One problem related to brake master cylinder has been reported for the 2001 Chevrolet 1500. The most recently reported issues are listed below.
As I was coming down a hill toward stopped traffic I applied my brakes. The brake started to slow the truck then went all the way to the floor. To avoid the stopped car in front of me I turned toward the shoulder of the right side of the road. I was able to navigate around the car and stay between the car and a drain runoff on the shoulder. I continued on the should still trying to stop I split between a telephone pole and a tree. I finally came to a stopped about 75ft after that. I got out to check under the truck at each tire. There was no fluid. I proceeded to open the hood and check the master cylinder. It was full. I went back under the driverside door and under the door hinges on the frame the was brake fluid all over.