Lost Rear Bearing Shim Washers

[Matthew Abate]

Right but my car confirmed both the diagram and the tsb by having washers in two different places.


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[Zed Head]

I thought you said that you found one stuck in the grease, and couldn't remember how they came apart?  Regardless, Nissan, the company, has no record or documentation describing anything between the bearing races except the distance piece.  Seems like there's only one path forward though, when putting it back together.  I think that the diagram is just wrong and that's all there is to the bigger picture.

This puzzle is more about where the diagram originated.  And maybe about where those washers were in your car, but if your guy threw all the pieces in a box, who knows?

Or, somebody did measure the distance piece in the past and decided it needed to be thicker, so they stuck a washer in there.  There are letters on the hub and the distance piece.  Do they match?  that would be a clue.  No tools necessary.

Looks like carpartsmanual is the source.  I've often wondered where they got their information.

 

http://www.carpartsmanual.com/datsun/Z-1969-1978/axle/rear-axle-drive-shaft

[Captain Obvious]

And that's exactly why you need measurements.

At this point, I don't think you can trust the documentation. Nor do I think that you can trust that things were assembled correctly before you took them apart.

Measurements.

[beermanpete]

The use of any washer in the hub assembly that would affect the bearing preload is suspect considering there was a grading and matching process of the hub and collar used during the original manufacture. The use of washers (shims, really) would require the distance collar to be intentionally short and the bearing preload would be set-up using shims. In this case the shims would need to be hardened, precision ground, and available in a suitable array of thickness to allow proper set-up of the assembly. Since Nissan does not offer such shims nor mention them in the service manual it seems reasonable to assume the presence of the copper washers in Matthew's car are there in error and should be left out of the assembly. As The Captain already advised, the collar and hub should be measured and proper set-up verified before final assembly.

[Zed Head]

Actually, the complete procedure is well written and detailed in the FSM.  Mentioned, obliquely, in Posts 2, 3, 4, and CO's.  Just saying, the FSM procedure is actually an easy, informative, and pleasant read.  Some interesting observations - the bearings aren't really peloaded (like a tapered roller bearing might be ) even though they call it preload and actually have a torque measurement.  Plus they have a torque measurement AND an end-play spec.  Not sure that either of those is correct for a ball bearing, of this type. (Edit - and they don't tell you what to do if just one of the specs is off.  Grease the seal?) It's a set of balls riding in two races.  The distance piece is spec'ed to match the inner race separation distance to the out race separation distance (controlled by the hub casting), which should be the important part.  Getting those two races aligned.  It seems like Nissan might be allowing for the inner axle to expand a bit or they are setting the balls up to ride on the edge of the race.  The distance piece (inner race) is closer together than the outer races.

It really is interesting if you dig in to it.  http://www.skf.com/binary/tcm:12-114679/140-710 BIMG 11_2012_tcm_12-114679.pdf

Something that's come up in the past - using the axle nut to pull one of the bearings in to tis seat.  This loads the balls at singular points on the races and should be a no-no.

This puzzle is really about what came out of M. Abate's car, and why the carpartsmanual diagram is wrong, I think.

Sorry, I love a good technical deep-dig...

Edited November 15, 2017 by Zed Head

[Matthew Abate]

I have some numbers to report:

The distance bearings / spacers came in at 52.56 mm long. There was a small amount of variance as I went around the diameter of up to .02 mm and this was true of both.

The washers came in at 1.01 mm. The amount of variance around the diameter was .01 mm and from outside edge to inside edge was also .01 mm.

I have to wait for the POR-15 to dry to do the hubs, but the distance from the very outside of the area on the spindle where the outer bearing seats to the very inside of the same for the inside bearing is 86.32mm, although there’s a good chance this is wrong because of the radius at the point where the spindle flares into the wheel hub. I used the edges of the shiny spots where the bearings were as my guides.

I need to fish my bearings out later to add it all up. Hopefully they’ll add up to 32.75mm.

 

—-

 

Caveat: nothing but the bearings is available new so this is pretty much academic at this point. I’ll probably just put them together and cross my fingers.

 

[Captain Obvious]

I don't consider it academic at all. You say you took two of them apart and the washer was in a different place between the two sides. Now that you have measured the length of the distance piece and found them both the same, I consider only the following two possibilities:

1) One of those rear corners was assembled wrong. Very wrong. Or...

2) You were mistaken about the location of the washers upon disassembly, and they were both installed in the same relative position on both sides. Either both in series with the distance pieces, or both between the inboard bearing and the companion flange.

I had originally considered a third possibility that one of the rear knuckles had been machined to have longer distance between the two bearings than the other, but the factory spread from distance pieces (from length "A" to length "C") is 0.2 mm, and there would never ever be a need for a 1.0mm thick washer in there. So unless some repair shop went in there and added metal to the bearing seating surface, I consider this possibility very unlikely.

I think you still need to determine double dog sure where those washers go.

And back to it being academic? It's not. If there IS a measurement mismatch, it's not as bad as you think. It would be a relatively simple procedure to machine replacement distance pieces of the proper length. In fact as a side note, I just went through this a few weeks ago with the cheap-o aftermarket lawn mower blade spindles I purchased. They were incorrect as purchased, and I had to adjust the lengths of the distance pieces between the two bearings. During the process, I accidently cut the second one a thousandth too short (crap!!!) and had to make a completely new replacement.

BTW - I'm all in that the washers go between the inboard bearing and the companion flanges, but it's still prudent to wait for confirmation.   

[Captain Obvious]

Forgot... I don't remember how large the hole is in the rear knuckle.

Too small to feed the jaws of the caliper in there and measure the distance between the two bearing seats directly?

[Matthew Abate]

Regarding my possibly making a mistake, yes, that could have happened, but here is the sequence of events:

First I used a dremmel tool to cut the peened nuts so I could get them off the hubs. They appeared to have never been removed.

I took the assembled struts to a shop to have them pressed apart. They came back disassembled but the inner bearings were still inside the hubs and the outer ones were on the spindles.

Then I took the spindles to a different shop that could follow directions to have the bearings pressed off.

Then I putt everything except the struts in a tub and cleaned the grease off. This is when I noticed I only had one copper washer.

Then I pulled the seals out of the hubs. This is when I found another copper washer.

So from this I found that I had one washer between the bearing and the seal, and another one stuck onto a distance bearing with grease.

From this I assume it was always between the bearings because the first shop didn’t pull it out from under the seal and then put the seal back in. I know this from the dirt that hadn’t been disturbed.

—-

I used the depth gauge on my micrometer to measure from the outside of the inner bearing (it’s still in the hub and will be pressed out when I take it to the shop to have everything reassembled) to the outside of the outer bearing seat. It is 69.48mm.

I still have the new inner bearings coming in the mail so I can’t summarize all of this until I get them. I’ll get more numbers when I have a chance.

—-

Something else I noticed is the outer bearings go in one way only. The inside race is thinker (21.93mm) and offset from the outer race by about 2 or 3 mm. This extra bit protrudes toward the hub. The orange on in the illustration below:

Note this illustration also has the bearing washers.

—

Here are the numbers I have again:

52.56 - distance bearing

21.93 - outer bearing

86.32 - spindle bearing seats (edge to edge)

11.83 - available space on spindle minus distance bearing and outer bearing

16.64 - inner bearing (rough measurement)

5.01 - leftover space inside of hub minus distance bearing, inner bearing, and outer bearing

52.69 - space between outer bearing seat and inner bearing still inside of hub (this measurement gives me hope!)

16.97 - seat inside of hub for outer bearing

1.01 - copper washer

[Captain Obvious]

Well there's still possibility #1 that one of the rear corners was put together wrong. If that were the case, I would assume it would pan out like this:

They pressed the outer bearing onto the stub axle correctly.
They also pressed the inner bearing into the knuckle correctly.

But then they incorrectly put the distance piece AND a washer onto the stub axle before inserting it into the knuckle.

If that's the case, when they tightened the nut, it would draw the stub axle into the knuckle until it bottomed out. That bottoming out is SUPPOSED to occur at the exact same position when the outer race of the outer bearing makes contact with the seating surface machined into the knuckle.

But if they had a 1.0mm thick washer in place, the stub axle will bottom out against the inner bearing 1.0mm BEFORE the outer bearing is fully seated.

Not the end of the world resulting in an immediate spectacular failure, but would probably result in a load on that outer bearing that it wasn't real happy about. Would also result in your wheel being 1.0mm farther out than the other side. Not that you would notice that with your eye though.

As for measuring the distance between the seating surfaces... You could hold a short flat piece of something against one of the seating surfaces and then use a depth measuring tool from the other end to determine the distance? In other words, use one bearing surface as the seat for a depth measuring tool, and then use a temporary (hand held) anvil against the other surface as the stop for the depth measurement.

I'm trying to come up with a direct (instead of calculated) measurement of the counterbores inside the knuckle.

Using the still installed inner bearing is pretty good, but sometimes the inner and outer races are not ground to exactly the same width. Also, you will be pressing the inner race downward which takes up all available play. I would think this could explain your 52.69 measurement above. The one that gives you hope gives me hope as well and adds credence to the "installed incorrectly" theory.

Let me know if that makes sense, and if not, I can whip up a sketch or something.

[Zed Head]

Is the topic still "what happened" or "how to put it back together"?  The numbers say "B" hub to me.  Is there a B?

The extended race is described in the part description, if it helps.  It would be on the outside, so the inside portion of the inner and out races would be flush when assembled.

[Zed Head]

A thought on being sure the distance piece is correct for the hub.  Stick the piece in without the axle.  It should be flush with the outer race seat on the other side, within a few thousandths. 

It's kind of a goofy spec. because the ranges overlap.  They seem to want the distance piece to be smaller than the hub but the overlap and wide range makes the opposite possible.  "Blueprinted", the distance piece would be about .0012" smaller than the hub.  Without the perfect tools, a flush feel by finger is probably good.