One problem related to brake disc has been reported for the 2002 GMC Sierra. The most recently reported issues are listed below.
Consumer heard something pop ping and fell into the street. Consumer had no brakes in the rear. In the front the brake disc was badly pitted because of the poor quality of alloy. Consumer was driving up to a stop, trying stop, when the brakes failed. Consumer sailed on through the stop sign. The front brakes were grinding due to the metal on the disc. The consumer had to replace with a whole new braking system with aftermarket products. Consumer did not feel safe with the gm brakes. This happened all of a sudden, there were no prior problems. This vehicle only has 8,000 miles on it. This happened while slowing down between 10 and 15 mph.