Something to try is to raise the rear axle up as high as you can and bleed each rear brake, then lower back down and raise the front, anything you can do to get the air to the highest point. Pumping the pedal should do the same, but sometimes simple gravity helps. Parking on a steep hill works too.
Vacuum bleeding from master cylinder can pull air into a system from the wheel cylinders, I've been down that road once, it made the problem much worse. I have also seem vacuum bleeders pull air around open bleeder screw threads and the fellow just kept trying to get all the air for a very long time.
I've run my truck for 23 years with no residual valves, disk/drum, master under the floor. A good working system shouldn't need them, fluid is not going to return to the master cylinder without a leak.
Last edited by Joe H; 07/31/2023 12:49 PM.
