Hydro-boost brake problems

[trukman1]

Hoping someone can help[ me. I have had hydro-boost for years w/o problem. One day while driving I lost brakes (literally) then on the way back to the house I have brakes again. Back home I bled the brakes, buddy system and gravity, no brakes then suddenly on third attempt I had brakes. Took for test drive, all okay. Drove later in the week, same old thing again, brakes working fine then NO brakes then brakes again on way home. Any ideas?

Needless to say I'm afraid to even test drive it at this point.