[grandville455]

Originally Posted by Sirrotica

Darby, you pretty much said it.

If you've ever siphoned gas, it works on the exact same principle once you have fluid below the master cylinder reservoir level, your work is done. Gravity takes over from there. The small pump at the very top of the pedal travel gets the fluid running downhill, without drawing in air to the system. Atmospheric pressure, and gravity power it.

When done check to see if you have a firm pedal, if not open the bleeders and let it drip for a few more minutes. The procedure works because air will rise to the top of a fluid column, this bears out when you stroke the pedal while observing the reservoir. You'll see bubbles come up from the bottom of the reservoir if the lines have not been fully purged of air. You actually bleed an empty system from both ends using gravity bleeding. If you don't observe any more air in the reservoir, your most likely done. The rest of the air exits from the bleeders during the siphoning process.

It's a simple principle, yet some people make it overly complex.

Thanks! So when u barely pump at the top of the stroke it doesn’t pull air back in like if push all the way to the floor when bleeder is open! I may try again today on my truck , have good fluid at back Bleeder but u can see bubbles in master yet when I pump the pedal