CASE CONSTRUCTION 1150M - Hydraulic and Hydrostatic Drive Fluid

7-MAINTENANCE
Hydraulicandhydrostaticdriveuid
Contaminationinthehydraulicsystemisamajorcauseofthemalfunctionofhydrauliccomponents.Contamination
isanyforeignmaterialinthehydraulicoil.
Contaminationcanenterthehydraulicsysteminseveralways:
•
Whenyoudraintheoilordisconnectanyline
•
Whenyoudisassembleacomponent
•
Fromnormalwearofthehydrauliccomponents
•
Fromdamagedsealsorwornseals
•
Fromadamagedcomponentinthehydraulicsystem
Allhydraulicsystemsoperatewithsomecontamination.Thedesignofthecomponentsinthishydraulicsystemper-
mitsefcientoperationwithasmallamountofcontamination.Anincreaseinthisamountofcontaminationcancause
problemsinthehydraulicsystem.
Thefollowinglistincludessomeoftheseproblems:
•
Cylinderrodsealsthatleak
•
Controlvalvespoolsthatdonotreturntoneutral
•
Movementofcontrolvalvespoolsisdifcult
•
Hydraulicoilthatbecomestoohot
•
Pumpgears,housing,andotherpartsthatwearrapidly
•
Reliefvalvesorcheckvalvesheldopenbydirt
•
Quickfailureofcomponentsthathavebeenrepaired
•
Slowcycletimesareslow.Themachinedoesnothaveenoughpower.
Ifyourmachinehasanyoftheseproblems,checkthehydraulicoilforcontamination.
Therearetwotypesofcontamination:microscopicandvisible.
Microscopiccontaminationoccurswhenveryneparticlesofforeignmaterialaresuspendedinthehydraulicoil.
Theseparticlesaretoosmalltoseeorfeel.Laboratorytestingcandetectmicroscopiccontamination.Inaddition,if
youexperienceanyofthefollowingproblems,microscopiccontaminationcouldbethecause.
Examplesofproblemscausedbymicroscopiccontamination:
•
Cylinderrodsealsthatleak
•
Controlvalvespoolsthatdonotreturntoneutral
•
Thehydraulicsystemhasahighoperatingtemperature
Visiblecontaminationisforeignmaterialthatyoucanndbysight,touch,orodor.Visiblecontaminationcancausea
suddenfailureofcomponents.
Examplesofproblemscausedbyvisiblecontamination:
•
Particlesofmetalordirtintheoil
•
Airintheoil
•
Darkorthickoil
•
Oilwithanodorofburnedoil
•
Waterintheoil
Ifyoundcontamination,useaportableltertocleanthehydraulicsystem.
7-13