Detecting a bent axle

[dla]

How do you determine if an axle is very slightly bent? How much run out should they have? I've got a little bit of "wow-wow" noise left over after R&R of a rear axle bearing - shaft bearing surface looked fine. Now I'm wondering if it is slightly bent. Thanks.

 

[BeaterMan]

you could pull off the tire and drum and use a dial indicator to check the flange for being warped and do the same right behind the wheel flange.