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Bambikiller240

Replacing S30 Rear Wheel Bearings

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5 minutes ago, Zed Head said:

The bearing on the wheel side is staying on when you do the swaps right,press fit on the axle journal?  So you have either the axle or the bearing as the problem, probably.

There's much discussion about damaging races, "brinelling", by pulling on the outer race,if the inner race is pressed on.  But during installation, you're pushing backward on the outer race as you tighten the nut and they seem to survive  Seems like you could separate the bearing from the axle and test both independently.  If you had lots of free time...

Yup bearing is staying attached to the stub. I will likely test everything out once I get it running and then reach out to timken if the bearing was faulty. I'm really curious now as to what has failed.

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If I was desperate, I believe my conscience would allow me to re-use the outboard bearing even after pressing the stub back of once it had been installed. The outboard bore is sized such that it's a press fit, but not a uber tight one. That's why the slide hammer works. If it were a real tight press fit, you'd need hydraulics to take it apart because a slide hammer wouldn't cut it.

However, I'm not sure I'd do that if they'd been assembled and disassembled ten times.   LOL   In any event, it's academic since new ones are on order.

I also really really doubt it's a bearing issue. Even without seeing the parts, I'm at 90% sure the issue is the stub axle and not the bearing.

Just for the sake of the investigation, I hope you can eventually conclusively determine exactly what was going on.  I like the forensic stuff!

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I think it's the stub too. Being a scientist, i love the forensics stuff too. If it is a bearing issue, I am going to measure every little part of it and see just how much a difference made. if it's off by less than a thousandth, I will be very surprised by the precision required to make that whole system work.

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I'm leaning towards a seating issue.  Four surfaces, any one of which could cause a problem.  The inner races and distance piece form a solid tube of steel connecting the flanges together.  Might even be possible to take the bad axle and bearing set and use a pipe and a press to be sure that the inner race is fully seated.  Pound it down on the wheel flange surface.  Then reinstall and see if torquing still causes the problem.

Don't really the use of the nut as the final press of bearing installation.  It's not "right".  Aesthetically displeasing.  I haven't done one but if I did I'd try to knock each race in to place separately if I could figure out a way.

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We used a hydraulic press to seat everything and inspected all mating surfaces. I'm 99.9% certain it isn't a seating issue at this point. 

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Being certain before knowing just makes a person less likely to see what's there.  Cognitive bias.  No offense.

If you consider it mechanistically, like what, exactly, is touching and binding, then a race misalignment seems like a good possibility.  The bearings have play in them from the start, properly installed, you can lift your wheel up and down a noticeable amount when the back end is lifted.  And push-pull it in and out.  Seems like there'd have to be quite a bend in the shaft to get a bend-bind.  A short distance piece, giving zero end play, and any type of misalignment will be magnified.

Might be interesting to measure end play while you're torquing.  If it goes to zero before you get it fully torqued, that's a clue.  Zero end play would require perfect race alignment for the balls to ride in.  It must be ball-bind that's the issue.  Ouch.  They need room all the way around the track.  You might find varying end play as you rotate the flange.

It's an odd problem.  I've been surprised at how loose the rear bearings are, in general.  But that's how most rear wheel bearings are, even in live (solid) axles.  I had an old 55 Chevy truck that wore out a bearing completely, spitting the balls out, riding race to race.  You could lift the rear wheel up about 2 inches when it was on the jack.  And it just kept going until I sold it to a guy who was going to restore it.  I was a didn't-care teenager.

image.png

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Last thought - a bent wheel side flange would measure out as a bent axle, relative to the wheel flange.  The bearing seating surface would be off-perpendicular to the axle bearing journals, except for two exact postilions.  Seems like the most likely cause.  Somebody slid in to a curb in the past maybe.

 

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Quick Update: Just had everything arrive last night. I received two used axle stubs with companion flanges and B distance pieces so that should solve the issues. I need to blast and powdercoat one of them before I install it in the housing and I should be ready to go on Friday

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6 hours ago, the_unknown said:

Quick Update: Just had everything arrive last night. I received two used axle stubs with companion flanges and B distance pieces so that should solve the issues. I need to blast and powdercoat one of them before I install it in the housing and I should be ready to go on Friday

Have you measured the distance pieces?  They get deformed.

image.png

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I measured the old one and it was out of spec by about 0.02 mm. We also created some distance pieces on the lathe that were within spec. I measured the "new" used ones and they are square and measured in at 52.52mm and 52.50.

 

I swear if this doesn't fix it I'm gonna go 5250... amirite?!?

 

I'll see myself out. 

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She's a 72, # 55375 If I recall correctly. Bought her in the fall of 17 in Californina and drove her sight unseen home across the country to VA

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22 hours ago, the_unknown said:

Bought her in the fall of 17 in Californina and drove her sight unseen home across the country to VA

Oh wow! That's cool. And brave!!

Those sort of journeys are often good stories. Was it an entertaining eventful journey, or was it a smooth sailing boring story?

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Thanks 🙂

I had a friend that lived in Mammoth Lakes CA, only a couple hours from it. He's a pretty good mechanic and said it would make the journey with some basic maintenance. We ended up just changing fluids, bleeding brakes, new thermostat, and tried adjusting the clutch to get it to stop slipping at load in 4th and 5th. We decided to try the journey to SLC and if there were any major issues, just get it towed the rest of the way. He followed me to my brothers house in SLC and we had no issues. I rolled the dice and got it home the rest of the way weith the slipping clutch. It should have been scary and I shouldn't have made it in hindsight but it ended up being a boring story. Nothing broke save for a fuse that wasn't making good contact in the fuse block. It has a L28 with twin SUs and a 5 speed, it's seems pretty damn bullet proof!

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Well we put the new axle and bearing into the hub and everything is great! It was likely a bearing issue at this point, but I haven't had a chance to rule out the stub. There is a tiny gap that you can see light through on the bad stub between the collar of the bearing and the seating surface. I can barely get my thinnest feeler gauge through it which is 0.0016. I think it just never got fully seated. It doesn't explain why it was binding in the same spot when rotated though. I'm gonna pull the bearing off for the 5th time now and really inspect that surface to see if I can figure it out.At least I have an extra set of hubs and bearings just in case now 😂

 

Thanks again for all the help and advice!

Edited by the_unknown
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I'm glad the story was that boring! Although a harrowing hair raising saga would have been much more entertaining!   LOL 

And I'm also glad that you've got a set of hubs put together now that are issue-free. And if you've got a gap between the flange and the outboard bearing, that's definitely a raging clue as to the previous issue.  1.6 thousandths can be a LOT when talking about bearings.

Just for forensic analysis... See if you can determine if that gap is the same all the way around the bearing. If it's the same all the way around, in theory it shouldn't cause what you saw. But if it's .0016 on one side and zero on the other (which is what I suspect), then it's indicative that something is bent or you got some piece of grit or metal shaving trapped under the bearing race. In any event, it's almost definitely related to the problem.

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luxKwFm.jpg

This is the gap. It is even on all sides which would make sense. I'd imagine it would be difficult to get it that far onto the seating surface if it was ****-eyed. I'm thinking the distance piece at this point was too long and binding the balls against the outer races. I pulled the bearing off last night and everything seemed ok. Nothing there that it should have bound on. I'm just glad I got to drive it some after it's been sitting on blocks for nearly a month.

 

The only "exciting" part of the story was coming back through Morgantown WV on I68 in the pouring rain and having the clutch slip going up the mountain passes. It got a little nerve wracking but I knew I was almost home and could easily get a tow at that point.

I've still got some work to do to her but the suspension and brakes are basically done now. I still need to powdercoat the mustache bar but the big oven at my local makerspace isn't quite ready yet. BCGtMlo.jpg

 

 

 

 

 

 

 

Edited by the_unknown
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Hi All,

So the only way to remove the rear wheel bearing locknuts is cut off the top pinched section? What a cluster! One time use parts? 

20190521_161137_resized.jpg

20190521_161127_resized 2.jpg

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Yes. The original ones are one use parts. After you do the hubs once, you won't really want to do it again. Besides it's been 45 years on the first ones! The 280zx nut is a self locking nut and could possible be used again. Although a lot of people advise against. So buyer beware!

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I first used a dremel tool to cut away the peened/staked part of the nut, but having changed many wheel bearings since, I just get a very small cold chisel and wedge it between the  bolt and the nut to push the deformed part outward. Works great.

Tip... use a grinder to keep the cold chisel tip in good form.

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I am surprised the peened part even needs to be addressed. With a larger breaker I would have guessed it just pushes out of the way. I assumed it was there to keep the nut from loosening from vibration, not the blunt force of a breaker bar.

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The FSM actually says you shouldn't have to address the peened (they call it "caulked" in the FSM) sections at all. They say just to take them off without messing with the bent portions at all.

However....... There was someone here who actually DID try that and it distorted the threads on the stub axle a little. I didn't dig up that thread, but it's in here somewhere. And after seeing what happened to his threads, I wouldn't recommend following the FSM. I would do something to the bent over portions first before taking the nut off.

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21 minutes ago, Captain Obvious said:

The FSM actually says you shouldn't have to address the peened (they call it "caulked" in the FSM) sections at all. They say just to take them off without messing with the bent portions at all.

However....... There was someone here who actually DID try that and it distorted the threads on the stub axle a little. I didn't dig up that thread, but it's in here somewhere. And after seeing what happened to his threads, I wouldn't recommend following the FSM. I would do something to the bent over portions first before taking the nut off.

after my post I did some googling, seems like has to do with if the threads are involved or not in the stake section. I am guessing the axle is treaded all the way to the end?

When I was working on the transmission I found the stake did not need to be undone. It just bent back up. The stake part was pretty thin. I don't recall the thread issue (to end or not).

Perhaps just how the staking was done would matter (cut and curled up or just dented down).

I cant see the harm in at least using a tool to get under the stake and at least getting it started on the way up if not removing it altogether.

 

Edited by Dave WM

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Thanks All, I'll try cutting a groove and bending out or off the treads. Concerned about cutting to the treads. Back with a report shortly. 

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Spreading the bent part out slightly with a chisel or drift should be enough.  Oil them up before removing so that they can re-expand more easily.  Think of it as a machining operation.

Sometimes, apparently, the threads next to the flats get damaged during nut removal.  But, because there are flats next to them I don't think that they supply any real holding power.  It looks bad but it doesn't matter as far as function.

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