Remove/Install. To remove and install the same item when required to perform service or other
maintenance functions. Install may be the act of emplacing, seating, or fixing into position a spare, repair
part, or module (component or assembly) in a manner to allow the proper function of equipment or system.
Replace. To remove an unserviceable item and install a serviceable counterpart in its place. "Replace" is
authorized by the MAC and is shown as the 3rd position code of the SMR code.
Repair. The application of maintenance services, including fault location/troubleshooting,
removal/installation, and disassembly/assembly procedures, and maintenance actions to identify troubles,
and restore serviceability to an item by correcting specific damage, fault, malfunction, or failure in a part,
subassembly, module (component or assembly), end item, or system.
The following definitions are applicable to the "repair" maintenance function:
Services - Inspect, test, service, adjust, align, calibrate, and/or replace.
Fault location/troubleshooting-The process of investigating and detecting the cause of
equipment malfunctioning; the act of isolating a fault within a system or Unit Under Test
Disassembly/assembly-The step by step breakdown (taking apart) of a spare/functional group
coded item to the level of its least component, that is assigned an SMR code for the level of
maintenance under consideration (i.e. identified as maintenance significant).
Actions-Welding, grinding, riveting, straightening, facing, machining, and resurfacing.
Overhaul. That maintenance effort (service/action) prescribed to restore an item to a completely
serviceable/operational condition as required by maintenance standards in appropriate technical
publications (i.e., DMWR). Overhaul is normally the highest degree of maintenance performed by the
Army. Overhaul does not normally return an item to like new condition.
of those services/actions necessary for the restoration
of unserviceable equipment
like new condition in accordance with original manufacturing standards. Rebuild is the highest degree of
material maintenance applied to Army equipment. The rebuild operation includes the act of returning to
zero those age measurements (hours/miles, etc.) considered in classifying Army equipment/components.
Explanation of Columns in the MAC
Column 1, Group Number. Column 1 lists functional group code numbers, the purpose of which is to
identify maintenance significant components, assemblies, subassemblies, and modules with the next
higher assembly. End item group numbers are "00".
Column 2, Component/Assembly. Column 2 contains the names of components, assemblies,
subassemblies, and modules for which maintenance is authorized.
Column 3, Maintenance Function. Column 3 lists the functions to be performed on the item listed in
Column 2. (For detailed explanation, refer to the previous section entitled "Maintenance Functions").