GM Service Manual Online
For 1990-2009 cars only
  1. Run the engine at idle.
  2. Position the transaxle in NEUTRAL.
  3. Press the brake pedal and hold constant foot pressure.
  4. If the brake pedal recedes or goes all the way to the floor, inspect the hydraulic brake system for a leak. Perform the following visual inspection in order to locate and confirm the suspected leak:
  5. • Inspect the master cylinder fluid level. Normal brake lining wear may cause a slight drop in the reservoir fluid level. An abnormally low reservoir fluid level, causing illumination of the BRAKE warning lamp, may indicate a hydraulic brake system leak. The hydraulic brake system may be leaking internally or externally. Refer to Master Cylinder Diagnosis .
    • Inspect for leaks at the brake pipe and brake hose connections. If leakage exists, verify the torque of the fasteners/fittings and replace the pipe or hose.
    • Inspect the connecting brake components for damage. Rebuild or replace the connecting brake components as necessary.
    • Inspect the brake caliper and wheel cylinders for leakage. If leakage is evident, repair or replace the components as necessary.
       - For FRONT brake caliper leaks, refer to Front Brake Caliper Overhaul or Front Brake Caliper Replacement in Disc Brakes.
       - For REAR brake caliper leaks, refer to Rear Brake Caliper Overhaul or Rear Brake Caliper Replacement in Disc Brakes.
       - For wheel cylinder leaks, refer to Wheel Cylinder Overhaul or Wheel Cylinder Replacement in Drum Brakes.