What Causes the Brake Pedal to Feel Harder Than Before?
2 Answers
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.
I also experienced the issue of stiff brakes a couple of days ago, and after driving for ten years, it felt particularly noticeable. At first, I thought it was just a matter of getting used to it, but later I realized that the brake booster might be malfunctioning. This booster relies on engine vacuum to provide pressure to assist with braking. If it fails, pressing the brake pedal directly becomes extremely strenuous. Another possibility is insufficient or aged brake fluid—when the fluid thickens, it can make the entire system operate less smoothly, resulting in a stiff pedal feel. Air entering the brake lines can also often cause the pedal to feel harder, which requires checking the lines and fluid condition. Safety comes first, so I drove straight to the 4S shop for a comprehensive inspection. The mechanic said regular maintenance can prevent these issues, such as changing the brake fluid once a year, which is crucial. I suggest you not delay either—address it early for peace of mind. If you notice the pedal feeling unusually stiff and affecting braking distance while driving, it’s really best to get it fixed promptly.
