from Goss’ Garage by Pat Goss
Gene, a long-time viewer of Goss’ Garage recently asked for help in solving what he thought was a serious brake problem. During the last big snow storm he was trying to stop near the bottom of a hilly, icy, snow packed street when his ABS brake system didn’t work — at all! As a result his right front wheel kissed the curb causing several hundred dollars in suspension damage. Since then he has been to three shops trying to find the cause of his one-time lack of ABS but no one has been able to find a problem.
ABS brakes are a major safety feature that allows a car to be steered around obstacles during panic stops. They work by preventing wheels from locking which leads to a loss of control. ABS is great but like most safety features there are things it can’t do.
Warning: to remain active ABS systems require preventive maintenance and if you don’t perform that maintenance the damage will be pricey. Also most drivers, Gene included, haven’t a clue what ABS is, how it works, and what it can and can not do.
Happily, ABS preventive maintenance is neither difficult nor expensive. Maintenance is just flushing the old moisture-contaminated brake fluid out of the system every two years. Brake fluid attracts and absorbs moisture from humidity in the air which can reach a critical concentration in two years. Moisture-contaminated brake fluid reduces brake efficiency and shortens brake-parts life. And no matter what your dealer tells you there is no such thing as a sealed brake system that can’t absorb moisture.
Equally important to benefiting from ABS is knowledge. Most drivers receive no meaningful explanation or training about how to use and what to expect from their computerized ABS brake system. Some owner’s manuals make a feeble attempt to describe the feeling and sounds the system produces but words can’t accurately convey the ABS experience to first timers.
To be prepared and react properly during an ABS-active stop, you should rehearse. Find a safe location such as a deserted parking lot or unobstructed, wide, dirt or gravel area. Wherever you go, safety is your number one concern so it’s recommended you take someone with ABS experience along. Practice by applying the brakes very hard at low speed. When the wheels attempt to lock you’ll probably feel and hear an alarming, but normal, thumping or buzzing. This causes many accidents.
How? The noise and vibration scares drivers into releasing the brake pedal, which releases the brakes, which causes them to hit the very thing they’re trying to miss. So ABS benefits require you to be familiar with its sound and feel. Also know the rules of ABS: in most panic stops (see the exception below) Stomp on the brake Stay on the brake and Steer around the object. Familiarity means you’ll react properly when you’re faced with the real thing.
My ten-cent ABS explanation: A sensor at each wheel monitors the speed of that wheel. If during braking one of the sensors determines the wheel it monitors is locked up (turning more slowly than the rest or not turning at all) it signals the ABS computer. The ABS computer then releases the brake on that wheel allowing the tire to rotate and regain traction which allows the driver to maintain control.
Finally, two things ABS can’t do! ABS does not make a car stop faster it only provides steering control during braking. The second ABS foible is almost universally unknown to drivers. If all four wheels are on an extremely slippery surface such as ice or packed snow it’s possible for all four wheels to lock up and quit turning. With no wheels rotating the ABS thinks the car is standing still and doesn’t activate and you lose control. Under such conditions you may find it necessary to revert to pump your brakes to maintain control of your car. Actually, Gene’s car didn’t have an ABS problem. Gene’s problem was his lack of ABS knowledge!
© Copyright 2/9/2010 Pat Goss. All Rights Reserved.
