Brakes are the unsung hero of the car.
Stepping on the accelerator and moving down the road is the fun part and gets all the glory, but even more important is the ability to stop or slow down. Effective braking is something we take for granted—until it’s too late.
Thankfully, brakes are good about giving warning signs when they are wearing, indicating that it’s time for a refresh. Understanding how different types of braking systems work is a good foundation for knowing when it’s time. Each braking system comprises different parts that work together to brake safely.
How Do Braking Systems Work?
When you press the brake pedal, you activate a cylinder, which sends brake fluid to your brake calipers, to engage your brake pads. The brake pads apply pressure to your rotors. The resulting friction is what slows and stops your car.
That’s a powerful thing, considering how much your car weighs and how much forward momentum it may have at the time you apply the brakes.
Different vehicles use different types of braking systems, including disc brakes, ABS brakes, and drum brakes.
Disc Brake Systems
If you’ve ever used hand brakes on a bicycle, you will understand easily how disc brakes on a car work. The wheels of a car are bolted to rotors, which are steel discs. A caliper encloses each rotor, holding two hard ceramic brake pads.
When depressed, the brake pedal initiates hydraulic pressure from the brake master cylinder. This send brake fluid through brake lines to activate a piston in the calipers, which closes the brake pads against the rotor.
ABS Brake Systems
Cars from the last few decades often have antilock, or ABS brakes. What is unique about these is that they are designed to prevent brakes from totally locking up, which prevents skidding.
Sensors in ABS brake systems monitor the rotational speed of each wheel and send pulses to a processor, which monitors each wheel’s speed. If one slows down more than the rest do, the ABS system, using the processor and a system of pumps and valves, meters the braking force differently to any wheels that are slowing more quickly than others.
Drum Brake Systems
Drum brakes are not common today but are found on many older vehicles. Some cars today may have disc brakes on the front wheels and drum brakes on the rear.
In drum brake systems, the wheel studs pass through a pan-shaped drum, inside which are two curved brake shoes. When you press the brake pedal, the shoes are forced outward against the lining of the drum by a hydraulic wheel cylinder.
When you let off the pedal, return springs make the shoes retract against the drum’s lining.
How to Know When You Need Brake Repair
Use your eyes and ears to know when it’s time for new brake pads and/or rotors.
If you hear a high-pitched squeaking or squealing sound, you are hearing the “indicator,” which is a small piece of metal designed to make that sound, alerting you that your brake pads are in need of replacing.
Make sure the sound is persistent. Sometimes brakes can squeal just because the car has been parked in rain or otherwise the rotors have gotten wet and formed a slight amount of rust on the rotor. In that case, the sound should go away soon. If not, head to a brake repair shop.
A visual way to monitor your brakes’ status is to look between the spaces in your wheels. You will be able to see the brake pads. If the pad is less than 1/4-inch thick, you should have your brakes checked.
If the sound you hear is, instead of squealing, a grinding sound, your brakes are in very bad shape. The pads are shot, and the rotor and the caliper are in direct contact. You’ll need not just new pads but to have your rotors turned or replaced.
Any kind of vibration or pulsation when braking should be taken seriously. It can indicate that your rotors are warped. Keep in mind, though, that vibration is normal if you suddenly slam on your brakes and have an ABS/anti-lock braking system. However, the car vibrates when ABS is not engaged, it likely is a brake problem.
And obviously if your brakes are not performing like they should be, be sure to have them checked. Also, if you see a small puddle of brake fluid where your car was parked, get to a shop soon.
Don’t Wait to Maintain Brakes
If you hear or experience any warning signs that your brakes may need to be repaired or replaced, bring your car in for an inspection. Milex Complete Auto Care, a full-service auto repair shop, is expert in diagnosing and repairing braking issues, to keep your travels safe. Review more information about brake service warning signs here.