It’s easy to take car brakes for granted. We all know pressing the brake pedal slows the vehicle down, yet few people understand the combination of valves, hoses and calipers responsible for transforming light pedal pressure into effective braking. Even fewer people could explain how anti lock brakes contribute to this process, even though ABS has saved countless lives since Chrysler launched it in 1971.
In modern vehicles, depressing the brake pedal forces fluid out of a cylinder towards brake pads beside each wheel. Fluid pressure pushes the pads onto discs which rotate in accordance with the car’s tyres, creating friction. This slows wheel rotation, reducing the vehicle’s speed. And in an ideal world, the pressure applied by these pads would lead to steady, predictable deceleration.
Sadly, we don’t live in an ideal world. The winter months are particularly challenging for braking systems, with slippery road surfaces caused by everything from ice and snow to leaves and layers of grit. These substances reduce grip levels, potentially causing the wheels to lock up under heavy braking. This could jeopardise the vehicle’s stability, causing it to skid while disproportionately wearing out whichever section of tyre is in contact with the road.
For maximum safety, keep your brake pads in tip-top shape with Fixter.
ABS to the rescue
Anti lock brakes use computing power to monitor wheel movement when the brake pedal is firmly depressed. The driver doesn’t need to do anything to engage ABS, which intervenes automatically once a wheel ceases to rotate normally. It will rapidly release and then re-apply braking pressure as strongly as possible, until irregular rotation is detected again. This cyclical process used to manifest itself in older vehicles as a judder through the brake pedal, though modern systems are more discreet.
By braking each wheel up to the limits of grip, but not beyond it, the vehicle slows as quickly as ambient conditions allow. ABS responds to wheel locking much faster than a human could, improving straight-line stability while maintaining steering control. This lets drivers navigate around obstacles while continuing to brake, potentially avoiding a collision.
Looking after anti lock brakes
ABS has been compulsory on new cars sold within the EU since 2004, and like any safety aid, it requires ongoing maintenance. To ensure your anti lock brakes work effectively even in poor weather, we recommend the following tips:
Maintain even tread levels on every wheel. ABS won’t work optimally on a vehicle with uneven tyre tread, or significantly different tread depths. The legal tread minimum is 1.6mm, but we’d recommend fitting new rubber well before this point.
Regularly change and top up brake fluid. You can either pump out old fluid from the master cylinder until clear brake fluid flows through the system cleanly, or expel old liquid from the bleed fittings on each wheel mounting.
Keep the brakes clean. Pressure-washing brake discs and pads will remove some impurities and grit, without deploying a jack. Propping the car up and removing the wheel enables a deep clean, allied to a visual inspection of each brake component for wear.
Respond to any warning signs. If the ABS dashboard light won’t go out, there may be a software error. Loud noises under braking could indicate worn pads, while pulling to one side suggests uneven brake wear. Investigate and resolve issues immediately.
Sort any warning light issues with a diagnostic inspection service.