One problem related to brake drum wheel cylinder has been reported for the 2002 Chevrolet S10. The most recently reported issues are listed below.
First incident approximately 2/15/2015, brakes pedal went close to floor when trying to stop vehicle, downshifted transmission to help stop vehicle. It was determined rust had caused a hole to develop in brake line cooler behind radiator of vehicle. Significant loss of brake fluid. Second incident approximately 5/15/2015, brakes became mushy loss of brake fluid. Rust caused pin hole leak in brake line at rear wheel brake cylinder. Third incident approximately 7/26/2015 significant loss of brake fluid. Cause yet undetermined.