Pre-war (up to 1942) 1939 LaSalle - Pinion Crush Sleeve-May Have Torpedoed Myself

[39LaSalleDriver]

Following up on my previous posting about replacing the pinion seal on my car

https://forums.cadillaclasalleclub.org/index.php?topic=169436.0)

Fatefully, I decided to go ahead and try to do it myself. Everything was going along fairly well until this afternoon when I started putting it all back together again.

I had faithfully marked all of my positions (pinion shaft, nut, yoke) with a center punch to make sure I could get everything back to the same position; taken my drag measurements before disassembling, etc.

I used a .005 shim as recommended in Brad Ipsen's instructions as well as doing a dry fit test before final assembly and everything was looking good.

Put it all together for real, and started tightening the pinion nut (with breaker bar) and got it right dead on to the marks I made before starting. All of the information I had read indicated that I was going to need to go just a slight bit past that to get the proper value, so I was getting ready to measure the torque value for accuracy. Decided to give the yoke a spin to get a feel for what kind of drag I was getting, and discovered that I could barely spin it     

What to do at this point?

Back off on the pinion nut to get the proper drag?

Take it all apart again and install a .010 shim and take another stab at it?

if so,

Should I ignore my punch marks and do it strictly with torque values?

Have I ruined the crush sleeve beyond use and can I replace it to get to where I need to be?

Or most horrifyingly...have I ruined the differential and now need to seek a replacement?

[Dave Shepherd]

All those marks are just references, you have to sneak up on the crush collar setting using a torque  wrench to check your progress, you cannot  loosen the collar to get where you want, start from scratch, with a new collar.

[39LaSalleDriver]

All those marks are just references, you have to sneak up on the crush collar setting using a torque  wrench to check your progress, you cannot  loosen the collar to get where you want, start from scratch, with a new collar.

Fair enough. But...if the recommendation is to:

"At this time do not install the new
seal but trial fit the bearing, bearing
washer, yoke, and nut. Add .005 to
.010 shim thickness. Tighten the nut
snuggly and check to see that there
is some play and it rotates easily
with no drag. If not, disassemble
and add shims. This endplay will be
removed when the nut is tightened
and the sleeve collapses further."

Could I not replace the .005 shim I used, with the .010 shim and have yet another chance to set the torque to the proper value? Don't know enough about the topic to argue one way or another about it, but it would seem to me that this could work.

If I require a new crush sleeve, where would I find one, and what dimensions should I order to match what was originally used?

[The Tassie Devil(le)]

G'day Jon,

The problem with relying on the markings you made is that when the pressure was released when you undid it, everything in that area changed.

The Collapsible spacer may have shifted slightly, as in falling to a new position on the shaft, plus, the pressure on the bearings has also been released.

When I have to create a ring to assist in re-collapsing the old crush sleeve, I would go nothing less than say 0.020" so that the sleeve has to physically be moved (crushed further).

How hard was it to remove the front pinion cone from the pinion itself?   You did you actually get the bearing off the pinion without disassembling the diff, or was it a loose fit?

Bruce.

[39LaSalleDriver]

Bruce,

When I have to create a ring to assist in re-collapsing the old crush sleeve, I would go nothing less than say 0.020" so that the sleeve has to physically be moved (crushed further).

As I mentioned earlier, the reason I went with the .005 shim was because that was what Brad Ipsen recommended in his procedural writeup. You are recommending .020 so that sounds very much like you see no problem with me using my same sleeve and stepping up to a .010 shim, and perhaps even a .020 shim if needed? I hope so, because truthfully, I can't see that it would "ruin" that sleeve no more movement than there is. Then again, I don't fully understand the mechanics at play with this and could be wrong. On top of that, I have no idea where to get a new crush sleeve, or what to even ask for size wise should I even find someone who sells them.

How hard was it to remove the front pinion cone from the pinion itself?  You did you actually get the bearing off the pinion without disassembling the diff, or was it a loose fit?

Bruce.

Not sure what you mean about "disassembling the diff". All I had to do was get the pinion nut off, remove the washer behind that, then pull the yoke. After that, was able to get a slide hammer in to pull the cup shaped seal retainer. Behind that was another washer, followed by the front taper bearing, then the crush sleeve. Quite frankly, once I figured out what was going on, it was all rather simple. I was literally able to pull the taper bearing and crush sleeve out with my finger tips...no tools or special force required.

[The Tassie Devil(le)]

That tube looks nothing like what I am used to for a crush sleeve.

Looks more like a solid spacer.

A crush sleeve is like in the picture, with a differing diameter between the ends, that allows the sleeve to actually compress.

To get the power to crush that straight tube, you would have to apply excessive pressure, and the thing wouldn't progressively crush, but distort itself without retaining any of the elasticity of a specially-made, collapsible crush washer/spacer.

Bruce.

[39LaSalleDriver]

That tube looks nothing like what I am used to for a crush sleeve.

Looks more like a solid spacer.

A crush sleeve is like in the picture, with a differing diameter between the ends, that allows the sleeve to actually compress.

To get the power to crush that straight tube, you would have to apply excessive pressure, and the thing wouldn't progressively crush, but distort itself without retaining any of the elasticity of a specially-made, collapsible crush washer/spacer.

Bruce.

Well, I'm back to square one then and don't know what to say. I have absolutely no doubt that this crush sleeve or spacer is how it left the factory. It is hard to see in the photo, but it does indeed have a slight, almost imperceptible bulge around the circumference on one end. Perhaps this type of crush sleeve is why the Assembly Manual indicates that the torque value is 1,200-1,400 ft. lbs. upon initial installation. Note paragraph 13 from Brad Ipsen's instructions.

"13. In 1939 Cadillac started to use the
collapsible sleeve design. For 1937
and 1938 cars see step 21. The
purpose was to provide the factory
with a simple method to preload the
pinion tapered roller bearings. The
preload in force is approximately
1200 to 1400 pounds. This force is
provided by the designed
deformation of a precisely machined
collapsible sleeve. This results in
the bulge noted in step 11. The risk
on disassemble is that the sleeve
will now be slightly short which will
excessively load the bearings before
the yoke nut is tight enough. On
reassembly shims can be added to
insure that this does not happen."

Upon rereading this paragraph myself, particularly the last two sentences, it sounds to me like maybe all is not lost. Perhaps this is exactly what I need to do...swap out for a thicker shim(s) and see if that solves my problem. Hopefully Brad or somebody else will pop in here and confirm or deny my suspicion.

[The Tassie Devil(le)]

Jon,

Looking ever-so closer, I think I can see a slight expansion, which would indicate that it could well be an early form of crush washer.

Having said that, and with the figures mentioned, this is definitely not attainable with the car on jack stands or a hoist, as if anything goes wrong, someone is going to get hurt.

The initial setting would surely have been performed during construction, held in a substantial jig, with very large tools.   Even my almost 4 foot torque wrench would be too small.

Now, why it felt too tight with the 0.005" shim, could it be that the sleeve had already been over-crushed, and was simply just sitting there loosely between the front and rear bearings?   You would never hear it if it was loose, and nobody would be listening for any noise in this area.   Diff oil would be around it, and stopping it from even rattling.

Bruce.  

[Dave Shepherd]

Agreed on the design of that crush collar sleeve. To get that crushed enough to pre-load the bearings as Tassie said, would require a lot of force. Try the thicker shim, at this point you gotta do something. 

[39LaSalleDriver]

Now, why it felt too tight with the 0.005" shim, could it be that the sleeve had already been over-crushed, and was simply just sitting there loosely between the front and rear bearings?  You would never hear it if it was loose, and nobody would be listening for any noise in this area.  Diff oil would be around it, and stopping it from even rattling.

Bruce.  

Anything is possible I suppose, but I have to start with the presumption that the factory knew what they were doing originally, and it was all installed correctly. That being the case, I have to believe that it was torqued down to spec and was not loose. Since the pinion nut was staked to the pinion shaft with no signs of being tampered with or replaced, and there was a leather seal in there such as the factory originally used; I have to conclude it has never been touched since leaving the factory.


Commentary from Brad Ipsen in the previously mentioned thread bears repeating here:

"The large force of 1200 to 1400-pound force has nothing to do with anything you can measure in the field.  That number comes from the 1940 Manufacturing Information.  This is the instructions from the engineering department to the factory floor on how to put the car together.  They were just discussing the design.  It is not a torque.  It is the force that is on the collapsible sleeve and in turn on the bearings on their tapered shell.  The torque on the nut results in this force on the sleeve.  The sleeve yields (deforms) permanently to result in this force.  From reading the Manufacturing Information Manual Cadillac tested every one of these differentials for noise.  The question addressed was can we reuse the sleeves on another new differential and the answer was yes as long as you make sure on the next one that the sleeve is still long and can be collapsed some more.  In the Cadillac shop manuals this whole question of how to replace this seal was not addressed until the 1949 Shop Manual.  With the introduction in 1939 of the collapsible sleeve I guess they did not recognize that there may be a problem.  With the old design of shims and a thick sleeve there was no problem.  You just tighten it up to torque.  Drag was fixed by the shim pack and thick sleeve.  When they first addressed this in 1949 this statement is made.  "When it is necessary to replace the rear axle pinion oil seal or yoke it is very important that the procedure outlined below is followed to avoid overloading the pinion bearings or collapsing the spacer".  Earlier manuals just say to replace it with no instructions.  I have attached a rewrite of the Cadillac manual adding comments, modern part numbers and adding a shim.  I like that idea especially since Cadillac essentially did that at the factory with new production by reusing sleeves as long as they were long."

It sure sounds to me like Cadillac engineers felt the sleeve could be reused to a point. The question then becomes, what is that point, and how much "crushing" is too much? I'm back to thinking since the parameters for advised shim thickness is .005-.010 (or even up to .020 as you suggest) and I only used a .005 shim to try and get it zoned in, in theory I still have a minimum of .005 of shimming coming to me. In other words, pull it all back apart and insert my .010 shim and tighten it back down and see if I now have the proper drag.

Does that sound reasonable, or am I missing something in my logic?

[Dave Shepherd]

Go for it, as the end play  disappears, go slow, frequently  checking the torque  required to turn the yoke, modern diffs like are 20" rotating resistance.Tap the yoke occasionally to square things up.

[The Tassie Devil(le)]

In my days of rebuilding Ford 9" Diffs, and there has been a lot, there was two items that differed.   The basic centre had the crush washer/sleeve, and the performance centre, a solid spacer.

I only found these Solid spacers in the Nodular Centres (carried the letter N cast into the case) and using the Detroit Locker.   With those, it was a case of fit, test, fit a different size, test again, and on and on till one selected the correct one.   These Solid Spacers were the worst to get right, as one had to press off the front bearing with a press to access the placement or removal of the shim.   With yours, and the looseness of the yoke and front bearing, it shouldn't take that long to get it right.

Depending on the thickness of the metal in your sleeve, you could use it as a solid spacer, and test, add shim, test, add or remove, and so on, till you got it right.

I don't think I can add much more as my memory bank looks like it has been drained.  

Bruce.

[Brad Ipsen CLC #737]

Add another shim.  Again the 1200 lbs. to 1400 lbs. is not a torque.  It is the force that it takes to crush the sleeve or in other words it is the force pushing the bearings apart to their seats.  The torque of 225 ft-lbs results in a force of 1200 lbs via the threads.

[39LaSalleDriver]

Add another shim.  Again the 1200 lbs. to 1400 lbs. is not a torque.  It is the force that it takes to crush the sleeve or in other words it is the force pushing the bearings apart to their seats.  The torque of 225 ft-lbs results in a force of 1200 lbs via the threads.

Thank you so much for the clarification Brad! After several days of deliberation I felt pretty certain that this is what I needed to do, but wanted to hold off until someone with far more experience than me came forward. Clearly I was overthinking this whole thing and I apologize for pushing the panic button, but given the ramifications of messing up, I was determined to proceed with the utmost caution.

[fishnjim]

I don't agree that this is "good practice", trying to do something one is untrained or unprepared for and asking "strangers" for advice.  You've had your attempt.
Get a Diff specialist and let them sort it out.  Even if you think you "got it", and it isn't, it'll disintegrate or make noise, etc. if it's not right.  Man has to know his limits.
There's just somethings I draw the line on and messing with the rear diff is one.  I'm OK, taking the axles out or end seals, but internal gear adjusts, bearings, and I send them out.  Check the reputation before you use.  too many war stories...It's how good cars end up sitting for years untouched.