yep, if your nitrogen cylinder fails, it will cause your fluid to froth and foam up and then puke out. Flushing and refilling will get you by, but the cylinder is toast. With a good nitrogen cylinder, you should be able to get about 2 boosted pedal applications with the truck shut off. You will not get any brake assist (truck shut off)with a bad cylinder. Your brake system should still operate correctly with the truck running.