Use the following procedure in order to test for brake problems that may be caused by fluid leaks:

1. Run the engine at idle speed.
2. Shift the transmission into park.
3. Apply pressure to the brake pedal. Maintain constant foot pressure on the brake pedal. If the pedal slowly sinks to the floor, the hydraulic system may have internal leakage, external leakage or improperly adjusted components.
4. If the pedal slowly sinks to the floor, the hydraulic system may have the following problems:

•	External leakage

•	Internal leakage

•	Incorrect component adjustment

5. Perform a visual inspection of the hydraulic system.
6. Check the fluid level of the master cylinder.

•	A slightly low fluid level in either reservoir can result from normal wear of the front brake lining.

•	An abnormally low fluid level indicates a leak in the hydraulic system.

•	Even with a high fluid level there may be small leaks. Refer to Master Cylinder Reservoir Filling in Hydraulic Brakes.

If you find no external leaks, internal leakage may be the cause. The master cylinder must be disassembled in order to diagnose internal leakage. Refer to Master Cylinder Overhaul in Hydraulic Brakes.