The reason why I have to step extra hard on the brake pedal to stop the car
(1) Problem with the power brake.
Car troubleshooting
Car's has power brakes and their purpose is to make braking easier. When something is wrong with the power brake unit, it requires a lot more effort on the driver's part to stop the car. Most cars are equipped with vacuum-assisted power brake units. This type uses vacuum from the engine to help in applying the brakes. There is a vacuum hose that runs from the engine to a round metal or plastic canister located between the master cylinder and the firewall. A couple of indications which can help pinpoint the problem are:1) If the engine always runs rough, it's likely the problem only involves a broken/leaking vacuum hose, and..
2) If the engine runs roughly mainly when depressing the brake pedal while the vehicle is standing still, the power brake canister has failed.
The other type of power brake unit, a "hydro-boost", feeds off the power steering unit. If the engine speed doesn't change when depressing the brake pedal, the vehicle has a hydro-boost unit.
What to do?
First, let's determine if this vehicle has a vacuum-assisted power brake unit. Open the hood and locate the master cylinder. Find it? Refer to the car's manual if you are having trouble. Now, the power brake unit (whatever type) is located between the master cylinder and the firewall.
A vacuum-assisted unit will be a round plastic or metal canister, about 10" - 14" in diameter and about 4" - 7" deep. Is this what you found? If yes, you'll want to check the hose which connects the unit with the engine. Look for cracks or leaks and replace as necessary. If the hose looks OK or if this car has a hydro-boost power brake unit (i.e. you did not identify a canister-type device as described above), seek the help of a qualified mechanic. Unfortunately, power brake units are "throwaway" items and therefore when one goes bad, you'll probably have no choice but to replace it with a new one as opposed to a rebuilt.
Know your car brake problems diagnosis and troubleshooting guide based on actual workshop experience of a car technicians.
Learn more: Brake Problems Troubleshooting Guide