Rear Caliper (Disc Brakes - C & K Series): Inspection
WARNING: This page does not describe the selected car, but rather 30 other vehicles, including the 1998 Pontiac Trans Sport, 1998 Oldsmobile Silhouette, 1998 Oldsmobile Bravada, 1998 GMC Yukon, and 1998 GMC Suburban. However, it is still accessible from the selected car via links, so may be relevant.
Inspect inside of the caliper assembly for signs of fluid leakage. If any is found, rebuild or replace caliper.