AN ABS QUIRK

Although we’ve had virtually no snow and not much ice there is still the possibility we could. If it happens there is one highly important but very misunderstood factor about driving on snow and ice you should know. All modern cars have ABS brakes and they’re a great help to keep cars from skidding. ABS brakes are a major safety feature that allows a car to be steered around obstacles during panic stops.

But unfortunately you probably received zero meaningful information or training about how to use and what to expect from your ABS brake system when you bought the car. Some owner’s manuals make a half-fast attempt to describe the feeling and sound ABS makes but words really can’t convey the ABS experience to first timers.

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 and you to maintain control. Works exceptionally well as long as you know what to do and what to expect.

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. 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 because 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.

Generally using ABS is pretty basic. First is properly using the brake pedal. Back in the days before ABS the rule was to pump the brake pedal to help avoid skidding. But not with ABS brakes. Pumping the pedal will keep the ABS system from doing its job and could lead to an accident. The normal and basic rule in most situations for using ABS brakes is stomp — stay — steer! What that means is to stomp on the brake pedal, stay on the brake pedal and do not release it and steer around anything in your path.

The exception to that rule is if all four wheels are on a slippery surface. In that case the ABS system will not work; at all! The reason is that when the car is sitting still at the traffic light you certainly do not want the ABS to release the brakes so if all four wheels have stopped turning the ABS system thinks the car is sitting still. Unless at least one wheel is turning the ABS system has no way to know the car is moving. Even if you’re sliding along at high speed with all four wheels locked the ABS thinks you’re placidly sitting still. In that situation you should revert to the old ways and pump the pedal to maintain or regain control. Also remember that ABS doesn’t make a car stop faster it just allows you to steer during a panic stop.

Warning: to remain active ABS systems require preventive maintenance and if you don’t perform that maintenance the resulting damage will be pricey. Brake fluid attracts and absorbs moisture from the air which leads to corrosion on very expensive electronic and hydraulic parts. Happily, ABS preventive maintenance is neither difficult nor expensive. Maintenance is just flushing old moisture-contaminated brake fluid out of the system every 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. Just thought you should know.

 

© Copyright 01/10/11 Pat Goss all rights reserved.

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