Pic. 15.70. Elements of the anti-lock braking system: 1 - hydraulic device; 2 – a rotor of the gauge of frequency of rotation of a forward wheel; 3 - front wheel speed sensor; 4 - diagnostic socket; 5 - rear wheel speed sensor; 6 – a rotor of the gauge of frequency of rotation of a back wheel; 7 - control unit; 8 - relay block
Some cars of 1987 release are equipped with disc brakes of the rear wheels, some of the cars of 1988 release are additionally equipped with an anti-lock brake system (ABS). The anti-lock braking system, installed since 1988, is designed to increase the stability of the car during heavy braking. This is achieved by monitoring the speed of rotation of each wheel and controlling the pressure in the brake system, which prevents the wheels from locking up. The presence of a system malfunction is signaled by a yellow control lamp in the instrument cluster. The anti-lock braking system consists of a hydraulic device, a relay unit, a control unit and wheel speed sensors (pic. 15.70). The control unit is located in the cabin and is essentially «brain» systems, providing reception and processing of signals from wheel speed sensors and generating commands to control the relay unit and hydraulic device. Due to the complexity of the device, it is advisable to perform diagnostics and repair of the system in a car service. When working near the wheels, brake system or suspension of the vehicle, be careful not to damage the wheel speed sensors.