what is procedure for bleeding brake booster ? on 2001 Ford F-250 Super Duty

hydralic brake booster whines real load and brake pedal is soft,need to replace brake booster.

Asked by for the 2001 Ford F-250 Super Duty
check the power steering fluid first. that is what runs the booster.
if the pedal is soft, i would look at the brake system also for leaks or a bad master.