Brake Fluid Leaks
With the engine running at idle and the shift lever in neutral, depress the brake pedal and hold a constant foot pressure on the pedal. If the pedal gradually falls away with the constant pressure, the hydraulic system may be leaking.
^ Perform a visual inspection to confirm any suspected leak.
^ Check the master cylinder fluid level. While a slight drop in reservoir level does result from normal lining wear, an abnormally low level in either reservoir may indicate a leak in the system.
^ The hydraulic system may be leaking either internally or externally. Also, the system may appear to pass this test but still have slight leakage. If the fluid level is normal and no external leaks are found at the brake pipe or hose connections or at the caliper or wheel cylinder boots, check the service brake pedal travel, brake adjustment and the parking brake adjustment