GM Service Manual Online
For 1990-2009 cars only
  1. Check for a cracked casting on the master cylinder, or for brake fluid around the master cylinder. Leaks are indicated only if there is at least a drop of fluid. A merely damp condition is not abnormal.
  2. Check for binding at the pedal linkage and for incorrect length of the pushrod. If there is no binding at the brake pedal, and if the brake pedal travel is OK, disassemble the master cylinder. Refer to the Light Duty Truck Unit Repair Manual.
  3. Check the master cylinder for piston seals that are swollen or elongated