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Bambikiller240

Replacing S30 Rear Wheel Bearings

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25 minutes ago, the_unknown said:

According to his measurements, the space between the seating surfaces is longer than the B housing / the stock unit.  The bearing bores are slightly smaller than the stock unit as well and are a little more out of round. When he says small, I'm assuming a thousandth or two.

I'm starting to think that the new housings were warped from the heat during welding and are slightly warped in one way or another.  The seating surfaces could look like this _/-----\_ or like _\------/_ instead of _|------|_ if that makes sense. Sorry for the crappy ASCII art.

I understand the ASCII art perfectly. And if the seating surfaces are not square to eachother, there will be big problems.

There will unquestionably be dimensional changes caused by the welding operations and my expectation would be that T3 would have started with raw materials and designed the housings such that after welding, there would be extra material that would have to be machined off to square up the surfaces and make them precise. Above, you mentioned looking for a thousandth or two, but when it comes to bearing placement, you're actually looking for the tenths of thousandths. A thousandth or two is usually way way way too much. In fact, a thousandth or two would make the difference between 200T required to press a bearing in vs. one that drops in free with just it's own weight.

If those bearing bores are out of round and/or not coplanar to within a fraction of a thousandth, then I think you ought to put in a call to T3.     :blink:

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2 minutes ago, Captain Obvious said:

I understand the ASCII art perfectly. And if the seating surfaces are not square to eachother, there will be big problems.

There will unquestionably be dimensional changes caused by the welding operations and my expectation would be that T3 would have started with raw materials and designed the housings such that after welding, there would be extra material that would have to be machined off to square up the surfaces and make them precise. Above, you mentioned looking for a thousandth or two, but when it comes to bearing placement, you're actually looking for the tenths of thousandths. A thousandth or two is usually way way way too much. In fact, a thousandth or two would make the difference between 200T required to press a bearing in vs. one that drops in free with just it's own weight.

If those bearing bores are out of round and/or not coplanar to within a fraction of a thousandth, then I think you ought to put in a call to T3.     :blink:

I have a feeling that's what I'm going to spend most of my day doing (talking with T3). I can't seem to find anyone else that has used their setup either to see if I am the first person to run into this issue. I forgot to mention that before tightening down the companion flange, he measured runout at 0.001 of the stub shaft.

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1 minute ago, the_unknown said:

before tightening down the companion flange, he measured runout at 0.001 of the stub shaft.

Yeah, that's not cool. If that shaft is straight, there's no way you should be seeing that. Maybe out at the edge of a big rotor or something, but no way you should be seeing that at the axle without the mechanical amplification of big disk.

Are you seeing that on both axles? One of them turned out OK, right?

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I think he is seeing it on one axle but I will confirm tomorrow. I just reread some of my texts with him and he said it was less than a thousandth of run out. He seemed pretty confident it wasn't a bent stub shaft. 

I haven't been impressed with T3's product so far. They look pretty but I've had multiple other issues with these coilovers.

 

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4 hours ago, the_unknown said:

My buddy did some measuring on the new t3 housing. Keep in mind these are the fabricated ones and not the converted ones from people sending in their cores. According to his measurements, the space between the seating surfaces is longer than the B housing / the stock unit.  The bearing bores are slightly smaller than the stock unit as well and are a little more out of round. When he says small, I'm assuming a thousandth or two.

Do you have any closeup pictures of the bearing mounting area?  It would be interesting see.  That's a fairly complex area to fabricate to those tolerances, from scratch.  Matching two bores in concentricity, parallelality, along with dimensions.  I made the second word up myself.  I didn't know anybody was trying to match the Nissan product there.  That would take some skills.

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8 minutes ago, Zed Head said:

Do you have any closeup pictures of the bearing mounting area?  It would be interesting see.  That's a fairly complex area to fabricate to those tolerances, from scratch.  Matching two bores in concentricity, parallelality, along with dimensions.  I made the second word up myself.  I didn't know anybody was trying to match the Nissan product there.  That would take some skills.

https://technotoytuning.com/nissan/240z/evolved-rear-coilover-conversion-datsun-240z

 

Those are the ones I purchased. I don't have any closer up photos yet and I won't until tomorrow. One of the biggest things I noticed right off the bat is that there is no grease storage cavity where the distance piece goes like the stock housing has. Not sure if it would matter or not. 

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So it's just a boring and honing operation, probably.  Should have left the final sizing for after it was all welded together.

You might see some scrape marks in the bore, showing where the fitment problems are.  A bright light and a camera could help.

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1 minute ago, Zed Head said:

So it's just a boring and honing operation, probably.  Should have left the final sizing for after it was all welded together.

You might see some scrape marks in the bore, showing where the fitment problems are.  A bright light and a camera could help.

I'll definitely be taking a bunch of photos and carefully inspecting and measuring everything tomorrow assuming the other stub axle binds as well. 

 

I will need to do a long write up regarding their QC on here and maybe Hybrid Z as well. I documented a lot of what I've done on a thread in the Off Topic section of a Subaru forum but this would be good to put in Z focused forums as well. I've been working on doing fronts and rears since January now and I'm still not close to being done now. 

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So I swapped the other stub shaft in and it fit just fine. We also put the suspect one into the other housing and it was binding in that housing too which means it's an issue with the shaft or outer bearing. We used feeler gauges to check under the outer bearing collar and the gap was the same all the way around which leads me to believe its an issue with the stub shaft. I've got a set of two new used ones on order from ebay that should be here next week. Hoping that fixes it and I can enjoy some of this nice spring weather soon.

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Well that's pretty definitive about the stub shaft. Hopefully the replacements from ebay will solve the problem! That would be a really easy solution. A lot easier than pulling everything back apart and starting completely over. Unless you have a neat way of pulling the outboard bearing off the stub shaft without putting pressure on the balls, you might consider using yet another new outboard bearing on the new replacement ebay stub. Depends on how you feel about reusing the one you already pressed on.

On ‎8‎/‎16‎/‎2018 at 2:42 AM, Jason240z said:

Hi

 

yes tried without the seal.... checked the hubs too,  measured bearings against the lip they sit on, then the height of the hub.  Fully home...

And all this talk about wheel bearings and the resurrection of this thread reminds me... We never heard back from @Jason240z about the final outcome with his car. I believe his car is back on the road (so his issues have been resolved), but I don't think the loop was ever closed about what the problem was. Hopefully he can fill us in?

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1 hour ago, Captain Obvious said:

Well that's pretty definitive about the stub shaft. Hopefully the replacements from ebay will solve the problem! That would be a really easy solution. A lot easier than pulling everything back apart and starting completely over. Unless you have a neat way of pulling the outboard bearing off the stub shaft without putting pressure on the balls, you might consider using yet another new outboard bearing on the new replacement ebay stub. Depends on how you feel about reusing the one you already pressed on.

Already ahead of ya, I ordered new timken bearings on and plan on discarding the old ones or keeping them as backups. Both inner and outer have seen some abuse by being pressed in and out a few times so i'd rather just be safe and do it right instead of doing it twice. Thanks again for all the insight.

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15 hours ago, the_unknown said:

We used feeler gauges to check under the outer bearing collar and the gap was the same all the way around which leads me to believe its an issue with the stub shaft. 

Do you have any way to measure runout?  Should be there.  Sounds like you removed the shaft and the installed bearing.  Could be a damaged bearing.

There's also tolerancing.  If T3's bores are on the small side and you got a "big" bearing race, maybe it's still a fit issue.

Sounds like you'll get it fixed, just not clear, exactly, what the problem is.

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10 hours ago, the_unknown said:

Already ahead of ya, I ordered new timken bearings on and plan on discarding the old ones or keeping them as backups.

Cool. It's money, but those bearings aren't the kind of thing you want to do any more times than necessary. Glad to help and good luck with the rest of it. Keep us posted as to how it all turns out.

8 hours ago, Zed Head said:

Do you have any way to measure runout?  Should be there. 

I'm having a hard time picturing a good way to measure things to look for problems (like a bend) with a stub axle. You need good reference points and I'm not sure what you would use and how you would fixture it. The only precision surfaces on the axle are the bearing journals, but how would you detect a minute bend in the shaft between the two?

What you're really looking for is that the two bearing journal circles are not on the same axis center anymore. How would you fixture to detect that?

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True.  A lathe might be the way to do it.  Set it up so that one journal is centered and the other should be too.

Maybe a flat surface with the axle journals on it and a bright light under the contact points, or some very fine feeler gauges.  But the dilemma here is the axles could be fine, but the seating of the inner race is not.  Just looking for confirmation.

Since he has new bearings coming, he might as well pull the ones he has and reseat them.  Maybe swap bearings on the axles in question and see if the problem follows the axle or the bearing, or neither.  Maybe one of the bearings has a bent ball retainer, for example.  Once the two races get aligned the retainer locks up?  Or the inner race itself is defective.  Could be cracked.  Just guessing.  A bearing swap might tell something. 

 

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I considered something like the lathe, but the problem is that even though you can chuck something up and adjust it to be perfectly centered (within the limits of your measuring equipment), that centering is still only at one point along it's length. The jaws are never good enough that you can assume the shaft sticking out of the chuck is perfectly normal to the chuck jaws.

The optical method you described crossed my mind as well, but I don't know if the gap would be large enough to see. I've got a granite block designed for such things, but don't know if I would be able to see a quarter thousandth gap even with a strong light. And a quarter thousandth off from center at the journal could translate to more than that at the edge of the outer bearing race.

Back when they made the stub shaft, they turned it "between centers" (That's the two little holes in the ends.) To produce the shaft, they mounted the raw stock between two points that were located in those holes. But the problem now is that those holes are all rusty and worn and I doubt you can trust the accuracy anymore to the level required to check the journals for runout. But if you could, that's probably the right way to do it. Fixture the whole thing up on the granite block... Mount the stub between centers and indicate each journal.

I'm not a machinist and I'm sure someone working in a metrology lab would be able to do this in a snap.

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On 4/24/2019 at 2:54 PM, Captain Obvious said:

Well that's pretty definitive about the stub shaft. Hopefully the replacements from ebay will solve the problem! That would be a really easy solution. A lot easier than pulling everything back apart and starting completely over. Unless you have a neat way of pulling the outboard bearing off the stub shaft without putting pressure on the balls, you might consider using yet another new outboard bearing on the new replacement ebay stub. Depends on how you feel about reusing the one you already pressed on.

And all this talk about wheel bearings and the resurrection of this thread reminds me... We never heard back from @Jason240z about the final outcome with his car. I believe his car is back on the road (so his issues have been resolved), but I don't think the loop was ever closed about what the problem was. Hopefully he can fill us in?

Hi Mr CO.

Its 10000000000% not on the road. 😞

However did make a some shims that 'fixed the issue, I might check the new bearings size against the old though(annoyed I didn't think of that before).

Stub axles are run true in the bearings, its just that they bind when torqued up.  Reading the above, it seems the new Timken bearings could be the issue?  I might make a new distance piece for the centre of the hub and then its a single shim for the outside......

Bloody annoying really.

  • Sad 1

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We tried using his metal lathe to test run out and used the housing with axle and the measured the runout against the hub. It was over a thousandth at that point but still difficult to tell. I should have the stubs in next week and plan to toss new bearings into it just to try and eliminate that possibility. 

So far, the only thing we have ruled out is a housing issue. It could still be a bent stub shaft, bearing, or distance piece issue (I ordered those most liekly culprit to least likely culprit. I forgot we re used the stock distance piece but I doubt it is that as none of the sizes that we machined and tried made a difference on the first housing. I'm more curious than annoyed now as to what the hell it could be. I hope it isn't a bearing issue, I thought timken made some of the best bearings for these cars.

 

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Timken has an excellent reputation. It would be disappointing if they were the issue

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20 hours ago, Jason240z said:

Hi Mr CO.

Its 10000000000% not on the road. 😞

Jason,  Oh! Sorry! I must have gotten my wires crossed... I thought you were on the road already.

It's easy for me to rule stuff out from the comfort of my chair, but I really doubt that it's an issue with the new bearings.

So I think that if you're still chasing this issue, you really need to figure out a way to stick something down inside the hub and take a direct measurement on the distance between the two bearing mounting surfaces and see if that number lines up with the length of the distance pieces. Sacrifice a pair of cheap calipers like I did or something.

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18 hours ago, the_unknown said:

We tried using his metal lathe to test run out and used the housing with axle and the measured the runout against the hub. It was over a thousandth at that point but still difficult to tell.

I think the best way to look for runout would be to put the whole thing together as intended and then indicate (mag mount on the strut tube or something) off the hub. Maybe check both along the drum mounting surface for runout in the longitudinal direction, and also along the four rounded sections of the outer perimeter of the squared off hub for runout in the axial direction. Of course, this is all assuming the old rusted hubs are clean enough to even get reliable measurements.

Did you make double dog sure that the distance pieces were square ended? Some of the distance pieces that have crossed my bench had been modified by previous handlers and were ground on one or more of the ends chasing a problem. Not only were they too short, but they weren't square on the ends anymore.

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3 hours ago, Captain Obvious said:

I think the best way to look for runout would be to put the whole thing together as intended and then indicate (mag mount on the strut tube or something) off the hub. Maybe check both along the drum mounting surface for runout in the longitudinal direction, and also along the four rounded sections of the outer perimeter of the squared off hub for runout in the axial direction. Of course, this is all assuming the old rusted hubs are clean enough to even get reliable measurements.

Did you make double dog sure that the distance pieces were square ended? Some of the distance pieces that have crossed my bench had been modified by previous handlers and were ground on one or more of the ends chasing a problem. Not only were they too short, but they weren't square on the ends anymore.

He's been teaching me to run his lathe so I may give this a shot as practice for measuring the runout. Just not sure how accurate the initial tooling holes. The hubs aren't in terrible shape but they aren't perfect either and I'm not sure I can get an accurate reading based on the surface rust on the hubs.

 

The stock distance piece was fairly square and pieces we turned were square down to .00001. Neither made a difference in the binding. I haven't ruled it out yet but it's low on the list. New stubs should be here tuesday and I'll post a (hopefully happy) update then.

21 hours ago, Patcon said:

Timken has an excellent reputation. It would be disappointing if they were the issue

That's what I've always heard and never had an issue with their bearings. I'd be surprised if that was the culprit.

 

Edited by the_unknown

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Don't forget the other two seating surfaces, besides the distance piece. One on the axle and one on the companion flange.  A piece of grit or a metal shaving could have a big impact.  Edit - the distortion might not happen until the nut is torqued and the inner race gets cocked.

image.png

Edited by Zed Head

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We had the "bad" axle in and out more than a few times, then switched axles and the problem went away. We installed the bad axle in the other good housing and it locked it up too. So it's definitely an issue with the stub axle, bearing, or a small chance it's the distance piece.

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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...

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