TM-5-2350-378-24-P
HYDRAULIC DIAGNOSTIC CENTER (HDC) SUPPORTING ARMORED COMBAT EARTHMOVER (ACE), M9
TECHNICAL MANUAL; UNIT, DIRECT SUPPORT, AND GENERAL SUPPORT MAINTENANCE MANUAL INCLUDING REPAIR PARTS AND SPECIAL TOOLS LIST
TM-5-2350-378-24-P - Page 738 of 790
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TM 5--2350--378--24&P
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UNIT MAINTENANCE
MAINTENANCE ALLOCATION CHART (MAC)
INTRODUCTION
The Army Maintenance System MAC
This introduction provides a general explanation of all maintenance and repair functions authorized at various
maintenance levels under the standard Army Maintenance System concept.
The MAC (immediately following the introduction) designates overall authority and responsibility for the perfor-
mance of maintenance functions on the identified end item or component. The application of the maintenance
functions to the end item or component shall be consistent with the capacities and capabilities of the designated
maintenance levels, which are shown on the MAC in column (4) as:
Unit -- includes two subcolumns, C (operator/crew) and O (unit) maintenance.
Direct Support -- includes an F subcolumn.
General Support -- includes an H subcolumn.
Depot -- includes a D subcolumn.
The tools and test equipment requirements (immediately following the MAC) list the tools and test equipment
(both special tools and common tool sets) required for each maintenance function as referenced from the MAC.
The remarks (immediately following the tools and test equipment requirements) contain supplemental instructions
and explanatory notes for a particular maintenance function.
Maintenance Functions
Maintenance functions are limited to and defined as follows:
1.
Inspect. To determine the serviceability of an item by comparing its physical, mechanical, and/or electrical
characteristics with established standards through examination (e.g., by sight, sound, or feel). This includes
scheduled inspection and gagings and evaluation of cannon tubes.
2.
Test. To verify serviceability by measuring the mechanical, pneumatic, hydraulic, or electrical characteristics
of an item and comparing those characteristics with prescribed standards on a scheduled basis, i.e., load
testing of lift devices and hydrostatic testing of pressure hoses.
3.
Service. Operations required periodically to keep an item in proper operating condition; e.g., to clean
(includes decontaminate, when required), to preserve, to drain, to paint, or to replenish fuel, lubricants,
chemical fluids, or gases. This includes scheduled exercising and purging of recoil mechanisms.
4.
Adjust. To maintain or regulate, within prescribed limits, by bringing into proper position, or by setting the
operating characteristics to specified parameters.
5.
Align. To adjust specified variable elements of an item to bring about optimum or desired performance.
6.
Calibrate. To determine and cause corrections to be made or to be adjusted on instruments of 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.
7.
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 system.
8.
Replace. To remove an unserviceable item and install a serviceable counterpart in its place. “Replace” is
authorized by the MAC and assigned maintenance level is shown as the third position code of the Source,
Maintenance and Recoverability (SMR) code.
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