It is an interesting thought, and I've wondered about it, but it's gotta be the slowest thing going, getting the fluid from the calipers back to the master cylinder. It may well be better than doing nothing, and if done frequently enough, so as to keep what is in the master cylinder very low in moisture (so as to cause the greatest gradient) maybe it'd be good enough--especially most don't change at all yet manage a decade plus on the system.
Originally Posted by Oro_O
A lot of people are under that mis-perception. But it does. Immediately, no. But over a period of use it will mix fully and become homogeneous. Brownian motion guarantees it.
Originally Posted by hallstevenson
I'm not sure that brake fluid circulates that much so I think you just have clean fluid mostly in the reservoir and not so much in the lines or more importantly, the calipers.