Most likely you have a bad brake booster or a vacuum problem going to the booster. The booster is what gives the power assist to make the car stop. If the booster has gone bad or the vacuum source to the booster has failed you will experience a hard high pedal and very little stopping power. A less common power brake system is called a hydra boost system, this system uses power steering fluid to produce the power brake action.
#brakes #hard #stopping