Repair and/or rebuild brake systems including disc, drum, and air brakes; replace brake shoes and pads; turn drums and rotors on a brake lathe; rebuild master cylinder and wheel cylinders and replace brake lines; repair or replace defective air brake components such as air valves, compressors, air tanks, air dryers, air lines, and air chambers. Determine the cause and extent of component or system failure through test drives, pressure and temperature checks, visual inspection, use of diagnostic equipment, and reference to technical service manuals, service information bulletins, blueprints, and schematic manuals; diagnose malfunction and order parts required for repairs by researching parts manual to locate proper parts, contact vendors if necessary, and complete purchase requisitions.