The biggest pain and time consuming part of our wheel bearing jobs are getting the races out since Mazda was so kind as to not make them servicable. Now from what ive seen, most people will notch the hubs and drive them out with a punch. i dont like the idea of cutting up a part just to service it, so my best buddy and fellow 7 owner had me come over to show me another way around it. Basically you weld a ring around the middle inside of the race. this will cause it to shrink by just a couple thousandths, but more importantly it now gives you a surface to drive out the race with a punch and hammer. I realize not everyone has a welder, but if you do, this is a quick and effective method that doesnt destroy the hub. below is a link to the video i took.


feel free to chime in with any comments or concerns. Btw there was no warpage in the hub or rotor when done, checked with dial indicator.

 

i don't think it shrinks, I'd say it expands, but the aluminum expands too, at twice the rate (double coefficient of thermal expansion), and that's what makes it "fit looser". Nice trick tho!