Toro Groundsmaster 4300-D - Lift;Lower Circuit Problems

Lift/LowerCircuitProblems
Problem
PossibleCauses
Onecuttingdeckraisesslowlyornotatall.
•Thecuttingdeckhasexcessiveunwantedelements.
•Theliftarmorliftcylinderisbinding.
•Theowcontroloriceinliftcontrolmanifoldfortheaffected
cuttingdeckisplugged,stuck,ordamaged.
•Theliftcylinderleaksinternally.
Oneormorecuttingdeckraises,butdoesnotstayup.
Note:Theliftcylindersandcontrolmanifoldcartridgevalves
cannotprovideanabsolutelyperfectseal.Thecuttingdecks
willeventuallylowerifleftintheraisedposition.Atminimum,
thecuttingdecksshouldremainintheraisedtransport
positionlongenoughtosafelymovefromonefairwayto
thenext.
•Theliftcircuithydrauliclinesorttingsareleaking.
•Airexistsintheliftcircuit.
•Theliftcylinderfortheaffectedcuttingdeck(s)leaks
internally.
•Thesolenoidvalve(S2)inliftcontrolmanifoldisdamaged
orleaks.
Noneofthecuttingdeckswillraiseorlower.
Note:Theoperatormustbeintheseatortheparkingbrake
engagedandmowspeedlimitermustbeinmowspeed
positioninordertolowerthecuttingdecks.
•Theuidlevelinthehydraulicreservoirislow(other
hydraulicsystemsareaffectedaswell).
•Anelectricalproblemexiststhatpreventsliftcontrol
manifoldsolenoidvalveoperation(refertoTroubleshooting
(page5–24)ortheElectricalSchematicandWireHarness
Drawings/DiagramsinAppendixA(pageA–1)).
•ThesolenoidvalvePRVintheliftcontrolmanifoldis
damaged.
•ThelogiccartridgeLCinliftcontrolmanifoldisdamaged.
•ThesolenoidvalveS2inliftcontrolmanifoldisdamaged.
•Thegearpumpsection(P4)iswornordamaged.
Neitheroftherearcuttingdeckswillraiseorlowerbutthe
frontcuttingdeckswillraiseandlower.
•Theowcontroloriceinliftcontrolmanifoldfortherear
cuttingdecks(portC8)isplugged,stuckordamaged.
Onecuttingdecklowersveryslowlyornotatall.•Theliftarmorliftcylinderfortheaffectedcuttingdeckis
binding.
•Theliftcylinderfortheaffectedcuttingdeckisdamaged.
•Theowcontroloriceintheliftcontrolmanifoldforthe
affectedcuttingdeckisplugged,stuckordamaged.
HydraulicSystem:Troubleshooting
Page4–42
Groundsmaster
®
4300-D
16226SLRevC