Professional racers rely on exceptional braking systems to allow them to reduce their speeds closest to the turn to optimise their lap times. While ordinary drivers take the modern car’s brake system for granted, paying attention to how it works, taking cognisance of the telltale signs of an impending brake failure, and keeping it in tiptop condition can spell the difference between life and death. As efficient and fast as modern cars go, everything will be for nought if you cannot bring your vehicle to a complete stop before disaster strikes (or striking disaster). Here’s your guide to this critical, albeit taken-for-granted component of your car.
The Anatomy of a Car Brake System
Depending on your car’s brake system, you can have disc brakes, drum brakes, or a combination of both. A conventional disc brake system comprises the brake disc, rotor, brake calliper, and brake pads.
Brake disc or rotor
Many consider the rotor or disc the heart and soul of the modern car braking system. These large metal discs come in various designs. Race cars often have slotted rotors, which allow for better heat management. The holes in a slotted rotor also remove water from its surface in wet weather, helping improve braking performance even in damp and otherwise slippery conditions.
There are also brake rotors that are made of cheap metal. These are relatively inexpensive. Unfortunately, they don’t provide exceptional heat management, which leads to overheating problems. And as metal overheats, it tends to warp. Low-quality metal rotors are also not known to give you the short stopping distance you require. More often than not, you’ll fix or even replace a low-quality brake rotor more often than a premium high-quality disc. It is important to replace brake discs in axle sets and drive gently on new brake parts to prevent potential damage.
Brake caliper
The calliper is like a vice that grips the brake rotor when the brake pedal is applied. It contains hydraulic pistons connected to a series of hoses supplying brake fluid. When the brake is applied, fluid is forced into the master cylinder, pushing the pistons in the calliper. This pushes the face of the brake pad towards the surface of the brake disk, clamping on the spinning rotor. Here’s the thing: the harder the clamping action of the calliper, the more heat it generates. And if you happen to have a low-quality brake disc, you know what it means.
Brake pads
These babies are the ones that get in direct contact with the brake rotor. They are pushed by the calliper towards the brake rotor, which is the brake component that takes the most abuse. As such, brake pads must be used to manage generated heat efficiently. You cannot get a brake pad made of extra-hard compound if you live in freezing temperatures. The brake pads must work at an optimum temperature for more efficient kinetic energy transfer. The friction material on brake pads is responsible for converting kinetic energy into heat energy and it wears down over time.
Brake lines
As the name suggests, these hoses convey hydraulic fluid to the brake calliper assembly. It is the passageway for that critical fluid so that the brake pads will be pushed against the rotors to help bring your vehicle to a stop. Unfortunately, the brake lines are some of the most problematic since they can get punctured, broken, or damaged, leading to leaks. A leaking brake line is never a good thing. You won’t have the proper force to push the callipers and brake pads onto the rotors; in other words, stopping your vehicle may be exceptionally difficult.
Drum brake systems have essentially the same components as disk brakes but are named differently and have different actions. The brake drum is equivalent to the brake rotor on a disk brake system. It is fixed to the car’s wheel. During braking, hydraulic fluid is delivered to the wheel cylinder, forcing the brake shoes to move away from each other. This pushes the brake shoes against the rotating drum, slowing the car. Once the brakes are released, the brake shoes are returned to their starting position by the action of the return spring.
How Do Car Brakes Work?
Compared to other parts of the modern vehicle, the brake system is pretty simple, with few parts. Applying the brakes activates a master cylinder. This is also sometimes referred to as a brake or vacuum booster. The goal of the vacuum booster is to multiply the force generated by your foot as it steps on the brake pedal. This makes it relatively easy to apply the brakes. You can imagine how heavy it will be to depress the brake pedal without this booster. The hydraulic braking system uses brake fluid to create hydraulic pressure, which in turn generates the braking force needed to stop the vehicle.
As mentioned above, applying the brakes transmits this ‘boosted’ force to the master cylinder filled with your vehicle’s brake fluid. Modern cars always come with two brakes, one on the front and another at the rear. Brake lines are distributed from the master cylinder to the brake calliper assembly (for a disc brake system) and the wheel cylinder (for drum brake systems). These brake lines are also filled with hydraulic brake fluid. The master cylinder delivers just the right amounts of pressure towards the front and rear brake systems, giving you a safety net just in case one system fails. The braking force generated by different types of braking systems, such as hydraulic and mechanical, can vary significantly.
Technically, with each step on the brake pedal, you are forcing brake fluid into your brake system’s callipers or wheel cylinders. This forces the brake pads to move towards the rotors or the brake shoes to separate and contact the brake drum, which causes you to stop or decelerate.
What are the Different Types of Brakes, Including Disc Brakes?
The disc and drum brakes are just two types of brakes found in cars. There are two other types, and we’ll examine them individually.
Disc brake
Most modern cars have a disc brake system, usually found in the front wheel. The system comprises rotors, callipers, and brake pads on both sides of the rotor. When brakes are applied, hydraulic fluid is pushed towards the callipers, bringing together the brake pads to clamp down on the rotor.
Disc brakes are preferred because they provide more stopping power than drum brakes. The heat generated is also more efficiently dissipated through the larger surface area of the rotor, and the exposed components also improve dissipation. Heat dissipation is made even more efficient in the case of slotted rotors. Disc brakes dry quickly in wet weather while protecting the system against brake fade.
Drum brake
In principle, drum brakes operate pretty much like disc brakes, except that the movement of the brake shoes is outwards from the midline to allow them to contact the brake drum. Drum brakes are less expensive than disc brakes and are a lot easier to repair or even replace.
Unfortunately, drum brakes don’t like heat. They tend to get hotter the more frequently they are used, reducing their ability to stop the vehicle. Moreover, because of the system’s inherent drum-like design, water tends to collect in the interior, reducing its stopping ability and exposing it to the risk of corrosion.
Emergency brake
While the parking brake can hardly be considered a service brake because it is not operated or activated by brake fluid-filled lines, it does serve its purpose exceptionally well. Emergency or parking brakes are connected to the service brakes by cables, typically the pair located at the rear.
Different car manufacturers have different emergency brake mechanisms. Most cars have a stick lever parked in the centre, usually beside the driver’s seat and between the front seats. Emergency brakes are also activated by another pedal, usually next to the floor pedals. Some are found next to the steering column. These are mainly used to keep the car stationary. In many ways, they function as emergency brakes when the brake system fails.
Anti-lock brakes
These are not brakes per se, but rather an advanced technology integrated into the design of modern brake systems. Anti-lock brake systems, or ABS, consist of sensors that keep track of the rotational speed of the individual wheels. In sudden braking, especially in wet road conditions, there’s a tendency for the wheels to lock up and the tyres to skid because of the loss of contact with the ground secondary to the wheel’s speed. If skidding is detected, the ABS pulses the vehicle’s brake pressure rapidly on and off, reducing the rotational speed of the wheels and allowing the tyres to reestablish contact with the road.
Mechanical Brakes
Mechanical brakes were historically used in cars and operated manually using mechanical linkages. These brakes were primarily used for the parking brake. Over time, mechanical brakes were phased out in favor of hydraulic and regenerative systems due to concerns about reliability and precision.
Regenerative Braking
Regenerative braking is a modern technology used in hybrid and electric vehicles. It captures kinetic energy from braking and uses it to recharge the vehicle’s batteries. This system improves efficiency by converting energy that would otherwise be lost into usable electrical energy. Regenerative braking is often compared to hydraulic, electromagnetic, servo, and mechanical braking systems, highlighting its benefits in terms of energy conversion and efficiency.
How to Maintain a Car’s Brake System and Brake Fluid
Because a car’s brake system is relatively simple, keeping it in tiptop shape should be easy. Here are some tips on maintaining the optimum operating performance of your car’s brakes.
Check and maintain brake fluid levels.
Make it a habit to check your brake fluid levels. That being said, you should know where your car’s brake fluid reservoir is located. The reservoir comes with level marks. Make sure that your reservoir is filled to the correct level. Perhaps more important is to use the right type of brake fluid. Car manufacturers always have their recommendations when it comes to fluids that work best with their systems. Check your owner’s manual for the specific type of brake fluid you need on your car.
Replace brake fluid
Most car owners have this habit of simply topping off their brake fluids once the level is low. Unfortunately, condensation may infiltrate the fluid over time. If the brake fluid is contaminated, the former cylinder will be damaged. The wheel cylinders may also be affected. That said, you should replace or change your brake fluid every 25,000 miles or every two years, whichever comes first. You may need to check your manual as well.
To replace your brake fluid, locate the bleeder screw located at the back of each brake. Make sure you have the right tool for the job so you can easily open the bleeder screw without necessarily damaging it. Open the bleeder screw only slightly to allow the brake fluid to drain. You can attach a rubber hose to drain into a container so you don’t contaminate the ground under you or the car’s finish. While the brake fluid is draining, ask a friend to pump the brakes. At the same time, new brake fluid is poured into the brake fluid reservoir.
You know that you’ve done an excellent job if the fluid that drains through the bleeder screw looks like the same fluid you’re pouring in the reservoir. Once done with one brake, tighten the bleeder screw and continue working on the rest. Once all brakes are done, please give it a few pumps to ensure you have them on the pedals. Now’s also a great time to check for any leaks in the bleeder screws.
Check the lines and master cylinder.
The brake lines and the master cylinder are two essential components of the brake system that convey brake fluid from the reservoir to the individual brakes. As such, you must follow the lines and look for any sign of a leak. The joint between the brake lines and the master cylinder can be a good starting point, although the brake lines from the reservoir deserve some attention, too.
Check and replace the brake pads if necessary.
The brake pads are often the most abused parts of the brake system. They’re the ones getting heated up during braking. As such, they wear thin over time. Some cars have brake pads that can be easily seen from the outside. Some vehicles, however, have their brake pads hidden from view. You will need to remove the wheels to check the condition of the pads. The pads should have even wear and still be at least 5 millimetres thick. Checking the brake pads can be done every 6,000 miles. If they need replacing, you must replace them with an appropriate type. It is also important to check the rear brake pads, especially since the parking brake mechanism relies on them to lock the rear wheels and prevent the rear rotor or drum from moving.
Check and maintain the brake rotors or discs.
The rotors should always be inspected with the brake pads, as these two components are always in contact when the brakes are applied. Rotors should have a smooth surface. If you see concentric grooves forming on the surface of the rotor, it usually means your brake pads are already slowly eating away at the rotor’s surface. In many instances, rotors can be resurfaced in a machine shop. The rotors are removed and smoothened using a grinder-like machine. If the damage is too extensive to be remedied by resurfacing, you may need to replace the rotor. Always install new pads after getting the rotors resurfaced. This ensures that the grooves left by the rotor will not be transferred to the new surface.
Identifying Brake Problems and Worn Brake Pads
A strict maintenance schedule for your car’s brake system can save you a lot of trouble. Sadly, even a well-maintained vehicle can easily break down. It’s good that hate is always a warning sign of an impending brake problem. Your knowledge of these can help you zero in on a solution.
Grinding
This can mean two things. First, your brake pads are long overdue for replacement. Second, something else gets stuck on the rotors every time you step on the brakes. This could very well be the calliper itself or, perhaps, more seriously, the metal part of the pads. Whatever the case, you should have it checked and serviced immediately.
Squealing
High-pitched squeals emanating from the brakes as soon as you step on the pedal usually mean your brake pads are wearing thin. Modern brakes are equipped with wear indicators that touch the rotors when the brake is applied.
The presence of brake dust that has accumulated on the pads can also produce that high-pitched noise. Other potential causes include rust or debris on the rotor surface and glazing of the brake pads secondary to excessive heat. Has it been inspected by a professional?
Loss of brake pedal pressure
When you apply the brakes, the pedal should feel firm, increasing as you push towards the floor. If it feels somewhat spongy or you can press the pedal relatively quickly, you may look at a leak in your brake lines. It can also mean that your brake pedal needs adjustment or your entire brake system is already failing. In this instance, you must pull over quickly and as carefully as possible and then contact your mechanic or emergency roadside assistance.
Vibrations on the brake pedal
You may feel the pedal a bit ‘bumpy’ or ‘pulsing’ because the brake rotors are already warped or worn, usually because of excessive heat or friction. This should not be confused with the ABS of modern cars, which can give you almost the same sensation. When in doubt, it is best to have it checked.
Whenever you take to the road, you want to feel safe. Keep your car’s brake system at optimum operating performance, and never go cheap on brake parts. Safety should be your priority.