What causes brake fade and how to minimise it

2022-10-01 -

Brake fade doesn’t just happen on the racetrack, it can also occur in passenger cars, four-wheel-drives and commercial vehicles particularly under heavy braking conditions and during hotter temperatures.

It leads to a temporary reduction in braking performance that’s caused by the added heat that’s generated from repeated or sustained braking, or braking under heavy loads. When the heat doesn’t effectively dissipate, the braking becomes compromised.

Such conditions can arise more than we realise through the course of day-to-day driving – think of a heavily accessorised fourwheel-drive with larger tyres, or a passenger car towing a caravan descending a large hill or mountain road.

For large trucks the effects are even greater, which is why so many are equipped with secondary technology such as retarders and engine and exhaust brakes, which help to further slow them down without solely relying on friction-based braking systems.

When brake fade occurs it’s predominantly because the disc brake pads have exceeded their maximum operating temperature range, this affects the friction material which begins to deteriorate. The process can cause the pads to leave matter on the rotors lubricating them and making braking less effective.

Brake fade can also occur if the brake fluid overheats. If the fluid boils from prolonged braking any moisture within vapourises, which makes the fluid more compressible, this results in longer brake pedal travel and reduced braking effectiveness.

Minimising brake fade

Drivers can minimise the likelihood of brake fade in several ways, beginning with ensuring the braking system is in good working order – upgrading some components might also be considered if the vehicle is regularly used in situations where the brakes are worked hard.

Through its Ultimate, Ultimate 4WD and Euro+ Disc Brake Rotor’s, Bendix offers packages for a range of passenger cars and four-wheel-drive, to increase braking performance and help reduce brake fade.

In the case of brake fluid, the quality should be regularly checked to ensure it doesn’t contain excessive moisture, which will erode performance considerably. The following article explains further: www.bendix.com.au/bendix-news/ bendix-explains-brake-fluid-and-which-oneto-choose

Brake pads that haven’t been properly ‘bedded in’ – a process that deposits a thin layer of pad material on the disc brake rotor – can make the brakes more susceptible to fading. For users of Bendix brake pads, this won’t be a concern because the Bendix range features Blue Titanium Stripe technology, meaning there’s instant pedal feel from the first brake application and longer-term protection to minimise fading.

Adapting your driving style

Another important way to reduce brake fade is by change driving habits – driving more slowly and with greater mechanical sympathy, especially in more demanding conditions, will result in less pressure being placed on the braking system. Tips that can reduce the risk of brake fade while minimising braking system wear and tear includes:

Avoid riding the brakes without giving them a chance to cool down – repeated heavy use can easily overheat the braking system.

Slow down. The faster you drive, the more work your brakes must do when you do need to stop.

Anticipate the need to slow down by thinking ahead and reading the road conditions.

Lighten the load in your vehicle or trailer if practical. More weight means the brakes work harder.

On downhill stretches – especially if towing – change into a lower gear and make use of engine braking. This will provide additional opportunities for heat in the braking system to dissipate. If not enough, pull over when safe and let the brakes cool.

With a more considered driving style and some Bendix braking system enhancements, brake fade can largely be eliminated.

Brake shims are an important component in the braking system that help absorb vibration and reduce noise, leading to a quieter and more enjoyable driving experience.

Attached to the friction pad backing, brake shims provide a barrier between the brake pad and the caliper, helping to prevent small vibrations.

It’s important to recognise that some level of noise is inevitable when brakes are applied, given the friction that’s occurring between the pad and disc rotor. When the brake pad meets the rotor, coupling occurs and subsequently vibrations follow, building into noise.

A well-engineered braking system and accompanying hardware can minimise the noise, with high quality shims playing a part in this process. Using a clever multi-layered design and composition that includes varying grades of metal, viscoelastic polymers, elastomeric rubbers, fiberglass and bonding materials, brake shims provide dampening qualities.

Bendix brake pad shims for passenger cars are fibre impregnated, rubber shims designed and engineered to meet OE standards and to work within manufacturers’ tolerances, ensuring they continue to meet the original engineering ‘tune’ of the vehicle. This tune which is honed during vehicle NVH (noise, vibration and harshness) testing, aims to keep brake noise emissions to a range that falls outside human hearing, or at the very least to minimise it so it’s not audible in the cabin.

In Bendix’s high performance brake pad, the ‘Street Road track’, the shim is made from carbon steel with nitrate rubber coating on both sides. This unique formulation delivers even quieter braking performance, while improving vibration installation and longevity.

Brake pad shims also help prevent heat transmission from the brake pad to the caliper and other components – braking performance is increased when heat is minimised and can’t impact system components such as fluid, lubricants and moving parts. Bendix’s coated shims minimise heat transmission much better than standard shims, while also lasting longer.

Given the important role that brake shims play in reducing braking vibration and noise, as well as assisting braking performance through their heat suppression, it’s recommended to replace brake shims at the same time as the brake pads.

Bosch has decades of experience in the manufacturing of braking systems. The Bosch range covers every sector and extends from individual components to complete systems. With Bosch, you will find the right component for practically every vehicle. You benefit from first-class Bosch quality, while also ensuring customer satisfaction.

Research and development

Bosch is the world’s leading supplier of anti-lock braking systems (ABS), traction control systems (TCS) and electronic stability programs (ESP).

Bosch makes a substantial investment each year in the research and development of braking products and systems.

With continuous development and the use of innovative techniques and materials, Bosch assures product quality through constant checks during the entire production process.

Bosch’s technological competence is evident in the fact that it is a world leader in the number of patent applications it submits each year. Innovations from Bosch have had a decisive influence on automobile history. As one of the world’s largest parts supplier to the automotive industry, Bosch significantly contributes toward making driving safer, cleaner and more economical.

Why choose Bosch brake pads? Global trusted brand

• Bosch is a renowned global automotive innovator with over 90 years of brake development.

• Vehicle brakes are subjected to extreme loads. For example, braking horsepower is about 10 times engine horsepower, which is why brake pads reach such high temperatures. During long mountain descents or when driving in stop-and-go highway traffic, temperatures can easily reach as high as 650°C. To ensure safety, brake pads therefore need to be regularly inspected and replaced only with high quality products such as Bosch brake pads.

Quality and performance guaranteed

• Bosch European brake applications are designed to meet the increasing demand of today’s vehicles.

•

Bosch brake pads have been developed to withstand extreme loads and are manufactured from especially high quality materials. Extensive performance and NVH dynamometer testing along with extreme environment testing ensures that Bosch brake pads demonstrate a high level of performance and service life before being approved for sale.