Toro 30344 - Page 134

ChargePressureTest(UsingPressureGauge)(MachineSerial
Numbersbelow316000000)(continued)
4.Cleantheareaaroundthe1/8inchpipepluglocatedonthetopofthe
transmissionbetweenthe2checkvalves(Figure59andFigure60).Remove
theplugfromthetransmission.
5.Connecta6,900kPa(1,000psi)hydraulicpressuregaugetothetransmission
opening.
6.Afterinstallingpressuregauge,startengine,andrunatidlespeed.Checkfor
anyhydraulicleakagefromtestconnectionsandcorrectbeforeproceeding
withtest.
7.Runengineatfullspeed(3,150to3,250rpm).Useatachometertoverify
thatenginespeediscorrect.
8.Observepressuregauge.Thepressurereadingshouldbeapproximatelythe
sameascounterbalancepressure.
9.Turnoffmachine.Recordtestresults.
10.Performadynamicchargepressuretesttoidentifypossiblehydrostat(pump
ormotor)problemsasfollows:
A.Withpressuregaugestillconnected,sitintheoperatorseat,startengine,
andpressthetractionpedaltoforward.
B.Whilemachineismovingstraightaheadonlevelground(noturning
ordecklifting),monitorthepressurereadingonthepressuregauge.
Recordtestresults.
11.Thepressureshoulddropnomorethan15%frominitialtestreading(step8).
Apressuredropofmorethan15%mayindicateatractioncircuitleak(e.g.,
checkvalvenotseating,wornordamagedhydrostat).
Ifchargepressuredropismorethan15%,inspecttheconditionofthe
chargepumpgerotorandinternalhousing;refertoChargePumpService
intheSauer-Danfoss(Sundstrand)15SeriesServiceManualattheendof
thischapter.
Ifthechargepumpisingoodcondition(noscoring,scratches,orexcessive
wear),thegeneralconditionofthetransmission’spistonpumpandpiston
motormightbesuspectedofwearandinefciency.
12.Disconnectpressuregaugefromthetransmission.Installpipeplugbackin
thetransmission.Checkhydraulic-uidlevelinreservoir(frontaxle).
HydraulicSystem:TestingtheHydraulicSystem
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