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Groundsmaster 4500--D/4700--D Hydraulic SystemPage 4 -- 5
Relieving Hydraulic System Pressure
Before disconnecting or performing any work onthe hy-
draulic system, all pressure in the hydraulic system
mustberelieved.Parkmachineonalevel surface,lower
cutting decksfully,stop engineandapply parkingbrake.
To relieve hydraulic pressure in traction circuit, move
traction pedalto both forwardand reverse directions.To
relieve hydraulic pressure in steering circuit, rotate
steering wheel in both directions.
Systempressure inmow circuit isrelieved whenthe cut-
ting decks are disengaged (PTO switch in OFF posi-
tion).
To relieve hydraulic pressure in lift circuit, fully lower the
cutting decks to the ground. Turn ignition switch to OFF.
Traction Circuit Component Failure
The traction circuit on Groundsmaster 4500--D and
4700--D machines is a closed loop system thatincludes
the piston (traction) pump, two (2) front wheel motors
and the rear axle motor. If a component in the traction
circuit should fail, debris and contamination from the
failed component will circulate throughout the traction
circuit. This contamination can damage other compo-
nents in the circuit so it must be removed to prevent
additional component failure.
If a component failure occurs in the traction circuit, it is
recommended that the entire traction circuit be disas-
sembled,drained andthoroughly cleanedto ensurethat
all contamination is r emoved from the circuit. If any de-
brisremains inthe tractioncircuit andthe machine isop-
erated, the debris can cause additional component
failure.
An alternative method of removing traction circuit con-
tamination would be to temporarily install a high pres-
surehydraulicoilfilter(seeSpecialTools)intothecircuit.
Thefiltershould beusedwhenconnecting hydraulictest
gauges in orderto test tractioncircuit components or af-
ter replacing a failed traction circuit component (e.g.
traction (piston) pumpor wheel motor). Thefilter will en-
sure that contaminates are removed from the closed
loop and thus,do not cause additionalcomponent dam-
age.
Oncethe filterhasbeen placedin thecircuit,operate the
traction circuitto allowoil flowthrough thecircuit. Thefil-
ter will remove contamination from the traction circuit
during circuit operation. The filter can be removed from
the machine after contamination has been removed
from the traction circuit.
IMPORTANT: When operating the traction system
with the high pressure filter installed, make sure
that flow is always directed through the filter before
entering a replaced component (e.g. do not press
the traction pedalin the reverse direction if the filter
is placed for forward direction flow). If flow is re-
versed, debris from the filter will re--enter the trac -
tion circuit.
NOTE: If traction circuit contamination exists, the trac-
tion pump case drain could allow contaminates to enter
other hydraulic circuits on the machine.
Hydraulic
System