Job Description Help for Job Description. Opens a new window. Diagnose, adjust, repair, or overhaul trucks, buses, and all types of diesel engines. Includes mechanics working primarily with automobile diesel engines. Use handtools such as screwdrivers, pliers, wrenches, pressure gauges, and precision instruments, as well as power tools such as pneumatic wrenches, lathes, welding equipment, and jacks and hoists. Inspect brake systems, steering mechanisms, wheel bearings, and other important parts to ensure that they are in proper operating condition. Adjust and reline brakes, align wheels, tighten bolts and screws, and reassemble equipment. Raise trucks, buses, and heavy parts or equipment using hydraulic jacks or hoists. Perform routine maintenance such as changing oil, checking batteries, and lubricating equipment and machinery. Test drive trucks and buses to diagnose malfunctions or to ensure that they are working properly. Examine and adjust protective guards, loose bolts, and specified safety devices. Attach test instruments to equipment, and read dials and gauges to diagnose malfunctions. Inspect, test, and listen to defective equipment to diagnose malfunctions, using test instruments such as handheld computers, motor analyzers, chassis charts, and pressure gauges. Inspect, repair, and maintain automotive and mechanical equipment and machinery such as pumps and compressors. Operate tow truck as needed.