TM-5-2350-378-24-P

TM 5--2350--378--24&P

0004 00--1

INTRODUCTION TO TROUBLESHOOTING AND REPAIR OF THE M9 ACE

HYDRAULIC SYSTEM

0004 00

SCOPE

This work package contains introductory, but essential, information necessary to troubleshoot and repair the M9

ACE vehicle hydraulic system that incorporates the Hydraulic Diagnostic Center (HDC) System modification. It

includes locating and describing major components of the hydraulic system, a description of the M9 hydraulic

system principles of operation, general hydraulic system repair methods, and general hydraulic system

troubleshooting procedures.

LOCATION AND DESCRIPTION OF MAJOR COMPONENTS

Figure 3. M9 ACE Hydraulic System Major Components

(1) APRON CYLINDER. Raises and lowers apron and dozer assembly (one each side).

(2) RETURN LINE FILTER. Filters out contaminants from hydraulic oil that is returning to reservoir.

(3) HIGH PRESSURE FILTERS. Two high--pressure filters located directly in front of driver’s compartment filter

hydraulic fluid from the main hydraulic pump while it is enroute to the directional control valve bank.

(4) DIRECTIONAL CONTROL VALVE (DCV) BANK. Activated by mechanical linkages from the operator’s

controls to activate hydraulic functions in the vehicle. Controls direction of fluid flow and pressure.

(5) WINCH MOTOR. Operates the winch which is used in recovery operations.

NOTE

Although the Bilge Pump is considered Not Mission Essential and will no longer be

supported with spare and repair parts, this manual contains troubleshooting procedures For

Your Information Only. See TB 43 0001--62--7 (dated Oct 98) for Instructions to Isolate and

Disconnect a Non--functional Bilge Pump.

(6) BILGE PUMP MOTOR. Starts bilge pump operation through hydraulic pressure when bilge pump control

lever is activated.

(7) FORWARD MANIFOLD. Routes the flow of hydraulic fluid to components.

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