Service Manual
GeneralHydraulicSystemProblems
Thechartsthatfollowcontainsuggestionsthatcanbeusedtoassistin
diagnosinghydraulicsystemperformanceissues.Thesuggestionsarenot
all−inclusive.Also,considerthattheremaybemorethanonecausefora
machineproblem.
Reviewthehydraulicschematicandinformationonhydraulicsystemoperation
intheHydraulicFlowDiagramssectionofthisChapter.Thisinformationwillbe
usefulduringthehydraulictroubleshootingprocess.
RefertotheT esting(page5–36)forprecautionsandspecichydraulictest
procedures.
Problem
PossibleCause
HydraulicoilleaksfrommachineFitting(s),hose(s)ortube(s)is(are)looseor
damaged.
O−ring(s)orseal(s)is(are)missingor
damaged.
HydraulicsystemoperateshotEngineRPMistoolow.
Brakesareappliedorsticking.
Hydraulicreservoiroillevelislow.
Hydraulicoiliscontaminatedorthewrongtype.
Pistonpumpby-passvalveisopenor
damaged.
Coolingsystemisnotoperatingproperly.
Chargepressureislow.
Note:Anindicationthatthehydraulicsystem
isoperatingatexcessivetemperatureswould
befrequentreversingofthecoolingfananda
normalenginecoolanttemperature.
Tractioncircuitpressureisincorrect.
Pump(s)ormotor(s)aredamaged.
Hydraulicoilinreservoirfoams
Hydraulicreservoiroillevelislow.
Wrongtypeofoilisinthehydraulicsystem.
Airisleakingintoapumpsuctionline.
Groundsmaster
®
4000-D&4010-D
Page3–3Troubleshooting:
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