Description of the design of the brake system

The Ford Focus has four disc brakes as standard: the internally ventilated front disc brakes are 22 mm thick and 258 mm in diameter. They are clamped in tongs by pistons of 54 mm. On the rear axle are discs 10 mm thick with a diameter of 252.7 mm, pistons with a size of 34 mm act on them. In order for the cam calipers to work without applying much force, they are assisted in the Focus by a 10-inch brake booster, which is directly connected to the brake pedal. Direct contact with the brake pedal eliminates the otherwise common intermediate lever. Focus drivers spot the missing part by the comfortable pressure center and the well-metered pressure buildup in the brake system.

ABS in combination with EBD is always standard on the Focus braking system. EBD uses ABS sensors to detect wheel speed. During braking, the rear wheels under «supervision» EBD, only such brake pressure is released at which they are always braked with maximum deceleration force just before the blocking limit. The system automatically takes into account each load condition, thanks to which it shortens the braking distance, including the overshoot of the ABS control range. The ABS in the Focus is state of the art with up to 12 control intervals per second. It provides maximum deceleration without limiting controllability and forms the basis for ASR and ESP.

ASR brakes only individual wheels in the lower speed range. Above a speed of 50 km/h, it additionally assists the engine control by reducing the torque by selective cylinder fuel diet and/or modified ignition timing, etc., until uniform traction conditions again prevail on the drive wheels.


Since 1999, Ford has increased the safety margins of the Focus' undercarriage with ESP as an option. ESP, being an interactive system, reduces engine power with the help of a progressive identifier and purposefully brakes individual wheels. ESP, by its intervention, provokes a yaw moment, which automatically stabilizes the car. The system works completely autonomously with the active brake booster.



At this point, we quite consciously repeat ourselves: against «headless» drivers ESP is powerless: if the limits of the physics of movement are really exceeded, departure off the road is inevitable.