In some shops there are enginemen, axlemen, transmission men, and other mechanical experts. All of these may be classified as mechanics. Other men found in repair shops are known as trouble-finders or inspectors, helpers, foremen, and carburetor specialists.
The mechanic should be able to do skilled work on all mechanical parts of any car. His work consists in adjustment, care, overhauling, and repairing. Adjustment and care include valve, carburetor, clutch-spring, brake, and steering-mechanism adjustment, and cleaning and lubrication of parts. Much of this work can, however, be done by the automobile driver or helper in a garage. Overhauling includes repairing, but refers generally to the tearing down of the whole machine for cleaning, inspection, adjustment, and testing, together with replacement of worn and broken parts. Work on the engine requires in many cases its removal from the chassis, and disconnection of all attached parts. Some of the jobs to be done on automobile engines are removal of carbon from pistons, refitting of pistons, regrinding valves, replacing and scraping bearings, adjustment of fans and valve rods, setting timing gears, correcting the firing order of cylinders, repairing and replacing broken parts.
The mechanic is required to remedy clutch troubles, by adjustment or replacing of worn leather on the cone. Transmission repairs include replacement of gears, fitting keys, taking up the wear in the main bearings, or complete replacement and repair of shifting-rod connections to overcome looseness. The universal joints in driving mechanisms often require disassembling and rebushing, while the mesh of the drive pinion and bevel gear of the differential will need adjusting. Work on the differential and rear axle may involve tearing down the rear construction. Such work requires skilled mechanics, especially to determine the trouble and make the proper reassembly. The play in wheels needs careful attention and exact adjustment, although it requires no particular skill or knowledge. Trouble found in the front wheels is ordinarily due to lack of alignment, and must be remedied to relieve not only a tremendous wear on tires but to prevent uncertain and difficult steering. A sagging in the frame, often caused by a fracture, can best be repaired by welding. Brakes require attention to eliminate noises and dragging, which causes a noticeable lack of power, and worn brake linings must be replaced.
The cooling system, made up of pump, fan, radiator, and connections, will require adjustment and repair, including replacing the rubber hose, mending broken parts of the pump, putting on new fan belts, and soldering leaks in the radiator. Cleaning the radiator and taking cold-weather precautions against freezing also are necessary tasks.
An inspector or trouble finder in a repair shop or garage service department is the foreman or mechanic, but in large shops men are employed solely for the purpose of diagnosing trouble. Such a man must be highly skilled. His work is to locate trouble and determine and report its nature and extent. Trouble is located by inspection and examination of the car standing still, by testing at the start and at various speeds, and by coasting. The trouble-finder expert makes a list of all worn and broken parts, indicates necessary repairs and adjustments, and then turns the job over to the men who are to do the work.
Usually the foreman is in charge of all repair-shop work. He should be a man of clean personal habits, should have a thorough knowledge of automatic construction, and be able to direct work and handle men with courtesy and tact, to compute jobs, estimate cost of time and materials, keep time and stock records, and route work through on repair-order forms specifying work, parts, and costs for each job. A manager or superintendent often is in charge of the business end of the work, in which case the foreman gives his time to seeing that jobs are correctly done.
Helpers are usually assigned to heavy lifting and pulling, to cleaning parts, and to general shop sweeping. They run errands, help pull down and assemble motors, transmissions, and rear axles, and do other work requiring little skill.
Tools, Machines, Equipment, and Materials Used
A variety of hand tools are used in repair work, including adjustable and fixed jaw wrenches, hammers, snips, breast and hand drills, screw drivers, hack saws, center punches, cold and cape chisels, soldering coppers, pliers, files, brushes, blow torches, vises, and other small tools. The machine equipment includes lathes, drill presses, grinders, and forges equipped with motor power and having full sets of tools for use with each. The shop must be further provided with benches, chain hoists, motor and rear-axle stands, creepers, and special tools and devices for special work. An oxy-acetylene welding and cutting outfit of the portable type is one of the greatest conveniences in any repair shop.
Most of the parts, supplies, and materials come to the shop prepared and ready for use. For some jobs, however, it may be convenient and more satisfactory to construct the necessary parts, such as shims, gaskets, and small metal pieces, from stock material. It is inadvisable, however, to make anything that can be secured already prepared.