "weak clunk") from either axle when I checked the end play, as I have read from previous posts in this thread.  Now, mind you, the bearings are nicely greased at this point.  So I am presuming that (not hearing any weak clunk) is not any big deal since the reading on the dial indicator is what really matters, correct?

 

Sorry that I could not figure out how to rotate the pictures when they were inserted into this post - no matter what editing I attempted.  ?

 

Thanks again for your continued assistance.  ? 

Bruce

 

 

[BHondle'40]

I apologize that one picture got included twice in my previous post.

Bruce

[Dodgeb4ya]

As for the slight clunk yanking in and out on the axles..

You have to do it firmly in and out...but don't worry about that.

The indicator tells the true reading.

Looks like you got the end play in middle of the. 003" - .008".range.

Normally when checking these axles end play the indicator would be attached to the backing plate.

Magnetic or clamp style base.

But as you did works because I assume your rear axle is resting on jack stands preventing any movement.

You did good! You have a little axle end play and not too much after double checking your work.

As for needing to remove shims when no bearings were replaced?

You did tighten the backing plates up to roughly 25 ft lbs?

If the bearings were galled/ worn out that would cause excessive end play.

End of axle shart same but doubt it.

That's why a axle end play check before axle repairs let's you know whats up.

It's a new learning experience for you.

Look at it as some old car repair fun?

 

 

[BHondle'40]

Thank you once again for your reply, Dodgeb4ya!  I was eagerly awaiting it, and you did not disappoint.  ?

 

Thanks for telling me that when checking the end play for these axles that the indicator would normally be attached to the backing plate.  I attempted to do that, but after several of frustrating hours (no kidding) I gave up and came up with a new idea.  The indicator I purchased is the clamp-on style.  But the telescoping arm that attached to the clamp on one end and the indicator on the other end was impossible for me to properly align.  But since the rear axle is on jack stands there was no movement of the actual axle housing during the measurements.  The axle housing was solid.

 

I appreciate you telling me that I have to yank on the axle firmly, and also I needed to move the axle in and out while yanking.  So, then, I was correct in concluding that the distance the axle is yanking "in" would be added to the distance that registered on the indicator when the axle was yanked "out", in order to get the total axle end play? 

 

With regard to needing to remove shims when no bearings were replaced, I did indeed tighten the backing plates up to roughly 25 ft lbs.  Now, I must tell you that I have not yet used my torque wrench to verify that, but I believe that I have done that (and more) with my hand tightening thus far because I have a tendency to over-gorilla things.  But I will verify that when I put on the outer seal, which I have not yet done because I was awaiting further direction from you mentors.  ?

 

I appreciate you saying that excessive end play would result if the bearings were galled or worn out, or the end of axle shaft was worn.  But since I actually had to remove two shims in order to obtain the required end play it would appear that just the opposite is probably the case.  I'm certainly not a bearing expert but they appeared to be in good shape to me.  I can tell you that the vehicle was not well maintained prior to my parents acquiring it.  So I am thinking that because there was no grease in the bearings, and the fact that both the inner oil seal as well as the outer oil seal on the passenger side were not correct for the vehicle (according to Todd Fitch's cross reference information, which is most useful indeed - and kudos go to him as well), that the end play was way out of whack to begin with.  BUT, NOW I know to always check the axle end play check before undertaking any axle repairs.  ?

 

And, yes, it's a totally new learning experience for me.  I do indeed view at it as fun.  My parents purchased this vehicle in the early 1960's for $40.  Soon thereafter the wiring under the dash shorted and burned, so a restoration project was born.  While the engine was rebuilt in the early 1970's, the vehicle laid around in the garage in parts (with essentially only the body bolted on the frame) for the next 46 or more years.  Anyway, I have undertake the restoration project.  It is coming along nicely, in my humble opinion, and has provided me much joyful education.  ?

 

With gratitude,

Bruce

[Dodgeb4ya]

If the bearing cones or races have severe wear which would be obvious you would have excessive end play.

New bearings can also require shim removal though the need to add shims is typical...not a lot...say a .005" maybe a .010". I have a stack of them I collected over time.

But let's say the bearings are worn a bit..to tighten them up to spec you would need to remove shims.

Typically the rear axle bearings last many many miles and years and do not require shim service.

If the bearings (rollers and cups) after careful cleaning look like new and feel buttery smooth forcing the cup down hard on the cone while rotating back and forth use them!

Maybe the last work on the axle seals those folks set the end play...? Incorrectly...IDK.

That's great that the car was your parents car and now you are bring it back to good use!

Edited November 1, 2021 by Dodgeb4ya

[BHondle'40]

Ahhhh, your pictures were great, thank you!  I purchased the clamp-on type of dial indicator because I did not understand how the magnetic portion would be attached to the backing plate.  Dummy me never considered the way you have shown it in your pictures, thanks!  But I do have one question about the pictures.  How is it that the dial is registering at about .005" when you are not yanking on it?  Unless that particular type of gauge stops the needle at the maximum reached "out" point automatically, something like a stopwatch?

 

So, then, I was correct in concluding that the distance the axle is able to be pushed "in" would be added to the distance that registered on the indicator when the axle was yanked "out", in order to get the total axle end play? 

 

I appreciate you saying that removing shims might be because the bearings were worn.  I guess I shouldn't be surprised if that were actually the case, after "going through" the vehicle during this restoration process.  I will say that when I washed the bearings (initially in gasoline, and then followed up with lacquer thinner) to remove the differential oil from them (since the bearings on both sides were full of differential oil but no grease), I then blew them out with my small air compressor and the air made the bearings move nicely.  As a result, I never took particular note of when I squeezed the actual bearing into the race and then turned it back and forth.  However, I didn't notice any "catching" or scoring or scratching or anything other than the fact that it rolled nicely as I would expect it to.  But, despite my neophyte observations, logic is telling me that the bearings are either worn or the end play was way out of specs to begin with.  In either case, the bearings are now nicely greased and the axle end play is within specs.  ?

 

The vehicle is going to a stock driver, except I have already done the back package tray, trap door, and rear side panels the way I wanted them to look, rather than how they looked when stock.  Further, I have installed sound proofing throughout (except for the floorboards that I have yet to do).  I will be installing seat belts after this axle adventure is concluded, and it's to the point now where paint and tires would be the next project in order to finish the interior and get this puppy back on the road.  It still has the bias ply tires it had on it when my parents acquired the vehicle in the early 1960's!  

 

The Plymouth Service Manual merely tells a person what the axle end play needs to be adjusted to, but it doesn't explain how that should be done, so I truly appreciate the continued education!  ?

 

Bruce

[Dodgeb4ya]

The dial  indicator I used has 1" of total plunger travel. I usually set up the indicator say midway of the 1" travel.

***Next I very very firmly push or pull the axle to it's limit..Doesn't matter which way.

***Next while still holding the axle shaft I zero the indicator (rotate the dial face to align the zero to the needle...

***Next push or pull the axle opposite way and read the total end play.

The reading you see is the total end play reading for both sides.

The pic above I posted is a old picture shot to show general Indicator setup and reading.

As for the .005" shown sometimes the axle and end play reading will stay when you let go of the axle.

I honestly don't know/remember if that was what happened on that job.

Pic was just one I shot for reference...ended up here!

[BHondle'40]

Great explanation, thanks again!

Bruce

[James_Douglas]

I use about .010 on the Desoto Suburban as I drive at 70MPH on long freeway runs. The axles grow at higher speeds and I do not want them bottoming out on the block in the rear end.

 

Like I said, I read it in a manual from the mid-1950's years ago and noted it in my service manual...I just cannot remember which of my 100 car books it was in or perhaps it was in one of the hundreds of pages of factory service bulletins I have from 1946 to 1957.

 

James

[Plymouthy Adams]

sorry.......right post.....wrong thread...

Edited November 6, 2021 by Plymouthy Adams

[Sniper]

3 minutes ago, Plymouthy Adams said:

by design these worked very well 60 years ago and will work again when 60 years of rust/corrosion is corrected and good connections established.  Dedicated grounds is a plus but I do not see a need to go all the way back to the battery for this.

Because some of us wear belts AND suspenders, lol.  In my case it wasn't an issue.  I needed to run a good ground to the rear for the bluetooth amp so it was simple enough to run the added grounds for the lights to that terminal in the trunk.  The front runs were short enough that they weren't an issue either.  I also used uninsulated crimp connectors, crimped and soldered with heat shrink covering them.

 

Was this absolutely needed?  Nope.  But I sleep well at night anyway ? 

[Dodgeb4ya]

Axle end play specs grew on the mid to late 50's cars..     .013" to .018"