One problem related to brake hoses, lines/piping, and fittings has been reported for the 1997 Chevrolet Express 3500. The most recently reported issues are listed below.
I was picking up items in a home depot parking lot, when the brakes went to the floor, and I discovered the brake lines to the rear had rusted through and emptied out all the brake fluid. When it was on the lift and being repaired, I found that the rear leaf spring mounts are nearly corroded away. This is not a part designed to be replaced.