What Causes the Brake Pedal to Feel Harder Than Before?

[MacAutumn]

The reasons for the brake pedal feeling harder include vacuum booster pump leakage or failure, and pressing the brake after the engine is turned off. Below are some extended details about automotive brakes: 1. Drum Brakes: Inside the wheel hub, two semi-circular brake shoes are installed, and the "lever principle" is used to push the brake shoes into contact with the inner surface of the brake drum, creating friction. The inner surface of the drum is where the braking torque is generated. For the same braking torque, the diameter of the drum brake can be much smaller than that of a disc brake. 2. Disc Brakes: The brake caliper controls two brake pads to clamp onto the brake disc attached to the wheel. When the pads clamp the disc, friction is generated between them. When the brake pedal is pressed, the piston inside the master cylinder is pushed, creating pressure in the brake fluid lines. This pressure is transmitted through the brake fluid to the pistons in the brake calipers. The pistons, under pressure, move outward and push the brake pads to clamp the brake disc, causing friction between the pads and the disc to reduce wheel speed, thereby slowing down or stopping the vehicle.