Servofrân

Servofrân (frână servo) is a braking system component that provides pneumatic or hydraulic assistance to braking by using pressure differences to amplify the force the driver applies to the brake pedal. It is commonly referred to as a brake booster and is typically located between the brake pedal and the master cylinder. The device makes it easier to brake and allows for more precise control, especially at lower pedal efforts.

In operation, when the driver presses the brake pedal, a valve within the booster admits or alters vacuum or hydraulic pressure on a diaphragm or piston inside the booster. This pressure difference pushes the booster piston, adding force to the movement transmitted to the master cylinder. The master cylinder then increases the hydraulic pressure in the brake lines, producing braking force at the wheels. A check valve and seals ensure the booster maintains pressure when the pedal is released and prevent unwanted leaks.

There are several types of servo-frân. The most common is the vacuum-assisted (diaphragm) booster, which uses engine vacuum as the source of pressure. Some vehicles use hydraulic or electro-hydraulic boosts, often in heavy-duty or high-performance applications. Modern vehicles may employ electric or electrohydraulic boosters that do not rely on engine vacuum.

Advantages include reduced pedal effort, improved braking response, and better control under varying loads and speeds. Limitations can include dependence on a sufficient vacuum source (in vacuum-based systems) and the potential for booster failure, which results in a harder brake pedal. Regular maintenance focuses on vacuum lines, seals, and the booster’s integrity.