Calibrate. To determine and cause corrections or adjustments to be made on instruments or test, measuring,
and diagnostic equipment used in precise measurement. Consists of comparisons of two instruments, one of which is a
certified standard of known accuracy, to detect and adjust any discrepancy in the accuracy of the instrument being
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 functioning of equipment or a 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 3d 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.
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.
Rebuild. Consists of those services/actions necessary for the restoration of unserviceable equipment to a like-
new condition in accordance with original manufacturing standards. Rebuild is the highest degree of materiel
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.
B-3. EXPLANATION OF COLUMNS IN THE MAC, SECTION II
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 number shall be 00.
Column 2 Component/Assembly. Column 2 lists the names of components, assemblies, subassemblies, and
modules for which maintenance is authorized.
Column 3 Maintenance Functions. Column 3 lists the functions to be performed on the item listed in column 2.
(For detailed explanation of these functions, see para B-2.)