When a vehicle’s brakes lock up at a sudden stop, you lose control of the vehicle. It could cause you to slide or spin out. During a lock-up, the tire stops rotating. If you are old enough to have learned to drive a vehicle that didn’t have ABS, you were most likely taught to pump the brakes to get out of a skid or to prevent a skid. ABS replaces manually pumping the brakes since it can pump them faster and at the correct time. It also allows the driver to concentrate more on steering to avoid crashing. The ABS allows you to control the vehicle better should you need to brake hard. The ABS can apply and release the brake on each tire up to 20 times in one second, which is much faster than a human can. The constant application and release of the brakes allows you to slow down quicker without the wheels locking up and forcing you into a slide. In newer vehicles, the ABS works with the electronic stability control and traction control systems to make driving even safer. Additional Brake System Components In addition to ensuring the anti-lock brake system works properly, you need to ensure the rest of the brake system works properly. Each time you take your vehicle in for maintenance, your auto technician should check the brake system, including: The brake fluid. Since the brake system is a closed airtight system, you most likely have a leak if the brake fluid is low. Additionally, if air gets into the lines or you don’t have enough brake fluid, the vehicle’s brakes will not work properly. Brake hoses and brake lines. Most of the brake lines are metal with compression fittings. They can eventually rust, so it’s imperative that your auto technician checks them when you go in for maintenance. A short rubber brake hose runs from the metal line to the caliper. As with other rubber hoses, the brake hose degrades over time, letting air into the system or collapsing. Brake calipers and wheel cylinders. Most vehicles have four-wheel disc brakes, meaning all four wheels have calipers. Some trucks might have shoes instead of pads in the rear, in which case, you will have wheel cylinders. Calipers and wheel cylinders open and close as you press and let off the brake pedal. Both can leak brake fluid. Brake pads and shoes. Disc brakes use brake pads, while drum brakes use shoes. The pads or shoes rub on the rotors or drums to create friction to stop the vehicle. If the brake pads or shoes get too hot, they could cause the brakes to lock up. The thinner the pads or shoes get, the faster they heat up. Rotors and drums. The calipers or wheel cylinders press the pads or shoes against the rotors or drums when you step on the brakes to slow the vehicle. The ABS mimics this motion much faster to prevent a wheel from locking up if you have to brake hard. Your auto tech should check the entire braking system when you bring your vehicle in for maintenance. Brakes are a wear-and-tear item, which means you must replace the pads, rotors, calipers (shoes, drums, wheel cylinders), and rubber brake lines as they wear out. How to Tell if You Need Brakes You can prevent an accident by paying attention to the braking system. Since it is difficult to see the pads unless you remove the wheels, you can use other tells to know when the vehicle’s brakes are low, including: The distance the brake pedal travels to the floor. If it goes more than halfway, have an auto technician check the brakes. The emergency brake pedal or handle travels more than half the distance to engage the emergency brake fully. In most cases, the emergency brake is a manual brake—you pull the handle or press the foot pedal, which pulls a cable and presses the pads against the rotors. If you have drum brakes on the rear, your auto tech can adjust the rear brakes if there is enough material on the shoes. The vehicle takes longer to stop. The brake fluid in the master cylinder (located on the firewall, usually on the driver’s side of the engine compartment) is low. Another cause of poor brake function is if you have a vacuum leak and the brake booster isn’t getting enough vacuum. Sometimes, if you listen to the engine running with the hood open, you can hear the hissing of a vacuum leak. A leaking vacuum line anywhere on the engine could affect the brake booster.