Groundsmaster 4500--D/4700--D Hydraulic SystemPage 4 -- 5
Relieving Hydraulic System Pressure
Beforedisconnectingor performing any workonthehy-
draulic system, all pressure in the hydraulic system
mustberelieved.Parkmachineonalevelsurface,lower
cuttingdecksfully,stopengineandapplyparkingbrake.
To relieve hydraulic pressure in traction circuit, move
tractionpedaltobothforwardandreversedirections.To
relieve hydraulic pressure in steering circuit, rotate
steering wheel in both directions.
Systempressureinmowcircuitisrelievedwhenthecut-
ting decks are disengaged (PTO switch in OFF posi-
tion).
Torelievehydraulicpressureinlift circuit, fully lower the
cuttingdeckstotheground.Turnignition switch toOFF.
Traction Circuit Component Failure
The traction circuit on Groundsmaster 4500--D and
4700--Dmachinesisa closed loop systemthatincludes
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 r emoved 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,drainedandthoroughlycleanedtoensurethat
all contamination is r emoved from the circuit. If any de-
brisremainsinthetractioncircuitandthemachineisop-
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.
Thefiltershouldbeusedwhenconnectinghydraulictest
gaugesinorderto testtractioncircuitcomponentsoraf-
ter replacing a failed traction circuit component (e.g.
traction(piston) pumporw heelmotor).Thefilterwillen-
sure that contaminates are removed from the closed
loopand thus,donotcauseadditionalcomponentdam-
age.
Oncethefilterhasbeenplacedinthecircuit,operatethe
tractioncircuittoallowoilflowthroughthecircuit.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 alwaysdirectedthroughthe filter before
entering a replaced component (e.g. do not press
thetraction pedal inthe reverse directionif thefilter
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
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