Test mechanical products and equipment after repair or assembly to ensure proper performance and compliance with manufacturers' specifications., Diagnose faults or malfunctions to determine required repairs, using engine diagnostic equipment such as computerized test equipment and calibration devices., Clean, lubricate, and perform other routine maintenance work on equipment and vehicles., Read and understand operating manuals, blueprints, and technical drawings., Assemble gear systems, and align frames and gears., Fit bearings to adjust, repair, or overhaul mobile mechanical, hydraulic, and pneumatic equipment., Weld or solder broken parts and structural members, using electric or gas welders and soldering tools., Clean parts by spraying them with grease solvent or immersing them in tanks of solvent., Adjust, maintain, and repair or replace subassemblies, such as transmissions and crawler heads, using hand tools, jacks, and cranes., Repair, rewire, and troubleshoot electrical systems.