Set-up with set-up bearings is perfect, but can't fit pressed bearing back in housing
 

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:

You can't simply measure the old shims and expect it to work.

There are far to many variables that prevent this type of install to work the way you think it should.

Try downloading any one of the many installation manuals that are out there on the web. You'll quickly figure out that setting up gears is not an easy tast.

Throw the set-up bearings in the trash. The problem with using them is that the new bearings are not an exact match....so you'll end up with an axle that won't last very long.

Carriers on old axles are easy to remove because the bearings have worn down. New bearings with the correct shims are hard to install without a case spreader, or knowing a few tricks to get the carrier installed.

The tools you really need to do the job right...
12 ton press
Clamshell bearing puller
1/2" drive socket set
300 ft ld torque wrench
50 in ld dial torque wrench
Dial indicator and magnetic base
Dial calipers or a micrometer
Time
Patience

Thanks, Serious -

I've got the tools and done it a couple times with other people on their rigs. I understand that I can't simply take the old shim stack measurements and shove and go. I've got new shims, and have worked through the whole set-up using BillaVista's pirate write-up for guidance. Instead of using a case-spreader I'm using a little diff oil on the outside of the races and a 4lbs dead-blow to seat the carrier.

I was just completely blown away that one set of bearings could be soooooo different from another of the exact same part number, especially using the SAME races.

So, if I am going to toss the set up bearings, my question becomes, how many times can you press a set of bearings on/off before they are also garbage?

If you're measurements are spot-on, you shouldn't have to pull them more than once or twice.