As part of a wheel redo, we also did the main gear axle to better than factory.  They were not painted, just bare alum.

Here is the starting point. Pretty right?  Okay so take everything apart, making sure you know what shims are where and what way they face (this is your toe-in/tow-out)!  Bead blast the gear after masking off the axle.  Put new hardware, shims back in, and bolt up.  Rebuild the caliper also while here.