How to Fix a Stiff Brake Pedal?

[DelMelanie]

Reasons and solutions for a stiff brake pedal: 1. Related to braking before engine shutdown: The vehicle's braking system operates at maximum efficiency only when the engine is running. The brake booster is the key component that amplifies the force applied to the pedal. When the engine is off, the brake booster ceases to function, typically depleting its residual vacuum force after about 3 pedal presses. The stiffness you feel is essentially the lack of booster assistance. Solution: Simply restart the engine and firmly press the brake pedal again. Once the engine is running, the brake booster will reactivate, and the pedal will return to normal operation. 2. Brake booster air leak or malfunction: If you experience pedal stiffness without prior engine shutdown braking, or encounter this issue while driving, it likely indicates a faulty brake booster. Solution: If detected before driving, for safety reasons, have the vehicle towed to a repair shop for inspection. If occurring during driving, remain calm and gradually decelerate to stop. Try pumping the pedal multiple times to potentially restore braking function. Applying strong pressure can often still generate braking force.