A master cylinder can seize on a motorcycle due to several reasons. Here are a few common causes:
Corrosion: Over time, moisture can enter the brake system and cause corrosion within the master cylinder. Corrosion can lead to the piston or other internal components sticking, causing the master cylinder to seize.
Contaminated Brake Fluid: If the brake fluid is not regularly flushed and replaced, it can accumulate contaminants such as dirt, debris, or moisture. These contaminants can interfere with the smooth operation of the master cylinder, leading to seizing.
Lack of Lubrication: The master cylinder relies on proper lubrication to ensure smooth movement of the internal components. If the lubrication breaks down or becomes insufficient, the piston may start to stick, causing the master cylinder to seize.
Overheating: Continuous hard braking or riding in hilly terrains can generate excessive heat in the braking system. When the master cylinder gets too hot, the brake fluid can boil, leading to the formation of gas bubbles and loss of hydraulic pressure. This can cause the master cylinder to seize.
Internal Component Wear: Over time, the internal components of the master cylinder, such as the piston or seals, can wear out. As the wear progresses, the piston may start to bind or become misaligned, resulting in a seized master cylinder.
If you encounter a seized master cylinder on your motorcycle, it is crucial to address the issue promptly. Severe seizing may require replacement of the master cylinder, while less severe cases may be resolved through cleaning, lubrication, or rebuilding the cylinder with new seals and components. It's recommended to consult a qualified motorcycle mechanic to properly diagnose and fix the problem.