We were trying to drive to Oakland, California. Near San Rafael, on the freeway 101, our brakes quit. Turns out we lost all air in the air brake system.
The tow man was very helpful. He found that all our brake lines were loose, and we had lost the air through the fittings. He tightened up all the fittings (which should have been done correctly at the factory), and we were on our way again. Whew!