Service Manual

Steering/LiftCircuitTesting–GearPump(P3)FlowandCircuit
ReliefValveTest(continued)
Gearpump(P3)isdesignedtosatisfybothsteeringcylinderandliftcylinder
needssimultaneously(atfullspeedthrottle).TheGearPump(P3)FlowT est
comparesuidowatNoLoadwithuidowUnderLoad.Adropinowunder
loadofmorethan15%indicatesthegearsandwearplatesinthepumphave
worn.Continuedoperationwithawornpumpcangenerateexcessiveheatand
causedamagetothesealsandothercomponentsinthehydraulicsystem.
Thereliefvalveforthesteeringandliftcircuitisintegratedintothesteering
controlvalve.Ifbothsteeringandliftoperationsperformpoorly,performthegear
pump(P3)owtestandthecircuitreliefvalvetest.
Ifmachinesteeringissluggishorotherwiseperformspoorly,refertoSteering/Lift
CircuitTesting–SteeringControlValveandSteeringCylinderT est(page4–67).
Ifcuttingdeckliftoperationisunsatisfactory,checkliftcontrolcartridgevalves
and/orliftcylinders.Additionalinformationonthesecomponentsisavailablein
theServiceandRepairsectionofthischapter.
SpecialEquipmentRequired:
•FlowMeterwithPressureGaugethathasatleasta16LPM(5GPM)capacity.
•Phototach(non−contacttachometer).
1.Parkmachineonalevelsurfacewiththecuttingunitslowered.Makesure
engineisOFFandtheparkingbrakeisengaged.
2.ReadandadheretotheinformationprovidedinT estingtheHydraulicSystem
(page4–35).
3.Measureandrecordthesystemchargepressure(withoutload).Referto
TractionCircuitT esting–ChargePressureT est(page4–38)foradditional
information.
HydraulicSystem:TestingtheHydraulicSystem
Page4–60
Greensmaster3120
17230SLRevD