Brake issue - an odd one

[kyriian]

So my Z4M recently developed another little niggle
-One of my wheels show significantly more brake dust than the other wheel
-The dust pattern is only on the side to the outside, the inside is far cleaner (I have white wheels, so this is VERY obvious)

-I had replaced my brake caliper bushings, and brought a rebuilt caliper, it bled fine
-It drives fine, it does not show sign that it is pulling or a seized caliper, nor do i hear it dragging.
-BUT, the dirty wheel's rotor is defenitely hotter than the other side.

should I spend the coin to replace my 10k old rotor? What else could it be

[Clearancediver]

Likely the piston on one side of the caliper isn't pushing onto the brake pad. The other piston/brake pad is compensating … hence the excess of dust and one side of the rotor heating up excessively.

I'd replace the rotor with new not rebuilt…