Rear Wheel Collar Bearing

[Ponder]

Thought I had a rear wheel bearing problem and got a set from Dean at datsunparts.com. I Noticed that his part matches the one in the picture below (part 11):



But, when I pulled the axles, the collar bearings on the axles don't match the replacement part. They don't have that central ridge. They seem to have the same OD as the smaller diameter of the replacement. I haven't measured them accurately yet. Why would this be? The axle housing is large enough to accept the replacement piece. They seem to be the same length.

Turn out the bearings are in pretty good shape. I think I'm just going to put it back together and look elsewhere for my problem. But, I'm curious about what I put on the axle if/when I replace the bearings.

Thanks a lot.
Steve

[oilleak]

FWIW - The only one I've ever take apart had/has that center ridge