Gee, I got sidetracked when I unexpectely bought a ZZ502 (http://www.chevelles.com/forums/showthread.php?t=308436). Anyway, back to the 12 bolt, I noticed that the right side outer bearing was about 1/8" from being bottomed in the housing. I installed it about 8 years ago. Do these bearings ever walk outwards?

I installed the bearings with new Toms axles, which didn't have the smoothest bearing wear surface, they had what I consider a pretty course machined texture. They have about 10K of running on them now. They aren't worn, but you can see where the bearing was. I am assuming that if I put a new bearing in, and the patter shifts sideways a bit on the axle, that will be OK, huh?

And finally, anyone know the Timken part number for the outer bearings, and Chicago Rawhide number for the seal? Or is there a better seal?

Thanks!

Thought I'd posted this in one of your other post's http://www.jdrace.com/Rear_ID/12bCHEVY.htm

Axle bearing is DB67309 and National seal is 8660S.

Hey Freddie, do these bearings ever migrate once they are seated in the bores?

Depends on how tight they fit in the housing. If they are a tight fit then they usually don't move. I have seen some that fit loose. I use a center punch to dimple the housing end and use Locktite to hold it in place.