Do you have to push really hard on brakes?
2 – Hard Brake Pedal
If the brake pedal is hard to push, the problem is most likely in the power assist mechanism. Do you have to press down hard on brakes? Vacuum Pressure. Vacuum – or really lack of vacuum pressure – is the most common cause of a hard brake pedal, and therefore the first thing to look at when a hard pedal is present. Any brake booster (whether from Master Power or any other supplier) needs a vacuum source to operate.