kubota U48-4, U55-4 WORKSHOP MANUAL
WORKSHOP MANUAL
KiSC issued 03, 2010 A
KUBOTA EXCAVATOR
U48-4, U55-4
CONTENTS
KiSC issued 03, 2010 A
TO THE READER
TO THE READER
INFORMATION
CONTENTS
INFORMATION
1. SAFETY FIRST ............................................ I-1
2. SAFETY DECALS ........................................ I-4
GENERAL
CONTENTS
GENERAL
1. CHECKING EXCAVATOR
IDENTIFICATION ........................................G-1
2. ENGINE IDENTIFICATION .........................G-2
3. GENERAL PRECAUTIONS.........................G-4
4. HANDLING PRECAUTIONS FOR
ELECTRICAL PARTS AND WIRING...........G-8
5. TIGHTENING TORQUES..........................G-12
6. NEW PRODUCT FEATURE
(EUROPEAN VERSION) ...........................G-17
7. NEW FEATURES OUTLINE......................G-20
8. QUALITY SPECIFICATIONS ....................G-22
9. WATER AND OIL QUANTITY ...................G-33
10. DESCRIPTION OF PARTS .......................G-34
11. MAINTENANCE CHECK LIST ..................G-41
MACHINE BODY
CONTENTS
SERVICING
1. FRONT OPERATING MACHINE............... 1-S1
2. SWIVEL FRAME........................................ 1-S3
3. TRACK FRAME....................................... 1-S21
ENGINE
CONTENTS
GENERAL
1. ENGINE.....................................................2-G1
2. SPECIAL TOOLS ......................................2-G5
MECHANISM
1. FEATURE................................................. 2-M1
2. ENGINE BODY......................................... 2-M2
3. LUBRICATING SYSTEM.......................... 2-M7
4. COOLING SYSTEM ................................. 2-M8
5. FUEL SYSTEM....................................... 2-M10
SERVICING
1. TROUBLESHOOTING............................... 2-S1
2. SERVICING SPECIFICATIONS ................2-S4
3. TIGHTENING TORQUES........................ 2-S10
4. CHECKING, DISASSEMBLING AND
SERVICING .............................................2-S13
HYDRAULIC SYSTEM
CONTENTS
MECHANISM
1. DIAGRAM OF HYDRAULIC CIRCUIT...... 3-M1
2. HYDRAULIC DEVICE LAYOUT ............... 3-M3
3. FEATURES............................................... 3-M4
4. PUMP ....................................................... 3-M8
5. CONTROL VALVE.................................. 3-M32
6. SWIVEL MOTOR.................................... 3-M54
7. TRAVEL MOTOR.................................... 3-M60
8. HYDRAULIC CYLINDER........................ 3-M82
9. PILOT VALVE......................................... 3-M92
10. UNLOAD VALVE .................................. 3-M103
11. HOLDING VALVE ................................. 3-M107
12. SERVICE PORT ................................... 3-M111
SERVICING
1. PUMP......................................................... 3-S1
2. CONTROL VALVE...................................3-S34
3. SWIVEL MOTOR.....................................3-S63
4. SWIVEL JOINT........................................3-S77
5. TRAVEL MOTOR.....................................3-S81
6. HYDRAULIC CYLINDER.......................3-S140
7. PILOT VALVE (CONTROL)...................3-S153
8. PILOT VALVE (TRAVEL).......................3-S163
9. PILOT VALVE (BLADE, SWING)...........3-S173
10. UNLOAD VALVE ................................... 3-S184
11. THIRD LINE VALVE ASSEMBLY ..........3-S189
12. ROUTING OF HYDRAULIC HOSES.....3-S191
13. BOOM HOLDING VALVE ...................... 3-S217
14. MEASURING HYDRAULIC DEVICE
PERFORMANCE...................................3-S223
15. TROUBLESHOOTING...........................3-S244
ELECTRICAL SYSTEM
CONTENTS
SERVICING
1. ELECTRONIC DEVICE LAYOUT ..............4-S1
2. WIRING CIRCUIT...................................... 4-S2
3. TROUBLESHOOTING (START-UP
EQUIPMENT VERSION) .........................4-S13
4. INSPECTIONS.........................................4-S15
5. Instrument Panel Operating Guide ..........4-S22
6. TROUBLESHOOTING (METER
PANEL EDITION) ....................................4-S77
CABIN
CONTENTS
MECHANISM
1. AIR CONDITIONING SYSTEM................. 5-M1
2. WIPER .................................................... 5-M20
SERVICING
1. TROUBLESHOOTING...............................5-S1
2. MAINTENANCE AND
SERVICE RELATED SPECIFICATIO
NS..............................................................5-S4
3. TORQUE.................................................... 5-S5
4. PRECAUTIONS WHEN REPAIRING
THE REFRIGERANT SYSTEM .................5-S6
5. INSPECTING AND CHARGING THE
REFRIGERANT SYSTEM .......................5-S12
6. INSPECTION AND DISASSEMBLY........5-S21
7. CABIN REMOVAL AND MOUNTING ......5-S38
8. WINDOW WASHER ................................5-S40
9. LIGHTING DEVICES (CAB WORK
LIGHT, INTERIOR LIGHT) ......................5-S43
10. REMOVAL AND INSTALLATION OF
GLASS..................................................... 5-S46
11. FRONT WINDOW.................................... 5-S49
TO THE READER
NOTE
KiSC issued 03, 2010 A
This Workshop Manual provides service personnel with information about the mechanisms, service
and maintenance of the construction machinery. This Workshop Manual is divided into 3 sections,
General, Mechanisms and Service.
Q General
This section contains information such as engine and equipment ID numbers, general precautions,
maintenance schedules, inspections and maintenance items and special tools.
Q Mechanisms
This section describes the structure of mechanisms and explains their functions.Be sure that you
fully understand this Mechanisms section prior to performing any service work, such as troubleshooting
or when performing any disassembly or assembly work.
Q Service
This section contains information and procedures for performing maintenance on the backhoe, such
as troubleshooting, service specification tables, torque specifications, items to be inspected and
adjusted, disassembly and assembly procedures, as well as precautions, maintenance standard values
and usage limits.
All of the illustrations, specifications and other information in this manual were created based on the
latest model at the time of publication.
Please be aware that changes to the content may be made without prior notice.
• Corresponding model list
Machine Model Engine Model
U48-4
U55-4
© KUBOTA Corporation 2010
For European Union V2607-DI-E3-BH
March, 2010
U48-4,U55-4, WSM
KiSC issued 03, 2010 A
Record of Revisions
Last digit
of the
Date Main Revised Point and Corrective Measures Person-in-charge
Code No.
1
2
TO THE READER
3
4
-2
I INFORMATION
KiSC issued 03, 2010 A
INFORMATION
KiSC issued 03, 2010 A
CONTENTS
1. SAFETY FIRST .............................................................................................................................. I-1
2. SAFETY DECALS .......................................................................................................................... I-4
U48-4,U55-4, WSM
SAFETY FIRST
DANGER
WARNING
CAUTION
IMPORTANT
NOTE
KiSC issued 03, 2010 A
INFORMATION
1. SAFETY FIRST
• This symbol, the indus try's "Safety Alert Symbol", is used throughou t this manual and on labels on the
machine itself to warn of the possibility of personal injury. Read these instructions carefully.
• It is essential that you read the instructions and safety regulations before you attempt to repair or use
this unit.
• Indicates an imminently hazardous situa tion which, if not avoided, will result in death or serious injury.
• Indicates a potentially hazardous situation which, if not avoided, could result in death or serious injury.
• Indicates a potentially hazardous situation which, if not avoided, may result in minor or moderate
injury.
• Indicates that equipment or property damage could result if instructions are not followed.
• Gives helpful infor mation.
RY9212007INI0001US0
BEFORE SERVICING AND REPAIRING
• Read all instructions and safety instructions in this
manual and on your engine safety decals.
• Clean the work area and engine.
• Park the machine on a stable and level ground.
• Let the temperature of the engine decrease before
you start a job.
• Stop the engine, then remove the key.
• Disconnect the battery negative cable.
• Hang a "DO NOT OPERATE" tag in the operator
station.
RY9212007INI0002US0
SAFETY STARTING
• Do not do the procedures below when you start the
engine.
– short across starter terminals
– bypass the safety start switch
• Do not make unauthorized modifications to the
engine. This can cause damage and decrease the
engine life.
RY9212007INI0003US0
I-1
U48-4,U55-4, WSM
KiSC issued 03, 2010 A
INFORMATION
SAFETY WORKING
• Do not use the machine after you consume alcohol
or medication or when you are tired.
• Put on applicable clothing and safety equipment.
• Use applicable tools only. Do not use alternative
tools or parts.
• When 2 or more persons do servicing, make sure
that you do it safely.
• Do not touch the hot parts or parts that turn when the
engine operates.
• Do not remove the radiator cap when the engine
operates, or immediately after it stops. If not, hot
water can spout out from the radiator. Only remove
the radiator cap when it is at a sufficiently low
temperature to touch with bare hands. Slowly loosen
the cap to release the pressure before you remove it
fully.
• Released fluid (fuel or hydraulic oil) under pressure
can cause damage to the skin and cause serious
injury. Release the pressure before you disconnect
hydraulic or fuel lines. Tighten all connections before
you apply the pressure.
• Do not open a fuel system under high pressure.
The fluid under high pressure that stays in fuel lines
can cause serious injury. Do not disconnect or repair
the fuel lines, sensors, or any other components
between the fuel pump and injectors on engines with
a common rail fuel system under high pressure.
• Put on an applicable ear protective device (earmuffs
or earplugs) to prevent injury against loud noises.
• Be careful about electric shock. The engine
generates a high voltage of more than DC100 V in
the ECU and is applied to the injector.
RY9212007INI0004US0
AVOID FIRES
• Fuel is very flammable and explosive under some
conditions. Do not smoke or let flames or sparks in
your work area.
• To prevent sparks from an accidental short circuit,
always disconnect the battery negative cable first
and connect it last.
• The battery gas can cause an explosion. Keep the
sparks and open flame away from the top of battery,
especially when you charge the battery.
• Make sure that you do not spill fuel on the engine.
RY9212007INI0005US0
I-2
U48-4,U55-4, WSM
KiSC issued 03, 2010 A
INFORMATION
KEEP A GOOD AIRFLOW IN THE WORK AREA
• If the engine is in operation, make sure that the area
has good airflow. Do not operate the engine in a
closed area. The exhaust gas contains poisonous
carbon monoxide.
RY9212007INI0006US0
DISPOSE OF FLUIDS CORRECTLY
• Do not discard fluids on the ground, down the drain,
into a stream, pond, or lake. Obey related
environmental protection regulations when you
discard oil, fuel, coolant, electrolyte and other
dangerous waste.
RY9212007INI0007US0
PREVENT ACID BURNS
• Keep electrolyte away from your eyes, hands and
clothing. Sulfuric acid in battery electrolyte is
poisonous and it can burn your skin and clothing and
cause blindness. If you spill electrolyte on yourself,
clean yourself with water, and get medical aid
immediately.
RY9212007INI0008US0
PREPARE FOR EMERGENCIES
• Keep a first aid kit and fire extinguisher ready at all
times.
• Keep emergency numbers for doctors, ambulance
service, hospital and fire department near your
telephone at all times.
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I-3
U48-4,U55-4, WSM
KiSC issued 03, 2010 A
INFORMATION
2. SAFETY DECALS
The following safety decals are installed on the machine.
If a decal becomes damaged, illegible or is not on the machine, replace it. The decal part number is listed in
the parts list.
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DANGER, WARNING AND CAUTION LABELS
(1) Part No. TA040-49580 - Do not touch hot parts such as exhaust etc.
(2) Part No. RC418-57370 - Keep away from fan and fan belt.
(3) Part No. RA028-57240 - Attention to the danger of burning.
RY9212007INI0011US0
I-4
U48-4,U55-4, WSM
KiSC issued 03, 2010 A
INFORMATION
(1) Part No. RD809-57450 - Do not touch hot parts such as exhaust etc.
(2) Part No. RD809-57250 - Do not allow any persons within the working range.
(3) Part No. T1060-30090 - Keep sparks, flame, cigarettes away.
(4) Part No. TD179-30130 - Battery recycle label
(5) Part No. RD359-57840 - Battery cut switch label
RY9212007INI0012US0
I-5
U48-4,U55-4, WSM
KiSC issued 03, 2010 A
INFORMATION
(1) Part No. RD809-57390 - When using a wider or deeper bucket, take good care when swinging or pulling in
(2) Part No. RB419-57930 - Label front door lock
(3) Part No. RD809-57430 - Fasten the seatbelt.
(4) Part No. 69198-57840 - Label manual
(5) Part No. RA228-93380 - Anti-theft system
(6) Part No. RD809-57140 - Emergency exit
the front attachments to make sure that the bucket does not hit the cab.
RY9212052INI0001US0
I-6
U48-4,U55-4, WSM
KiSC issued 03, 2010 A
INFORMATION
(1) Part No. RD809-57950 - For information about loosening the crawler, consult the operating instructions.
(2) Part No. RC108-57960 - Attachment point for lifting gear.
(3) Part No. RD809-57250 - Do not enter the manoeuvring area.
(4) Part No. RB419-57960 - Not an attachment point for lifting gear!
(5) Part No. RD451-57480 - Diesel fuel only, no open fire.
(6) Part No. RA809-57330 - Use the attachment point only for clamping the excavator securely to a transport
(7) Part No. RD359-57260 - Fuel supply label
vehicle.
RY9212052INI0002US0
I-7
U48-4,U55-4, WSM
KiSC issued 03, 2010 A
INFORMATION
CARE OF DANGER, WARNING AND CAUTION LABELS
1. Keep danger, warning and caution labels clean and free from obstructing material.
2. Clean danger, warning and caution labels with soap and water, dry with a soft cloth.
3. Replace damaged or missing danger, warning and caution labels with new labels from your KUBOTA dealer.
4. If a component with danger, warning and caution label(s) affixed is replace with new part, make sure new label(s)
is (are) attached in the same locations(s) as the replace component.
5. Mount new danger, warning and caution labels by applying on a clean dry surface and pressure any bubbles to
outside edge.
RY9212007INI0015US0
I-8
G GENERAL
KiSC issued 03, 2010 A
GENERAL
KiSC issued 03, 2010 A
CONTENTS
1. CHECKING EXCAVATOR IDENTIFICATION.............................................................................. G-1
2. ENGINE IDENTIFICATION .......................................................................................................... G-2
[1] MODEL NAME AND SERIAL NUMBER ................................................................................ G-2
[2] E3B ENGINE .......................................................................................................................... G-3
[3] CYLINDER NUMBER............................................................................................................. G-3
3. GENERAL PRECAUTIONS.......................................................................................................... G-4
4. HANDLING PRECAUTIONS FOR ELECTRICAL PARTS AND WIRING .................................... G-8
[1] WIRING .................................................................................................................................. G-8
[2] FUSES.................................................................................................................................. G-10
[3] CONNECTOR ...................................................................................................................... G-10
[4] WASHING THE EXCAVATOR WITH A HIGH-PRESSURE WASHER................................ G-11
5. TIGHTENING TORQUES........................................................................................................... G-12
[1] GENERAL USE SCREWS, BOLTS AND NUTS .................................................................. G-12
[2] STUD BOLTS ....................................................................................................................... G-12
[3] TORQUE FOR HYDRAULIC HOSE FITTINGS ................................................................... G-13
(1) Torque for Hydraulic Hose Fittings................................................................................. G-13
(2) Torques of Lock-Nuts for Elbows with Male Seats and Adaptors with O-rings
(Straight Threads)........................................................................................................... G-14
(3) Torque for Tapering Adaptors ........................................................................................ G-14
[4] HOSE CLAMP SCREW TORQUE ....................................................................................... G-15
6. NEW PRODUCT FEATURE (EUROPEAN VERSION) .............................................................. G-17
7. NEW FEATURES OUTLINE....................................................................................................... G-20
8. QUALITY SPECIFICATIONS ..................................................................................................... G-22
9. WATER AND OIL QUANTITY .................................................................................................... G-33
10. DESCRIPTION OF PARTS ........................................................................................................ G-34
[1] BUCKET ............................................................................................................................... G-34
(1) Bucket dimensions ......................................................................................................... G-34
(2) Bucket installation relevant dimensions.......................................................................... G-35
[2] RUBBER CRAWLER............................................................................................................ G-36
[3] STEEL CRAWLER ............................................................................................................... G-36
[4] TRUCK ROLLER, IDLER, SPROCKET ............................................................................... G-37
[5] CYLINDER .......................................................................................................................... G-38
[6] PARTS WEIGHT .................................................................................................................. G-39
11. MAINTENANCE CHECK LIST ................................................................................................... G-41
U48-4,U55-4, WSM
KiSC issued 03, 2010 A
1. CHECKING EXCAVATOR IDENTIFICATION
When consulting with your local KUBOTA dealer about this
mini-excavator, please provide the model of the mini-excavator, its
frame and engine numbers and the number of hours on the hour
meter.
(1) Mini-excavator Nameplate
(Model, frame number, engine
number)
(2) Frame Number
(3) Engine Number
(a) Model Nameplate
RY9212032GEG0003US0
GENERAL
G-1
U48-4,U55-4, WSM
KiSC issued 03, 2010 A
2. ENGINE IDENTIFICATION
[1] MODEL NAME AND SERIAL NUMBER
Be sure to check the engine nameplate and serial number when
you wish to consult about the engine.
The model and serial number of the engine need to be checked
prior to servicing the engine or replacing any of its parts.
Q Engine Serial No.
The engine serial number is the numerical ID of the engine and
is printed after the engine's model number.
The year and month of manufacture are indicated as follows
Year Manufactured
Letter or
Number
1 2001 F 2015
2 2002 G 2016
3 2003 H 2017
4 2004 J 2018
5 2005 K 2019
6 2006 L 2020
7 2007 M 2021
8 2008 N 2022
9 2009 P 2023
A 2010 R 2024
B 2011 S 2025
C 2012 T 2026
D 2013 V 2027
E2014
Year
Letter or
Number
GENERAL
Year
*The letters I, O, Q, U and Z are not used.
Month Manufactured
Month Lot Number
January A0001 to A9999 B0001 to BZ999
February C0001 to C9999 D0001 to DZ999
March E0001 to E9999 F0001 to FZ999
April G0001 to G9999 H0001 to HZ999
May J0001 to J9999 K0001 to KZ999
June L0001 to L9999 M0001 to MZ999
July N0001 to N9999 P0001 to PZ999
August Q0001 to Q9999 R0001 to RZ999
September S0001 to S9999 T0001 to TZ999
October U0001 to U9999 V0001 to VZ999
November W0001 to W9999 X0001 to XZ999
December Y0001 to Y9999 Z0001 to ZZ999
*The letter I and O are not used.
(a)
(b)H(c)
(d)
- 8
e.g. V2607
(a) Engine Model : V2607-DI
(b) Year Manufactured : The 8 indicates 2008.
(c) Month : April is indicated by either G or H.
(d) Lot Number : (Either 0001 to 9999 or A001 to Z999)
A001
(1) Engine Model and Serial Number
RY9212001END0009US0
G-2
U48-4,U55-4, WSM
KiSC issued 03, 2010 A
GENERAL
[2] E3B ENGINE
[Ex. : Engine Model V2607-DI-E3B-XXXX]
While the exhaust emissions regulations in each country that have been implemented to date to prevent air
pollution are constantly changing, regulations governing off-road exhaust emissions are expected to be implemented
more quickly. The date that specific off-road exhaust emissions regulations will take effect depends on the output
category of the engine.
For some years now KUBOTA has been supplying regulation-compliant diesel engines in countries where
off-road exhaust emission regulations have been introduced. KUBOTA's E3B series of engines meet the next phase
of exhaust emission regulations. (See the table below.)
Whenever repairs or service is performed on a ###-E3B series engine, E3B engine replacements parts, which
are in the applicable E3B KUBOTA Parts List, must be used and the KUBOTA Operator's Manual and E3B Workshop
Manual must be used for maintenance. Use of incorrect replacement parts or replacement parts from other emission
level engines (for example : E2B engines), may result in emission levels out of compliance with the original E3B
design, EPA and/or other applicable regulations. Check the output category and emissions data on the emissions
label on the header cover of the engine. E3B engines have the suffix ET after the model name on the EPA label. E3B
is not marked on the engine.
Class (1) Engine Output Category EU Regulation
K 19 to/not including 37 kW STAGE IIIA
J 37 to/not including 75 kW STAGE IIIA
I 75 to/not including 130 kW STAGE IIIA
[3] CYLINDER NUMBER
Class (2) Engine Output Category EPA Regulation
Less than 19 kW Tier 4
ET
(1) EU Regulation engine output classification
(2) "E3B engines" have the suffix ET after the model name on the EPA label.
"E3B" models meet Tier 3, Interim Tier4 or Tier4 regulations, depending on the
engine output category.
19 to/not including 56 kW Interim Tier 4
56 to/not including 75 kW Tier 3
75 to/not including 130 kW Tier 3
RY9212001END0010US0
KUBOTA diesel engines are numbered as indicated in the
figure.
Cylinders are numbered from the front cover (fan side) in the
order 1, 2, 3 and 4.
RY9212001END0011US0
G-3
U48-4,U55-4, WSM
KiSC issued 03, 2010 A
3. GENERAL PRECAUTIONS
Whenever performing maintenance on the mini-excavator,
always read the Safety Precautions in this manual and the
Operator's Manual carefully, become familiar with them and perform
the work safely.
Before performing any maintenance on the mini-excavator,
make sure it is sufficiently clean and choose a sufficiently clean
location to perform any disassembly.
Before performing maintenance on the mini-excavator, always
disconnect the negative battery cable first.
Whenever a special tool is required, use the special tool that
KUBOTA recommends. Make any special tools that are not used
very frequently according to the diagrams in this manual.
Always use genuine KUBOTA parts to maintain the
performance and safety characteristics of the mini-excavator.
Plumber's Tape
• Wrap plumber's tape on the threads before tightening taper
couplings. After wrapping (2 wraps) the plumber's tape, tighten
to the specified torque. Once the coupling is tightened, do not
loosen it as this will cause an oil leak.
(1) Plumber's Tape
(2) External Thread
(3) Internal Thread
GENERAL
RY9212001GEG0011US0
(4) Gap
(5) Leave 1 to 2 threads
RY9212001GEG0012US0
O-Ring
• Clean the groove the O-ring goes in and remove any burrs.
Apply grease on the O-ring when inserting it in the groove.
(Except floating seals)
• When putting the O-ring in the groove, be careful as it is easy at
the very end to twist the O-ring against the inside of the groove.
If it gets twisted, roll it gently with your fingertip to untwist it.
(1) O-ring Groove
(2) O-ring
(3) Check for burrs
(4) If the ring touches this corner, it will
twist
RY9212001GEG0013US0
Oil Seal
• Do not face the lip of the oil seal in the wrong direction. Face the
main lip toward the material to be sealed.
• After oil seals are replaced, apply grease to the moving parts
around the lip to prevent the dry surfaces from wearing against
each other when the engine is started. If the seal has a dust lip,
fill the gap between the lips with grease.
• As a general rule, use a press to insert the oil seal in place. If
that is not possible, use an appropriate tool to gently and evenly
tap it into place, taking care that it does not go in at a slant.
Press the seal all the way so it seats in the boss.
(1) Gasket
(2) Metal Ring
(3) Spring
(4) Main Lip
(5) Grease
(6) Dust Lip
A : Air (outside)
B : Hydraulic chamber (in side)
RY9212001GEG0014US0
G-4
U48-4,U55-4, WSM
KiSC issued 03, 2010 A
GENERAL
Floating Seal
• Be sure to wipe off any oil from the O-ring or surfaces that touch
the O-ring. (For wheel motors, apply a light film)
• When putting an O-ring into a floating seal, make sure the
O-ring does not twist.
• Apply a light film of oil to surrounding surfaces when working to
get the floating seal with O-ring in place; take care that the
surrounding surfaces, O-ring and housing are parallel with each
other.
• After getting the seal in place, turn the engine over 2 or 3
revolutions, to both create a film of oil on surrounding surfaces
and to properly seat the face of the seal.
(1) Surrounding Surfaces (2) O-ring
RY9212001GEG0015US0
Snap Ring Related
• When installing external or internal snap rings, orient them as
shown in the diagram so the angled side faces the direction of
force.
(1) Position so the angled part receives
the force
(A) External
(B) Internal
RY9212001GEG0016US0
Spring Pins
• When driving a spring pin, face the split in the direction that
receives the force, as shown in the diagram.
(1) With lateral movement (2) With rotational movement
RY9212001GEG0017US0
Locktite
• Clean and dry the area where Locktite will be applied with a
solvent so it is free of moisture, oil and dirt.
• Apply locktite all around the threads of the bolt except the first
set of threads at the tip and fill the grooves between the threads.
If the threads or the grooves are large, adjust the amount of
locktite accordingly and apply it all around the bolt hole as well.
(A) Bolt Through-hole (nut)
(B) Pocket Bolt Hold
(capsule shape, etc.)
(a) Apply here
(b) Do not apply
(c) Drip on
RY9212001GEG0018US0
G-5
U48-4,U55-4, WSM
KiSC issued 03, 2010 A
GENERAL
Tightening Bolts and Nuts
• Tighten bolts and nuts to their specified torque.
• Tighten nuts and bolts alternately top/bottom (a) (b), left/right so
the torque is distributed evenly.
(A) Top/bottom alternately
(B) Across diagonally
(C) Diagonally across the center
RY9212001GEG0019US0
Assembling Hydraulic Hoses
• Tighten to their specified torque.
• Before assembling, wipe the inside of metal fittings clean of any
dirt.
• After assembly, put the fitting under normal pressure and check
that it does not leak.
RY9212001GEG0020US0
Elbow with Male Seat Assembly Procedure
When assembling an elbow with male seat, adhere to the
following procedures to prevent deformation of O-rings and leaks.
1. Connecting to Valves
• Clean the blow with male seat and the surface of the seal
opposite and mount with the lock-nut on top.
• Finger tighten till it touches the washer.
2. Positioning
• Turn the mouth of the elbow back so it faces the right
direction. (not back over 1 turn)
3. Fasten
• Tighten the lock-nut to the specified torque with a wrench.
(1) Lock-nut
(2) Washer
(3) Seal (O-ring)
(4) Wrench for holding
(5) Hose
(6) Torque wrench for tightening
RY9212001GEG0021US0
G-6
U48-4,U55-4, WSM
KiSC issued 03, 2010 A
GENERAL
Installing and Removing Quick Couplings
• To remove a quick hose coupling, push the fitting (2) in the
direction of the arrow and pull on the plastic part (1) in the
opposite direction.
• To attach a quick coupler, push it in firmly in the direction of the
arrow. Then check that it will not pull off.
(1) Plastic part (2) Fitting
RY9212001GEG0022US0
G-7
U48-4,U55-4, WSM
IMPORTANT
KiSC issued 03, 2010 A
GENERAL
4. HANDLING PRECAUTIONS FOR ELECTRICAL
PARTS AND WIRING
Follow the precautions below for handling electrical parts and
wiring to ensure safety and prevent damage to the mini-excavator
and nearby equipment.
• Inspect electrical wiring for damage and/or loose
connections.
• Do not alter or rewire any electrical parts or wiring.
• Always remove the negative battery cable first when
disconnecting the battery and attach the p ositive cable first
when connecting it.
(1) Battery Cable (-) Side (2) Battery Cable (+) Side
RY9212001GEG0023US0
[1] WIRING
• Tighten wiring terminals securely.
(1) Correct (Tightened securely) (2) Incorrect (Poor contact if loose)
RY9212001GEG0024US0
• Keep wiring away from hazards.
(1) Hazardous Positioning
(2) Wiring Position (wrong)
(3) Wiring Position (right)
(4) Hazardous Position
RY9212001GEG0025US0
• Immediately repair or replace old or damaged wiring.
(1) Damaged
(2) Torn
(3) Electrical Tape
RY9212001GEG0026US0
G-8
U48-4,U55-4, WSM
KiSC issued 03, 2010 A
GENERAL
• Insert grommet securely.
(1) Grommet (A) Correct
(B) Incorrect
RY9212001GEG0027US0
• Clamp wiring securely but do not damage wires with the clamp.
(1) Clamp (Spiral clamp around wire)
(2) Wire
(3) Clamp
(4) Welding Mark
RY9212001GEG0028US0
• Clamp wiring so it is not twisted, pulled too tight or sag too
much. However, moving parts may require play in the wiring.
(1) Wire
(2) Clamp
(A) Correct
(B) Incorrect
RY9212001GEG0029US0
• Do not pinch or bind wiring when installing parts.
(1) Wire (A) Incorrect
RY9212001GEG0030US0
• After wiring, double-check terminal protectors and clamps
before connecting battery cables.
(1) Cover (Install covers securely)
RY9212001GEG0031US0
G-9
U48-4,U55-4, WSM
KiSC issued 03, 2010 A
[2] FUSES
[3] CONNECTOR
GENERAL
• Always use fuses of the specified capacity.
Never use over or undersized fuses.
• Never use copper or steel wire in place of a fuse.
• Do not install accessories such as work lights, radios, etc., if
your mini-excavator does not have an auxiliary circuit.
• Do not install accessories as they will exceed the capacity of
fuses.
(1) Fuse
(2) Fusible Link
(3) Slow-blow Fuse
RY9212001GEG0032US0
• Press the lock to disconnect locking connectors.
(A) Push
RY9212001GEG0033US0
• Hold the connectors when separating them.
• Do not pull on the wire harness to separate the connectors.
(A) Correct (B) Incorrect
RY9212001GEG0034US0
• Straighten bent prongs and make sure none are sticking out or
missing.
• Remove corrosion from terminals with sandpaper.
(1) Missing terminal
(2) Bent Prong
(3) Sandpaper
(4) Corrosion
RY9212001GEG0035US0
• Female connectors must not be spread too far open
(A) Correct (B) Incorrect
RY9212001GEG0036US0
G-10
U48-4,U55-4, WSM
CAUTION
KiSC issued 03, 2010 A
• The plastic covers of connectors must cover them completely.
(1) Cover (A) Correct
(B) Incorrect
RY9212001GEG0037US0
[4] WASHING THE EXCAVATOR WITH A HIGH-PRESSURE
WASHER
Using a high-pressure washer incorrectly can lead to personal
injury and/or damage, break or cause parts of the mini-excavator to
fail, so use the power washer properly according to its user's
manual and labels.
• Stand at least 2 meters from the mini-excavator and adjust
the nozzle for a wide spray so it does not cause any
damage. If you blast the mini-excavator wit h wa ter or wash
it from too close a distance,
1. It may cause a fire due to damaged or cu ts in the insulation
of electrical wiring.
2. An injury may result if hydraulic oil gushes out under high
pressure, due to damaged hydraulic hoses.
3. It may damage, break or cause parts of the mini-excavator
to fail.
(Ex.)
(1) Stickers or labels may come off
(2) Electrical parts or the engine may fail due to water in them.
(3) Damage glass, resins, etc. or the rubber of oil seals.
(4) Tear off paint or the film from plating
(1) Do not blast with water
(2) Never wash from too close
(A) Blasting
(B) Wide Spray
(C) Less than 2 m (80 in.)
(D) Over 2 m (80 in.)
RY9212001GEG0038US0
GENERAL
G-11
U48-4,U55-4, WSM
KiSC issued 03, 2010 A
GENERAL
5. TIGHTENING TORQUES
[1] GENERAL USE SCREWS, BOLTS AND NUTS
Screws, bolts and nuts whose tightening torques are not specified in this Workshop Manual should be
tightened according to the table b elow .
Indication on top of bolt
Indication on top of nut
Material of opponent part Ordinariness Aluminum Ordinariness Aluminum Ordinariness
Unit N·m kgf·m lbf·ft N·m kgf·m lbf·ft N·m kgf·m lbf·ft N·m kgf·m lbf·ft N·m kgf·m lbf·ft
7.9
0.80
M6
M8
M10
M12
M14
M16
M18
M20
to
9.3
18
to
20
40
to
45
63
to
72
108
to
125
167
to
191
246
to
284
334
to
392
to
0.95
1.8
to
2.1
4.0
to
4.6
6.4
to
7.4
11. 0
to
12.8
17.0
to
19.5
25.0
to
29.0
34.0
to
40.0
No-grade or 4T 7T 9T
No-grade or 4T
5.8
7.9
0.80
5.8
9.81
1.00
7.24
7.9
0.80
5.8
to
to
to
1.7
to
2.0
3.2
to
3.5
to
6.5
13
to
14
24
to
25
6.8
8.8
0.90
13
17
to
to
15
19
32
29
to
to
33
34
47
to 53–––
79.6
to
92.5
–––
123
to
–––
141
181
to
–––
209
246
to
–––
289
to
11. 2
24
to
27
48
to
55
78
to
90
124
to
147
197
to
225
275
to
318
368
to
431
to
1.15
2.4
to
2.8
4.9
to
5.7
7.9
to
9.2
12.6
to
15.0
20.0
to
23.0
28.0
to
32.5
37.5
to
44.0
to
8.31
18
to
20
36
to
41
58
to
66
91.2
to
108
145
to
166
203
to
235
272
to
318
to
to
8.8
0.90
18
1.8
to
to
20
2.1
40
4.0
to
to
44
4.5
63
6.4
to
to
72
7.4
––
–––
–––
–––
12.3
to
to
6.5
14.2
13
30
to
to
15
34
29
61
to
to
32
70
47
103
to
to
53
117
167
–
to
196
260
to
304
344
to
402
491
to
568
RY9212032GEG0001US0
6T
1.25
to
1.45
3.0
to
3.5
6.2
to
7.2
10.5
to
12.0
17.0
to
20.0
26.5
to
31.0
35.0
to
41.0
50.0
to
58.0
9.05
to
10.4
22
to
25
45
to
52
76.0
to
86.7
123
to
144
192
to
224
254
to
296
362
to
419
[2] STUD BOLTS
Material of opponent part Ordinariness Aluminum
Unit N·m kgf·m lbf·ft N·m kgf·m lbf·ft
12
1.2
8.7
M8
M10
M12
M14
M16
M18
to
15
25
to
31
30
to
49
62
to
73
98.1
to
112
172
to
201
to
1.6
2.5
to
3.2
3.0
to
5.0
6.3
to
7.5
10.0
to
11. 5
17.5
to
20.5
8.9
to
to
11
11
18
20
to
to
23
25
22
to 3631 3.2 23
46
to 54–––
72.4
to
83.1
–––
127
to
–––
148
0.90
to
1.2
2.0
to
2.6
6.5
to
8.6
15
to
18
RY9212032GEG0002US0
G-12
U48-4,U55-4, WSM
KiSC issued 03, 2010 A
[3] TORQUE FOR HYDRAULIC HOSE FITTINGS
(1) Torque for Hydraulic Hose Fittings
Union Nuts
GENERAL
Torque
(1) Union Nuts
Tapered Nuts
1/8
1/4
3/8
1/2
3/4
1
1-1/4
7.8 to 11.8 N·m
0.8 to 1.2 kgf·m
5.7 to 8.7 lbf·ft
24.5 to 29.2 N·m
2.5 to 3.0 kgf·m
18.1 to 21.7 lbf·ft
37.2 to 42.1 N·m
3.8 to 4.3 kgf·m
27.5 to 31.1 lbf·ft
58.8 to 63.7 N·m
6.0 to 6.5 kgf·m
43.4 to 47.0 lbf·ft
117.6 to 127.4 N·m
12.0 to 13.0 kgf·m
86.8 to 94.0 lbf·ft
181.3 to 191.1 N·m
18.5 to 19.5 kgf·m
133.8 to 141.0 lbf·ft
220.5 to 230.3 N·m
22.5 to 23.5 kgf·m
162.8 to 170.0 lbf·ft
RY9212001GEG0041US0
Torque
(1) Taper
1/8
1/4
3/8
1/2
3/4
19.6 to 29.4 N·m
2.0 to 3.0 kgf·m
14.5 to 21.7 lbf·ft
36.6 to 44.1 N·m
3.7 to 4.5 kgf·m
26.8 to 32.5 lbf·ft
68.6 to 73.5 N·m
7.0 to 7.5 kgf·m
50.6 to 54.2 lbf·ft
83.4 to 88.3 N·m
8.5 to 9.0 kgf·m
61.5 to 65.1 lbf·ft
166.6 to 181.3 N·m
17.0 to 18.5 kgf·m
123.0 to 133.8 lbf·ft
RY9212001GEG0042US0
G-13
U48-4,U55-4, WSM
KiSC issued 03, 2010 A
GENERAL
(2) Torques of Lock-Nuts for Elbows with Male Seats and Adaptors with
O-rings (Straight Threads)
(1) Lock-nut
(2) Washer
(3) Torque for Tapering Adaptors
Torque
Torque
1/8
1/4
3/8
1/2
3/4, 1
1-1/4
(3) Seal (O-ring)
1/8
1/4
3/8
1/2
3/4
15.0 to 16.5 N·m
1.5 to 1.7 kgf·m
11.1 to 12.2 lbf·ft
24.5 to 29.4 N·m
2.5 to 3.0 kgf·m
18.1 to 21.7 lbf·ft
49.0 to 53.9 N·m
5.0 to 5.5 kgf·m
36.1 to 39.8 lbf·ft
58.8 to 63.7 N·m
6.0 to 6.5 kgf·m
43.4 to 47.0 lbf·ft
117.6 to 127.4 N·m
12.0 to 13.0 kgf·m
86.8 to 94.0 lbf·ft
220.5 to 230.3 N·m
22.5 to 23.5 kgf·m
162.8 to 170.0 lbf·ft
RY9212001GEG0043US0
19.6 to 29.4 N·m
2.0 to 3.0 kgf·m
14.5 to 21.7 lbf·ft
36.6 to 44.1 N·m
3.7 to 4.5 kgf·m
26.8 to 32.5 lbf·ft
68.6 to 73.5 N·m
7.0 to 7.5 kgf·m
50.6 to 54.2 lbf·ft
83.4 to 88.3 N·m
8.5 to 9.0 kgf·m
61.5 to 65.1 lbf·ft
166.6 to 181.3 N·m
17.0 to 18.5 kgf·m
123.0 to 133.8 lbf·ft
(1) Taper
RY9212001GEG0044US0
G-14
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