One problem related to brake master cylinder has been reported for the 2001 Chevrolet C/k 3500. The most recently reported issues are listed below.
Brake lines on my truck rusted thru and brakes failed while on the road. The rusted lines ran from the abs system to the master cylinder and front brakes. It occurred at low speed and I used emergency brake to get home. The lines have not been replaced as yet. I will save parts.