Whits end with brakes

[lil hoodlum]

Sounds like you've covered all of the usual things. I'm not much help, but the only thing I could think that may have been installed incorrectly are the disc brake calipers. Are the bleeders facing up or down?

Another thing I've had to do with a stubborn brake system that had an air pocket was to get a turkey injector with the needle removed. Fill the injector up with brake fluid, attach it to small hose that fit over it, and forced brake fluid up through the bleeder to the master cylinder. Air bubble was forced up and out the master cylinder.