Brake bleeding is always a fun topic. Like Sirrotica, I work alone 95% of the time. Gravity bleeding works great nearly all the time. I have a venturi style vacuum bleeder as well. To save time I often use it to start the bleeding procedure faster, especially in cars with ABS where fluid to the calipers passes through the ABS modulator first before getting to them. Vacuum speeds the process. Once flowing fluid, I remove and let it gravity bleed. I have XM radio in my shop and listen to the 60's mostly. Once the fluid is flowing, I let each wheel gravity bleed 2 songs, about 6 minutes each. That gives me a great pedal almost every time. Some vehicles with ABS can be a bear to get the air out of if the system has gone dry. (ABS modulator). Some have bleeder screws on the unit, which helps. They can be gravity bled. Some don't. The scan tool in bleed mode really just energizes all the valves and solenoids in the ABS unit and helps vent any tiny air bubbles to the MC. I have had some GM trucks I had to scan tool bleed 6 cycles to get a nice pedal. Changing brake fluid is a good idea as it absorbs water. I change fluid for customers all the time. ATE now sells brake fluid in 3 colors, Amber, green and red I think. You suck out the MC and put a different color fluid in the MC. Then when you bleed the brakes at the wheels, you look for the color change to know you have the old stuff out. Kind of a neat idea.
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