Anti Lock Braking System

2406 Words Jul 1st, 2011 10 Pages
Chapter Four ABS Training
4.1 What is ABS?
Anti-Lock Brake System (ABS) is a combination of vehicle hardware and software that work together to maintain steering control and vehicle stability during hard braking. Initially developed as a special option for topof-the-line models, today’s ABS units are compact, easy to service, inexpensive and widely available. Now every major automotive manufacturer offers some form of ABS vehicle control that provides safe, maximum braking under all weather conditions and road surfaces.

Fig. 1

Integral. INTEGRAL systems incorporate the power unit (pump and accumulator), master cylinder, and control valve mechanism into one hydraulic unit. An external microprocessor and individual wheel sensors
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The ABS components include wheel speed sensors, an electronic control module, and a hydraulic modulator assembly that includes electrically-operated solenoid valves.

Everything starts with the wheel speed sensors. Wheel sensors consist of a magnetic pickup and a toothed sensor ring or a slotted collar. In some applications, the sensor is an integral part of the wheel bearing and hub assembly. In others, the sensor ring(s) may be mounted on the axle hub behind the brake rotor, on the brake rotor itself, inside the brake drum, on the transmission

Many repair technicians are turning away ABS equipped vehicles because they perceive these systems as too complex, too tough to diagnose, or requiring special tools and repair skills. What these technicians don’t realize is that the same brake components they’ve worked on for years still do the job of stopping the vehicle. It’s simply the addition of the ABS unit and its components that make the system special. Service technicians had the same reaction when ECM controlled vehicles first appeared. What we quickly learned was that 80% of the driveability problems were still engine related. The same will hold true for ABS systems. Proper training to recognize and understand the differences between ABS systems and how they function will be necessary, and some special test equipment and
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