Brake Hoses, Lines/piping, And Fittings problems of the 1999 Chevrolet C2500

Complete rear brake failure in parking lot just as I was leaving work. Had to quickly pump brakes to keep truck from moving. Brake pedal went to floor in an instant. I put truck in park got out and there was fluid all over the place on the ground,and on the drivers side under carriage just behind the cab door. Looked underneath with flashlight and could see that the brake line had severe rusting where each plastic hold down is located and one had rusted to point of failure. Glad I hadn't pulled out and onto the highway at that point. Had to have most of the line replaced along the frame rail,( about 15').