The brakes are one of the most important parts of your vehicle when it comes to safety. While there are several parts on your car that will give you trouble if they aren't maintained, brake maintenance is directly correlated with your vehicle's ability to stop. Not being able to stop effectively is dangerous for you and the others on the road.
As a vehicle owner, it is important that you understand the different types of brakes and brake pads, and when they need to be replaced. Do not skimp on brake pad replacement and brake maintenance. Taking too long to stop, or not being able to stop, could end in serious injury or a damaged braking system.
Types of Brakes
There are two kinds of brakes typically put on vehicles; disc brakes and drum brakes. A disc brake is attached to the wheel and is usually made of cast iron. To stop the car, brake pads push on both sides of the disc to create friction and stop the moving disc.
The drum brake is 'drum-shaped,' and it operates in much the same way: The brake pads press against the surface of the drum to stop the spinning and stop the vehicle.
Disc brakes are more effective but are more expensive to put in, so lower-end cars tend to have drum brakes. Some vehicles will have both types of brakes, one in the front and one in the rear. Either way, the mechanics of how the brakes work are very similar.
The brake system is made up of rotors, calipers, brake pads, and brake shoes (if you have a drum brake). All of these parts work together to smoothly slow and stop your vehicle on command. All parts of the system do need to be maintained and sometimes replaced. The brake pads, in particular, wear more quickly and will need to be replaced on a regular basis. The brake pads will need to be replaced more often than the rotors and calipers, although those parts should also be checked when any brake maintenance is done.
The entire braking mechanism also includes a master compressor, a series of tubing, and hydraulic fluid (or brake fluid). When the driver presses the pedal, the brake fluid is released through a series of pipes, causing a high enough pressure to press the brake pads or brake shoes against the spinning rotor, which causes the car to slow or stop.
Emergency brake systems are different in that they are not connected to lines with brake fluids, but are more of a direct physical mechanism that is connected to the rear wheels. The purpose of an emergency brake is to have an override in case the regular braking system fails.
Types of Brake Pads
There are four common types of brake pads, semi-metallic, non-asbestos organic, low-metallic NAO, and ceramic. Each type of brake has unique properties and vehicle types that they are best suited for.
This is the most common brake pad used in many vehicles. They are made of 30% to 65% metal. Semi-metallic brakes have good heat transfer capability, and also long-term durability. Due to the high metal content, the downsides are that they are louder, wear fairly quickly, and do not perform as well in cold temperatures.
These are made of fibers, fillers, and resins. They used to be made of asbestos, but this was discontinued when the adverse health effects of asbestos became known. They are softer and quieter than the semi-metallic brakes, but they also wear more quickly, creating more dust. Organic brakes can be used on small, light cars, but don't have enough stopping power to be used on heavier vehicles.
The Low-metallic NAO brakes are similar to the semi-metallic brakes but have a lower percentage of metal, between 10% and 30%, and are usually copper or steel. They are noisier than semi-metallic brakes and make more dust, but they have great heat transfer abilities. This type of brake pad is not very common, as most people opt for the semi-metallic variety instead.
Ceramic brake pads are made mostly of ceramic, bonding agents, and fillers. They sometimes have small bits of metal in them as well. These brake pads are quieter and last longer than other brake pads and also create less dust. While ceramic brake pads have a lot of positives, they are not typically used because they are prohibitively expensive.
Which Brake Pad is Best?
For most people, the semi-metallic brake pads are a good choice. They are durable, perform well, and don't require extra maintenance. They are also appropriate for most vehicles, even larger vehicles that haul equipment or carry a lot of passengers. Low-metallic NAO brakes are also appropriate for many situations if you want a lower-metal option. These will create more brake dust and wear more quickly than the semi-metallic pads, but the braking will feel smoother. If you drive a compact or sports car and want something smoother and quieter, the non-asbestos organic may be a good choice. For sports car enthusiasts who use their vehicle for racing, ceramic brake pads are the best option. If money is no obstacle, ceramic brake pads can be used on any vehicle if you're looking for quiet operation, longevity, and great stopping power.
How Long Do Brake Pads Last?
Brake pads generally last for about 50,000 miles, but this can vary greatly as there are a lot of external factors that affect the longevity of the pads. These factors include:
Hardness of the Brake Pads
Different types of brake pads are made of different materials and compounds. Some hold up to heat well, while others will wear more quickly. If your vehicle has brake pads that are wearing quickly, you will probably notice more brake dust accumulation.
How often and how hard you brake will affect how quickly your brakes wear. Every time you press the brake, a little bit of the material on the brake pad wears away. So if you are braking aggressively and often, it will cause more material to be worn away and your brake pads won't last as long.
Typical Driving Type
The life of your brake pads also is determined by the type of driving that you do on a day-to-day basis. The more often you brake, the quicker the pads will wear. Those who find themselves driving in the city or in stop-and-go traffic usually will brake more often. Those who drive primarily on back roads may see the brake pads that last longer because they brake less often. Driving in areas with a lot of hills will also wear out the brakes faster, as most people will brake a lot during descents to control their speed.
Symptoms of Bad Brakes
There are several signs to watch, listen, and feel for that may indicate that your brake pads are starting to reach the end of their useful life. Once the brake pad is worn down to this metal strip, you will hear a screeching sound that alerts you to get the pads changed. Keep alert for any sign that your brakes are taking longer to stop, grinding or screeching, and any vibrations. If you notice any of these signs, the brake pads should be checked right away. Some brakes have electronic sensors that will turn on a dashboard light when the brakes need to replaced. Some also have a metal wear indicator embedded at the point where there is about a quarter of the pad left.
You can also perform a visual check on your brake pads on most vehicles, as they are visible through the wheel. If your brake pads look thin (less than 1/4 inch thick) through a visual check, then they probably need to be replaced. If you notice that there is less brake dust being produced than normal, this is another sign that your brake pads are likely worn.