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 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 compared.
g. 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 an equipment or
h. Replace. To remove an unserviceable item and install a serviceable counterpart in its place. "Replace" is
authorized by the MAC and the assigned maintenance level is shown as the third position code of the SMR
i. Repair. The application of maintenance services1 including fault location/troubleshooting2,
removal/installation and disassembly/assembly3 procedures, and maintenance actions4 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.
j. 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
(e.g., DMWR). Overhaul is normally the highest degree of maintenance performed by the Army. Overhaul
does not normally return an item to 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
material maintenance applied to Army equipment. The rebuild operation includes the act of returning to zero
those age measurements (e.g., hours/miles) considered in classifying Army equipment/components.
B-3. EXPLANATION OF COLUMNS IN THE MAC, SECTION II.
a. Column (1), Group No. 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
b. Column (2), Component/Assembly. Column 2 contains the item names of components, assemblies,
subassemblies, and modules for which maintenance is authorized.
c. Column (3), Maintenance Function. Column 3 lists functions to be performed on the item listed in
Column 2. (For detailed explanation of these functions, see paragraph B-2.)
1. Services - Inspect, test, service, adjust, align, calibrate, and/or replace.
2. 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 (UUT).
3. 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
4. Actions - Welding, grinding, riveting, straightening, facing, machining, and/or resurfacing.