A crucial component in a vehicles braking system, the Brake Master Cylinder is the piston that creates pressure on which the rest of the braking system relies. When the feel of the brake pedal changes, especially when no fluid can be found escaping the system, inspect the master cylinder. Life spans of brake master cylinders vary widely, depending more on usage and maintenance than time.
It is important to bleed a Brake Master Cylinder during installation. This is a good time to refresh all brake fluid in the system, protecting your vehicle from further maintenance related failures in the future.