For 1990-2009 cars

1. Run the engine at idle.
2. Shift the gear lever into NEUTRAL.
3. Depress the brake pedal and hold the pedal with a constant foot pressure.
4. If the pedal gradually falls away with the constant pressure, the hydraulic system may be leaking. Perform the following visual inspection in order to confirm any suspected leak:

4.1. | Inspect the master cylinder fluid levels. Normal lining wear may cause a slight drop in the reservoir level. An abnormally low level in either reservoir may indicate a leak in the system. The hydraulic system may be leaking either internally or externally. Refer to Master Cylinder Diagnosis . The system may appear to pass this test but still have slight leakage.

4.2. | If the fluid level is normal and no external leaks are found at the brake pipe, the hose connections, the caliper or the wheel cylinder boots, inspect the service brake pedal travel, brake adjustment and the parking brake adjustment. Refer to Drum Brake Adjustment .