Kubota U48-4 Instruction manual

WORKSHOP MANUAL
KUBOTA EXCAVATOR
U48-4, U55-4
KiSC issued 03, 2010 A

CONTENTS
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
KiSC issued 03, 2010 A

TO THE READER
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.
QGeneral
This section contains information such as engine and equipment ID numbers, general precautions,
maintenance schedules, inspections and maintenance items and special tools.
QMechanisms
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.
QService
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.
NOTE
• Corresponding model list
March, 2010
© KUBOTA Corporation 2010
Machine Model Engine Model
U48-4
U55-4 For European Union V2607-DI-E3-BH
KiSC issued 03, 2010 A

TO THE READER
U48-4,U55-4, WSM
-2
Record of Revisions
Last digit
of the
Code No. Date Main Revised Point and Corrective Measures Person-in-charge
1
2
3
4
KiSC issued 03, 2010 A

I INFORMATION
KiSC issued 03, 2010 A

CONTENTS
1. SAFETY FIRST .............................................................................................................................. I-1
2. SAFETY DECALS .......................................................................................................................... I-4
INFORMATION
KiSC issued 03, 2010 A

INFORMATION
U48-4,U55-4, WSM
I-1
1. SAFETY FIRST
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
SAFETY FIRST
• This symbol, the industry's "Safety Alert Symbol", is used throughout 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.
DANGER
• Indicates an imminently hazardous situation which, if not avoided, will result in death or serious injury.
WARNING
• Indicates a potentially hazardous situation which, if not avoided, could result in death or serious injury.
CAUTION
• Indicates a potentially hazardous situation which, if not avoided, may result in minor or moderate
injury.
IMPORTANT
• Indicates that equipment or property damage could result if instructions are not followed.
NOTE
• Gives helpful information.
KiSC issued 03, 2010 A

INFORMATION
U48-4,U55-4, WSM
I-2
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
KiSC issued 03, 2010 A

INFORMATION
U48-4,U55-4, WSM
I-3
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.
RY9212007INI0009US0
KiSC issued 03, 2010 A

INFORMATION
U48-4,U55-4, WSM
I-4
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. RY9212007INI0010US0
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
KiSC issued 03, 2010 A

INFORMATION
U48-4,U55-4, WSM
I-5
(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
KiSC issued 03, 2010 A

INFORMATION
U48-4,U55-4, WSM
I-6
(1) Part No. RD809-57390 - When using a wider or deeper bucket, take good care when swinging or pulling in
the front attachments to make sure that the bucket does not hit the cab.
(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
RY9212052INI0001US0
KiSC issued 03, 2010 A

INFORMATION
U48-4,U55-4, WSM
I-7
(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
vehicle.
(7) Part No. RD359-57260 - Fuel supply label
RY9212052INI0002US0
KiSC issued 03, 2010 A

INFORMATION
U48-4,U55-4, WSM
I-8
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
KiSC issued 03, 2010 A

G 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
GENERAL
KiSC issued 03, 2010 A

GENERAL
U48-4,U55-4, WSM
G-1
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.
RY9212032GEG0003US0
(1) Mini-excavator Nameplate
(Model, frame number, engine
number)
(2) Frame Number
(3) Engine Number
(a) Model Nameplate
KiSC issued 03, 2010 A

GENERAL
U48-4,U55-4, WSM
G-2
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.
QEngine 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
*The letters I, O, Q, U and Z are not used.
Month Manufactured
*The letter I and O are not used.
e.g. V2607
(a)
- 8
(b)
H
(c)
A001
(d)
RY9212001END0009US0
Letter or
Number Year Letter or Number Year
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
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
(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)
(1) Engine Model and Serial Number
KiSC issued 03, 2010 A

GENERAL
U48-4,U55-4, WSM
G-3
[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.
RY9212001END0010US0
[3] CYLINDER NUMBER
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
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
Class (2) Engine Output Category EPA Regulation
ET
Less than 19 kW Tier 4
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
(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.
KiSC issued 03, 2010 A

GENERAL
U48-4,U55-4, WSM
G-4
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.
RY9212001GEG0011US0
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.
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.
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.
RY9212001GEG0014US0
(1) Plumber's Tape
(2) External Thread
(3) Internal Thread
(4) Gap
(5) Leave 1 to 2 threads
(1) O-ring Groove
(2) O-ring
(3) Check for burrs
(4) If the ring touches this corner, it will
twist
(1) Gasket
(2) Metal Ring
(3) Spring
(4) Main Lip
(5) Grease
(6) Dust Lip
A : Air (outside)
B : Hydraulic chamber (inside)
KiSC issued 03, 2010 A