Brake Master Cylinders push the braking liquid through the brake lines so that the pads pressure against the rotors to stop the car. The usual lifespan of a brake master cylinder is about 10-15 years, but can vary if you regularly change your braking fluid. 

A few signs of brake master cylinder gone bad are:

• abnormal or soft brake pedal
• polluted brake fluid
• on check-engine lights

We can get these cylinders repaired by fixing the leak in the seals. But the possibility of this repair differs based on the model and make of the car.