One problem related to brake master cylinder has been reported for the 2001 Chevrolet Silverado. The most recently reported issues are listed below.
Transferring some materials from neighbors house to ours, dirt road / driveway. Got to our house, brake pedal went to the floor. Refilled master cylinder, parked the truck. Checked fluid later, entire master cylinder was empty as truck was parked. Brake lines seem to be rotted out.