Auto servicing for mums

Why Do You Get a Pulsing Sensation through the Brake Pedal of Your Car?

Your car's braking system is of course one of its most crucial components. It's very important to ensure that this system is working perfectly not only for everyday operation, but also to make sure that you are as protected as possible in the event of an emergency. If you can sense something unusual, a strange "pulsing" sensation through the pedal, you may be concerned. What is this and what do you need to know?

How Your Braking System Works

Modern cars today are fitted with anti-lock braking systems in order to help you maintain control in difficult driving conditions. How do they work?

Anti-Lock Braking

The ABS system in your car is programmed to determine when one of the wheels loses traction as a consequence of it meeting a slippery road surface. This could be ice on the road in very cold conditions, or more likely you've encountered a wet and oily surface in a rainstorm. When your wheels meet this type of surface they have no traction and will simply slide. The ABS system prevents your wheels from sliding in this way, enabling you to maintain control and bring the vehicle to a stop much more quickly.

ABS in Action

These systems are very complex. They have speed sensors on each wheel which are constantly sending information to the car's computer and can detect when a wheel is about to lock. Secondly, there's a valve in the braking system attached to each wheel. These valves have three positions; open (which allows normal function), blocked (which isolates that wheel) and released (which releases pressure from the brake itself).

A crucial part of the operation is to release pressure from the brake in the third of those valve positions, but the system then has to have a way of reimposing the pressure. This is where a special pump comes in to do just that.

The computer system that controls the ABS will be able to detect when one of the wheels rapidly decelerates as would be the case when it starts skidding on a slippery surface. It is able to very quickly adjust the pressure to the brake attached to that wheel, by opening and closing those valves in rapid succession. It is the action of the pump adjusting the pressure to that wheel in rapid succession that causes that strange "pulsing" that you feel through the brake pedal.

Normal Operation

In short, therefore, you needn't be worried about that sensation when you encounter slippery driving conditions, as it is perfectly normal.

Just to Be Safe

However, if you are in any way worried about the efficiency of your braking system you should take it in to your nearest car service centre to check it over for your peace of mind.