U20-3, U25-3 WSM
Hydraulic system (Service section)
IV
-S-67
3) Disassembling
1. Preparations
(1) Prepare a workbench that is spacious enough for the parts handled and strong and stable
enough to keep the parts in place.
(2) Also have the tools and jigs, discussed in Item 7-1, at hand.
2. General precautions
(1) The parts are precision-machined. Handle them with enough care not to hit them against each
other or drop them.
(2) Even if any part is hard to remove, do not strike it out or pry out forcibly. Such handling may
cause burrs or damages, which may invite oil leak or poor performance later. Try to do the job
with patience.
(3) Do not leave the taken-out or exposed parts unprotected. Moisture or dust may get stuck on
them, causing rust. If unavoidably the job is interrupted halfway, be careful to protect such
parts against rust and dust.
3. Disassembling procedure
Procedure
Precautions
1
Clean up the pilot valve with kerosene.
* Apply blind plugs to all the open ports.
2
Fix the pilot valve on a vise using copper (or lead) sheets.
3
Remove the bellows (501). [Photo 7-1]
* Be careful not to break the bellows (501).
4
Apply a wrench across the adjusting nut (312) and disc
(302). Loosen and remove the adjusting nut and disc.
[Photos 7-2, 7-3 and 7-4]
5
With the specified jig, turn the joint (301) counterclockwise
to get it loose. [Photos 7-5 and 7-6]
* Photo 7-5 shows the jig in its specified position.
CAUTION:
* When the return spring (221) is strong in force, take
care in loosening and drawing out the joint (301). The
plate (151), plug (211) and push rod (212) may pop
out together when taking out the joint.
6
Remove the plate (151).
(When the return spring (221) is strong in force) [Photo 7-7]
(When the return spring (221) is weak in force) [Photo 7-8]
7
When the return spring (221) is weak in force, the sliding
resistance of the O-ring holds the plug (211) inside the
casing (101). Using a bladed screwdriver, draw out the
plug. [Photo 7-9]
* Using its outer groove, draw out the plug (211) with
care not to get it damaged by an unbalanced load.
CAUTION:
* Keep in mind that when the plug (211) may pop out by
the force of the return spring (221).
8
Pull the push rod (212), plug (211), reducing valve
assembly, and return spring (221) out of the casing (101).
[Photo 7-10]
* Keep record of the positional relation with the casing
hole.
9
Fix the pilot valve, with its port plate (111) upward, in the
vise.
10
Using the specified hex wrench, loosen and remove the
hex socket bolt (125). [Photo 7-11]
11
Detach the port plate (111) and O-ring (122) from the
casing (101). [Photos 7-12 and 7-13]
Draw the bushing (131) out of the casing (101).
12
To disassemble the reducing valve, do the following.
Press in the spring seat (216) to get the secondary-
pressure spring (241) warped. Then slide this spring seat
sideways and pass it through the larger hole and out of the
spool (201). [Photo 7-14]
Next separate the following parts: spool (201), spring seat
(216), secondary-pressure spring (241) and washer 2
(217). [Photo 7-15]
* Be careful not to scratch the surface of the spool
(201).
* Do not allow the spring seat (216) 6 mm or lower than
specified.
* Handle this group of parts as an assembly.
Summary of Contents for U20-3
Page 1: ...WORKSHOP MANUAL KUBOTA EXCAVATOR U20 3 Code No 97899 60740 U25 3 ...
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Page 32: ......
Page 48: ...U20 3 U25 3 WSM Machine body Mechanism section II M 17 U25 3 No 1 Hole 2 shaft ...
Page 50: ......
Page 62: ...U20 3 U25 3 WSM Machine body Service section II S 13 B Front attachment a Parts designation ...
Page 116: ......
Page 118: ...U20 3 U25 3 WSM Engine III 3 ...
Page 121: ...U20 3 U25 3 WSM Engine III 6 Performance curves Model D1105 EBH 10 ...
Page 122: ...U20 3 U25 3 WSM Engine III 7 Performance curves Model D1105 EBH 11 ...
Page 123: ...U20 3 U25 3 WSM Engine III 8 b Dimensions ...
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Page 126: ......
Page 127: ...U20 3 U25 3 WSM Engine Mechanism section III M 2 A Feature ...
Page 129: ...U20 3 U25 3 WSM Engine Mechanism section III M 4 3 Crankshaft 4 Piston and piston rings ...
Page 130: ...U20 3 U25 3 WSM Engine Mechanism section III M 5 5 Connecting rod 6 Rocker arm 7 Camshaft ...
Page 131: ...U20 3 U25 3 WSM Engine Mechanism section III M 6 8 Fuel camshaft 9 Flywheel ...
Page 132: ...U20 3 U25 3 WSM Engine Mechanism section III M 7 C Lubricating system 1 General ...
Page 133: ...U20 3 U25 3 WSM Engine Mechanism section III M 8 2 Oil pump 3 Relief valve ...
Page 134: ...U20 3 U25 3 WSM Engine Mechanism section III M 9 4 Oil filter cartridge 5 Oil pressure switch ...
Page 135: ...U20 3 U25 3 WSM Engine Mechanism section III M 10 D Cooling system 1 General 2 Water pump ...
Page 137: ...U20 3 U25 3 WSM Engine Mechanism section III M 12 5 Radiator cap ...
Page 139: ...U20 3 U25 3 WSM Engine Mechanism section III M 14 F Fuel system 1 General 2 Injection pump ...
Page 140: ...U20 3 U25 3 WSM Engine Mechanism section III M 15 ...
Page 141: ...U20 3 U25 3 WSM Engine Mechanism section III M 16 ...
Page 143: ...U20 3 U25 3 WSM Engine Mechanism section III M 18 5 Governor ...
Page 144: ...U20 3 U25 3 WSM Engine Mechanism section III M 19 ...
Page 146: ...U20 3 U25 3 WSM Engine Mechanism section III M 21 ...
Page 147: ...U20 3 U25 3 WSM Engine Mechanism section III M 22 G Electrical system 1 Charging system ...
Page 148: ...U20 3 U25 3 WSM Engine Mechanism section III M 23 H Turbo charger system ...
Page 149: ...U20 3 U25 3 WSM Engine Mechanism section III M 24 ...
Page 150: ...U20 3 U25 3 WSM Engine Mechanism section III M 25 ...
Page 151: ...U20 3 U25 3 WSM Engine Mechanism section III M 26 ...
Page 152: ...U20 3 U25 3 WSM Engine Mechanism section III M 27 ...
Page 162: ...U20 3 U25 3 WSM Engine Service section III S 10 B General 1 Engine identification ...
Page 163: ...U20 3 U25 3 WSM Engine Service section III S 11 2 General precaution ...
Page 164: ...U20 3 U25 3 WSM Engine Service section III S 12 3 Tightening torques ...
Page 165: ...U20 3 U25 3 WSM Engine Service section III S 13 4 Troubleshooting ...
Page 166: ...U20 3 U25 3 WSM Engine Service section III S 14 ...
Page 167: ...U20 3 U25 3 WSM Engine Service section III S 15 ...
Page 168: ...U20 3 U25 3 WSM Engine Service section III S 16 5 Servicing specifications ...
Page 169: ...U20 3 U25 3 WSM Engine Service section III S 17 ...
Page 170: ...U20 3 U25 3 WSM Engine Service section III S 18 ...
Page 171: ...U20 3 U25 3 WSM Engine Service section III S 19 ...
Page 172: ...U20 3 U25 3 WSM Engine Service section III S 20 ...
Page 173: ...U20 3 U25 3 WSM Engine Service section III S 21 ...
Page 174: ...U20 3 U25 3 WSM Engine Service section III S 22 ...
Page 175: ...U20 3 U25 3 WSM Engine Service section III S 23 ...
Page 176: ...U20 3 U25 3 WSM Engine Service section III S 24 ...
Page 177: ...U20 3 U25 3 WSM Engine Service section III S 25 6 Maintenance check list ...
Page 178: ...U20 3 U25 3 WSM Engine Service section III S 26 7 Check and maintenance ...
Page 179: ...U20 3 U25 3 WSM Engine Service section III S 27 ...
Page 180: ...U20 3 U25 3 WSM Engine Service section III S 28 ...
Page 181: ...U20 3 U25 3 WSM Engine Service section III S 29 ...
Page 182: ...U20 3 U25 3 WSM Engine Service section III S 30 ...
Page 183: ...U20 3 U25 3 WSM Engine Service section III S 31 ...
Page 184: ...U20 3 U25 3 WSM Engine Service section III S 32 ...
Page 185: ...U20 3 U25 3 WSM Engine Service section III S 33 ...
Page 186: ...U20 3 U25 3 WSM Engine Service section III S 34 ...
Page 187: ...U20 3 U25 3 WSM Engine Service section III S 35 ...
Page 188: ...U20 3 U25 3 WSM Engine Service section III S 36 ...
Page 189: ...U20 3 U25 3 WSM Engine Service section III S 37 ...
Page 190: ...U20 3 U25 3 WSM Engine Service section III S 38 ...
Page 191: ...U20 3 U25 3 WSM Engine Service section III S 39 C Engine body CHECKING AND ADJUSTING ...
Page 192: ...U20 3 U25 3 WSM Engine Service section III S 40 DISASSEMBLING AND ASSEMBLING ...
Page 194: ...U20 3 U25 3 WSM Engine Service section III S 42 3 Cylinder head and valves ...
Page 195: ...U20 3 U25 3 WSM Engine Service section III S 43 ...
Page 196: ...U20 3 U25 3 WSM Engine Service section III S 44 4 Gear case ...
Page 197: ...U20 3 U25 3 WSM Engine Service section III S 45 ...
Page 198: ...U20 3 U25 3 WSM Engine Service section III S 46 ...
Page 199: ...U20 3 U25 3 WSM Engine Service section III S 47 ...
Page 200: ...U20 3 U25 3 WSM Engine Service section III S 48 ...
Page 201: ...U20 3 U25 3 WSM Engine Service section III S 49 ...
Page 202: ...U20 3 U25 3 WSM Engine Service section III S 50 5 Piston and connecting rod ...
Page 203: ...U20 3 U25 3 WSM Engine Service section III S 51 ...
Page 204: ...U20 3 U25 3 WSM Engine Service section III S 52 ...
Page 205: ...U20 3 U25 3 WSM Engine Service section III S 53 6 Flywheel and crankshaft ...
Page 206: ...U20 3 U25 3 WSM Engine Service section III S 54 ...
Page 207: ...U20 3 U25 3 WSM Engine Service section III S 55 SERVICING 1 Cylinder head ...
Page 208: ...U20 3 U25 3 WSM Engine Service section III S 56 ...
Page 209: ...U20 3 U25 3 WSM Engine Service section III S 57 ...
Page 210: ...U20 3 U25 3 WSM Engine Service section III S 58 ...
Page 211: ...U20 3 U25 3 WSM Engine Service section III S 59 ...
Page 212: ...U20 3 U25 3 WSM Engine Service section III S 60 2 Timing gear and camshaft ...
Page 213: ...U20 3 U25 3 WSM Engine Service section III S 61 ...
Page 214: ...U20 3 U25 3 WSM Engine Service section III S 62 3 Piston and connecting rod ...
Page 215: ...U20 3 U25 3 WSM Engine Service section III S 63 ...
Page 216: ...U20 3 U25 3 WSM Engine Service section III S 64 ...
Page 217: ...U20 3 U25 3 WSM Engine Service section III S 65 4 Crankshaft ...
Page 218: ...U20 3 U25 3 WSM Engine Service section III S 66 ...
Page 219: ...U20 3 U25 3 WSM Engine Service section III S 67 ...
Page 220: ...U20 3 U25 3 WSM Engine Service section III S 68 ...
Page 221: ...U20 3 U25 3 WSM Engine Service section III S 69 ...
Page 222: ...U20 3 U25 3 WSM Engine Service section III S 70 ...
Page 223: ...U20 3 U25 3 WSM Engine Service section III S 71 5 Cylinder ...
Page 224: ...U20 3 U25 3 WSM Engine Service section III S 72 ...
Page 226: ...U20 3 U25 3 WSM Engine Service section III S 74 ...
Page 228: ...U20 3 U25 3 WSM Engine Service section III S 76 DISASSEMBLING AND ASSEMBLING ...
Page 229: ...U20 3 U25 3 WSM Engine Service section III S 77 ...
Page 231: ...U20 3 U25 3 WSM Engine Service section III S 79 ...
Page 232: ...U20 3 U25 3 WSM Engine Service section III S 80 2 Injection nozzle ...
Page 233: ...U20 3 U25 3 WSM Engine Service section III S 81 DISASSEMBLING AND ASSEMBLING 1 Injection pump ...
Page 234: ...U20 3 U25 3 WSM Engine Service section III S 82 2 Injection nozzle ...
Page 235: ...U20 3 U25 3 WSM Engine Service section III S 83 G Electrical system CHECKING 1 Starter ...
Page 237: ...U20 3 U25 3 WSM Engine Service section III S 85 2 Alternator ...
Page 238: ...U20 3 U25 3 WSM Engine Service section III S 86 ...
Page 239: ...U20 3 U25 3 WSM Engine Service section III S 87 ...
Page 240: ...U20 3 U25 3 WSM Engine Service section III S 88 SERVICING 1 Starter ...
Page 241: ...U20 3 U25 3 WSM Engine Service section III S 89 ...
Page 242: ...U20 3 U25 3 WSM Engine Service section III S 90 2 Alternator ...
Page 243: ...U20 3 U25 3 WSM Engine Service section III S 91 ...
Page 244: ...U20 3 U25 3 WSM Engine Service section III S 92 ...
Page 245: ...U20 3 U25 3 WSM Engine Service section III S 93 H Turbo charger system CHECKING ...
Page 246: ...U20 3 U25 3 WSM Engine Service section III S 94 ...
Page 247: ...U20 3 U25 3 WSM Engine Service section III S 95 DISASSEMBLING AND ASSEMBLING ...
Page 248: ...U20 3 U25 3 WSM Engine Service section III S 96 ...
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Page 279: ...U20 3 U25 3 WSM Hydraulic system Mechanism section IV M 28 ...
Page 280: ...U20 3 U25 3 WSM Hydraulic system Mechanism section IV M 29 b Pilot valve control diagram ...
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Page 312: ...U20 3 U25 3 WSM Hydraulic system Mechanism section IV M 60 b U20 3 Retractable undercarriage ...
Page 313: ...U20 3 U25 3 WSM Hydraulic system Mechanism section IV M 61 c U25 3 ...
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Page 330: ...U20 3 U25 3 WSM Hydraulic system Service section IV S 15 1 Travel mechanism check points ...
Page 397: ...U20 3 U25 3 WSM Hydraulic system Service section IV S 82 ...
Page 415: ...U20 3 U25 3 WSM Hydraulic system Service section IV S 100 3 Component parts of wheel motor ...
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Page 480: ...U20 3 U25 3 WSM Electrical system Service section V S 3 a Front ...
Page 482: ...U20 3 U25 3 WSM Electrical system Service section V S 5 c Swivel frame ...
Page 483: ...U20 3 U25 3 WSM Electrical system Service section V S 6 Around battery ...
Page 486: ...U20 3 U25 3 WSM Electrical system Service section V S 9 3 Around selector valve ...
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