Service Manual

Table Of Contents
ProcedureforTractionCircuitChargePressureTest(continued)
1.Parkmachineonalevelsurfacewiththecuttingdecksloweredandoff.
Makesurehydraulicoilisatnormaloperatingtemperature,engineisoffand
theparkingbrakeisapplied.
2.Raiseandsupportoperatorseat.
3.Connecta70bar(1000PSI)pressuregaugetotestttingattachedtotee
ttinginnalsectionofgearpump(Figure53orFigure54).
Note:Makesurethatsteeringwheelisnotturnedduringchargepressure
testing.Also,ifenginecoolanttemperatureiselevated,gearpumpowfrom
thenalpumpsectionmightbedirectedtothecoolingfanmotorwhichmay
affectchargepressuretestingresults.
4.Startengineandincreaseenginespeedtohighidlespeedwithnoloadon
thehydraulicsystem.
GAUGEREADINGTOBE13.8to20.6bar(200to300PSI).
5.Stopengineandrecordtestresults.
6.Ifthereisnopressureorpressureislow,checkforrestrictioningearpump
intakeline.Also,inspectchargereliefvalvelocatedinpiston(traction)pump
(seePiston(Traction)PumpService(Formachinesserialnumberbelow:
400000000)(page5–111)).Awornordamagedgearpumpsectioncould
alsobeconsidered(seeGearPumpFlow(UsingTesterwithPressureGauge
andFlowMeter)(page5–79)).
Note:Ifthegearpumpsectionthatsuppliesthechargecircuitiswornor
damaged,charge,steering,lift/lowerandenginecoolingfancircuitsmayall
beaffected.
7.Next,withthepressuregaugestillconnectedtothechargepressuretestport,
takeagaugereadingwhileoperatingthemachineinforwardandreverse.
Starttheengineandputthrottleathighidlespeed.Applythebrakesand
pushthetractionpedalforwardwhilemonitoringthepressuregauge.Repeat
forreversedirection.Stopengineandrecordtestresults.
8.Ifchargepressuremeetsspecicationsundernoloadconditions(step5
above),butconsistentlydropsmorethan15%whenundertractionload,
thepiston(traction)pumpand/ortractionmotor(s)shouldbesuspectedof
wearandinefciency.Whenthepumpormotorsarewornordamaged,
thechargepumpisnotabletokeepupwithinternalleakageinthetraction
systemcomponents.
9.Whentestingiscompleted,disconnectpressuregaugefromtesttting.
Securedustcaptotesttting.
10.Lowerandsecureoperatorseat.
HydraulicSystem:Testing
Page5–40
Groundsmaster
®
4100-D&4110-D
13203SLRevG