[Schurkey]

Originally Posted by ftwmlp

It's interesting you mention getting the master cylinder "tipped down" by raising the rear. In one of my conversations with a man at the remanufacturer, he told me a story about one time having to use a fork lift to lift the rear of a similar truck with a forklift to get a good bleed job. Like the wise old man I am, I dismissed this as a BS story since that is opposite of all my limited experience.

Air pockets rise in brake fluid unless prevented by fluid viscosity or surface tension.

Most master cylinders are mounted to the vehicle with the front tipped "up", to align them with the pushrod from the brake pedal.

Any air trapped in the master cylinder goes forward--"up"--AWAY from the drilled passages leading to the master cylinder reservoir. Finding a way to tip the front down allows the air pocket(s) to move toward the cylinder/reservoir drillings, and applying just a hint of pressure will blow the air from cylinder into reservoir. Pumping too far will move the master cylinder pistons enough to cover the ports--so you just barely tickle the pedal. Maybe the master cylinder pistons move 1/8 inch or so.