The first objective is to maintain the clearance between the moving and stationary parts of a brake in accordance with the manufacturer's instructions. Disassemble and inspect the brake periodically and examine the parts for wear, cracks, warpage, corrosion, elongated holes, etc. If any of these or other faults are indicated, repair, recondition, or replace the affected parts in accordance with the manufacturer's recommendations. Surface cracks on the friction surfaces of the brake drums occur frequently due to high surface temperatures. These surface cracks may be disregarded as seriously affecting the airworthiness until they become cracks of approximately 1 inch in length.
Hydraulic aircraft brakes
For proper hydraulic aircraft brake maintenance, periodically inspect the entire hydraulic system from the reservoir to the brakes. Maintain the fluid at the recommended level with proper brake fluid. When air is present in the brake system, bleed in accordance with the manufacturer's instructions. Replace flexible hydraulic hose which has deteriorated due to long periods of service and replace hydraulic piston seals when there is evidence of leakage. Service anti-skid units according to the manufacturer's instructions.
Mechanical aircraft brake maintenance.
Keep the working parts of mechanically operated brakes free from dirt and foreign matter so the brakes can work freely at all times. Slack in the linkage system must be kept to a minimum.
Hazards of aircraft brake maintenance and repair
Asbestos containing materials are a component of the brake systems in some light aircraft. It has been suggested there might be a danger of asbestos resulting from the installation and maintenance of these components, particularly if the brake changing process takes place in a closed, unventilated aircraft hanger. However, tests have shown that operations performed according to the manufacturer's recommended procedure, normal brake changing work practices on aircraft with asbestos containing brake pads, do not produce a harmful level of asbestos exposure for aircraft mechanics.