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Groundsmaster 4500--D/4700--D Hydraulic SystemPage 4 -- 5
Relieving Hydraulic System Pressure
Before disconnecting or performing any work on the hy-
draulic system, all pressure in the hydraulic syst em
must berelieved. Park machineon alevel surface, make
sure that PTO switch is OFF, lower cutting decks fully,
stop engine and engage parking brake. Wait for all mov-
ing parts to come to a complete stop.
System pressure inlift circuit isrelieved when thecutting
decks are fully lowered.
System pressure in mow circuit is relieved when the
PTO switch is disengaged.
To relieve hydraulic pressure in traction circuit, turn igni-
tion switch to ON (engine not running) andmove traction
pedal to both forward and reverse directions. Turn igni-
tion switch to OFF after relieving traction circuit pres-
sure.
To relieve hydraulic pressure in steering circuit, rotate
steering wheel in both directions.
After all hydraulic system pressures have been relieved,
remove key from ignition switch.
Traction Circuit Component Failure
The traction circuit on Groundsmaster 4500--D and
4700--D machines is a closed loop system that includes
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.
The recommended method of removing traction circuit
contamination would be to temporarily install the Toro
high flow hydraulic filter (see Special Tools in this chap-
ter) into the circuit. This filter should be used when con-
necting hydraulic test gauges in order to test traction
circuit components or after replacing a failed traction cir-
cuit component (e.g. traction (piston) pump or wheel
motor). The filter will ensure that contaminates are re-
moved from the closed loop and thus, do not cause addi-
tional component damage.
Once the Toro high flow hydraulic filter kit has been
placed in the circuit, raise and support the machine with
all wheels off the ground. Then, operate the traction cir-
cuit to allow oil flow throughout the circuit. The filter will
remove contamination from the traction circuit during
operation. Because the Toro high flow filter is bi--direc-
tional, the traction circuit can be operated in both the for-
ward and reverse direction. The filter should be
removed from the machine after contamination has
been removed from the traction circuit. See Filtering
Closed--Loop Traction Circuitin the Service andRepairs
section of this chapter for additional information on us-
ing the Toro high flow hydraulic filter.
ThealternativetousingtheTorohighflowhydraulicfilter
kit after a traction circuit component failure would be to
disassemble, drain and thoroughly clean all compo-
nents, hydraulic tubes and hydraulic hoses in the trac-
tion circuit. If any debris remains in the traction circuit
and the machine is operated, the debris can cause addi-
tional circuit component failure.
Hydraulic
System