Operations required periodically to keep an item in proper operating condition, i.e., to
decontaminate), to preserve, to drain, or to replenish fuel, lubricants, hydraulic fluids,
or compressed air supplies.
d. Adjust. To maintain within prescribed limits, by bringing into proper or exact position, or by
setting the operating characteristics to the specified parameters.
e. Align. To adjust specified variable elements of an item to bring about optimum or desired
f. Calibrate. To determine and cause corrections to be made or to be adjusted on instruments or
test measuring and diagnostic equipment used in precision measurement. Consists of comparison 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 compared.
g. Install. The act of emplacing, seating, or fixing into position an item, part, or module (com-
ponent or assembly) in a manner to allow the proper functioning of an equipment or system.
h. Replace. The act of substituting a serviceable like type part, a subassembly, or module (com-
ponent or assembly) for an unserviceable counterpart.
i. Repair. The application of maintenance services (inspect, test, service, adjust, align, calibrate,
or replace) or other maintenance actions (welding, grinding, riveting, straightening, facing, remachining,
or resurfacing) to 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.
j. Overhaul. That maintenance effort (service/action) necessary to restore an item to a completely
serviceable operational condition as prescribed 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 a like new condition.
k. 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 in-
cludes the act of returning to zero those age measurements (hours/miles, etc.) considered in classifying
B-4. EXPLANATION OF COLUMNS IN THE MAC, SECTION II
a. Column (1), Group Number. Column 1 lists functional group code numbers which are assigned
to identify maintenance significant components, assemblies, subassemblies, and modules to their next
b. Column (2), Component/Assembly. Column 2 contains the item names of components, assem-
blies, subassemblies, and modules for which group numbers (column 1) are assigned and for which
maintenance is authorized.
c. Column (3), Maintenance Function. Column 3 lists the functions to be performed on items
listed in column 2. (Function definitions are contained in paragraph B-3.)
d. Column (4), Maintenance Level. The maintenance levels, Unit, Intermediate, and Depot, are
allotted separate subcolumns within column 4.
Entry of a work time figure (such as 1.0, 0.2) in a
subcolumn indicates that that level is authorized to perform the function listed in column 3, and the