The brake pedal feel on a vehicle with an ABS system has a very different feel than that of a conventional braking system. While the Antilock Brake System is energized you can feel rapid pedal pulsations or brake pedal feedback until the system turns off or the car is stoped.
Even though this is normal operation some drivers may think that a serious defect is present in the brake system. Chances are when they road tested the vehicle before they bought it they did not try panic stops. Also the fact that emergency braking can be rare motorists could possibly drive a vehicle for years without using the ABS function.
Note that these pulsations are the result of the hydraulic fluid modulation that is controlled by the ABS computer and the hydraulic braking system. Some of the latest ABS braking systems are starting to use dampening valves in their modulation unit. This reduces the harsh brake pedal feel to the driver’s foot during a panic stop.
Some times vehicle owners will complain about the way the brake pedal feels when the Abs system is active. The best bet would be to compare the operation with a similar vehicle.
Why we need antilock brakes
With all the problems that come with an antilock brake system such as ABS warning lights being turned on, harsh feel from the brake pedal, why should we have these systems on our vehicles at all?
It’s all about stopping the vehicle in the shortest possible distance. In the old days people would have to pump their own brake pedal in a emergency braking situation. Now we have antilock brake systems that can modulate the pressure to the brakes as often as 15 times per second. By modulating the pressure to the brakes friction between the tires and the road is maintained and the vehicle is able to come to a controllable stop.
Steering is another important consideration of tires that are locked and skidding. Therefore one of the big advantages of ABS is the ability to keep control of the vehicle under these panic conditions. If your front tires are not locked up. Steering the car away from trouble is now easier.
Some people are not aware that antilock brake systems do not prevent all wheel lockups. Some wheel slip is allowed in order to achieve the best braking possible. During ABS operation, there is a target slip rate that can be anywhere from zero to 30%. This is why when the system is active you can still hear just a slight amount of tire lock up.
The antilock braking system is our friend. Cars stop in shorter distances then vehicles built several years ago thanks to the latest antilock braking systems. A few drivers will drive around with the warning light on because they are afraid of high repair costs.
The diagnosis and repair of the Antilock light should be priority one for maintain braking safety. Some ABS malfunctions are easily repaired, such as defective wheel speed sensors. In rare cases, antilock brake system electrical circuit malfunctions can be harder to repair and diagnose.