ABS - Anti-lock Braking System

ABS (Anti-lock Braking System) is a life saving technology which allows the driver to steer while braking heavily

ABS multifunction occurs due to the unit's design imperfection and failure of the components when the system overloaded. However most ABS modulus are repairable and can be restored instead of replaced by and expensive unit.

Objective of ABS
The system primary aims are;

• miximize braking power.
• Allow the driver to maintain control on the steering by preventing the wheel from locking and skiding.
• Shorten braking distance under most conditions.

Stopping a car in a hurry on a slippery road can be very challenging. Anti-lock braking systems (ABS) take a lot of the challenge out of this sometimes nerve-wracking event. In fact, on slippery surfaces, even professional drivers can't stop as quickly without ABS as an average driver can with ABS.

The ABS system - overview

An ABS system consists of the following components:

• Some wheel speed sensors
• Brake calipers
• A hydraulic motor
• Some pressure release valves
• A quick thinking computer (or control module) which coordinates the whole process

Diagram 1: Brake caliper (1) and wheel speed sensor (2)

How ABS works

When the driver hits the brakes this pressurises the hydraulic system which causes the brake pads to squeeze against the discs which causes the car to slow down. If the ABS system detects that one wheel is slowing down more rapidly than the rest (a symptom of wheel-lock) it automatically reduces the brake pressure on this wheel by opening a pressure release valve in the hydraulic system. ABS also has the ability to build the pressure back up via the hydraulic motor. The system reacts remarkably quickly, and compared wheel speeds many times a second. ABS systems can act on just the front wheels (which do most of the braking work), or all four depending on what car you're in.

Diagram 2: Wheel speed sensor (A), ABS control module (B),
hydraulic motor and pressure release valves (C), Brake pipe leading to caliper (D)