U20-3, U25-3 WSM
Hydraulic system (Service section)
IV
-S-4
b. Hydraulics
Problem
Cause
Correction
The entire hydraulic system fails
or responds too slow or too
weak.
(1) Hydraulic oil too short in the tank or oil
degraded.
Add or change the hydraulic oil.
(2) Suction line (suction filter) clogged.
Check the suction line and replace the
suction filter as required.
(3) Pump coupling defective.
Repair or replace the pump coupling.
(4) Pump drive shaft broken.
Replace the shaft.
(5) Pump internal parts seized or damaged.
Repair or replace the pump.
The boom, arm, bucket and
swivel mechanism fail or
respond too slow or too weak.
(1) Hydraulic pilot filter or hydraulic pilot line filter
clogged.
Clean or replace the pilot filter.
(2) Selector valve defective.
Overhaul or replace the selector valve.
(3) Pilot pump internal parts seized or damaged. Replace the pilot pump.
The boom, bucket and right-
travel mechanism fail or respond
too slow or too weak.
(1) Main relief valve (P1) not at specified
pressure.
Check the main relief valve (P1) and
readjust as required.
(2) P1 or P2 line pump internal parts seized or
damaged if the arm, service port and left-travel
mechanism fail too.
Overhaul or replace the pump.
The arm, service port and left-
travel mechanism fail or respond
too slow or too weak.
(1) Main relief valve (P2) not at specified
pressure.
Check the main relief valve (P2) and
readjust as required.
(2) P1 or P2 line pump internal parts seized or
damaged if the boom, bucket and right-travel
mechanism fail too.
Overhaul or replace the pump.
The swing, dozer and swivel
mechanism fail or respond too
slow or too weak.
(1) Main relief valve (P3) not at specified
pressure.
Check the main relief valve (P3) and
readjust as required.
(2) P3 line pump internal parts seized or
damaged.
Overhaul or replace the pump.
The boom alone fails or
responds too slow or too weak.
(1) Boom overload relief valve not at specified
pressure.
Check the overload relief valve and repair
as required.
(2) Control valve or boom section spool
malfunctioning.
Check the spool and repair as required.
(3) Pilot valve defective.
Measure the secondary pressure and
check the pilot valve.
(4) Boom cylinder rod packing broken.
Overhaul the cylinder and replace the
sealing.
The arm alone fails or responds
too slow or too weak.
(1) Arm overload relief valve not at specified
pressure.
Check the overload relief valve and repair
as required.
(2) Control valve or arm section spool
malfunctioning.
Check the spool and repair as required.
(3) Pilot valve defective.
Measure the secondary pressure and
check the pilot valve.
(4) Arm cylinder rod packing broken.
Overhaul the cylinder and replace the
sealing.
The bucket alone fails or
responds too slow or too weak.
(1) Bucket overload relief valve not at specified
pressure.
Check the overload relief valve and repair
as required.
(2) Control valve or bucket section spool
malfunctioning.
Check the spool and repair as required.
(3) Pilot valve defective.
Measure the secondary pressure and
check the pilot valve.
(4) Bucket cylinder rod packing broken.
Overhaul the cylinder and replace the
sealing.
Содержание U20-3
Страница 1: ...WORKSHOP MANUAL KUBOTA EXCAVATOR U20 3 Code No 97899 60740 U25 3 ...
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Страница 47: ...U20 3 U25 3 WSM Machine body Mechanism section II M 16 6 Steel crawler U20 3 No 1 Link 2 Bush 3 Pin ...
Страница 48: ...U20 3 U25 3 WSM Machine body Mechanism section II M 17 U25 3 No 1 Hole 2 shaft ...
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Страница 62: ...U20 3 U25 3 WSM Machine body Service section II S 13 B Front attachment a Parts designation ...
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Страница 118: ...U20 3 U25 3 WSM Engine III 3 ...
Страница 121: ...U20 3 U25 3 WSM Engine III 6 Performance curves Model D1105 EBH 10 ...
Страница 122: ...U20 3 U25 3 WSM Engine III 7 Performance curves Model D1105 EBH 11 ...
Страница 123: ...U20 3 U25 3 WSM Engine III 8 b Dimensions ...
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Страница 127: ...U20 3 U25 3 WSM Engine Mechanism section III M 2 A Feature ...
Страница 128: ...U20 3 U25 3 WSM Engine Mechanism section III M 3 B Engine body 1 Cylinder block 2 Cylinder head ...
Страница 129: ...U20 3 U25 3 WSM Engine Mechanism section III M 4 3 Crankshaft 4 Piston and piston rings ...
Страница 130: ...U20 3 U25 3 WSM Engine Mechanism section III M 5 5 Connecting rod 6 Rocker arm 7 Camshaft ...
Страница 131: ...U20 3 U25 3 WSM Engine Mechanism section III M 6 8 Fuel camshaft 9 Flywheel ...
Страница 132: ...U20 3 U25 3 WSM Engine Mechanism section III M 7 C Lubricating system 1 General ...
Страница 133: ...U20 3 U25 3 WSM Engine Mechanism section III M 8 2 Oil pump 3 Relief valve ...
Страница 134: ...U20 3 U25 3 WSM Engine Mechanism section III M 9 4 Oil filter cartridge 5 Oil pressure switch ...
Страница 135: ...U20 3 U25 3 WSM Engine Mechanism section III M 10 D Cooling system 1 General 2 Water pump ...
Страница 136: ...U20 3 U25 3 WSM Engine Mechanism section III M 11 3 Thermostat 4 Radiator not included in the basic engine ...
Страница 137: ...U20 3 U25 3 WSM Engine Mechanism section III M 12 5 Radiator cap ...
Страница 139: ...U20 3 U25 3 WSM Engine Mechanism section III M 14 F Fuel system 1 General 2 Injection pump ...
Страница 140: ...U20 3 U25 3 WSM Engine Mechanism section III M 15 ...
Страница 141: ...U20 3 U25 3 WSM Engine Mechanism section III M 16 ...
Страница 142: ...U20 3 U25 3 WSM Engine Mechanism section III M 17 3 Injection nozzle 4 Fuel filter not included in the basic model ...
Страница 143: ...U20 3 U25 3 WSM Engine Mechanism section III M 18 5 Governor ...
Страница 144: ...U20 3 U25 3 WSM Engine Mechanism section III M 19 ...
Страница 145: ...U20 3 U25 3 WSM Engine Mechanism section III M 20 6 Automatic advance timer not included in the basic model ...
Страница 146: ...U20 3 U25 3 WSM Engine Mechanism section III M 21 ...
Страница 147: ...U20 3 U25 3 WSM Engine Mechanism section III M 22 G Electrical system 1 Charging system ...
Страница 148: ...U20 3 U25 3 WSM Engine Mechanism section III M 23 H Turbo charger system ...
Страница 149: ...U20 3 U25 3 WSM Engine Mechanism section III M 24 ...
Страница 150: ...U20 3 U25 3 WSM Engine Mechanism section III M 25 ...
Страница 151: ...U20 3 U25 3 WSM Engine Mechanism section III M 26 ...
Страница 152: ...U20 3 U25 3 WSM Engine Mechanism section III M 27 ...
Страница 162: ...U20 3 U25 3 WSM Engine Service section III S 10 B General 1 Engine identification ...
Страница 163: ...U20 3 U25 3 WSM Engine Service section III S 11 2 General precaution ...
Страница 164: ...U20 3 U25 3 WSM Engine Service section III S 12 3 Tightening torques ...
Страница 165: ...U20 3 U25 3 WSM Engine Service section III S 13 4 Troubleshooting ...
Страница 166: ...U20 3 U25 3 WSM Engine Service section III S 14 ...
Страница 167: ...U20 3 U25 3 WSM Engine Service section III S 15 ...
Страница 168: ...U20 3 U25 3 WSM Engine Service section III S 16 5 Servicing specifications ...
Страница 169: ...U20 3 U25 3 WSM Engine Service section III S 17 ...
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Страница 177: ...U20 3 U25 3 WSM Engine Service section III S 25 6 Maintenance check list ...
Страница 178: ...U20 3 U25 3 WSM Engine Service section III S 26 7 Check and maintenance ...
Страница 179: ...U20 3 U25 3 WSM Engine Service section III S 27 ...
Страница 180: ...U20 3 U25 3 WSM Engine Service section III S 28 ...
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Страница 191: ...U20 3 U25 3 WSM Engine Service section III S 39 C Engine body CHECKING AND ADJUSTING ...
Страница 192: ...U20 3 U25 3 WSM Engine Service section III S 40 DISASSEMBLING AND ASSEMBLING ...
Страница 193: ...U20 3 U25 3 WSM Engine Service section III S 41 1 Draining water and oil 2 External components ...
Страница 194: ...U20 3 U25 3 WSM Engine Service section III S 42 3 Cylinder head and valves ...
Страница 195: ...U20 3 U25 3 WSM Engine Service section III S 43 ...
Страница 196: ...U20 3 U25 3 WSM Engine Service section III S 44 4 Gear case ...
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Страница 202: ...U20 3 U25 3 WSM Engine Service section III S 50 5 Piston and connecting rod ...
Страница 203: ...U20 3 U25 3 WSM Engine Service section III S 51 ...
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Страница 205: ...U20 3 U25 3 WSM Engine Service section III S 53 6 Flywheel and crankshaft ...
Страница 206: ...U20 3 U25 3 WSM Engine Service section III S 54 ...
Страница 207: ...U20 3 U25 3 WSM Engine Service section III S 55 SERVICING 1 Cylinder head ...
Страница 208: ...U20 3 U25 3 WSM Engine Service section III S 56 ...
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Страница 212: ...U20 3 U25 3 WSM Engine Service section III S 60 2 Timing gear and camshaft ...
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Страница 214: ...U20 3 U25 3 WSM Engine Service section III S 62 3 Piston and connecting rod ...
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Страница 217: ...U20 3 U25 3 WSM Engine Service section III S 65 4 Crankshaft ...
Страница 218: ...U20 3 U25 3 WSM Engine Service section III S 66 ...
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Страница 223: ...U20 3 U25 3 WSM Engine Service section III S 71 5 Cylinder ...
Страница 224: ...U20 3 U25 3 WSM Engine Service section III S 72 ...
Страница 225: ...U20 3 U25 3 WSM Engine Service section III S 73 D Lubricating system CHECKING SERVICING 1 Oil pump ...
Страница 226: ...U20 3 U25 3 WSM Engine Service section III S 74 ...
Страница 227: ...U20 3 U25 3 WSM Engine Service section III S 75 E Cooling system CHECKING 1 Fan belt 2 Radiator ...
Страница 228: ...U20 3 U25 3 WSM Engine Service section III S 76 DISASSEMBLING AND ASSEMBLING ...
Страница 229: ...U20 3 U25 3 WSM Engine Service section III S 77 ...
Страница 230: ...U20 3 U25 3 WSM Engine Service section III S 78 F Fuel system CHECKING AND ADJUSTING 1 Injection pump ...
Страница 231: ...U20 3 U25 3 WSM Engine Service section III S 79 ...
Страница 232: ...U20 3 U25 3 WSM Engine Service section III S 80 2 Injection nozzle ...
Страница 233: ...U20 3 U25 3 WSM Engine Service section III S 81 DISASSEMBLING AND ASSEMBLING 1 Injection pump ...
Страница 234: ...U20 3 U25 3 WSM Engine Service section III S 82 2 Injection nozzle ...
Страница 235: ...U20 3 U25 3 WSM Engine Service section III S 83 G Electrical system CHECKING 1 Starter ...
Страница 236: ...U20 3 U25 3 WSM Engine Service section III S 84 2 Glow plug DISASSEMBLING AND ASSEMBLING 1 Starter ...
Страница 237: ...U20 3 U25 3 WSM Engine Service section III S 85 2 Alternator ...
Страница 238: ...U20 3 U25 3 WSM Engine Service section III S 86 ...
Страница 239: ...U20 3 U25 3 WSM Engine Service section III S 87 ...
Страница 240: ...U20 3 U25 3 WSM Engine Service section III S 88 SERVICING 1 Starter ...
Страница 241: ...U20 3 U25 3 WSM Engine Service section III S 89 ...
Страница 242: ...U20 3 U25 3 WSM Engine Service section III S 90 2 Alternator ...
Страница 243: ...U20 3 U25 3 WSM Engine Service section III S 91 ...
Страница 244: ...U20 3 U25 3 WSM Engine Service section III S 92 ...
Страница 245: ...U20 3 U25 3 WSM Engine Service section III S 93 H Turbo charger system CHECKING ...
Страница 246: ...U20 3 U25 3 WSM Engine Service section III S 94 ...
Страница 247: ...U20 3 U25 3 WSM Engine Service section III S 95 DISASSEMBLING AND ASSEMBLING ...
Страница 248: ...U20 3 U25 3 WSM Engine Service section III S 96 ...
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Страница 279: ...U20 3 U25 3 WSM Hydraulic system Mechanism section IV M 28 ...
Страница 280: ...U20 3 U25 3 WSM Hydraulic system Mechanism section IV M 29 b Pilot valve control diagram ...
Страница 296: ...U20 3 U25 3 WSM Hydraulic system Mechanism section IV M 45 U25 3 KAYABA a Structure specifications ...
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Страница 311: ...U20 3 U25 3 WSM Hydraulic system Mechanism section IV M 59 I Hydraulic circuit diagram a U20 3 Fixed undercarriage ...
Страница 312: ...U20 3 U25 3 WSM Hydraulic system Mechanism section IV M 60 b U20 3 Retractable undercarriage ...
Страница 313: ...U20 3 U25 3 WSM Hydraulic system Mechanism section IV M 61 c U25 3 ...
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Страница 330: ...U20 3 U25 3 WSM Hydraulic system Service section IV S 15 1 Travel mechanism check points ...
Страница 386: ...U20 3 U25 3 WSM Hydraulic system Service section IV S 71 Photo 7 1 Photo 7 2 Photo 7 3 Photo 7 4 Photo 7 5 Photo 7 6 ...
Страница 387: ...U20 3 U25 3 WSM Hydraulic system Service section IV S 72 Photo 7 7 Photo 7 8 Photo 7 9 Photo 7 10 Photo 7 11 Photo 7 12 ...
Страница 397: ...U20 3 U25 3 WSM Hydraulic system Service section IV S 82 ...
Страница 415: ...U20 3 U25 3 WSM Hydraulic system Service section IV S 100 3 Component parts of wheel motor ...
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Страница 480: ...U20 3 U25 3 WSM Electrical system Service section V S 3 a Front ...
Страница 482: ...U20 3 U25 3 WSM Electrical system Service section V S 5 c Swivel frame ...
Страница 483: ...U20 3 U25 3 WSM Electrical system Service section V S 6 Around battery ...
Страница 486: ...U20 3 U25 3 WSM Electrical system Service section V S 9 3 Around selector valve ...
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