Joint Compound
Workers in many trades were unknowingly exposed to dangerous asbestos while working directly with joint compound or in the vicinity of those using it. Could you be one of them?

Asbestos Insulation
Asbestos insulation including asbestos cement and asbestos plaster was used in many industrial and building materials and on Navy warships.

Asbestos | Asbestos Industry

Products > Brake Linings and Clutch Facings

What are Brake Linings and Clutch Facings?

Brake linings and clutch facings are friction materials which help control movement of various parts of a vehicle.

Brakes use friction to transmit force to a moving part of a vehicle (usually the wheels) to slow or stop it completely. Among the components of a braking system are brake pads, or brake shoes, which consist of a brake lining bonded to a metal backing. When the brake is engaged, the pad or shoe is pressed against a metal disc or drum attached to the wheel, causing it to slow or stop. The forward motion of the wheel is converted into heat, subjecting the brake linings to high temperatures. Because of this, brake linings have customarily been made with asbestos.

Clutches allow the transfer of rotational motion between two objects, allowing them to move at the same speed, or at different speeds. In a car, the clutch transmits the rotation of the engine to the wheels, allowing the car to move. Disengaging the clutch allows the driver to slow or stop the wheels without halting or damaging the engine. The clutch facing consists of a disc of friction material attached to a circular clutch plate. When engaged, the facing contacts a flywheel. When the clutch plate and the flywheel rotate at different speeds, the plate can slip, causing wear. Clutch facings are also subject to high temperatures from energy transfer, and have been made with asbestos, similar to brake linings.

Most vehicles employ multiple sets of brake pads and one or more clutches. Brake pads and shoes are typically sold in pairs.

Who Works with Brake Linings and Clutch Facings?

Automotive mechanics remove and replace worn linings and facings. They may also resurface linings and facings. Many car owners, especially of older or vintage cars, may do this work themselves, and may have a friend or family member assist them.

Assembly-line workers may install brakes and clutches in new vehicles. Auto parts manufacturers may assemble new brakes and clutches, or reline old pads, shoes, and clutch plates. Operators of heavy machinery who do their own maintenance may also replace old linings and facings. Junkyard operators may also handle friction materials.

Where are Brake Linings and Clutch Facings Found?

Most motor vehicles, from cars to trains, have brakes and clutches, usually more than one set. Asbestos-containing brake linings and clutch facings are generally found in passenger cars, light- and heavy-duty trucks, motorcycles, buses and heavy machinery such as cranes, tractors and locomotives. Most people are aware that manual transmission cars have clutches, but may be surprised to learn that automatic transmission cars have them also.

Most passenger vehicles have disc brakes on the front wheels, drum brakes on the rear wheels, and a clutch as part of the transmission. Each set of brakes requires linings, and the clutch requires a facing. Larger vehicles, such as trucks and buses, require heavy-duty brake linings and clutch facings. Some heavy machinery may have multiple sets of brakes and clutches. For example, a crane may have brakes on the wheels or crawlers which move it forward, brakes to control the rotation of the cab, and brakes to control the boom, or arm, of the crane.

How Does Brake Lining and Clutch Facing-related Asbestos Exposure Occur?

When brakes and clutches are engaged, they are subject to high temperatures as the motion of the wheels or the flywheel is converted to heat energy. They also experience some gradual wear from contact with these moving metal parts. In order for brakes and clutches to function properly, the brake linings and clutch facings must be replaced or renewed periodically.

Auto mechanics may be exposed to asbestos dust in several ways. In a typical brake repair job, accumulated brake dust must be cleaned away before the old pads or shoes are removed. This is often done with a small brush, or with a blast of compressed air. Either method may cause asbestos particles to become airborne. If the old brake linings are still thick enough to be effective, the mechanic may use a bench grinder to restore the surface, or deglaze the linings of oil and dirt. When installing new brake pads or shoes, the mechanic may grind the surface to speed up the “breaking in” process, bevel the edges with a grinding wheel to reduce noise, and drill or punch holes for rivets. Some manufacturers also recommended scoring the center of the pad with a hacksaw. Any of these tasks could release asbestos particles.

Clutch replacement may also involve cleaning away asbestos dust, and handling deteriorated friction materials.

Common Diseases Associated with Asbestos Exposure

The strong link between asbestos exposure and pulmonary disease did not become commonly known until the mid-1970’s. Workers who have handled asbestos-containing friction materials and other workers or supervisory personnel working in the general vicinity, may have inhaled airborne asbestos fibers while at work, putting them at significant risk for developing one of these diseases: pleural mesothelioma, peritoneal mesothelioma, asbestos-related lung cancer and asbestosis. In addition, workers often brought their work clothes home for laundering, bringing asbestos fibers home which also put their family members at risk for developing one of the above diseases. A disease like mesothelioma can develop slowly, sometimes taking 30 or 40 years following initial asbestos exposure to appear. Prognosis for those diagnosed with mesothelioma is generally not favorable.

Some Popular Brands of Friction Materials

A wide variety of brake linings and clutch facings have been produced over the years. Some have been sold as OEM (Original Equipment Manufacturer) parts, and carry the name of the vehicle manufacturer. Others have been sold under the manufacturer’s own name and trademarks. Listed below are some common manufacturers and brands of friction materials which have at times contained asbestos.

Questions about brake linings, clutch facings and asbestos exposure? Please contact us.