SERV1851 02/08
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311D / 312D /314D HYDRAULIC SYSTEM
Swing Motor
Left Travel Motor
Text Reference Boom, Stick, and Bucket Circuits
IMPLEMENT CIRCUITS
Right Travel Motor
Stick 1 BR2
AR1 BL1
BL1
BR2
BL1 AL1
BR3
AR3
bR3
AR2 BR1
AR1
bR1
Bucket
Boom 1
Main Control Valve Group
bR3
AR2
AL1
bL1
AL2
BL2
bL2
bL4
BL4
aL4
Medium Pressure Circuit (If Equipped)
aR3
aR1
PR
aL1
aL4
aL2
PL
aR2
bL1
bR1
Travel Levers aR1
aL1
Pilot Manifold
Stick 2
P
Pilot Filter
PR
Main Hydraulic Pumps
aR2
Left Joystick
Pilot Pump
aL2
bR3
bR2
bL4
Right Joystick
M aL4
Tank aR3
Boom 2
Medium Pressure Pump (If Equipped)
PL
bL2 P
111
BOOM, STICK, AND BUCKET CIRCUITS This presentation covers in more detail each implement circuit used for the 311D/312D/319D Series Hydraulic Excavators. The circuits to be covered include: - boom - stick - bucket The idler pump provides oil to the boom 2 and stick 1 control valves. The drive pump provides flow to the bucket, boom 1, and stick 2 control valves. The boom, stick, and bucket control valves are shifted by pilot oil from the joystick pilot valves when they are activated. NOTE: The main control valve group and return system are covered in another presentation. The attachment/auxiliary circuits will be covered in the tool control section. The ISO schematics were created primarily from "312D Hydraulic Schematic" (KENR6556). Hydraulic schematics for the 311D and 314D may have variations from illustrations shown.
