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Cat Hydraulic Systems Management Guide Prevention Detection and Cleanup Inspection

ContentsElements of hydraulic systems management .3PreventionKnow what contaminants are .4Know the effects of contamination .5Know when your systems are exposed to contamination .6Control contamination during housekeeping.7Control contamination during oil and filter changes and oil storage.8Control contamination during hose assembly .8Control contamination during general maintenance.10Control contamination during equipment operation.11Detection/CleanupKnow what is happening inside your hydraulic systems .12Understand our S·O·SSM Services.12Use the correct method to take samples .13InspectionRecommended service intervals .14Custom Hydraulic Service.14Repair indicators.152

Elements of hydraulicsystems y hydraulic system problems can beprevented with attention to the system’snumber-one enemy: fluid contamination.By learning to control contamination, youcan help maintain system efficiency,extend component life and correctproblems before they lead to costlyrepairs and unscheduled downtime.Hydraulic systems are closed systems,which means much of what you need toknow is happening internally. To detectwear and other problems that can occurinside the system, we recommend regularuse of our S·O·SSM Fluid Analysis Services.One of these services, Particle Counting,is especially important for hydraulics. Itidentifies excessive contamination levelsthat can be brought under control throughhigh-efficiency filtration, “kidney looping”and other means.Daily hydraulic system inspectionsperformed by you and your operators cancatch leaks and other small problemsbefore they result in unscheduleddowntime. Efficiency loss is not easilydetected and silently robs your machineof performance. That’s why we alsorecommend technical inspectionsperformed by our trained technicians.These periodic inspections includechecks of system pressures, cycletimes and more—which can identifyproblems and help us recommendcorrective actions.

PreventionKnow what contaminants arePreventing hydraulic system problems begins by addressing fluid contamination.Contaminated oil is the primary threat to today’s hydraulic systems. Understanding whatcontamination is, why it’s harmful, how it gets in and how to control it can go a long wayin improving machine performance, extending component life and lowering your costs.Contamination is anything foreign in the hydraulic system. There are two types ofcontaminants: particulate and chemical.4Particulate contaminantsChemical contaminantsParticulate contaminants are the mostcommon, measurable and controllable. Theycan be built in at the factory, transferred inthrough new oil, generated internally or takenin during maintenance, attachment changesand machine operation. Examples ofparticulate contaminants include dirt, sand,paint and metal or rubber wear particles.Chemical contaminants include heat, waterand air. These combine to break down theoil’s chemical composition, producingcontamination in the form of oxidation andacids. Like particulate contaminants,chemical contaminants can originate insideor outside the system.

PreventionAbrasive wearKnow the effects of contaminationFluid contamination damages a hydraulic system in two ways.First, it reduces system efficiency. Machine productivity andefficient hydraulics go hand in hand. If a hydraulic system isn’tperforming at peak efficiency, it’s robbing the machine ofperformance. Efficiency losses usually occur slowly and canreach 16 percent to 20 percent before the operator detects aloss in performance. These “invisible” efficiency losses also canincrease fuel consumption.Contamination also accelerates component wear—75 percentto 85 percent of hydraulic pump, motor, cylinder and valvefailures can be traced to contamination. Due to the extremelysmall clearances in today’s hydraulic systems, even particlesyou cannot see can damage pumps, motors, cylinders andvalves in the form of abrasive, adhesive and fatigue wear.Abrasive particles scrape metal fromhydraulic components. Wear metal iscreated, multiplies and travels to other partsof the system to do more damage.Fatigue wearRepeated high-pressure stress loads causemetal to chip or break from components andcontaminate the hydraulic system.Cat HydraulicSystem ClearancesVisible to the eye5MICRONS3040Typical metal-to-metal clearances in Cat hydraulic systems are5-30 microns (one micron is one millionth of a meter). Therefore,even particles too small to see can do big damage.Human hair80Adhesive wear (Silting)Small particles build up on metal surfacesand clog the flow of fluids. The result isjamming and sticking of valves and reducedsystem efficiency.5

PreventionKnow when your systems areexposed to contaminationBecause contamination can have many sources throughout the life of a machine,controlling it must be a joint effort.Caterpillar is committed to shipping clean machines and components. As a result,in-plant process reviews and employee education are ongoing efforts. Caterpillar alsois working to educate its dealers and customers on ways to keep Cat products cleanonce they leave the factory.Let’s look closely at some of the things you can do to minimize contamination. You’ll besurprised how many are simply common sense.CaterpillarCat Dealer6

PreventionControl contamination during housekeepingIf you have a service shop, housekeeping is the best place to initiate contamination control. Each technicianneeds to understand the importance of contamination control and practice it daily. Here are some tips:Keep floors and workareas cleanSweeping floors daily and maintaininguncluttered work benches with surfacesthat won’t mar parts or add contaminantsare good ways to jump-start contaminationcontrol efforts.Put someone in chargeMaking someone responsible andaccountable for results will help ensurecontamination control becomes anongoing effort.Manage spills correctlyProtect work “in progress”Oil spills should be cleaned up promptlyand properly. Absorbent pads, mops andscrubbers are recommended overgranular methods that tend to pollute theair with contaminants.When possible and at the end ofeach shift, make sure in-processrepairs are protected from airbornecontaminants. Ask us about otherrepair processes that can beimplemented to control contamination.7

PreventionControl contamination during oil andfilter changes and oil storageSelect the right oilCat Hydraulic Oil contains the neededadditives, like oxidation and foam inhibitors,to help prevent contamination. It also has morethan twice as much zinc as standard industrialoils to provide maximum protection to pumps,motors, cylinders and valves. Be familiar withthe additives in your oil, and don’t compromisequality to save a small amount of money.Change oil regularly and always filter oilstored in bulkCaterpillar has extended the oil changeinterval for hydraulic systems to 4,000 hours,providing certain conditions for monitoring theoil are met. We also recommend changing oilwhen it’s warm and agitated, and alwaysfiltering new oil from barrels or other bulksystems before installation.Control contaminationduring hose assemblyPrecautions you take when assembling and storing hosescan go a long way in minimizing fluid contamination.8Use tight-fitting barrel coversTight-fitting covers, such as our 1U6156, canhelp prevent dirt, water, airborne particles andother contaminants from entering oil barrels.It’s also wise to store barrels inside.

PreventionBesides maintaining a clean facility, paying attention to the hydraulic oil is important.The oil you select and how you store and transfer it all have an impact oncontamination and component life. Filter and fluid changes also present contaminationcontrol opportunities. Here are a few tips:Change filters regularlyand carefullyUse quality filters betweensystem invasionsUse High Efficiency Filters aftermaintenance and serviceHydraulic filters should be changed at leastevery 500 hours. It’s also important to keepnew filters and other parts packaged untilthey’re ready to install and to remove oldfilters carefully.Using inadequate filters can compromiseperformance. To maintain the highest levels ofcleanliness and performance, we recommendinstalling genuine Cat Fluid Filters.Contaminants invade the hydraulic system anytime it’s open for maintenance or repair. Werecommend Cat High Efficiency Filters at 250service meter hours following any systeminvasion. Be sure to change High EfficiencyFilters before 250 hours if the bypass indicatorgoes on.Clean hoses properly during assemblyThe cutting and assembly of hoses introduce many contaminants that need to be removedbefore installation. We recommend use of the Cat Hose Cleaner Group, which fires a foamprojectile through hoses, tubes and couplings. This air-powered tool takes only seconds tostrip out metal and rubber contaminants traditional cleaning methods leave behind.Protect stored hose and assembliesBulk hose in storage and assemblies that have been properly cleaned should be protectedfrom airborne contaminants. Installation of caps and plugs is a low-cost means of deliveringthis protection.9

PreventionControlcontaminationduring generalmaintenancePerform daily inspectionsWhen performing the daily inspections,check for leaks and promptly fix any youfind. Look especially for worn cylinderwiper seals and pitted rods that may begiving dirt and other contaminants a freepass into the system.Earlier we discussed the importance offollowing recommended oil and filterchange intervals. A few other preventiontips include:Keep hydraulic tanks filledAlways keep the hydraulic tank between“Full” and “Add.” Insufficient fluid levelsare the leading cause of pump cavitation,leading to pump failure and contaminationof the entire system. Low fluid levels canalso result in high oil temperatures,causing oil to degrade.Maintain valvesMaintain oil cooler and relief valvesproperly. Relief valve settings should beadjusted only by our trained technicians.If a pressure loss is detected, it’simportant to find its source and repair it.Replace worn fan beltsInspect fan belts, radiators and oilcoolers regularly. Maintaining fan speedand cleaning debris from radiators andoil coolers will help keep the systemoperating at acceptable temperatures.10

PreventionControl contamination duringequipment operationA variety of contaminants can be introduced into your hydraulic systemon the job site. Here are a few ways to guard against contamination:Monitor hydraulic system temperaturesExcessive heat in hydraulic systems thins the oil, increases fluid oxidation, bakes sealsand blisters hoses. It is important to monitor system temperatures and, if equipped, watchtemperature gauges and sensor lights.Use rod protectorsIn extremely dry applications and others where banked rock, corrosive material and debrisare common, we recommend protective covers for the exposed portions of hydraulic cylinderrods. Ask us for details.Use care when changing work toolsWith today’s machines, operators frequently change work tools that are hydraulically driven.If not maintained, these tools can contaminate each machine they’re attached to. Alwaysinspect quick couplers and wipe off dirt from flush-face disconnects before coupling. Protectnipples and couplers with caps and plugs.Listen to your operatorsAn often-overlooked opportunity for contamination control is listening to your operators. Dayin and day out, these individuals live with your machines and can alert you to excessive drift,noises and other signs of possible contamination.