[speeder]

You can also open a bleeder screw slightly while compressing caliper pistons to avoid back flow. If you do it carefully, a very slight bleed at the wheel will assure that no air went in.

Lots of good points on this thread. One thing that came to mind is that you do not have to move the MC piston through its entire range, (pedal to floor), in order to bleed brakes with a good MC. It’s usually a bad idea, for the reasons mentioned above.

The comment about dirty fluid in lines after a supposed fluid change at a shop is prime reason why I do my own brake work whenever possible. It’s absolutely true that shops will only change the fluid in the reservoir, which of course has exactly zero effect on brake performance and safety. The fluid in the reservoir almost never mixes with the fluid actually doing the hydraulic braking. At the very least, you need to flush fresh fluid through all of the lines and even then, you can wind up with dirty, old fluid trapped in calipers. None of this comes into play if you change it on time. Almost no one does.