Brake and Clutch Repair Safety

Brakes systems use hydraulic pressure and friction to efficiently stop vehicles weighing thousands of pounds. The safety hazards when doing brake work are the result of pressurized fluids, heat generated by friction, and brake dust.

Basic brake and clutch repair precautions

To avoid unnecessary exposure to brake dust, wear gloves while working and wash your hands after any repairs. Don't eat, drink, or smoke near areas where brake and clutch work is being performed. To avoid contaminating the home environment, it's best to change clothes before leaving the shop or as soon as you arrive at home.

Mitigating asbestos exposure

The presence of asbestos in brake shoes, gaskets, and clutches poses a serious health risk to auto repair workers. Inhalation of asbestos particles may lead to lung cancer over time.

Even though the use of asbestos is no longer typically used to manufacture these parts in the United States, parts containing asbestos may be present in older vehicles. Asbestos may also be present in aftermarket parts, particularly those imported from outside the United States.

Parts containing asbestos can include brake pads, brake shoes, gaskets, and clutch plates. The material in these components wears out over time, leaving a residue of dust that can easily become airborne.

Environmental control methods

There are three approaches to mitigating exposure to asbestos during brake and clutch repairs. According to OSHA, repair shops that perform this work on five or fewer vehicles per week can opt for the "wet method." All other shops must use either a negative pressure enclosed HEPA vacuum system or the "low pressure/wet cleaning method."

Negative pressure enclosure HEPA vacuum systems

A negative pressure enclosure HEPA vacuum system is an enclosure and vacuum system which fits tightly around a brake or clutch assembly, preventing asbestos exposure during brake or clutch inspection, disassembly, and repair.

To use a negative pressure enclosure HEPA vacuum system:

• Seal the enclosure tightly and inspect it carefully for leaks before starting work.
• Make sure the plastic enclosure sleeves are transparent to enable employees to observe all work procedures.
• The enclosure sleeves must be impermeable, allowing employees to handle the brake and clutch assembly without penetrating the sleeves. Check the sleeves periodically for any signs of breaks or tears. If there are breaks or tears in the material, stop working. If necessary, use compressed air to remove asbestos particles from the enclosure.
• Use the HEPA filtered vacuum to loosen asbestos from brake and cultch parts, then remove the loosened parts from the enclosure into the vacuum filter.
• When asbestos particles have been vacuumed out of the enclosure, wipe the surfaces of the brake and clutch assembly to remove all traces of asbestos dust.
• Vacuum the enclosure area to remove any residual asbestos dust particles.

Low pressure/wet cleaning method

This method utilizes low pressure spray equipment to carefully remove dust that may contain asbestos. Technicians using this method must wear P1 or P2 respirators.

To use the low pressure/wet cleaning method:

• Place a catch basin or clean plastic sheet under the brake assembly to avoid splashes and spills.
• Use low pressure spray to flood the brake assembly with water containing an organic solvent to minimize dust dispersal.
• For drum brakes, make sure the waster solution flows between the brake drum and brake support before removing the brake drum. Once the brake drum is removed, wash the wheel hub and the back of the brake assembly. Before removing the old brake shoes, wash the brake support plate thoroughly as well as the brake shoes and other parts.
• Remove all asbestos contaminated water using a HEPA filtered vacuum or other approved wet methods.
• Change water based solutions on a regular basis.
• Dispose of filters and all other contaminated materials in designated tight-fitting asbestos debris containers.
• Technicians must change clothes before going home.

Wet method

The wet method uses a spray bottle to deliver a fine mist to wet all brake and clutch parts. Technicians using this method must wear P1 or P2 respirators along with suitable work gloves and clothing.

To use the wet method:

• Wet down brake and clutch parts with a fine mist.
• Wipe the brake and clutch parts with a clean cloth.
• All cleaning cloths must be placed in an impermeable, properly labeled hazardous waste container.
• Spilled water should be cleaned up with a HEPA filtered vacuum.
• Never use a brush to clean up spilled materials.
• Technicians must change clothes before going home.
• For brake assemblies:

  • Wet wipe the wheel before removing the wheel nuts.
  • Remove the wheel and deal with any dust with wet wipe method.
  • Wet wipe any dust on the brake assembly.
• For clutch repairs:

  • Once the gear box is separated from the engine, wet wipe the bell housing and around the pressure plate.
  • On removal of the pressure plate and clutch plate, wet wipe the wheel housing and components.

Disposal of asbestos contaminated materials

Cloths and rags must be placed in plastic bags before placing them in disposal containers. Use heavy duty plastic bags and make sure the bags are labeled with asbestos caution labels. Don't reopen or damage the bags.

HEPA vacuum filters and plastic sheeting must be stored in containers. All materials must be placed in steel drums with removable lids or sealed skips.

Containers must be disposed of in accordance with OSHA's Hazardous Waste Disposal regulations.

Other asbestos mitigation tips

Using pre-ground "ready to install" parts helps to reduce the creation of dust. When drilling cutting, lathe-turning, or other dust-producing work must be performed, machinery with built-in HEPA filtration at the exhaust helps to keep dust exposure to a minimum. Using the lowest effective speed will also help to avoid producing excess dust.

Avoiding dangerously botched repair jobs

Always use the correct grade of brake fluid specified by the vehicle manufacturer. This can be found on the master cylinder cap or reservoir body. DOT 5 (silicone) brake fluid can not be used in any vehicle equipped with ABS.

Don't open any brake lines or replace any components in a vehicle equipped with an ABS system without first depressurizing the system. This can usually be done by depressing the brake pedal around 40 times while the ignition key is turned to the "off" setting.

After completing any brake repairs, pump the brake pedal several times to confirm that the pedal is firm before attempting to test drive the vehicle. If the brake pedal feels soft or spongy after repairs are performed, there may be air trapped in the brake lines. Bleed the brake lines again to remove any air.

When servicing disc brakes, open the bleeder screws and vent the brake fluid if necessary in order to push the caliper pistons in. Sediment naturally collects in brake calipers over time, and if allowed to flow back into the master cylinder along with the brake fluid, it can damage the ABS hydraulic unit.

Don't attempt to jump start an ABS-equipped vehicle with a gasoline powered booster or 110V battery charger on the fast charge boost setting. ABS and other on-board computers can be easily damaged by high electrical system voltage. Slow charge the battery first before attempting to start the vehicle. If slow charging isn't possible, disconnect the negative battery cable before fast charging the battery.

Never unplug or connect any electrical ABS component with the ignition on. Doing so can cause a current surge and damage system components.

When replacing unitized wheel bearings, half shafts, steering knuckles, or any other component that could affect the air gap between the wheel speed sensor and sensor ring, the air gap must be checked afterward. Never hammer or pry on wheel speed sensors or sensor rings.