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Gear set up great with set-up bearings, but can't fit pressed bearings back in housin

thebyus

NAXJA Forum User
Location
Albuquerque, NM
Am setting up an Eaton-e locker in an a high pinion 30 with new gears (4.56) from Alloy USA. Pulled the axle from the JY with all gears and shims so I could measure shim stacks.

I made up a set of set-up bearings for the carrier (LM102949's), got the pinion depth all set up, worked the shim stack until the backlash was set to the gear set specs, got a perfect pattern and was happy with the carrier preload.

Figured I was all set -

So I pressed on the final install bearings (exactly the same as the set up bearings) and used the same races as for set-up, but once I pressed on the new bearings, I couldn't get the carrier back in the housing.

I pulled the final bearings off, reseated the set up bearings and everything was perfect. Installed one of the pressed bearings and could barely fit it into the housing, but not enough to actually seat correctly.

What the heck? :icon_redface:

Anyone ever heard of this before?

I tried pulling shims out of the stack on both sides but after pulling 5 thousandths out of each side and pressing them on I still can't get it to seat properly. :icon_redface:
 
Consider taking a set of calipers and measuring the thickness of each bearing/race combination, and compare all values to see if you have one that is out of spec.

Are the races LM102911s (just wondering because this is the combination that my 30 spline OX carrier uses)?

Are you using a housing spreader or dead blow hammer to install the carrier? It should not just slip into place. If it does, you need to add shims for preload.
 
Some people no longer use setup bearings for this reason. The slip fit allows them to angle slightly and can skew results. In my own case I had to remove some when using final bearings, but only about .005". It should take a bunch of whacks with a rawhide or soft faced mallet 2.5-4 lb to get the carrier to seat (if you aren't using a case spreader).
 
As I understand it, bearings and races are a "set". If that is true, then why use the set-up races with the final bearings? When I did my D30, I made set-up bearings also, got it all set up with set-up bearings and their races. For final install used final bearings with their matching final races.

And, yes, it will take blows with a hammer (soft deadblow or similar) to get the carrier into the housing unless you're using a case spreader.

Just my 2-cents.
 
As I understand it, bearings and races are a "set". If that is true, then why use the set-up races with the final bearings?

Are they really a set from manufacture or do they become a set as they wear together? Can't you buy the bearings and races separately? My inclination is to use setup bearings (or the setup race in the case of the inner pinion bearing) matched with the final races so that as few variables change as possible when going from setup to final configuration. If brands differ between setup and final bearings or races, extra variance may be introduced into the system.

I'm currently setting up a D30 that the pinion bearings went bad in. I'm using a setup race that is another brand than the final race. I'll let you know how the gear patterns compare when I put the real race in, which should be a day or two. I lost my setup bearings somewhere between now and the five or six years that have gone by since I last used them, so I am using a clamshell puller to adjust backlash, but since the bearings are now 5 or 6 years old, I'm thinking this is preferable for consistency reasons (new setup bearings vs. old actual bearings).
 
Thanks for the input, everyone.

I finally spec'd them and turns out I had one that was out of spec that preventing me from even getting it back into the housing at all. (it took a four different measurement points to find it!) Replaced that one and all is good.

As for the race/bearing combo, my understanding is a WavingPine says, they are sold separately and then wear together and become a set.
 
WavingPine, yes, they are 102949 bearings with 102911 races. Seems to be pretty universal for lockers. I buy them from my local truck pro; they come in an off-brand box, but are Timken inside :clap:
 
WavingPine, yes, they are 102949 bearings with 102911 races. Seems to be pretty universal for lockers. I buy them from my local truck pro; they come in an off-brand box, but are Timken inside :clap:

Cool--thanks for the information on the bearing/race combination.

Now for my follow-up on the inner pinion bearing set-up race. Sadly, my Timken setup race did not work well with the Koyo actual race. I spent a lot of time doing the setup and when I pounded in the actual press-fit race, which did appear to seat fully (I pulled the axle to do the install so easy to see), the pinion was way further forward. I bought the factory Miller tools from a guy on Ebay to remove the inner race without ruining it or the bore and will now have to pound out the Koyo race and remove pinion depth shims. Quite disappointing, really. But the two races are not from the same manufacturer, so I have lived and learned at least that manufacturer mismatch is asking for trouble with setup bearings, or in this case, the race. Wish I had been sent Timkem bearings so I could have done the more relevant test.
 
Cool--thanks for the information on the bearing/race combination.

Now for my follow-up on the inner pinion bearing set-up race. Sadly, my Timken setup race did not work well with the Koyo actual race. I spent a lot of time doing the setup and when I pounded in the actual press-fit race, which did appear to seat fully (I pulled the axle to do the install so easy to see), the pinion was way further forward. I bought the factory Miller tools from a guy on Ebay to remove the inner race without ruining it or the bore and will now have to pound out the Koyo race and remove pinion depth shims. Quite disappointing, really. But the two races are not from the same manufacturer, so I have lived and learned at least that manufacturer mismatch is asking for trouble with setup bearings, or in this case, the race. Wish I had been sent Timkem bearings so I could have done the more relevant test.

That completely sucks, man. Guess I got pretty lucky with the setup race and then installing the real race. Of course, I completely misread the torque setting for the pinion, so have been trying to get it to 20 ft/lbs as opposed to in/lbs :gee:
 
Of course, I completely misread the torque setting for the pinion, so have been trying to get it to 20 ft/lbs as opposed to in/lbs :gee:

That's pretty funny. Good thing you caught it before you ran it that way!
 
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