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Shop manual máy đào HuynDai R250: An toan, cấu trúc, sơ đồ điện, thủy lực,
6-4GROUP 2 HYDRAULIC AND MECHANICAL SYSTEM1. INTRODUCTIONMACHINE IN GENERALIf even a minor fault is left intact and operation is continued, a fatal failure may be caused,entailing a large sum of expenses and long hours of restoration.Therefore when even a small trouble occurs, do not rely on your intuition and experience, but lookfor the cause based on the troubleshooting principle and perform maintenance and adjustment toprevent major failure from occurring. Keep in mind that a fault results from a combination ofdifferent causes.The following lists up commonly occurring faults and possible causes with this machine. For thetroubleshooting of the engine, refer to the coming troubleshooting and repair. When carrying out troubleshooting, do not hurry to disassemble the components.It will become impossible to find the cause of the problem.Ask user or operator the following.Was there any strange thing about machine before failure occurred?Under what conditions did the failure occur?Have any repairs been carried out before the failure?Check before troubleshooting.Check oil and fuel level.Check for any external leakage of oil from components.Check for loose or damage of wiring and connections.1)(1)(2) (3)(4)(5)①②③①②③ YESYESNONO6-52. DRIVE SYSTEMUNUSUAL NOISE COMES OUT OF PUMP CONNECTION1)Remove dust plugunder engine flywheel andcheck if rubberpieces or particlesare not present.Coupling hubspline is worn orhub fasteningsetscrew is slack.If hydraulic pump or engine issuspected as a culprit refer to thismanual "Structure and function".Cause RemedyCoupling elementis broken.Disassembleand repair.Replace hub orretightensetscrew. 6-6ENGINE STARTS BUT MACHINE DOES NOT OPERATE AT ALL2)Hydraulic pump isbroken.ⓐPilot valve isfaulty.Pilot relief valve isfaulty.Gear pump isbroken.Replenishspecified oil tothe standardlevel.Disassembleand repair.See item 1).at page 6-5Clean pilotpiping interior orrepair piping.Disassembleand repair.Repair orreplace.Disassembleand repair.YESYESYESYESYESYESYESNONONONOIs oil level inhydraulic oiltank withinstandard level?Do not hydraulicpump and pumpconnectionsmake abnormalnoise?Abnormal noisecomes out ofpumpconnectionIs primary pilotpressure withinstandard level?Is not pilot pipingclogged or is notoil leakage presenton pilot piping?Is gear pumpdelivering oil?Abnormal noisecomes out ofhydraulic pumpⓐNOYESCause Remedy 6-7ⓐReplenishspecified oil tothe standardlevel.Clean oil cooler. Secure aircirculation route.Adjust belttension orreplace belt.Readjust setpressure.Reduce load.YESNOIs hydraulic oilvolume proper?Is not oil coolerclogged and isanything blockingair circulation?Is main reliefvalve used veryoften?Is not the setpressure of mainrelief, relief andtravel relief valvelower than thestandard level?Is fan belttension proper?ⓐYESNOYESYESYESYESNONONODrop hydraulic oilsample on hotplate and check iffoams come up.Water is mixed.Air is intruded.Put hydraulic oilstill, separatewater anddispose it orreplace hydraulicoil.Check suctionline and returnline and eliminatethe air intrudingsource.3. HYDRAULIC SYSTEMHYDRAULIC OIL IS CLOUDY1)HYDRAULIC OIL TEMPERATURE HAS RISEN ABNORMALLY2)Cause RemedyCause Remedy 6-8NONONONOYESNOYESYESYESIs hydraulic oilvolume proper?Is not air intrudingfrom pumpsuction line?Is not viscosityof hydraulic oiltoo high?Is not suctionstrainer clogged?Replenishspecified oil tothe standardlevel.Replace oil withone of properviscosity.Clean suctionstrainer.Check for airintrusion insuction line andretighten orreplace parts.CAVITATION OCCURS WITH PUMP3)HYDRAULIC OIL IS CONTAMINATED4)Has not hydraulicoil passedspecified replace-ment hours?Replacehydraulic oil to bespecified.Flush withhydraulic oil andreplace returnfilter.Has return filterbeen replaced atproper intervals?Cause RemedyCause Remedy YES6-94. SWING SYSTEMBOTH LH AND RH SWING ACTIONS ARE IMPOSSIBLE1)Are attachmentand travelmotionsimpossible at all?Is safety solenoidvalve pressurewithin standard?NOYESYESYESYESYESNONONONONONOYESIs gear pump pilotpressure withinstandard level?Is MCV pilotpressure withinstandard level?Is swing brakerelease valvefaulty?Are broken piecesof coupling presentwhen dust plugunder engine flywheel is removed?Does not symptomchange when frontand rear pumpdischarge hosesare exchanged?Is oil in hydraulictank withinstandard level?Does RH travelfunction?Cause RemedySafety valve faultyor not operated. Gear pump faulty.Pump connectioncoupling is broken.Hydraulic pump isout of order.Swing control valvespool is stuck.Hydraulic pump isbroken.Swing brakerelease valve isbroken.Swing reductionunit is broken.Swing motor isbroken.Pilot relief valve isfaulty.Gear pump is outof order.Pilot valve isbroken.Replenishspecified oil to thestandard level.Repair or replace.Repair or replace.Disassemble andrepair.Disassemble andrepair.Disassemble andrepair.Disassemble andrepair.Disassemble andrepair.Disassemble andrepair.Disassemble andrepair.Disassemble andrepair or replace.Disassemble andrepair.Clean pilot pipinginterior or repairpiping.Disassemble andrepair.ⓐⓑⓒⓐIs not main reliefvalve faulty?Does swingcontrol valvespool movelightly by hand?Does swingmotor rotate?Is gear pumpdelivering oil?Is not there oilleakage frompilot piping or isnot it clogged?ⓑⓒIs gear pump pilotpressure withinstandard level?YESYESYESYESYESYESNONONONONONONOYES NONONO6-10SWING SPEED IS LOW2)Is the trouble inone direction orin both direction?Clogged or oilleak.YESYESYESNONONONONONONONOYESYESNOYESYESNOYESNOYESDoes swing controlvalve spool movesmoothly by hand?Is not pilot pipingclogged or is notit leaking oil?Is MCV pilotpressure withinstandard level?Is gear pump pilotpressure withinstandard level?Is swing motor'sdrain rate withinstandard value?YESIs MCV pilotpressure sameon LH and RHsides?Is Arm speedwithin standardvalue?Cause RemedySwing port reliefvalve is faulty.Swing control valvespool is stuck.Pilot valve or shuttlevalve is faulty.ⓐSwing control valvespool is stuck.ⓑⓒSwing motor isbroken.Pilot valve orshuttle valve isfaulty.Pilot relief valveis defective.Gear pump isbroken.Main relief valvefaulty.Hydraulic pumpis broken.Shuttle valve isfaulty.Pilot relief valveis faulty.Gear pump isfaulty.Disassemble andrepair or replace.Disassembleand repair.Clean pilot pipinginterior or repairpiping.Disassembleand repair.Disassembleand repair.Disassembleand repair.Disassembleand repair.Clean pilot pipinginterior or repairpiping.Disassemble andrepair or replace.Disassembleand repair.Main relief valvepressure resettingor repair.Disassembleand repair.Repair or replace.Repair or replace.Repair or replace.ⓐⓑⓒCheck that pilotpiping is notclogged or oil isnot leaking fromit?Clogged or oil leak.Is gear pumpdelivering oil?Does the symptomchange when frontand rear pumpdischarge hosesare exchanged?Is gear pumpoutput pressurewithin standardlevel?Is safety valvepilot pressurewithin standardlevel?Both directionsSingle directionIs main relief valvesetting pressurenormal?YESYESDoes swingcontrol valvespool movelightly by hand? YESYESYESYESYESYESYESNONONONONONONO6-11YESIs MCV pilotpressure samefor LH and RH?Clogged or oilleak.Check if pilotpiping is notclogged or doesnot have oilleakage.Does swing controlvalve spool movesmoothly by hand?Does symptomchange when LHand RH port reliefvalves areexchangedSWING MOTION IS IMPOSSIBLE IN ONE DIRECTION3)Is swing controlvalve's returnspring normal?Is gear pump pilotpressure withinstandard level?Does swing controlvalve spool movesmoothly by hand?Is MCV pilotpressure withinstandard value?MACHINE SWINGS BUT DOES NOT STOP4)Pilot relief valve isfaulty. Gear pump isbroken.Pilot valve is faulty.Swing controlvalve spool isstuck.Return spring isfaulty.Disassemble andrepair or replace.Disassemble andrepair.Disassemble andrepair.Disassemble andrepair.Disassemble andreplace.Swing port reliefvalve is faulty.Shuttle valve isfaulty.Swing control valvespool is stuck.Pilot valve is faulty. Disassemble andrepair.Disassemble andrepair.Disassemble andrepair.Disassemble andrepair.Clean pilot pipinginterior or repairpiping.Cause RemedyCause Remedy 6-12YESYESYESYESNONONONONOYESIs return springof swing controlvalve normal?Is brake springnormal?Is swing shuttlevalve normal?Is drain rate ofswing motorwithin standardvalue?THE SWING UNIT DRIFTS WHEN THE MACHINE IS AT REST ON A SLOPE5)ⓐIs swing reliefpressure withinstandard level?ⓐShuttle valve isfaulty.Brake spring isfaulty.Return spring ofswing controlvalve is faulty.Swing relief valveis faulty.Swing motor isbroken.Disassembleand replace.Disassembleand replace.Disassembleand replace.Disassembleand repair orreplace.Disassembleand repair.Adjust swingrelief valvepressure orreplace swingrelief valve.Cause Remedy 6-13YESYESYESYESYESYESNO NONONONOYESIs bucket or armoperationpossible?Does counterbalancespool in travelbrake valve movelightly by hand?Does the symptomchange whenrelief valves intravel motor areexchanged?Has travelcontrol valvespool changedover positively?Does the symptomchange when frontand rear pumpdischarge hosesare exchanged?Is travel brakevalve pressurewithin standardlevel?Does spool movelightly by hand?NOⓐCounter spool intravel brake valveis stuck.Relief valve builtin travel motor isfaulty.Control system isdefective.Travel controlvalve spool isstuck.Travel reductionunit is faulty.Travel motor isout of order.Hydraulic pump isbroken.Travel reliefvalves are faulty. Disassembleand repair orreplace.Disassembleand repair.Disassembleinspect andrepair.Disassembleand repair.Disassembleand repair.Disassembleand repair.Disassembleand repair.Disassembleand repair orreplace. ⓐ5. TRAVEL SYSTEMTRAVEL DOES NOT FUNCTION AT ALL ON ONE SIDE1)Do not metallicparticles comeout of drain portin travelreduction unit?Cause RemedyDoes thesymptom changewhen LH/RHtravel relief valvesare exchanged?YESYESNO [...]... hose.(Put cups on piping and hose ends) A (29 0-7 TIER) 6-2 0(2) 3 Raise bucket OFF the ground by retracting the arm cylinder rod If oil leaks from piping side and boom cylinder rod is retracted there is an internal leak in the cylinder If no oil leaks from piping side and boom cylinder rod is retracted, there is an internal leak in the control valve 29076TS01 6 - 23 ... repair or replace no coupling element particles Particles present Coupling at pump Disassemble and Check oil volume in hydraulic oil repair connection is NO tank broken Replenish hydraulic oil Short 6 - 15 5) TRAVEL ACTION IS POWERLESS(Travel only) Cause YES Is travel brake ⓐ Is travel motor's YES drain rate within standard level? Travel motor is faulty NO YES pressure within standard level? Is travel... unit is defective Disassemble and repair Disassemble and repair 6) MACHINE RUNS RECKLESSLY ON A SLOPE Cause Travel brake valve (counterbalance valve) is faulty Remedy Disassemble and repair or replace 6 - 16 7) MACHINE MAKES A CURVED TRAVEL OR DOES NOT TRAVEL AT ALL WHEN TRAVEL AND ATTACHMENT OPERATIONS ARE EXECUTED AT THE SAME TIME Cause YES Remedy Normal YES Is select valve normal? Is pilot pressure... Is filter in pilot piping between gear pump and NO control valve not clogged? Repair or replace Remove dirt on pilot line filter YES Is pilot relief valve normal? Is gear pump NO delivering oil? NO 6 - 17 NO Pilot relief valve is Disassemble defective and repair or replace Gear pump is broken Disassemble and repair 6 ATTACHMENT SYSTEM 1) BOOM OR ARM ACTION IS IMPOSSIBLE AT ALL YES YES YES Is MCV pilot... valve spool move lightly by hand? Disassemble and repair or replace Disassemble and repair Replenish hydraulic oil Cylinder interior is Disassemble and repair broken NO Control valve spool is stuck 6 - 18 Disassemble and repair Disassemble and repair 2) BOOM, ARM OR BUCKET SPEED IS LOW Cause YES Are other YES Remedy Normal ⓐ YES attachment Is combination of oil streams YES normal at boom hoisting... within standard level? Adjust engine revolution YES ⓓ Is not orifice in control valve clogged? Clean orifice in control valve YES Is pilot piping not clogged or is oil NO not leaking from the piping? 6 - 19 Is pilot valve NO normal? Clean pilot piping interior or repair piping Pilot valve is faulty Disassemble and NO repair 3) BOOM, ARM OR BUCKET CYLINDER EXTENDS OR CONTRACTS ITSELF AND ATTACHMENT FALLS... Abnormal Pressure tightness between control valve casing and spool is poor Contact surface between poppet and seat is poor Disassemble and repair Disassemble and repair Cylinder is faulty Disassemble NO 6 - 20 4) BOOM, ARM OR BUCKET POWER IS WEAK Cause YES Check according to the procedure in Item "Speed is low" Is cylinder YES internal leakage within standard level? Is relief pressure YES in port relief... interior is Disassemble broken and repair NO YES Does the symptom change Does the when main relief symptom change NO valves are YES when hydraulic exchanged? NO pump's discharge hoses are exchanged? 6 - 21 Control valve spool is stuck Disassemble and repair Pilot valve is faulty NO Disassemble and repair Main relief valve is faulty Adjust pressure, repair or replace Hydraulic pump is broken Disassemble... between the sliding faces of boom cylinder's oil seal and boom proper Is boom foot pin greased sufficiently? ※ Frictional noise will disappear if they are kept used Boom foot pin has run out of grease NO 6 - 22 Supply grease to it ※ If seizure is in an initial stage, supply sufficient grease If seizure is in a grown state, correct it by paper lapping or with an oil stone ※ HOW TO CHECK INTERNAL BOOM CYLINDER... from it change when YES YES parking brake Travel motor's spring in the parking brake is slower travel Is leak rate of motor is removed? not released ⓐ travel motor within properly standard level? NO 6 - 14 Travel motor is faulty Disassemble and repair Disassemble and clean Disassemble and clean pilot piping Disassemble and repair 3) MACHINE DOES NOT STOP ON A SLOPE Machine is pulled forward as sprocket . ends )2. Lower the bucket teeth to the ground withbucket cylinder fully retracted and armcylinder rod retracted almost in full.1 .29 076TS01 (29 0-7 TIER) 6 -2 0 (2) 29076TS01 . replace.Adjust pressure,repair or replace.CauseRemedyCause RemedyYESNONO 6 -2 2YESNOIs boom foot pingreasedsufficiently?Boom foot pinhas run out ofgrease.Frictional