What is going on with this stub axle?
 

I've gone through two left rear wheel bearings in the past few years on my track car, so something is wrong.

The issue seems to be a loosening (or an inability to tighten in the first place) the stub axle to the hub. In the picture you can see a ridge built up, based on a little research I think that surface should be flat?

http://forums.pelicanparts.com/uploa...1430065466.jpg