Just as with all car parts, brake pads degrade over time and need to be replaced. They suffer excessive wear and tear as they are in constant demand by the driver.
Brake pads wear at different speeds and are dependent on several variables. The number of miles the vehicle covers, driving habits, and the regular environment the vehicle is used all have an impact. For instance, rural drivers find that their pads last longer than city drivers who sit in busy traffic and face multiple stops and starts on each journey.
As a general rule of thumb, brake pads should last for 25,000-miles and can last as long as 60,000-miles and more, depending on how and where the vehicle is driven.
What are Brake Pads
Brake pads are an integral part of a vehicle's braking system used to slow the car down or bring it to a halt. Each wheel relies on a brake disc, caliper, and a pair of brake pads to ensure it stops safely.
Brake pads sit inside the caliper and their friction material almost touches each side of the metal brake disc.
How Brake Pads Work
Each time you press the brake pedal, a piston is forced against the caliper. Hydraulic fluid (brake fluid) from the caliper squeezes the pads against the rotating disc. The friction that this creates is what brings the vehicle to a controlled stop.
Types of Brake Pads
There are 3-types of pad that vary by price, fabrication, and materials:
During the 50s and 60s, brakes used asbestos as a friction material as it absorbs heat really well. Asbestos is no longer used because it becomes a carcinogen in the air. As a result, car companies created non-asbestos or NAO brake pads. In the United States, nearly all vehicles come stock with NAO brake pads.
Depending on the manufacturer, NAO brake pads are made from fiber, glass, resin, rubber, and kevlar, and are cured to withstand substantial heat. Their softness prevents them from causing harm to the brake disc but results in them wearing down quicker than other types.
NAO brake pads are the cheapest and tend to have the shortest life expectancy.
Made from a hybrid compound of synthetics and metals, the semi-metallic pad can withstand excessive heat.
Sintered steel, graphite, or iron is bound with an organic resin, resulting in excellent heat conduction.
This type of brake pad has a long service life and can meet the high demands of heavy vehicles and performance vehicles.
While NAO brake pads solved the issues related to asbestos, there was still room for improvement. In the 1980s, manufacturers developed ceramic brake pads which use the same materials found in plates and mugs.
The clay in ceramic brake pad is dense and allows for a high friction coefficient. Ceramic brakes also typically have pieces of copper embedded in them to further improve their friction coefficient and heat conductivity.
How Long Do Brake Pads Last?
Modern disc brakes are far superior to old-style drum brakes; they are safer and have much-improved stopping power. However, brake pads tend to wear down quicker than their counterparts, the old-style brake shoe.
Multiple factors contribute to how long a pad lasts, including the quality of the pad itself and the braking system.
Further factors such as friction, pressure, and heat all determine the life-span of brake pads, as well as the driving style and conditions the vehicle is usually used in.
Data calculated from average annual mileage statistics provided by the Federal Highway Administration, suggests that typical brake pads last between 3 and 7 years.
There are multiple ways of knowing when it is the time to change your brake pads, but if you require assurance, ask the mechanic to give them a look over at each service.
Why Brake Pads Might Wear Down Quickly
- Driver Error – The most common cause of brake wear is due to poor, sudden braking habits.
- Poor Quality Pads – Cheaper pads may contain small chunks of metal that damage the discs, which in turn have a detrimental effect on the pads.
- Corroded Side Pins – They will disrupt the regular smooth sliding action of the caliper and if it doesn't sit flush, a small part of the pad will constantly touch the rotor and wear down faster and unevenly.
- Torn Piston Seal – As it is operated by brake fluid, any tear will result in leakage. If the piston is prevented from resetting after each movement it remains in contact with the rotor resulting in excessive wear and tear.
- Worn Rotor (discs) – Grooved, pitted, or burnt rotors directly affect the speed at which the pads wear. They may also cause pads to crack or groove which prevents them from doing their job correctly.
Accumulation of dust that is allowed to build up excessively will also cause degradation of brake pads.
How to Make Brake Pads Last Longer
It might involve making small adjustments to your driving habits to extend the life of your brake pads.
- Fit the best brake pads that you can afford – High-quality brakes comes with a longer life expectancy.
- Drive within the speed limits – Sudden braking puts undue pressure on brake pads.
- Maintain a safe follow distance – If the car in front brakes suddenly, you should have enough space to slow down steadily.
- Use engine braking – Try lifting your foot from the accelerator to bring the vehicle to a slow, steady stop. Fuel injection ceases and the throttle virtually closes which restricts airflow.
- Regular servicing – Worn components will add excessive pressure on healthy ones, try to keep everything in top shape.
- Lighten the load - Carrying around unnecessary weight adds to the pressure and demand put on the braking system.
- Clean the brake rotors – Give the rotors a quick splash with the hose each time you wash the car, just to remove dust and debris. Dust = increased friction and adds to wear and tear.
How to Tell When it's Time to Change Brake Pads
There are several signs and even dedicated indicators to tell the driver that the brake pads are failing.
Some brakes come equipped with sensors on the brake pads that will trigger the dashboard warning light alerting the driver that action is required.
When brake pads wear low you will hear about it. Inside the pads, beneath the friction material, are metal wear indicators. As the material wears away, the indicator tabs come into contact with the metal brake disc, resulting in a squeak or metal-on-metal grinding noise each time the brake is pressed.
If the car pulls to one side as you drive, it may be an issue with the pads and the could be suffering from uneven wear. Pull over to the roadside and take a look. You might also experience a loss in power as the brakes get hot.
It is also possible to check the status of the brake pads by sight; by looking through the spokes of the wheel. If the pads are less than 1/4” thick, it's time to change them.
Possible causes are damaged parts in the hydraulic system, caliper components, or the handbrake. It is sometimes a result of improper bedding in procedure being carried out. This should be done immediately after new pads are fitted:
- Find a safe, empty, and open stretch of road, the quieter the better.
- Accelerate to 35mph and apply moderate pressure to slow down to 5mph
- Repeat 4 times to heat up the pads
- Increase the heat by repeating the process, only this time up to 45mph and down to 10mph
- After you have done this 4 times coast for 10 minutes if possible
- Park up and wait for at least an hour for the brakes to cool down
Most motorists realize that stopping power is as important to a vehicle as horsepower. As such, it is imperative to take meticulous care over the health of your braking system.
Knowing how long brake pads last can make it easier to estimate when it's time to get get them changed.