Brake Fade in Cars: Meaning, Symptoms, Types & More
What is Brake Fade?
Brake fade refers to the gradual loss of braking power and performance in vehicles over time due to overheating of the brake components such as the brake pads, rotors, drums etc (Collins Dictionary, 2023). It is different from brake failure, where the brakes stop working suddenly and completely.
Unlike sudden brake failure, brake fade is a progressive phenomenon where the brakes start feeling soft and spongy, and the pedal travel increases gradually before braking performance is lost completely. The main reason why brake fade occurs is overheating from heavy braking or constant use of brakes over long descents (SmartDriveUK, 2023).
Brake fade happens when the heat generated during braking exceeds the dissipation capacity of the brakes. The overheated components like brake pads and rotors then degrade, reducing friction and braking performance. Correct driving techniques and maintaining brake components can help prevent brake fade.
Causes of Brake Fade
Brake fade occurs when the braking system overheats and loses braking power. There are several common causes of brake fade:
Overheating brakes – Excessive use of the brakes results in the brake pads and rotors generating extreme heat. At very high temperatures, the pads and rotors can no longer grip effectively, reducing braking power. Frequent hard stops from high speeds, such as when driving downhill, are a common cause of overheating brakes.
Excessive braking – Using the brakes too much over a short period of time can cause the system to overheat. This commonly happens in stop-and-go traffic when the brakes are applied frequently without enough time to cool in between.
Wrong brake pads – Using brake pads that are not designed for high temperatures can result in fade. Performance brake pads made from better materials are required for repeated heavy braking.
Contaminated brake fluid – Over time, brake fluid can become contaminated with water, air bubbles or debris. This lowers the fluid’s boiling point, causing it to boil and create vapor in the lines when heated. Vapor reduces braking power and allows more heat transfer to other components.
Worn brake rotors/drums – Excessively worn brake rotors or drums reduce the braking surface area in contact with the pads. This requires higher pressure for the same braking force, generating more heat.
According to Main Causes of Brake Fade, overheating brakes from repeated hard stops is a key factor leading to brake fade.
Symptoms of Brake Fade
Brake fade has some telltale signs and symptoms that indicate your brakes are overheating and losing effectiveness. Being aware of these symptoms can help you identify brake fade and take action before it becomes dangerous.
The most common symptoms of brake fade include:
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Longer stopping distances – Your brakes will take longer to slow and stop the vehicle as they lose power.
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Soft or mushy brake pedal – The pedal will start to feel spongy or soft as braking power is reduced.
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Vibrations in the pedal – You may feel the brake pedal pulsating or vibrating as brakes overheat.
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Noise from brakes – Squealing, scraping or grinding noises can indicate overheated brakes.
These symptoms occur because high heat builds up in the brake system from heavy or repeated braking. The heat causes the brake pads and rotors to glaze over and lose friction. Fluid can also boil, creating gas bubbles in the brake lines. All of this reduces stopping effectiveness.
If you notice any of these warning signs, it’s important to ease off the brakes and allow them to cool. Continuing to brake heavily when fade is present can result in complete brake failure and loss of control.
Types of Brake Fade
There are three main types of brake fade:
Mechanical Fade
Mechanical fade occurs when the brake pads and rotors become glazed over from heat buildup, reducing friction between the surfaces. This causes the brake pedal to feel spongy and braking distances to increase. Mechanical fade can often be fixed by replacing the brake pads and resurfacing or replacing the rotors.[1]
Thermal Fade
Thermal fade, also known as heat fade, happens when the brake components get extremely hot from heavy braking. The high temperatures cause the brake fluid to boil, creating gas bubbles in the hydraulic lines that lead to a loss of braking power. This type of fade will go away once the brakes have cooled down.[2]
Chemical Fade
Chemical fade occurs when the properties of the brake fluid change under high temperatures, resulting in a loss of friction. The brake fluid essentially breaks down, compromising braking performance. Replacing old, degraded brake fluid can help prevent chemical fade.[3]
The main difference between these types of brake fade is the underlying cause. Mechanical fade is due to physical wear, thermal fade is from heat buildup, and chemical fade is caused by changes in the brake fluid itself. But all result in reduced braking power under continued use.
Effects of Brake Fade
Brake fade can have serious consequences if left untreated. The main effects of brake fade include:
- Increased stopping distance – As the brakes overheat and lose effectiveness, the distance needed to bring the vehicle to a complete stop increases, which can lead to potential accidents if the driver is unable to stop in time (https://www.fleetequipmentmag.com/truck-brake-fade-why-how-minimize/).
- Potential accidents – With decreased braking power, the risk of rear-end collisions and other accidents rises exponentially. Failing brakes put the driver, passengers, and others on the road in grave danger (https://knowhow.napaonline.com/riding-brakes-bad-idea/).
- Damage to brake components – The high heat of brake fade can warp rotors, glaze pads, and boil brake fluid. Prolonged overheating ruins brake system parts, necessitating repairs or replacement (https://www.drivejohnsons.co.uk/learning-centre/driving-dictionary/brake-fade/).
Preventing Brake Fade
There are several steps drivers can take to help prevent brake fade:
Upgrading the brake pads and rotors to higher performance options can greatly reduce brake fade. Higher quality pads like ceramic pads can withstand more heat without fading. Slotted, cross-drilled or ventilated rotors also dissipate heat better than standard solid rotors (Source).
Flushing old brake fluid and replacing it with fresh, high quality DOT 4 brake fluid will raise the fluid’s boiling point, allowing it to withstand more heat without fading. Brake fluid should be flushed at least once every 2 years or according to the owner’s manual (Source).
Bedding-in or burning-in new brake pads and rotors properly will help transfer an even layer of friction material onto the braking surfaces. This allows the pads and rotors to operate at maximum performance. The bedding-in procedure should be followed any time new brake hardware is installed.
Avoiding excessive braking by anticipating stops and braking early and gradually can help minimize heat buildup and reduce brake fade. Drivers should avoid riding the brakes downhill or during prolonged braking events.
Diagnosing Brake Fade
Diagnosing brake fade typically involves both visual inspection of the brakes and testing the pedal response.1
A visual inspection can reveal signs of overheated and damaged brake components. Look for discoloration or warping of the rotors and any signs of fluid leakage or worn brake pads. The thickness of the rotor can also be measured, as warped, scored, or worn rotors under the minimum thickness specification can contribute to brake fade.
The firmness of the brake pedal should also be tested. A soft or spongy pedal can indicate air in the hydraulic lines or worn brake components that are allowing too much pedal travel. The pedal should still feel firm and responsive when held down, without excessive travel or fading.
If brake fade is suspected through visual inspection and pedal testing, a professional brake inspection can help pinpoint the cause, such as insufficient brake fluid, leaks, worn pads or rotors, or other underlying issues.
Treating Brake Fade
If you experience brake fade while driving, the most important thing is to safely slow down and bring the vehicle to a stop while avoiding using the brakes as much as possible. This will allow the overheated brake system to cool down and regain normal braking performance.
One of the best ways to treat brake fade is to bleed the brake fluid according to your vehicle’s maintenance schedule. Old brake fluid that has absorbed moisture can boil at lower temperatures, causing fade. A proper brake system bleed will remove the old fluid and any air bubbles in the lines, restoring the system’s designed performance. When bleeding the brakes, make sure to use the manufacturer-recommended brake fluid type for your vehicle (Grassroots Motorsports).
If you have installed new brake pads and rotors, bedding them in properly will also help prevent brake fade. The bed-in procedure heats up the new components at moderate temperatures to transfer material evenly across the surfaces. Follow the recommended bed-in steps when installing new brake hardware.
While brake fade can be dangerous, being aware of the causes and following proper maintenance procedures will keep your vehicle’s braking system performing safely.
When to Seek Professional Help
If the symptoms of brake fade persist after trying DIY remedies like replacing brake fluid and pads, it’s time to seek professional help. Brake fade is a serious issue that affects braking performance and vehicle safety.
Take your vehicle to a certified mechanic for a comprehensive brake inspection if you experience any of the following:
- Brake pedal feels soft or spongy
- Braking distance has increased
- Brakes are making squealing or grinding noises
- Vehicle pulls to one side when braking
- Brake warning light comes on
A professional brake inspection can pinpoint the cause of brake fade, whether it’s contaminated fluid, worn brake pads, a leak in the hydraulic system, or other issues. The mechanic can then recommend the right repairs and maintenance to restore optimal braking function.
Don’t put off brake problems. Getting brake fade fixed quickly improves safety and prevents more costly repairs down the line. With professional help, your brakes can go back to performing reliably for thousands more miles.
Maintaining Your Brakes
Proper brake maintenance is crucial for preventing brake fade. Here are some tips for keeping your brakes in top shape:
Regular brake inspections – Have a mechanic inspect your brake pads, rotors, calipers and brake fluid at least once a year or per your vehicle’s maintenance schedule. They can spot issues before they lead to brake failure.
Replacing pads/rotors per recommendations – Follow your vehicle manufacturer’s guidelines on when to replace brake pads and rotors. Replacing them regularly prevents them from wearing down too much and reduces brake fade.
Flushing brake fluid per maintenance schedule – Brake fluid can become contaminated over time which leads to a loss of braking power. Flushing the old brake fluid and refilling with new fluid every 2-3 years helps keep your brakes working properly.
Regular brake maintenance keeps all the brake components in top shape and ensures your brakes work as designed without fade. Consult your owner’s manual or mechanic for specific maintenance recommendations for your vehicle.