What Are Anti-lock Brakes & How Do They Work?

As far as technical jargon goes, the automotive (that means ‘car’) industry is one of the worst offenders for speaking in riddles and bombarding the average car owner with terminology that they wouldn’t understand. That’s where Scrap Car Comparison comes in, on hand to let you know what the shorthand, acronyms and fancy-sounding words actually mean.

With ABS – or Anti-lock Braking Systems – being a legal requirement on cars in the UK since 2004, it’s quite important that you know what it is, what it does and how to identify when it’s not working as it should.

ABS light. Car dashboard in closeup

What Are Anti-lock Brakes (ABS)?

Anti-lock brakes are used in all modern cars as they ensure that the driver of the vehicle will be able to maintain control even when braking heavily. On older vehicles without ABS, drivers would have slammed on the brakes in an emergency and been forced to travel in a straight line, praying that the car or van they’re in would stop before an impact. This is because the brakes would ‘lock’ the wheels.

Anti-lock brakes prevent this from happening, allowing a driver to turn their wheels and aim go around an obstacle if the vehicle is unable to brake in time. It also gives drivers the chance to keep their vehicle on the road while swerving, as opposed to locking the wheels and careening off into the crash barrier, trees, or even pedestrians!

What Does ABS Do?

In a nutshell, ABS acts when you hit the brakes to ensure the wheels keep turning whilst you slow down in a controlled manner, as opposed to having them lock up, produce clouds of smoke and leave you with zero control over the direction you’re travelling in. If your wheels lock and stop spinning, you can’t voluntarily change direction, meaning that evading an obstacle is no longer an option – you can only hope to stop before you reach it, or spin out of its way.

The way the system works can be explained in a fairly short passage but the real computing that goes into its implementation is staggering, especially when you consider that this tech has been around since Willy Wonka & the Chocolate Factory hit cinemas – yes, the Gene Wilder one!

Sensors in each of the vehicle’s wheels measure the speed at which the wheel is spinning, along with how quickly the car is accelerating or decelerating. ABS recognises when the wheels are about to lock up once a driver hits the brakes and counteracts this by adjusting the braking pressure to keep the level optimal. This process is undertaken by the car multiple times per second.

Are ABS Brakes The Same As Regular Car Brakes?

On the surface, the two types do work in almost the same way. They both cause the vehicle to stop, rapidly if needed, and historically both have done a good job of it – even regular brakes. However, the vastly improved safety standard that comes with ABS is very different. The technology involved is much more advanced, and as more electrical components are added to cars, it’s only going to keep improving.

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How To Use Anti-lock Brakes

First and foremost, you’ll want to check that your ABS is actually working. If your car has been MOT’d or serviced recently, it should have been looked into. Or, if your ABS light on the dashboard is not illuminated, then you can safely assume that it’s operating as intended.

So how do you actually put it into action? Well, you simply press the brake pedal down, and keep it held down. There’s nothing more to it. You might feel a bit of feedback from the pedal if you need to be especially rough with it, but this is normal.

How To Check If Your Car Has ABS

There are several ways to check if your car has anti-lock braking. We’re going to cover them all, even though a couple of them are almost guaranteed to answer the question for you no matter your situation.

As we mentioned above, if your car was made in the UK from 2004 onwards, it is required by law to have ABS fitted as standard. However, if you have your doubts about a particular car – perhaps you’ve just bought it and some inconsistencies in the car’s history are starting to show – then the following methods can be used to check if it has ABS installed.

  • Read the manual – Assuming you have the manufacturers manual that came with the car when it was initially purchased, you’ll have a definitive answer in black and white regarding your ABS query. If the car has anti-lock braking systems, the manual will say so.
  • Check the lights  – Not the headlights. No, what you want to do here is turn the key just one or two clicks (not far enough to start the engine) and, as you do so, take a look at the little symbols that light up across your dashboard behind the steering wheel. You should see one that clearly says ‘ABS’ in capital letters, often with a circle and brackets around it.
  • Find the sensor – You’ll need to remove a wheel and look under the car for this method, so consider it the last resort. On the axles, look for a small sensor with a fairly thick wire attached to it. It may be hard to identify, but if you can find it, your car has ABS.

Can You Add ABS To A Car?

So, you’ve got an import that doesn’t come with ABS as standard? Or you drive a classic car that’s too old to have been produced with this feature? Can you get an aftermarket ABS kit added to your vehicle?

The answer is yes, but it’s often very, very difficult. Many drivers would argue that it’s probably not worth the time, effort or money to do so. It’s not as simple as repairing a broken Anti-lock Braking System, which will already have all of the components and sensors in place. Retrofitting all of that into a car from scratch is likely to be a massive undertaking.

Brake and accelerator pedal of automatic transmission car

Is My Car Safe To Drive With the ABS Light On?

Despite ABS being mandatory on modern cars, it is technically not illegal to drive with the dashboard warning light illuminated. Whether it’s safe to do so, is another matter.

If the ABS light is lighting up your dashboard, it means that the system may not be working as intended. While your brakes will still work, should you need to make an emergency stop, the anti-lock braking system might fail to keep your wheels turning, leaving you skidding towards danger at speed.

Because of the importance of this safety feature, it’s absolutely worth getting the system looked at by a professional as soon as possible, even if it means jumping in ahead of its regular service. A DIY job is not advisable here.

Will An ABS Light Fail My MOT?

Yes. If you ABS light is on when it’s rolled into the garage for its MOT, it will fail instantly. No ifs, no buts. The legal requirement to have ABS fitted into every new vehicle shows that this tech is very important for road safety, and since that’s what the MOT test is primarily about, it should come as no surprise that faulty braking is big trouble.

What Causes Your ABS Light To Come On?

Once the ABS light has come on, you’ll want to figure out why. Again, it’s best left to a professional, but if you want to try to diagnose the issue yourself, here’s a few common issues with anti-lock braking systems.

  1. A blown fuse – The ABS has a fuse of its own, which could have blown. This would result in the light illuminating straight away.
  2. Broken speed sensor – The speed sensor tells the car how fast each wheel is moving, so that it can adjust them as necessary. This process can’t happen if the sensor is broken.
  3. Low brake fluid – Leaking brake fluid can cause the anti-lock braking system to fail and light up the dashboard. Listen out for a grinding sound when braking.
  4. Faulty ABS module – Typically a wiring issue, corrosion can cause the electrical signals between the module and the sensors to be cut out.
  5. Hydraulic pump – The device that pumps brake fluid around the system can wear out, but if the pump isn’t working properly, the ABS won’t be able to operate as it should either.

How To Fix the Faulty ABS In Your Car

As we already mentioned a couple of times, the anti-lock braking system is a device that could potentially save your life one day. It’s not something to poke around in and try to fix by trial-and-error. For that reason, the best course of action would be to take the car to a professionally trained mechanic to be assessed and have the specific problem diagnosed and then fixed.

Do Cars Need ABS?

In this day and age, and in the UK at least, cars really do need ABS. They’re not allowed off the production line without it! But, from a safety perspective, it’s absolutely worth having and has saved countless lives over the years. Did car drivers survive getting from A to B before ABS was a thing? Of course they did, but there were more opportunities for fatal accidents – something that modern technology is very good at eliminating.

If your car has been letting you down and is bordering on dangerous, or it’s old and you want to get rid before something goes wrong, sell it with Scrap Car Comparison and we’ll find you the best price for it in just 30 seconds. With our network of scrap dealers spanning the whole of the UK, you’re guaranteed to be sent a top offer and better still, we’ll even arrange for the vehicle to be picked up for free. Use our online valuation calculator to find out just how much your old car is worth as scrap or salvage today!

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