Heavy vehicle and mobile equipment service technicians typically do the following:

• Consult equipment operating manuals, blueprints, and drawings
• Perform scheduled maintenance, such as cleaning and lubricating parts
• Diagnose and identify malfunctions, using computerized tools and equipment
• Inspect, repair, and replace defective or worn parts, such as bearings, pistons, and gears
• Overhaul and test major components, such as engines, hydraulics, and electrical systems
• Disassemble and reassemble heavy equipment and components
• Travel to worksites to repair large equipment, such as cranes
• Maintain logs of equipment condition and work performed

Heavy vehicles and mobile equipment are critical to many industrial activities, including construction and railroad transportation. Various types of equipment, such as tractors, cranes, and bulldozers, are used to haul materials, till land, lift beams, and dig earth to pave the way for development and construction.

Heavy vehicle and mobile equipment service technicians repair and maintain engines, hydraulic systems, transmissions, and electrical systems of agricultural, industrial, construction, and rail equipment. They ensure the performance and safety of fuel lines, brakes, and other systems.

Service technicians use diagnostic computers and equipment to identify problems and make adjustments or repairs. For example, they may use an oscilloscope to observe the signals produced by electronic components. Service technicians also use many different power and machine tools, including pneumatic wrenches, lathes, and welding equipment. A pneumatic tool, such as an impact wrench, is an air tool powered by compressed air.

Service technicians also use many different hand tools, such as screwdrivers, pliers, and wrenches, to work on small parts and in hard-to-reach areas. They generally purchase these tools over the course of their careers, often investing thousands of dollars in their inventory.

After identifying malfunctioning equipment, service technicians repair, replace, and recalibrate components such as hydraulic pumps and spark plugs. This may involve disassembling and reassembling major equipment or making adjustments through an onboard computer program.

Farm equipment mechanics and service technicians service and repair farm equipment, such as tractors and harvesters. They also work on smaller consumer-grade lawn and garden tractors. Most work for dealer repair shops, where farmers increasingly send their equipment for maintenance.   

Mobile heavy equipment mechanics repair and maintain construction and surface mining equipment, such as bulldozers, cranes, graders, and excavators. Most work for governments, equipment rental and leasing shops, and large construction and mining companies.

Rail car repairers specialize in servicing railroad locomotives, subway cars, and other rolling stock. They usually work for railroad, public and private transit companies, and rail car manufacturers.

For information about technicians and mechanics who work primarily on automobiles, see the profile on automotive service technicians and mechanics.

For information about technicians and mechanics who work primarily on large trucks and buses, see the profile on diesel service technicians and mechanics.

For information about technicians and mechanics who primarily work on motorboats, motorcycles, and small all-terrain vehicles, see the profile on small engine mechanics.