Note:On some machine configurations an
additional pump 2A draws oil from tank 1 to supply
an additional flow to the excavator valve 4, which is
required for certain machine options/attachments.
Hydraulics
9803/7130 Issue 1
Component Location
Component Key:
1 Hydraulic Tank
1B Return Line Filter (inside hydraulic tank)
1C Suction Strainer (inside hydraulic tank)
2 Hydraulic Pump (engine driven)
2A Auxiliary Hydraulic Pump (engine driven)
(if fitted)
3 Loader Valve Block
3D Main Relief Valve
3H Hose - High Pressure Cary Over
4 Excavator Valve
5 Steer Circuit Priority Valve
7 Hydraulic Oil Cooler
7A Return Line Check Valve
8 Pressure Test-point Connector
13 Smooth Ride Accumulator and Control Valves
Neutral Circuit Description
Oil is drawn through suction strainer 1C from
hydraulic tank 1 by the engine-driven single stage
hydraulic gear pump 2. From the pump, oil flows to
the steering circuit and/or the loader valve block 3
by way of the priority valve 5, which always gives
priority to the steering circuit requirements.
A pressure test-point connector 8 is located in the
pipe fitting adjacent to the priority valve 5.
From the loader valve neutral gallery, oil flows via a
high pressure carry-over line 3H to the excavator
valve 4.
Some exhaust oil from the excavator and loader
valves flows back direct to the tank and some
through cooler 7. Oil flowing back to tank passes
through return line filter 1B (mounted within the
tank).
To help prevent excavator dipper ram and loader lift
ram cavitation, there is a check valve 7A fitted in
the return line, which raises the return line pressure
and improves the operation of the respective anti-
cavitation valves.
3 - 2 3 - 2
Basic System Operation
Section E Section E
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