What Is Brake Lining

Brake lining is the friction material inside brake pads that slows down a vehicle or machine. It used to be mainly made of chrysotile asbestos, but since that was linked to pleural and peritoneal mesothelioma most manufacturers have been using more premium materials.

Poor quality brake lining can lead to uneven wear of the brake rotor and other components. This can cause jerking vibrations when you apply the brakes or a noticeable pulsation in the pedal.

Brake Pads

Brake pads absorb friction and reduce the stress of slowing or stopping your car. They also protect brake rotors from heat damage.

In the past, brake pads were often made from asbestos -- a good material for absorbing and dissipating heat. Asbestos, however, can release dangerous dust when it wears down. That's why modern non-asbestos organic or semi metallic pads are used on most passenger cars.

The kind of braking you do on your everyday commute and the weight of your vehicle will influence how quickly your pads wear down. Driving over rough roads or frequent stops at traffic lights will wear them down faster than cruising down the highway on a clear day.

Your car's brake pads usually have a built-in mechanism for warning you when they are getting too thin. One common technique involves a small central groove whose eventual disappearance indicates when the pad has reached its end of life. A soft metal wear tab that closes an electrical circuit when uncovered by worn pad material can also be incorporated into the pad, which illuminates your dashboard warning light.

Brake Rotors

If you've ever seen a shiny metal disc mounted in the wheel hub of your car, then you have seen the brake rotor. These are molded solid "blanks" made of different metal alloys, most commonly cast iron or steel. Depending on the vehicle and driving style, they may be topped with various coatings to protect against corrosion or add visual appeal.

The rotor's working surface is typically grooved or slotted and the brake caliper is clamped against it with spring pressure when the brake pedal is applied. These machining features prevent brake heat from heating the surface too quickly, minimizing the potential for warping.

Before installing a new set of pads, the rotors and drums should be resurfaced to create a smooth and even surface for friction against the pads. A resurfacing service is usually cheap and will significantly extend the life of these important components. The resurfacing process also eliminates the annoying squeal some brakes emit when they are wearing thin, warning the driver that it's time for new brake linings.

Brake Fluid

The brake lining absorbs most of the heat, weight and energy of the vehicle during braking. Once the lining reaches its minimum thickness, it must be replaced or resurfaced. The resurfacing process removes all friction material from the brake disc and leaves a smooth metal surface that can then be re-surfaced with new lining.

Brake fluid is a clear liquid that helps maintain proper braking performance. It contains corrosion inhibitors that protect the metal parts of your calipers, wheel cylinders and master cylinders. Brake fluid is also hygroscopic, meaning it attracts and absorbs water from the air. It is important to completely replace old brake fluid with fresh brake fluid to prevent contamination and moisture from affecting the braking system.

To change your own brake fluid, you will need a few tools and a safe place to work. You will need jack stands or a floor jack to safely lift your car, a few disposable plastic cups to contain the old fluid and a Sharpie(r) to label the bolts and parts as you take them apart.

Brake Linings

Brake linings convert the vehicle’s kinetic energy into heat, so they must be able to withstand high temperatures without excessive wear (leading to frequent brake replacement) or outgassing (causing brake fade, which decreases stopping power). The best brake lining materials are also capable of handling abrasive operating conditions.

Today’s brake linings are made of safe, natural materials including rubber, resin, Kevlar, and glass. Non-asbestos, or organic, brake linings have very little metal in them and are quieter than semi-metallic liners. They are a better option for preserving the life of the rotor.

Semi-metallic brake linings contain up to 65% metals, usually brass, copper, iron and steel, along with fillers and graphite lubricant. They are more durable than non-asbestos linings and can last longer because their metallic composition helps dissipate heat from the rotor. However, they are noisier and produce more dust.