TestProcedure(continued)
3.Raiseandsupporttheoperatorseat,removetheseatplatetogetaccessto
thehydraulicpumpassembly.
4.Cleanthejunctionofthehydraulictubeandleftsideelbowttingonthe
chargepump.Disconnectthehydraulictubefromtheleftsideofthepump
tting.
IMPORTANT
Ensurethattheuidowindicatorarrowontheowmeteris
showingthattheuidwillowfromthehydraulictube,throughthe
tester,andintothechargepump.
5.Installatesterwiththepressuregaugeandowmeterinseriesbetweenthe
chargepumpttingandthedisconnectedtube.Ensurethattheowcontrol
valveonthetesterisfullyopen.
6.Ensurethatthehydraulicuidisatnormaloperatingtemperatureby
operatingthemachineforatleast10minutes.
7.EnsurethatthetractionpedalisintheNEUTRALposition,steeringwheelis
stationary,andparkingbrakeisset.
8.Starttheengineandrunitatlow-idlespeed(1,500to1,650rpm).Checkfor
hydraulic-uidleaksfromthetestconnectionsandcorrectbeforecontinuing
thetest.
9.Withtheenginerunning,movethethrottletofullspeed(3,100to3,250rpm)
position.Useatachometertocheckthattheenginespeediscorrect.
10.VerifythepumpowatNoLoadasfollows:
A.Recordthetesterpressureandowreadingsatnoload.Unrestricted
pumpoutputshouldbeapproximately14L/minute(3.7gallons/minute).
11.VerifythepumpowUnderLoadasfollows:
CAUTION
Donotclosethetestervalvefullywhenperformingthistest.Inthis
test,thehydraulictesterispositionedinanunprotectedpartofthe
steeringcircuit.
Pumpdamagecanoccuriftheuidowisfullyrestrictedbyfully
closingthetesterowcontrolvalve.
A.Monitorthetesterpressuregaugecarefullywhileyouslowlyclosethe
owcontrolvalveuntilyouget5,790kPa(840psi).
B.Recordthetesterpressureandowreadingsunderload.
12.Movethethrottletolowspeed(1,500to1,650rpm)positionandshutoff
theengine.
13.Theunderloadtestowreading(step11B)shouldnotdropmorethan15%
whencomparedtothenoloadtestowreading(step10A).Adifferencein
owofmorethan15%,ortheinabilitytoachievespeciedpressuremay
indicate:
A.Arestrictioninthepumpinletline.
HydraulicSystem:TestingtheHydraulicSystem
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Groundsmaster
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3280-D/3320
05138SLRevB