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 90 of 790
TM 5--2350--378--24&P
USING THE HYDRAULIC DIAGNOSTIC CENTER (HDC) SYSTEM TO TROUBLESHOOT
THE M9 HYDRAULIC SYSTEM -- Continued
0005 00
Table 5. POSSIBLE SYMPTOMS OF FAILED HDC SYSTEM COMPONENTS -- Continued
HDC SYSTEM
POSSIBLE CONSEQUENCES
Solenoid Valve V19--Shutoff valve --
Suspension relief valve port 17R (normally
closed)
STUCK OPEN
SPRUNG MODE:
S
Compensating pump pressure is directed to reservoir
return.
S
No hydraulic fluid supply (9) to wheel valves.
S
No hydraulic fluid supply (9) to actuators.
S
Vehicle will not be raised.
S
Track may be thrown if vehicle is backed.
S
No suspension shock absorbing capability.
UNSPRUNG MODE:
S
Main accumulator/compensating pump pressure is directed
to right front intermediate control valve.
S
Main accumulator pressure is directed to right front actuator
lower side.
S
No vehicle change in height since raise side pressure is
trapped.
UNSPRUNG MODE--LOWER:
S
No impact.
UNSPRUNG MODE--RAISE:
S
Hydraulic fluid supply is directed to return.
Solenoid Valve V20--Shutoff valve -- Ejector
cylinder extend to main accumulator (normally
closed).
STUCK OPEN:
S
Undesired compensating pressure on ejector cylinder
extend.
S
Ejector will slowly extend due to leakage.
UNSPRUNG MODE:
S
Maximum suspension pressure 2000 psi (13789.51 kPa).
S
Vehicle can’t be fully raised.
Solenoid Valve V21--Shutoff valve -- (manual)
S
No hydraulic fluid supply to 5/15 micron filters, suspension,
bilge pump, apron, winch, main ejector from one side of
main pump.
S
Main pump output is cut off on one side, no flow.
Solenoid Valve V22--Shutoff valve -- (manual)
S
No hydraulic fluid supply to main pump filters, suspension,
winch, main ejector, bilge pump, apron from one side of
main pump.
S
Main pump output is cut off on one side, no flow.
Solenoid Valve V23--Shutoff valve -- (manual)
S
Cannot extend ejector cylinder or can’t retract ejector
cylinder.
S
Can’t dump load or can’t retract ejector to fill load.
S
Can’t fold dozer blade.
END OF WORK PACKAGE
0005 00--31/32 blank
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