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 89 of 790
TM 5--2350--378--24&P
0005 00--30
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 V16--Shutoff valve -- Left hand
suspension raise/lower relief
UNSPRUNG MODE--RAISE:
S
No hydraulic fluid supply (3) to left front actuators 1 & 2
through left front wheel valve.
S
Can’t raise left front of vehicle (Was raised in sprung mode
and now supply is cut off and cannot get 3500 psi
(24131.65 kPa) pressure.))
UNSPRUNG MODE--LOWER:
S
No hydraulic fluid supply (3) from front actuators 1 & 2
through left front wheel valve.
S
Can’t lower left front of vehicle.
S
Degraded dozing or scraping capability.
Solenoid Valve V17--Shutoff valve -- Apron
retract
S
No hydraulic fluid supply going to (raise) or from (lower)
apron cylinders.
S
Apron can’t be raised or lowered.
S
Can’t unload or can’t retain load in bowl.
Solenoid Valve V18--Shutoff valve -- No. 4
actuator, left suspension port 9 to port 2
(normally closed)
STUCK OPEN
SPRUNG MODE:
S
Compensating pressure continuously supplied to left rear
actuators 3 & 4.
UNSPRUNG MODE:
S
Compensating pressure at 2850 psi (19650.06 kPa)
continuously supplied to left rear actuators 3 & 4 and right
rear actuators 3 & 4. If this is normal pressure in unsprung
mode, there is no impact.
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