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.

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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.

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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.

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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

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(4) Gap
(5) Leave 1 to 2 threads

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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

U48-4,U55-4, WSM

KiSC issued 03, 2010 A

[4] HOSE CLAMP SCREW TORQUE

Type 1

Torque

10- 14 6C040-58721

12- 16 09318-89016

19- 25 09318-89024

31- 40 09318-89039

36- 46 09318-89045

44- 53 09318-89052

51- 59 09318-89058

86- 96 RD809-42241

GENERAL

2.5 to 3.4 N·m
25 to 35 kgf·cm

1.8 to 2.5 lbf·ft

2.5 to 3.4 N·m
25 to 35 kgf·cm

1.8 to 2.5 lbf·ft

2.5 to 3.4 N·m
25 to 35 kgf·cm

1.8 to 2.5 lbf·ft

2.5 to 3.4 N·m
25 to 35 kgf·cm

1.8 to 2.5 lbf·ft

2.5 to 3.4 N·m
25 to 35 kgf·cm

1.8 to 2.5 lbf·ft

3.9 to 4.9 N·m
40 to 50 kgf·cm

2.9 to 3.6 lbf·ft

3.9 to 4.9 N·m
40 to 50 kgf·cm

2.9 to 3.6 lbf·ft

3.9 to 4.9 N·m
40 to 50 kgf·cm

2.9 to 3.6 lbf·ft

RY9212001GEG0045US0

G-15

U48-4,U55-4, WSM

KiSC issued 03, 2010 A

Type 2

Torque

13- 20 RB101-63631

15- 25 RC101-64581

19- 28 R1401-63211

22- 32 R1401-63151

26- 38 68311-72821

32- 44 RD411-63821

44- 56 35820-15181

50- 65 RC401-63191

58- 75 36919-04591

60- 80 RD809-63101

68- 85 RD809-63061

77- 95 69284-63171

GENERAL

2.5 to 3.4 N·m
25 to 35 kgf·cm

1.8 to 2.5 lbf·ft

4.9 to 5.9 N·m
50 to 60 kgf·cm

3.6 to 4.3 lbf·ft

4.9 to 5.9 N·m
50 to 60 kgf·cm

3.6 to 4.3 lbf·ft

4.9 to 5.9 N·m
50 to 60 kgf·cm

3.6 to 4.3 lbf·ft

4.9 to 5.9 N·m
50 to 60 kgf·cm

3.6 to 4.3 lbf·ft

4.9 to 5.9 N·m
50 to 60 kgf·cm

3.6 to 4.3 lbf·ft

4.9 to 5.9 N·m
50 to 60 kgf·cm

3.6 to 4.3 lbf·ft

4.9 to 5.9 N·m
50 to 60 kgf·cm

3.6 to 4.3 lbf·ft

4.9 to 5.9 N·m
50 to 60 kgf·cm

3.6 to 4.3 lbf·ft

4.9 to 5.9 N·m
50 to 60 kgf·cm

3.6 to 4.3 lbf·ft

4.9 to 5.9 N·m
50 to 60 kgf·cm

3.6 to 4.3 lbf·ft

4.9 to 5.9 N·m
50 to 60 kgf·cm

3.6 to 4.3 lbf·ft

RY9212001GEG0046US0

G-16

U48-4,U55-4, WSM

KiSC issued 03, 2010 A

GENERAL

6. NEW PRODUCT FEATURE (EUROPEAN VERSION)

Quick chart - Machine type classification should be defined (L type)

Basic specification Operation

Robust Machine Weight (Machine class

(1)

upgraded to 5.5 ton)
(2) V2607 New DI Engine Serviceability
(3) Advanced Three Pump Load Sensing System * (14) Sheet-metal processed covers
(4) Strong bucket breakout force (15) One side engine maintenance

Performance (16) Bush with flange at arm tip end

(5) Bigger Lifting Capacity (17)

Dual Speed with Auto-shift as standard
(6)

(Bigger travel force)
(7) Higher Blade (18) Travel parking brake as standard

Shortened distance between blade and bucket
(8)

teeth

Operator comfort (19) KUBOTA original digital panel at the Front *

(9) Spacious and comfort cabin (20)

(10) Powerful Air conditioning (21) Battery Isolator *

Versatility

(11)

(12)

* : New Feature

AUX1" and "AUX2" with proportional control on

joystick is adopted. *

The maximum oil flow of both AUX lines can be

adjusted by digital panel. *

(13)

Safety

Others

Pilot hydraulic remote-control system for all
actuators

Prolonged return filter life 500 hours
→ 1000 hours

Leading-edge Anti-theft system for greater
security

RY9212052GEG0001US0

G-17

U48-4,U55-4, WSM

KiSC issued 03, 2010 A

Standard Equipment
Safety system

• Engine start safety system on the left console

• Travel motor with disc brake

• Swivel motor with disc brake

• Overload warning buzzer

• KUBOTA original anti-theft system

• Anti-drop valve on the boom (ISO8643)

Working equipment

• Auxiliary hydraulic circuits (SP1 and SP2*) piping to the arm end *for Types L and M.

• 2 working lights on cabin and 1 light on the boom

• 1450 mm arm length (U48-4)

• 1570 mm arm length (U55-4)

Cabin

• ROPS (Roll-over Protective Structure, ISO3471)

• OPG (Operating Protective Guard) Level1

• Wight-adjustable full suspension seat

• Seatbelt

• Hydraulic pilot control levers with wrist rests

• Travel levers with foot pedals

• Air conditioning (Type L)

• Cabin heater for defrosting and demising

• Emergency exit hammer

• Front window power assisted with gas damper

• 12 V power source

• 2 speakers and radio aerial

• Location for radio

• Back mirror (left, right and rear)

• Cup holder

Engine / Fuel system

• Double-element air filter

• Electric fuel injection pump system

• Auto idling system

Undercarriage

• 400 mm rubber track

• 1 x upper track roller

• 5 double-flange track rollers on each track

• 2-speed travel switch on blade lever

• Two-speed travel with auto-shift

• Water separator with drain cock

Hydraulic system

• Pressure accumulator

• Hydraulic pressure checking ports

• Straight travel circuit

• Third line hydraulic return

• Load-sensing hydraulic system

• Adjustable maximum oil flow on auxiliary circuits (SP1 and SP2) *For (Type L and M)

• Double auxiliary circuit accessories

• Auxiliary switch (SP1) on right control lever

• Auxiliary switch (SP2) on left control lever (Type L and M)

GENERAL

RY9212052GEG0002US0

G-18

U48-4,U55-4, WSM

KiSC issued 03, 2010 A

Optional Equipment
Undercarriage

• 400 mm steel track (+ 100 kg)

• 550 mm steel track (+ 300 kg)

Safety system

• Anti-drop valve unit (arm and blade)

• Bracket and harness for beacon light

Others

• Special paint upon request

Standard Equipment For Each Type

GENERAL

RY9212007GEG0003US0

Type

L OO / O
M – O / O
S – O / –

Air

conditioning

AUX1 / AUX2

SP

RY9212052GEG0003US0

G-19

U48-4,U55-4, WSM

KiSC issued 03, 2010 A

7. NEW FEATURES OUTLINE

New Design Digital Meter Panel
Features :

1. Large LCD display

2. Display and anti-theft controllers are unified into 1 ECU.

3. Main display and ECU are independent items connected by
CAN (Controller Area Network) technology.

(1) GENERAL

*CONTROL ECU
*AUTO IDLE
*ANTI-THEFT
*AUTO SHIFT TRAVELING SPEED

AUX 1 and 2 Operation Control
Hard-control system

The hydraulic control grip has proportional Flow Control built in.

Signals from this sensor activate the proportional solenoid valve to
control the flow rate at the hydraulic service port.

(1) Control knob (Auxiliary circuit)

GENERAL

(2) MAIN DISPLAY METER PANAL

(a) CAN

RY9212007GEG0005US0

RY9212007GEG0006US0

Battery Isolator

(1) Battery cut switch (a) "ON"

(b) "OFF"

RY9212007GEG0007US0

G-20

U48-4,U55-4, WSM

KiSC issued 03, 2010 A

Three pump Load Sensing System
Hydraulic operation for all actuators

All actuators are hydraulically locked when the unlock lever is raised.
(travel, swing, blade and AUX are also hydraulically controlled.)
It realizes smoother movement with fine inching control.

3-pump load sensing system

• U55-4 adopts the same 3-pump load sensing system as
KX057-4.

• 1st and 2nd pumps that normally supply the oil to front
attachments change the oil flow to travel actuator when
travelling in order to realize the strong travel performance.

• The travel slow down while operating front attachments is
minimized by adopting 3-pump load sensing system (ex. when
blading and travelling.

(1) Travel (R), Travel (L)
(2) Boom, Arm, Bucket, AUX1, Swivel
(3) AUX2, Blade, Swing

GENERAL

(A) When not travelling
(B) When travelling

RY9212052GEG0004US0

G-21

U48-4,U55-4, WSM

KiSC issued 03, 2010 A

GENERAL

8. QUALITY SPECIFICATIONS

Machine specification : Auxiliary port1, Wrist rest, Cab, Japan STD-bucket [125 kg (277 lbs) with 2 pins 7 kg

(15.5 lbs)]

Item

Machine size

• Total length (Transport)

5330 ± 107 mm

209.8 ± 4.2 in.

Factory Specification

U48-4 U55-4

5500 ± 110 mm

216.5 ± 4.3 in.

Remarks

• Total width

• Total height

Weight

• Machine weight
(Operating weight)

Performance

• Swivel speed

• Travel speed

ROPS

CAB

L

R

Rubber F1

Rubber F2

1960 ± 20 mm

77.2 ± 0.8 in.

2550 ± 25 mm

100.4 ± 1.0 in.

–

46.8 ± 2 kN

4775 ± 235 kg

10527 ± 517 lbs

9.0 ± 0.9 rpm

9.0 ± 0.9 rpm

2.8 ± 0.3 km/h

1.74 ± 0.2 mph

4.9 ± 0.5 km/h

3.04 ± 0.3 mph

1960 ± 20 mm

77.2 ± 0.8 in.

2550 ± 25 mm

100.4 ± 1.0 in.

–

53.0 ± 3 kN

5400 ± 270 kg

11905 ± 594 lbs

9.3 ± 0.9 rpm

9.3 ± 0.9 rpm

2.8 ± 0.3 km/h

1.74 ± 0.2 mph

4.9 ± 0.5 km/h

3.04 ± 0.3 mph

Fuel tank : Full
Truck : Rubber, Japan
STD Bucket [Including
operator's weight 75 kg
(170 lbs)]

Front horizontal bucket
crowd with no load
Engine Max. speed
Oil temp. : 50 ± 5 °C
(122 ± 9 °F)

Traveling stance :
Engine Max. speed
Oil temp. : 50 ± 5 °C
(122 ± 9 °F)

Steel F1

Steel F2

• Gradeability

Rear end min. tuming radius 990 ± 20 mm

Swivel frame rear ground clearance 624.5 ± 12.5 mm

Tumbler center distance 1990 ± 60 mm

Crawler total length 2500 ± 75 mm

Crawler total width 1960 ± 39 mm

Min. ground clearance 310 ± 9 mm

F1

2.6 ± 0.3 km/h

1.62 ± 0.2 mph

4.6 ± 0.5 km/h

2.86 ± 0.3 mph

30 ° <

39.0 ± 0.8 in.

24.6 ± 0.5 in.

78.3 ± 2.4 in.

98.4 ± 3.0 in.

77.2 ± 1.5 in.

12.2 ± 0.4 in.

2.6 ± 0.3 km/h

1.62 ± 0.2 mph

4.6 ± 0.5 km/h

2.86 ± 0.3 mph

1045 ± 21 mm

41.1 ± 0.8 in.

629 ± 12.6 mm

24.8 ± 0.5 in.

30 ° <

Hill-climbing stance,
E/G Max speed

Including bottom plate

G-22

U48-4,U55-4, WSM

KiSC issued 03, 2010 A

GENERAL

Item

Front attachment

• Bucket heaped capacity

• Bucket struck capacity

• Bucket width

• Swing angle

• Max. digging radius

• Ground level Max. digging
radius

SAE, JIS

ROPS L

ROPS R

CAB L

CAB R

Factory Specification

U48-4 U55-4

0.16 ± 0.006 m

0.2 ± 0.008 yd

0.11 ± 0.004 m

0.1 ± 0.006 yd

3

3

3

3

550 ± 11 mm

21.7 ± 0.4 in.

71 ± 2 °

54 ± 2 °

5850 ± 88 mm

230.3 ± 3 in.

5710 ± 86 mm

224.8 ± 3 in.

0.16 ± 0.006 m

0.2 ± 0.008 yd

0.12 ± 0.005 m

0.2 ± 0.006 yd

600 ± 12 mm

23.6 ± 0.5 in.

71 ± 2 °

54 ± 2 °

6105 ± 92 mm

240.4 ± 4 in.

5960 ± 89 mm

234.6 ± 4 in.

3

Slope angle : 1×1

3

3

3

Without side cutter

0 ° swing

0 ° swing

Remarks

• Ground level Min. finish
radius

• Max. digging depth

• Max. vertical digging depth

• Max. digging height

• Max. dump height

ROPS

CAB

ROPS

CAB

1975 ± 40 mm

77.8 ± 2 in.

3380 ± 68 mm

133.1 ± 3 in.

2670 ± 80 mm

105.1 ± 3 in.

–

5440 ± 109 mm

214.2 ± 4 in

–

3770 ± 75 mm

148.4 ± 3 in.

2045 ± 41 mm

80.5 ± 2 in.

3630 ± 73 mm

142.9 ± 3 in.

2830 ± 85 mm

111.4 ± 3 in.

–

5665 ± 113 mm

223.0 ± 4 in.

–

4005 ± 80 mm

157.7 ± 3 in.

0 ° swing
Bucket bottom
horizontal

G-23

U48-4,U55-4, WSM

KiSC issued 03, 2010 A

GENERAL

Front attachment

• Max. dump height
(Arm vertical)

• Min. turning radius

• Min. turning radius
(Left swing)

Blade

• Width (STD)

•Height (STD)

Item

ROPS

CAB

ROPS

CAB

ROPS

CAB

Factory Specification

U48-4 U55-4

–

1425 ± 43 mm

56.1 ± 2 in.

–

2390 ± 72 mm

94.1 ± 3 in.

–

1960 ± 59 mm

77.2 ± 2 in.

1960 ± 5 mm

77.2 ± 0.2 in.

408 ± 10 mm

16.1 ± 0.4 in.

Remarks

–

1825 ± 55 mm

71.9 ± 2 in.

–

2460 ± 74 mm

96.9 ± 3 in.

–

2020 ± 61 mm

79.5 ± 2 in.

1960 ± 5 mm

77.2 ± 0.2 in.

408 ± 10 mm

16.1 ± 0.4 in.

• Max. lift above GL (STD)

440 ± 50 mm

440 ± 50 mm

17.3 ± 2 in.

• Max. below GL (STD)

410 ± 50 mm

410 ± 50 mm

16.1 ± 2 in.

Bucket tooth slaggish 73 mm >

2.87 in. >

Front boom lateral declination 10 mm >

0.39 in. >

Blade's lateral declination 10 mm >

0.39 in. >

Clearance between bucket crow
and boom cylinder cover

100 ± 19 mm

4.72 ± 0.7 in.
Approach angle STD 30 ± 3 °
Crawler height 523 ± 10 mm

20.59 ± 0.4 in.

Max. crawler height 555 ± 11 mm

21.85 ± 0.4 in.

17.3 ± 2 in.

16.1 ± 2 in.
Without shockless

F=30 kgf (66 lbf)

Boom max. height,
Arm crowd

Include grouser height
of the crawler

G-24

U48-4,U55-4, WSM

KiSC issued 03, 2010 A

Engine performance

Max, engine rpm

• no load

Item

Factory Specification

U48-4 U55-4

2400 rpm >

2400 rpm >

GENERAL

Remarks

• 2 pump relief
(Variable displacement pump)

• Blade + 2 pump relief

1980 rpm <

(1 pump relief)

–

(Variable displacement pump)

• Idling RPM 1125 ± 75 rpm

Travelling performance

Factory Specification

U48-4 U55-4

0 mm

0 in.

0 mm

Travel motor block
performance

Item

L

R

0 in.

Max, Traction force F1

3426 kgf <

33.6 kN <
7554 lbf <

1980 rpm <

1980 rpm <

0 mm

0 in.

0 mm

0 in.

4140 kgf <

40.6 kN <
9127 lbf <

Arm and bucket Slow
operation to relief,
Oil temp. : 50 ± 5 °C
(122 ± 9 °F)

Blade relief, Arm and
bucket Slow operation
to relief, Oil temp. :
50 ± 5 °C (122 ± 9 °F)

Remarks

20 deg. slope, 10 min,
Engine stop
Oil temp. : 50 ± 5 °C
(122 ± 9 °F)
With parking brake

Slip 70% theoretical
torque Travel stance,
Oil temp. : 50 ± 5 °C
(122 ± 9 °F)

F2

Travel straightness F1

F2

Travel straightness Blade F1

Blade R1

Track shoe sag distance Steel

Rubber

–

600 mm >

23.62 in. >

600 mm >

23.62 in. >
600 mm >

23.62 in. >

600 mm >

23.62 in. >

80 to 85 mm

3.15 to 3.35 in.

10 to 15 mm

0.39 to 0.59 in.

–

600 mm >

23.62 in. >

600 mm >

23.62 in. >
600 mm >

23.62 in. >

600 mm >

23.62 in. >

80 to 85 mm

3.15 to 3.35 in.

10 to 15 mm

0.39 to 0.59 in.

Data N/A, traveling
speed reduce to low
range.

Travel stance, 10 m
(394 in.) distance
Engine Max. speed
Oil temp. : 50 ± 5 °C
(122 ± 9 °F)

Travel stance, Blade up
and down 10 m (394 in.)
distance
Engine Max. speed
Oil temp. : 50 ± 5 °C
(122 ± 9 °F)

G-25

U48-4,U55-4, WSM

KiSC issued 03, 2010 A

Work performance

Item

Factory Specification

U48-4 U55-4

Arm digging force 2131 kgf <

20.9 kN <
4699 lbf <

Bucket digging force 3192 kgf <

31.3 kN <
7037 lbf <

Blade force Down 3314 kgf <

32.5 kN <
7306 lbf <

Boom speed (ROPS)

• Up (Ground to max. up)

• Up (max. down to max. up)

• Down (max. up to Ground)

–

–

–

2770 kgf <

23.3 kN <

5238 lbf <

4315 kgf <

40.2 kN <
9037 lbf <

3952 kgf <

36.8 kN <
8273 lbf <

–

–

–

GENERAL

Remarks

Bucket tooth root
[Arm cylinder length :
1403 mm (55.2 in.)]

Bucket tooth root
[Bucket cylinder length
:1098 mm (43.2 in.)]

Cutting edge down
force at ground level

Arm extend.
bucket dump with no
load.
Oil temp. 50 ± 5 °C
(122 ± 9 °F)
exclude cushioning

• Down (max. up to max. down)

Boom speed (CAB)

• Up (Ground to max. up)

• Up (max. down to max. up)

• Down (max. up to Ground)

• Down (max. up to max. down)

Arm speed Crowd

Dump

Bucket speed Crowd

Dump

Blade speed Up

(Ground to
max. up)

Up (max.
down to
max. up)

Down
(max. up to
Ground)

–

2.7 ± 0.3 sec.

4.5 ± 0.3 sec.

3.1 ± 0.3 sec.

4.9 ± 0.3 sec.

3.2 ± 0.3 sec.

2.8 ± 0.3 sec.

2.9 ± 0.3 sec.

2.2 ± 0.3 sec.

1.1 ± 0.3 sec.

2.4 ± 0.3 sec.

1.5 ± 0.3 sec.

–

2.7 ± 0.3 sec.

4.5 ± 0.3 sec.

3.4 ± 0.3 sec.

4.9 ± 0.3 sec.

3.2 ± 0.3 sec.

2.8 ± 0.3 sec.

3.0 ± 0.3 sec.

2.1 ± 0.3 sec.

1.1 ± 0.3 sec.

2.2 ± 0.3 sec.

1.5 ± 0.3 sec.

Cylinder full stroke
Oil temp. 50 ± 5 °C
(122 ± 9 °F)

Cylinder full stroke
Oil temp. 50 ± 5 °C
(122 ± 9 °F)

Cylinder full stroke
Oil temp. 50 ± 5 °C
(122 ± 9 °F)

Arm cylinder cavitation 5 mm >

Down(max.
up to max.
down)

2.3 ± 0.3 sec.

G-26

0.2 in. >

2.9 ± 0.3 sec.

Oil temp. 50 ± 5 °C
(122 ± 9 °F)
Engine speed :
1300 rpm
Bucket loaded at
heaped.

U48-4,U55-4, WSM

KiSC issued 03, 2010 A

GENERAL

Item

Max. digging height radius ROPS

CAB

Max. dump height radius ROPS

CAB

Bucket bottom height at arm

ROPS

3285 ± 329 mm

129.3 ± 12.9 in.

3420 ± 205 mm

134.6 ± 8.1 in.

Factory Specification

U48-4 U55-4

–

–

3430 ± 343 mm

135.0 ± 13.5 in.

–

–

3550 ± 213 mm

139.8 ± 8.4 in.

–

–

vertical

CAB

1790 ± 54 mm

70.5 ± 2.1 in.

1825 ± 55 mm

71.9 ± 2.2 in.

Bucket wrist angle 184.5 ± 3.0 ° 185.0 ± 3.0 °

Remarks

at bucket pin

Bucket horizontal Boom
max. height, Arm dump
max.

G-27

U48-4,U55-4, WSM

KiSC issued 03, 2010 A

Swivel, swing performance

Item

Swivel torque

Swivel capable slope angle L

Swivel block performance
(with negative break)

• Engine stop

• Engine idling

GENERAL

Factory Specification

U48-4 U55-4

L

1237 kgf·m <

12.1 kN·m <
8947 lbf·ft <

1237 kgf·m <

12.1 kN·m <
8947 lbf·ft <

Arm extend, Quick
operation
Engine Max. speed

Remarks

Oil temp. : 50 ± 5 °C

R

1237 kgf·m <

12.1 kN·m <
8947 lbf·ft <

17 ° <

1237 kgf·m <

12.1 kN·m <
8947 lbf·ft <

17 ° <

(122 ± 9 °F)

Front horizontal, Bucket
load heaped [420 kg

R

17 ° <

17 ° <

(926 lbs) : including
bucket], Engine Max.
speed, Oil temp.:
50 ± 5 °C (122 ± 9 °F)

Bucket load heaped
[420kg (926 lbs) :

L

5 ° >

5 ° >

including bucket],
Slope angle at

R

5 ° >

5 ° >

L

20 degrees for 1 min.
Engine stop.
Oil temp. : 50 ± 5 °C
(122 ± 9 °F)

R

30 ° >

30 ° >

Swivel start-up speed L

R

Swing speed (ROPS) L

R

Swing speed (CAB) L

R

Swing Lock Swivel

R and L

30 ° >

2.8 ± 0.3 sec.

2.8 ± 0.3 sec.

5.5 ± 0.5 sec.

6.4 ± 0.5 sec.
10 mm >

0.39 in. >

30 ° >

2.8 ± 0.3 sec.

2.8 ± 0.3 sec.

6.5 ± 0.5 sec.

7.9 ± 0.5 sec.

Front horizontal, 90 °
swivel Bucket load
heaped [420 kg
(926 lbs) : including
bucket].
Engine Max. Speed
Oil temp. : 50 ± 5 °C
(122 ± 9 °F)

Front horizontal, bucket
crowd with no load.
Engine Max. speed
Oil temp. : 50 ± 5 °C
(122 ± 9 °F)

90 ° swivel, 100 times
actual
Bucket load heaped
[420 kg (926 lbs) :
including bucket].
Oil temp. : 50 ± 5 °C
(122 ± 9 °F)

G-28

U48-4,U55-4, WSM

KiSC issued 03, 2010 A

Hydraulic performance

Item

Cylinder oil sealing capacity (Boom)

• 50 ± 5 °C (122 ± 9 °F)

• 95 ± 5 °C (203 ± 9 °F)

Cylinder oil sealing capacity (Arm)

• 50 ± 5 °C (122 ± 9 °F)

Cylinder oil sealing capacity (Bucket)

• 50 ± 5 °C (122 ± 9 °F)

Cylinder oil sealing capacity (Blade)

• 50 ± 5 °C (122 ± 9 °F)

Boom cushioning performance

• 30 °C (86 °F)

• 50 °C (122 °F)

Factory Specification

U48-4 U55-4

20 mm >

0.79 in. >

20 mm >

0.79 in. >
20 mm >

0.79 in. >
10 mm >

0.39 in. >
20 mm >

0.79 in. >

3 sec. >

0.4 to 1.3 sec.

0.4 to 1.3 sec.

20 mm >

0.79 in. >

20 mm >

0.79 in. >

3 sec. >

GENERAL

Remarks

Arm extend. Bucket
crowd for 10 min.
Bucket load heaped
[420 kg (926 lbs) :
including bucket].

Arm vertical.
blade cylinder extended
for 10 min. engine stop.

Arm extended, bucket
crowd with no load.
Engine Max. speed.

• 80 °C (176 °F)

Lever operating force and stroke

Item

Boom lever Up

Down

Arm lever Crowd

Dump

Bucket lever Crowd

Dump

Swivel lever R

0.3 sec. <

Factory Specification

U48-4 U55-4

1.2 ± 0.5 kgf

1.2 ± 0.5 kgf

12 ± 5 N

2.7 ± 1.1 lbf

1.4 ± 0.5 kgf

2.7 ± 1.1 lbf

1.4 ± 0.5 kgf

14 ± 5 N

3.1 ± 1.1 lbf

1.2 ± 0.5 kgf

3.1 ± 1.1 lbf

1.2 ± 0.5 kgf

12 ± 5 N

2.7 ± 1.1 lbf

1.4 ± 0.5 kgf

2.7 ± 1.1 lbf

1.4 ± 0.5 kgf

14 ± 5 N

3.1 ± 1.1 lbf

1.0 ± 0.5 kgf

3.1 ± 1.1 lbf

1.0 ± 0.5 kgf

10 ± 5 N

2.2 ± 1.1 lbf

1.0 ± 0.5 kgf

2.2 ± 1.1 lbf

1.0 ± 0.5 kgf

9 ± 5 N

2.0 ± 1.1 lbf

1.0 ± 0.5 kgf

2.2 ± 1.1 lbf

1.0 ± 0.5 kgf

10 ± 5 N

2.2 ± 1.1 lbf

2.2 ± 1.1 lbf

0.3 sec. <

12 ± 5 N

14 ± 5 N

12 ± 5 N

14 ± 5 N

10 ± 5 N

10 ± 5 N

N

± 5

10

Remarks

Measuring point :
20 mm (0.79 in.) lower
from the lever top.
Pilot lever with engine
Max. speed.

L

1.0 ± 0.5 kgf
10 ± 5 N

2.2 ± 1.1 lbf

1.0 ± 0.5 kgf
10 ± 5

2.2 ± 1.1 lbf

G-29

U48-4,U55-4, WSM

KiSC issued 03, 2010 A

em

It

Blade lever Up

Down

Travel lever (L) Forward

Fac

tory Specification

U48-4 U55-4

1.6 ± 0.5 kgf
16 ± 5 N

3.6 ± 1.1 lbf

1.6 ± 0.5 kgf
16 ± 5 N

3.6 ± 1.1 lbf

1.9 ± 0.5 ± kgf
19 ± 5 N

4.3 ± 1.1 lbf

1.6 ± 0.5 kgf
16 ± 5 N

3.6 ± 1.1 lbf

1.6 ± 0.5 kgf
16 ± 5 N

3.6 ± 1.1 lbf

1.9 ± 0.5 kgf
19 ± 5 N

4.3 ± 1.1 lbf

GENERAL

Remarks

Up and down
Measuring point :
15 mm (0.59 in.) lower
from the lever top

Measuring point :
20 mm (0.79 in.) lower
from the lever top.

Back

Travel lever (R) Forward

Back

Swing pedal R

L

Safety lock lever (L) Up

Down

1.9 ± 0.5 kgf
19 ± 5 N

4.3 ± 1.1 lbf

1.9 ± 0.5 kgf
19 ± 5 N

4.3 ± 1.1 lbf

1.9 ± 0.5 kgf
19 ± 5 N

4.3 ± 1.1 lbf

6.0 ± 1.0 kgf

59 ± 10 N

13.3 ± 2.2 lbf

6.0 ± 1.0 kgf

59 ± 10 N

13.3 ± 2.2 lbf

2.8 ± 1.0 kgf

27 ± 10 N

6.1 ± 2.2 lbf

7.0 ± 1.0 kgf

69 ± 10 N

15.5 ± 2.2 lbf

1.9 ± 0.5 kgf
19 ± 5 N

4.3 ± 1.1 lbf

1.9 ± 0.5 kgf
19 ± 5 N

4.3 ± 1.1 lbf

1.9 ± 0.5 kgf
19 ± 5 N

4.3 ± 1.1 lbf

6.0 ± 1.0 kgf

59 ± 10 N

13.3 ± 2.2 lbf

6.0 ± 1.0 kgf

59 ± 10 N

13.3 ± 2.2 lbf

2.8 ± 1.0 kgf

27 ± 10 N

6.1 ± 2.2 lbf

7.0 ± 1.0 kgf

69 ± 10 N

15.5 ± 2.2 lbf

Pedal edge.
45 ° inward

Travel Hi-Lo change – – This machine has a

switch.

Boom lever stroke Up

84 ± 10 mm

3.31 ± 0.4 in.

84 ± 10 mm

3.31 ± 0.4 in.

Measuring point :
The lever top.
Pilot lever with engine

Down

Arm lever stroke Crowd

84 ± 10 mm

3.31 ± 0.4 in.
84 ± 10 mm

3.31 ± 0.4 in.

84 ± 10 mm

3.31 ± 0.4 in.
84 ± 10 mm

3.31 ± 0.4 in.

Max. speed.

Dump

84 ± 10 mm

3.31 ± 0.4 in.

G-30

84 ± 10 mm

3.31 ± 0.4 in.

U48-4,U55-4, WSM

KiSC issued 03, 2010 A

GENERAL

Item

Bucket lever stroke Crowd

Dump

Bucket lever stroke R

L

Blade lever stroke Up

Down

Travel lever stroke (L) Forward

Back

Travel lever stroke (R) Forward

Factory Specification

U48-4 U55-4

74 ± 10 mm

2.91 ± 0.4 in.

74 ± 10 mm

2.91 ± 0.4 in.
74 ± 10 mm

2.91 ± 0.4 in.

74 ± 10 mm

2.91 ± 0.4 in.
60 ± 10 mm

2.36 ± 0.4 in.

60 ± 10 mm

2.36 ± 0.4 in.

100 ± 10 mm

3.94 ± 0.4 in.

100 ± 10 mm

3.94 ± 0.4 in.

100 ± 10 mm

3.94 ± 0.4 in.

74 ± 10 mm

2.91 ± 0.4 in.

74 ± 10 mm

2.91 ± 0.4 in.
74 ± 10 mm

2.91 ± 0.4 in.

74 ± 10 mm

2.91 ± 0.4 in.
60 ± 10 mm

2.36 ± 0.4 in.

60 ± 10 mm

2.36 ± 0.4 in.

100 ± 10 mm

3.94 ± 0.4 in.

100 ± 10 mm

3.94 ± 0.4 in.

100 ± 10 mm

3.94 ± 0.4 in.

Remarks

Measuring point :
The lever top.
Pilot lever with engine
Max. speed.

Measuring point :
The lever top.

Back

100 ± 10 mm

3.94 ± 0.4 in.

100 ± 10 mm

3.94 ± 0.4 in.

RY9212052GEG0005US0

G-31

U48-4,U55-4, WSM

NOTE

KiSC issued 03, 2010 A

Main Dimension

GENERAL

U48-4 U55-4 U48-4 U55-4 U48-4 U55-4

(1)

(2)

(3)

(4)

(5)

(6)

(7)

990 mm

39.0 in.

5440 mm

214.2 in.

815 mm

32.1 in.

625 mm

24.6 in.

1960 mm

77.2 in.

1830 mm

72.0 in.

1960 mm

77.2 in.

1045 mm

44.1 in.

5665 mm

223.0 in.

(8)

(9)

(10)

(11)

(12)

(13)

(14)

3770 mm

148.4 in.

3380 mm

133.1 in.

2670 mm

105.1 in.

2390 mm

94.09 in.
2550 mm

100.4 in.
440 mm

17.3 in.

410 mm

16.2 in.

4005 mm

157.7 in.

3630 mm

142.9 in.

2830 mm

111.4 in.

2460 mm

96.9 in.

(15)

(16)

(17)

(18)

(19)

• Above dimensions are based on the machine with KUBOTA original bucket.

• Above dimensions are based on the machine with rubber track.

• Specifications subject to change without notice.

5330 mm

209.8 in.

5710 mm

224.8 in.

5850 mm

230.3 in.

2500 mm

98.43 in.

1820 mm

71.65 in.
5500 mm

216.5 in.

5960 mm

234.6 in.

6105 mm

240.4 in.

RY9212052GEG0006US0

G-32

U48-4,U55-4, WSM

KiSC issued 03, 2010 A

9. WATER AND OIL QUANTITY

U48-4 U55-4 Remarks

Radiator

Reserve tank

Engine crank case

Full

Hydraulic oil

Tank

Travel motor

Track roller

Carrier roller

Front idler

Fuel tank

7.0 L

1.85 U.S.gal

1.1 L

0.29 U.S.gal

9.0 L

2.38 U.S.gal
79 L

20.87 U.S.gal
45 L

11.89 U.S.gal

0.9 L

0.24 U.S.gal
80 ml

4.88 cu.in
60 ml

3.66 cu.in
50 ml

3.05 cu.in

68 L

18.0 U.S.gal

GENERAL

KUBOTA LLC-N-50F 50%

SAE 10W-30 (CF or CI-4)

ISO VG46

ISO VG46

SAE90 (API GL-4)

SAE30 (CD)

SAE30 (CD)

SAE30 (CD)

Diesel Fuel JIS #3 (Initial)

RY9212052GEG0007US0

G-33

U48-4,U55-4, WSM

KiSC issued 03, 2010 A

10.DESCRIPTION OF PARTS

[1] BUCKET

(1) Bucket dimensions

NOTE : KUBOTA JAPAN BUCKET

GENERAL

(To be continued)

G-34

U48-4,U55-4, WSM

KiSC issued 03, 2010 A

GENERAL

(Continued)

No. U48-4 U55-4 No. U48-4 U55-4 No. U48-4 U55-4 No. U48-4 U55-4 No. U48-4 U55-4

(1)

(2)

(3)

(4)

(5)

(6)

(7)

550 mm

21.65 in.
600 mm

23.62 in.

600 mm

23.62 in.
650 mm

25.59 in.

247 mm

9.72 in.

145 mm

5.71 in.
65 mm

2.56 in.
35 mm

1.38 in.
16 mm

0.63 in.

(8)

(9)

(10)

(11)

(12)

(13) M16 x 1.5 x 2.5 (20)

(14)

83 mm

3.27 in.

100 mm

39.4 in.
45 mm

1.77 in.
45 mm

1.77 in.
28 mm

1.10 in.

483 mm

19.02 in.

(15)

(16)

(17)

(18)

(19)

(21)

12 mm

0.47 in.

743 mm

29.25 in.
30 mm

1.18 in.

230 mm

9.06 in.

150 mm

5.91 in.
72 mm

2.83 in.

m

m

98

3.86 in.

(22)

(23)

(24)

(25)

(26)

(27)

(28)

180 mm

28.5 mm

156 mm

6.14 in.

78.5 mm

3.09 in.
173 mm

7.09 in.
5 mm

0.20 in.

16 mm

0.63 in.

1.12 in.

6.81 in.

173 mm

6.81 in.
87 mm

3.41 in.

(29)

(30)

(31)

(32)

(33)

(34)

(35)

RY9212052GEG0008US0

80 mm

3.15 in.
35 mm

1.38 in.
80 mm

3.15 in.

165 mm

6.50 in.

1.5 mm

0.06 in.

165 mm

6.50 in.

849 mm

33.43 in.

(2) Bucket installation relevant dimensions

(A) Arm tip (B) Bucket, link 1

No. U48-4 U55-4 No. U48-4 U55-4 No. U48-4 U55-4 No. U48-4 U55-4

(1)

(2)

(3)

(4)

(5)

1250 mm

49.21 in.
338 mm

13.31 in.
217 mm

7.60 in.

350 mm

13.78 in.

200 mm

7.87 in.
1370 mm

53.94 in.
353 mm

13.90 in.
193 mm

7.60 in.

335 mm

13.19 in.

(6)

(7)

(8)

(9)

(10)

1343 mm

52.87 in.
315 mm

12.40 in.
335 mm

13.19 in.

10 mm

0.39 in.

145 mm

5.71 in.

1360 mm

53.54 in.

G-35

(11)

(12)

(13)

(14)

(15)

133 mm

5.24 in.

145 mm

5.71 in.
45 mm

1.77 in.
45 mm

1.77 in.

145 mm

5.71 in.

(16)

(17)

(18)

(19)

145 mm

5.71 in.
61 mm

2.40 in.
45 mm

1.77 in.
45 mm

1.77 in.

RY9212052GEG0009US0

U48-4,U55-4, WSM

KiSC issued 03, 2010 A

[2] RUBBER CRAWLER

U48-4 U55-4

Identification mark
(Core metal lapping position)

(1) Lug height

(2) Link height

(3) Crawler width

(4) Crawler sag distance

(5) Crawler height

Number of core metal 74

Circumference

Core metal pitch

24 mm

0.94 in.

88.0 mm

3.46 in.

19 mm

0.75 in.

400 mm

15.75 in.

10 to 15 mm

0.39 to 0.59 in.

5365 mm

211.2 in.

72.5 mm

2.85 in.

RY9212052GEG0010US0

GENERAL

∞

25 mm

0.96 in.

91.0 mm

3.58 in.

[3] STEEL CRAWLER

STD Wide

Crawler width

(1) 4 links length

(2) Height

(3) Bushing O. D.

(4) Bushing I. D.

(5) Master pin O. D.

(6) Grouser height

(7) Crawler sag distance

Number of links 39

400 mm

15.75 in.
540 mm

21.26 in.

67.0 mm

2.64 in.

35.0 mm

1.38 in.

22.5 mm

0.89 in.

22.15 mm

0.87 in.

20.0 mm

0.79 in.

80 to 85 mm

3.15 to 3.35 in.

RY9212052GEG0011US0

550 mm

21.65 in.

G-36

U48-4,U55-4, WSM

KiSC issued 03, 2010 A

[4] TRUCK ROLLER, IDLER, SPROCKET

(1) Guide diameter

(2) Outer diameter

(3) Roller width

(4) Carrier roller diameter

(A) Truck roller (B) Carrier roller

GENERAL

Remarks

85 mm

3.35 in.

135 mm

5.31 in.

200 mm

7.87 in.
80 mm

3.15 in.

RY9212052GEG0012US0

(1) Idler O.D.

(2) Guide width

(3) Idler width

(4) Sprocket wheel O.D.

(5) Sprocket wheel width

(A) Idler (B) Sprocket

300 mm

12.99 in.
52 mm

2.05 in.

93 mm

3.66 in.
429 mm

16.89 in.

43 mm

1.69 in.

Remarks

RY9212052GEG0013US0

G-37

U48-4,U55-4, WSM

KiSC issued 03, 2010 A

[5] CYLINDER

Max. retraction length (stroke)

GENERAL

Boom

Arm

Bucket

Swing

Blade

U48-4

U55-4

U48-4

U55-4

U48-4

U55-4

U48-4

U55-4

U48-4

U55-4

(1)(2)(3)(4)(5)(6)(7)(8)(9)

50 mm

1.97 in.
55 mm

2.17 in.
45 mm

1.77 in.
50 mm

1.97 in.
45 mm

1.77 in.
45 mm

1.77 in.
45 mm

1.77 in.
45 mm

1.77 in.
55 mm

2.17 in.
55 mm

2.17 in.

50 mm

1.97 in.
55 mm

2.17 in.
45 mm

1.77 in.
50 mm

1.97 in.
45 mm

1.77 in.
45 mm

1.77 in.
45 mm

1.77 in.
45 mm

1.77 in.
55 mm

2.17 in.
55 mm

2.17 in.

70 mm

2.76 in.
70 mm

2.76 in.
70 mm

2.76 in.
70 mm

2.76 in.
60 mm

2.36 in.
60 mm

2.36 in.
60 mm

2.36 in.
60 mm

2.36 in.
70 mm

2.76 in.
70 mm

2.76 in.

70 mm

2.76 in.
70 mm

2.76 in.
70 mm

2.76 in.
70 mm

2.76 in.
60 mm

2.36 in.
60 mm

2.36 in.
60 mm

2.36 in.
60 mm

2.36 in.
70 mm

2.76 in.
70 mm

2.76 in.

50 mm

1.97 in.
55 mm

2.17 in.
50 mm

1.97 in.
55 mm

2.17 in.
40 mm

1.57 in.
45 mm

1.77 in.
45 mm

1.77 in.
50 mm

1.97 in.
55 mm

2.17 in.
60 mm

2.36 in.

90 mm

3.54 in.
95 mm

3.74 in.
80 mm

3.15 in.
85 mm

3.35 in.
70 mm

2.76 in.
75 mm

2.95 in.
85 mm

3.35 in.
90 mm

3.54 in.
95 mm

3.74 in.

110 mm

4.33 in.

108 mm

4.25 in.

117 mm

4.61 in.
96 mm

3.78 in.

105 mm

4.13 in.
85 mm

3.35 in.
91 mm

3.58 in.

102 mm

4.02 in.

107 mm

4.21 in.

114 mm

4.49 in.

131 mm

5.16 in.

49 mm

1.03 in.
55 mm

2.17 in.
49 mm

1.03 in.
55 mm

2.17 in.
42 mm

1.6

in.

5

40 mm

1.57 in.
49 mm

1.03 in.
49 mm

1.03 in.
55 mm

2.17 in.
55 mm

in.

2.17

50 mm

1.97 in.
50 mm

1.97 in.
50 mm

1.97 in.
50 mm

1.97 in.
39 mm

1.54 in.
40 mm

1.57 in.
50 mm

1.97 in.
50 mm

1.97 in.
55 mm

2.17 in.
56 mm

2.20 in.

RY9212052GEG0014US0

Port screw

size

PF 1/2"

PF 1/2"

PF 1/2"

PF 1/2"

PF 1/2"

PF 1/2"

G 1/4"

G 1/4"

G 3/8"

G 3/8"

G-38

U48-4,U55-4, WSM

KiSC issued 03, 2010 A

[6] PARTS WEIGHT

Track frame

Swivel frame

Swing bracket

Boom

Arm (STD)

Bucket

Blade

Weight (rear)

Rubber crawler

Steel crawler (STD.)

Steel crawler (wide) –

Arch frame

Engine

Hydraulic tank

Fuel tank

Swivel bearing

Battery

Track roller

Upper roller

ROPS/FOPS cabin

Hydraulic pump

Traveling motor

Swivel motor

Sprocket

Idler ass'y

Control valve

Boom cylinder

Arm cylinder

246.9 lbs

379.2 lbs

235.9 lbs

632.7 lbs

584.2 lbs

137.0 lbs

130.0 lbs

106.0 lbs

U48-4 U55-4 Remarks

566 kg

1248 lbs

543 kg

1197 lbs

112.0 kg

172.0 kg

92 kg

203 lbs

107.0 kg

287.0 kg

265.0 kg

62.0 kg

34.0 kg

75.0 lbs

59.0 kg

48.0 kg

45.0 kg

99.2 lbs

241.0 kg

531.3 lbs

285.0 kg

628.3 lbs

51.0 kg

112.4 lbs

225.0 kg

496.0 lbs

38.0 kg

83.8 lbs

4.2 kg

9.3 lbs

22.7 kg

49.9 lbs

9.4 kg

20.7 lbs

3.3 kg

7.2 lbs

225.0 kg

496.0 lbs

50.0 kg

110.2 lbs

15.3 kg

33.8 lbs

46.4 kg

102.3 lbs
9

.5 kg

5

131.2 lbs

615 kg

1355.8 lbs
585 kg

1290 lbs

121.0 kg

266.8 lbs

208.0 kg

458.6 lbs
102 kg

224.9 lbs

110.0 kg

244.7 lbs

698 kg

1539 lbs

240.0 kg

529.1 lbs

385.0 kg

848.8 lbs

68.6 kg

151.2 lbs

42.0 kg

92.6 lbs

58.0 kg

127.9 lbs

60.0 kg

132.3 lbs

56.0 kg

123.5 lbs

Without teeth and side cutter

Dry weight

With filter

Without adaptors

GENERAL

G-39

U48-4,U55-4, WSM

KiSC issued 03, 2010 A

U48-4 U55-4 Remarks

Bucket cylinder

Swing cylinder

Blade cylinder

Rotary joint

26.0 kg

57.3 lbs

37.3 kg

82.2 lbs

28.6 kg

63.1 lbs

27.7 kg

61.1 lbs

32.0 kg

70.5 lbs

36.5 kg

80.5 lbs

The above weight list is based on calculation and slightly different from actual ones.

GENERAL

RY9212052GEG0015US0

G-40

U48-4,U55-4, WSM

KiSC issued 03, 2010 A

11.MAINTENANCE CHECK LIST

Operator Service

General

Maintenance

Check the fuel level daily
Check the coolant level daily
Checking the engine oil level daily
Check the hydraulic oil level daily
Grease the bucket bolt and

bucket linkage bolt
Check the V-belt daily
Check the fluid level of the

washer system reservoir
Check the electric cables and

connections
Clean the radiator and

condenser
Lubricate the front-end

attachments :
Grease the swing bracket
Other greasing points

Check the water separator PPPPPPPPPPPPPPPPPPP P 50 h
Drain water from the fuel tank PPPPPPPPPPPPPPPPPPP P 50 h
Check the battery electrolyte

level
Crawlers and track frame:

Clean, visually inspect and check
tension

Grease the swivel gear PPPPPPPPPPPPPPPPPPP P 50 h
Grease the pitch bearing PPPP P200 h
Check and clean the interior air

*1

filter

*1 Check, clean the air filter PPPP P200 h

Check the coolant hoses and
hose clamps

Check the fuel lines and air
intake hoses

Check the pipes and hoses of
the air conditioner

*1 : Under very dusty conditions, the air filter and the interior air filter must be cleaned more frequently or replaced.

50 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800 850 900 950 1000

PPPPPPPPPPPPPPPPPPP P 50 h

PPPPPPPPPPPPPPPPPPP P 50 h

PPPP P200 h

PPPP P200 h

PPPP P200 h

Elapsed Operating Hours

Interval

daily

daily

daily

daily

daily

annually

GENERAL

G-41

U48-4,U55-4, WSM

KiSC issued 03, 2010 A

GENERAL

Servicing by skilled personnel or KUBOTA dealer

General

Maintenance

Check the coolant hoses and
hose clamps

Replace the coolant hoses and

*3

hose clamps
Replace the fuel lines and air

*3

intake hoses
Check and adjust the V-belt PPP P250 h
Change the engine oil and oil

filter

*4 Replace the drive unit oil OP P500 h

Replace the fuel filter PP500 h
Replace the tank breather filter PP500 h

*2 Replace the return filter P 1000 h

Replace the pilot circuit filter P 1000 h
Change the hydraulic oil and

*2

replace the suction filter
*1 Replace the air filter elements P 1000 h
*1 Replace the interior air filter P 1000 h

Change the oil of the idler and
*3

track roller

Check alternator and starter
*3

motor

Replace the pipes and hoses of
*3

the air conditioner

Replace the coolant

*3 Change the hydraulic hoses

Check the coolant content

*5 Safety inspection annually

The servicing identified with O must be carried after the specified hours of operation after initial operation have been reached.
*1 : Under very dusty conditions, the air filter and the interior air filter must be cleaned more frequently or replaced.
*2 : When using a hydraulic hammer over 20 % → every 800 h.

When using a hydraulic hammer over 40 % → every 400 h.
When using a hydraulic hammer over 60 % → every 300 h.

When using a hydraulic hammer over 80 % → every 200 h.
*3 : Please contact your KUBOTA dealer.
*4 : Earlier if necessary.
*5 : At least annually.

50 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800 850 900 950 1000

PPP P250 h

Elapsed Operating Hours

PP500 h

Interval

every

2 years

every

2 years

P 1000 h

2000 h

2000 h

every

2 years

every

2 years

every

6 years
mainte-

nance on

demand

RY9212032GEG0005US0

G-42

1 MACHINE BODY

KiSC issued 03, 2010 A

SERVICING

KiSC issued 03, 2010 A

CONTENTS

1. FRONT OPERATING MACHINE.................................................................................................1-S1

[1] BLADE...................................................................................................................................1-S1

(1) Blade dimension..............................................................................................................1-S1

[2] FRONT PIN ...........................................................................................................................1-S2

2. SWIVEL FRAME..........................................................................................................................1-S3

[1] WEIGHT DIASSEMBLY / ASSEMBLY..................................................................................1-S3

[2] FUEL TANK...........................................................................................................................1-S5

[3] HYDRAULIC OIL TANK ........................................................................................................1-S8

(1) Hydraulic oil tank components.........................................................................................1-S8

(2) Hydraulic oil return filter replacement procedure.............................................................1-S9

(3) Filter (suction) replacement procedure..........................................................................1-S10

(4) Filter (breather) replacement procedure........................................................................1-S11

(5) Assembly of anti vibration support for the hydraulic oil tank..........................................1-S12

[4] ENGINE...............................................................................................................................1-S13

(1) Engine mount ................................................................................................................1-S13

(2) Muffler............................................................................................................................1-S14

(3) Arch, Air cleaner............................................................................................................1-S15

(4) Radiator.........................................................................................................................1-S16

(5) Oil cooler .......................................................................................................................1-S17

(6) Accelerator cable...........................................................................................................1-S18

[5] ASSEMBLING OF OPERATING LEVERS..........................................................................1-S19

(1) Travel lever....................................................................................................................1-S19

(2) Blade lever.....................................................................................................................1-S20

3. TRACK FRAME.........................................................................................................................1-S21

[1] ASSEMBLING OF SWIVEL BEARING ...............................................................................1-S21

[2] TRACK ................................................................................................................................1-S23

(1) Assembly / disassembly of rubber track........................................................................1-S23

(2) Assembly / disassembly of iron tracks...........................................................................1-S24

[3] FRONT IDLER.....................................................................................................................1-S27

(1) Assembly / disassembly of front idler ............................................................................1-S27

(2) Front idler structural components..................................................................................1-S27

[4] SPRING ASSY ....................................................................................................................1-S28

(1) Assembly / disassembly of spring assy.........................................................................1-S28

[5] CYLINDER ASSEMBLY......................................................................................................1-S29

(1) Assembly / disassembly of cylinder assy ......................................................................1-S29

(2) Cylinder assembly structural components.....................................................................1-S29

[6] TRACK ROLLER .................................................................................................................1-S31

(1) Assembly / disassembly of track roller ..........................................................................1-S31

(2) Track roller structural components ................................................................................1-S32

[7] CARRIER ROLLER .............................................................................................................1-S33

(1) Assembly / disassembly of carrier roller........................................................................1-S33

(2) Carrier roller structural components ..............................................................................1-S34

U48-4,U55-4, WSM

KiSC issued 03, 2010 A

1. FRONT OPERATING MACHINE

[1] BLADE

(1) Blade dimension

(a) Pin diameter x length 55 x 65 mm ( 2.2 x 2.6 in.)
(b) Pin diameter x length 55 x 25 mm ( 2.2 x 1 in.)
(c) Blade width 1960 mm (77.2 in.)
(d) Blade height 408 mm (16.1 in.)
(e) Blade length 1365 mm (53.7 in.)

Blade tip plate height

(f)

x thickness
Length between

(g)

blade arms

MACHINE BODY

Dimension (STD version)

65 x t12 mm (2.6 x t0.5 in.)

599 mm (23.6 in.)

RY9212050MBS0014US0

1-S1

U48-4,U55-4, WSM

NOTE

KiSC issued 03, 2010 A

[2] FRONT PIN

(1) Pin diameter x length

(2) Pin diameter x length

(3) Pin diameter x length

(4) Pin diameter x length

(5) Pin diameter x length

(6) Pin diameter x length

(7) Pin diameter x length

(8) Pin diameter x length

(9) Pin diameter x length

(10) Pin diameter x length

(11) Pin diameter x length

(12) Pin diameter x length

(13) Pin diameter x length

(14) Pin diameter x length

(15) Pin diameter x length

(16) Pin diameter x length

(17) Pin diameter x length

MACHINE BODY

Unit KX057-4

mm

in.

mm

in.

mm

in.

mm

in.

mm

in.

mm

in.

mm

in.

mm

in.

mm

in.

mm

in.

mm

in.

mm

in.

mm

in.

mm

in.

mm

in.

mm

in.

mm

in.

92 x 176

3.62 x 6.93
92 x 150

3.62 x 5.91
45 x 158

1.77 x 6.22
45 x 131

1.77 x 5.16
55 x 347

2.17 x 13.66
55 x 165

2.17 x 6.50
55 x 196

2.17 x 7.72
55 x 235

2.17 x 9.25
50 x 196

1.97 x 7.72
50 x 152

1.97 x 5.98
45 x 257

1.77 x 10.12
45 x 257

1.77 x 10.12
45 x 152

1.17 x 5.98
45 x 204

1.77 x 8.03
45 x 204

1.77 x 8.03
45 x 142

1.77 x 5.59
55 x 154

2.17 x 6.06

• Service limit of pin and bushing is 1.0 mm (0.04 in.) less and
more than original diameter respectively.

(a) Pin diameter (b) Pin length

RY9212007GEG0012US0

1-S2

U48-4,U55-4, WSM

CAUTION

KiSC issued 03, 2010 A

2. SWIVEL FRAME

[1] WEIGHT DIASSEMBLY / ASSEMBLY

Removing the bonnet (right)

1. Open the bonnet (right) (4), remove the two snap pins (1), (2),
and separate the gas damper from the bonnet.

2. Slide the bonnet (right) (4) to the front of the body and remove it.

• Have another person help you when removing/attaching
the bonnet (right).

• Bonnet (right) weight : 27 kg (60 lbs)

(1) Snap pin, flat washer
(2) Snap pin, flat washer

MACHINE BODY

(3) Gas damper
(4) Bonnet (right)

RY9212032MBS0009US0

Removing the bonnet (left)

1. Remove five mounting bolts (2), (3) of the bonnet (left) (4) and
remove the bonnet (left) (4).

(1) Cap, assy
(2) Bolt (M10 x 35)

(3) Bolt (M10 x 25)
(4) Bonnet (rear)

RY9212052MBS0011US0

Removing the bonnet (rear)

1. Remove the bolt (1), pull out the pin (2), and remove the bonnet
(rear) (3).

2. Remove the mounting bracket (4) and four mounting bolts (5) of
the bonnet (rear) and remove the bracket (4).

(1) Bolt (M8 x 16)
(2) Pin
(3) Bonnet (rear)

1-S3

(4) Bracket
(5) Bolt (M10 x 20)

RY9212052MBS0012US0

U48-4,U55-4, WSM

CAUTION

KiSC issued 03, 2010 A

MACHINE BODY

Removing the weight

1. Attach two eyebolts (2) to the weight (1), connect a nylon sling
(4) to these and support the weight using a crane.

2. Remove the three mounting bolts (3) of the weight, lift slightly
with the crane, slide the weight to the rear, lift the weight and
remove it from the frame.

367.7 to 431.5 N·m

Tightening torque Weight (1)

37.5 to 44.0 kgf·m

271.2 to 318.3 lbf·ft

Apply thread locking compound (Loctite 271)

• Weight of the weight :
290 kg, 639 lbs (U48-4)
700 kg, 1540 lbs (U55-4)

• When assembling the weight, align the protruding part B of
the weight with the indented part A in the frame and line up
the mounting holes.

(1) Weight
(2) Eyebolt (M24 × P3)
(3) Bolt (M20×90)
(4) Nylon sling

(1) Weight (3) Bolt (M20×90)

A : Indent part in frame
B : Protruding part of weight

RY9212052MBS0001US0

RY9212050MBS0008US0

1-S4

U48-4,U55-4, WSM

KiSC issued 03, 2010 A

[2] FUEL TANK

Assembling the fuel tank

MACHINE BODY

(1) Fuel tank assembly
(2) Band, assy (fuel tank)
(3) Lock nut
(4) Flat metal washer

(5) Plate, assy

(1, fuel tank support)
(6) Bolt (M10 x 20)
(7) Flat metal washer

(8) Plate, assy

(2, fuel tank support)
(9) Bolt (M10 x 25)
(10) Flat metal washer

(a) Tolerance from the frame

(swivel) partition plate to
band screw part : 20 to
25 mm, 0.79 to 0.98 in.

RY9212050MBS0001US0

Assembling the fuel hose

(1) Fuel tank assembly (2) Bolt (M10 x 25) (a) Cock closed position (b) Be careful to make sure the

hose does not get caught
between the frame (swivel)
and the fuel tank

RY9212050MBS0002US0

1-S5

U48-4,U55-4, WSM

KiSC issued 03, 2010 A

MACHINE BODY

Fuel hose clamp, guide position

(1) Guide
(2) Clamp

(3) Clamp

RY9212032MBS0014US0

1-S6

U48-4,U55-4, WSM

KiSC issued 03, 2010 A

Fuel hose route (U48-4, U55-4)

MACHINE BODY

(1) Drain cock
(2) Fuel tank

List of fuel hoses

(3) Water separator
(4) Fuel pump

Fuel tube Protection tube Hose band

Part Length Part Length In / Out side
(A) RD451-51332 730 mm, 28.7 in. RD451-51341 610 mm, 24 in. 09318-88130
(B) 09664-82100 2100 mm, 82.7 in, RC301-51151 2000 mm, 78.7 in. 14911-42751
(C) 09664-80340 340 mm, 13.4 in. RD451-51352 260 mm, 10.2 in. 14911-42751
(D) 09664-80260 260 mm, 10.2 in. RD451-51382 200 mm, 7.9 in. 14911-42751
(E) 09664-80260 260 mm, 10.2 in. RD451-51382 200 mm, 7.9 in. 14911-42751
(F) 09664-40500 500 mm, 19.7 in. RC461-51641 450 mm, 17.7 in. 14971-42751

(G) 09664-41750 1750 mm, 68.9 in. RD451-51392 1650 mm, 65 in. 14971-42751

(H) 09664-80040 40 mm, 1.6 in. – – 14911-42751

(I) 09664-80040 40 mm, 1.6 in. – – 14911-42751
(J) 09664-42100 2100 mm, 82.7 in, RB441-51221 2000 mm, 78.7 in, 14971-42751
(K) 09664-60420 420 mm, 16.5 in. – – –

(5) Fuel filter
(6) Engine

(7) Fuel cooler

RY9212052MBS0008US0

1-S7

U48-4,U55-4, WSM

KiSC issued 03, 2010 A

[3] HYDRAULIC OIL TANK

(1) Hydraulic oil tank components

MACHINE BODY

(1) Hydraulic oil tank
(2) Cover (tank)
(3) O-Ring
(4) Filter (return)
(5) Stopper (return filter)
(6) Bolt (M8 x 16)

Tightening torque Bolt (25)

(7) Plug (fill)
(8) O-Ring
(9) Bolt (M10 x 16)
(10) Filter, assy (suction)
(11) Pin (suction filter)
(12) O-Ring

77.5 to 90.2 N·m

7.9 to 9.2 kgf·m

57.2 to 66.5 lbf·ft

Apply thread locking compound (Loctite 271) to the bolt (25)

(13) Bolt (M10 x 16)
(14) Plug (G1/4)
(15) O-Ring
(16) Plug
(17) Sealing washer
(18) Filter (blazer)
(19) Metal washer

(20) Sealing washer
(21) Flange holder
(22) Tube (blazer)
(23) Magnet plug
(24) Sealing washer
(25) Bolt (M12 x 30)

RY9212050MBS0030US0

1-S8

U48-4,U55-4, WSM

CAUTION

KiSC issued 03, 2010 A

(2) Hydraulic oil return filter replacement procedure

Removing the cover (tank)

1. Loosen the hose clamp (3), remove the hose (return) (4), hose
(return, cooler) (5), from the cover (tank) (1) side.

2. Remove the cover (tank) (1) mounting bolt (2).

(1) Cover (tank)
(2) Bolt
(3) Hose clamp

3. Pull up the cover (tank) (1) and remove the filter (return) (6).

(1) Cover (tank) (6) Filter (return)

MACHINE BODY

(4) Hose (return)
(5) Hose (return, cooler)

RY9212001MBS0052US0

RY9212001MBS0053US0

4. Clamp in a vice, loosen the set bolt (7), and remove the stopper
(8).

(7) Set bolt (8) Stopper

RY9212001MBS0054US0

5. Remove the filter (return) (9) using a wrench (1).
Wrench : 41 mm, 1.6 in. (two opposite faces)

Tightening torque Filter (return) (9)

68.6 to 78.4 N·m

7.0 to 8.0 kgf·m

50.6 to 57.8 lbf·ft

• When tightening the filter (return), tighten with the wrench
(1) on the nut (b) shown in the diagram to the left.
If the wrench (1) is placed on the nut on (a) side, the filter
will break.

• Assemble the filter so that opposite sides of the hexagonal
part of the filter fully engages with the flat surfaces of the
stopper (2).

(1) Wrench
(2) Stopper

(9) Filter (return)

RY9212001MBS0055US0

1-S9

U48-4,U55-4, WSM

CAUTION

KiSC issued 03, 2010 A

(3) Filter (suction) replacement procedure

1. Remove the filter (return) from the tank.
(Refer to the chapter Filter (Return) Assembly/Disassembly.)
Remove the bracket (1).

(1) Bracket (2) Bolt (M10 x 16)

2. Remove the bolt and the suction filter mounting pin (3).

(3) Pin (suction)

MACHINE BODY

RY9212001MBS0056US0

RY9212001MBS0057US0

3. Hold onto the upper part of the filter (support) and remove the
filter (suction) (4) from the tank.

• Remove only the strainer (1) and when replacing with a new
part, set the overall length (A) to 380 mm (15 in.).

Tightening torque Nut (2)

(1) Strainer
(2) Nut
(4) Filter (suction)

(A) 380 mm, 15 in.

16 to 24 N·m

1.6 to 2.4 kgf·m
12 to 18 lbf·ft

RY9212050MBS0026US0

1-S10

U48-4,U55-4, WSM

KiSC issued 03, 2010 A

(4) Filter (breather) replacement procedure

1. Loosen the bolt (1), and remove the washer (2).

(1) Bolt (2) Metal washer

2. Remove the filter (breather) (3) from the tank.

(3) Filter (breather)

MACHINE BODY

RY9212001MBS0059US0

RY9212001MBS0060US0

1-S11

U48-4,U55-4, WSM

KiSC issued 03, 2010 A

(5) Assembly of anti vibration support for the hydraulic oil tank

MACHINE BODY

(1) Plate (stay, oil tank)
(2) Anti-vibration rubber

(3) Stay (tank, anti-vibration)
(4) Base (tank, anti-vibration)
(5) Frame (arch)

Tightening order for each bolt

(a) through (d) in the diagram to the left.

1. After assembly, fully tighten the (a) bolt to the arch.

2. Lightly tighten bolts (b), (c), and (d) together with the assembly

3. Tighten in the order of (b)→(c)→(d).

4. Be sure the (b) bolt is assembled straight and not cross

Tightening torque Bolts (a) (b) (c) (d)

(a) Flange bolt (M12 x 20)
(b) Bolt (M12 x 60)

(c) Bolt (M12 x 30)
(d) Bolt (M12 x 30)

RY9212001MBS0061US0

The tightening order for each bolt is indicated using the letters

of their associated components.

threaded.

77.5 to 90.2 N·m

7.9 to 9.2 kgf·m

57.2 to 66.5 lbf·ft

Apply thread locking compound (Loctite 271) to (b)

RY9212001MBS0062US0

1-S12

U48-4,U55-4, WSM

KiSC issued 03, 2010 A

[4] ENGINE

(1) Engine mount

[A] Engine mount structural components

MACHINE BODY

(1) Bracket (1, engine)
(2) Bolt (M12 x 35)
(3) Bracket (2, engine)
(4) Bracket (3, engine)
(5) Bracket (4, engine)

Tightening torque Bolt (9)

(6) Support (engine)
(7) Anti-vibration rubber (450)
(8) Cap
(9) Bolt (M16 x 110)
(10) Collar

196.1 to 225.6 N·m
20 to 23 kgf·m

144.7 to 166.3 lbf·ft

(11) Bolt (M16 X 70)
(12) Flat metal washer
(13) Tray (engine)
(14) Fuel tube

Apply thread locking compound (Loctite 271) onto part number (2), (9), (11) and (18).

(15) Pipe clip
(16) Flat washer assembly bolt
(17) Stay (harness clamp)
(18) Flat washer assembly bolt

RY9212050MBS0031US0

1-S13

U48-4,U55-4, WSM

KiSC issued 03, 2010 A

(2) Muffler

[A] Muffler structural components

MACHINE BODY

(1) Flange (muffler)
(2) Gasket (muffler, NA)
(3) Bolt (M10 x 25)
(4) Gasket (muffler)
(5) Bracket (muffler)
(6) Bolt (M8 x 20)
(7) Pipe (muffler)
(8) Band (flange muffler)
(9) Band (muffler pipe)
(10) Bolt (M8 x 85)
(11) Bolt (M8 x 75)
(12) Flat metal washer
(13) Spring washer
(14) Nut
(15) Insulation (1, muffler)
(16) Insulation (2, muffler)
(17) Wire

RY9212032MBS0027US0

[B] Assembling of muffler

Assembling pipe (muffler) clamp

(1) Band (flange muffler)
(2) Flange (muffler)
(3) Bracket (muffler)

(a) Bolt
(b) Bolt
(c) Bolt
(A) X surface
(B) Y surface
(C) Z surface

Being careful not to dent or deform the tail pipe, tighten with the

following torques.

3.9 to 5.9 N·m

Tightening torque Band (flange muffler) (1)

0.4 to 0.6 kgf·m

2.9 to 4.3 lbf·ft

RY9212032MBS0028US0

1-S14

U48-4,U55-4, WSM

CAUTION

KiSC issued 03, 2010 A

MACHINE BODY

Assembly procedure for the muffler assy

1. Lightly tighten the bolts (a), (b), (c).

• Be sure there are not any gaps on the X surface, Y surface,
or Z surface.

2. Tighten the (a) bolt.

3. Tighten the (b) bolt.

4. Tighten the (c) bolt.

(1) Tail pipe
(2) Bonnet

(3) Arch, Air cleaner

[A] Assembling of the Arch and Air Clearance

(A) Clearance 15 mm, 0.59 in. ≤

RY9212052MBS0003US0

(1) Air cleaner, assy
(2) Hose (inlet)
(3) Hose clamp (with screw)
(4) Hose (1, inlet)

(5) Pipe band
(6) Hose (3, inlet)
(7) Indicator
(8) Frame (arch)

(9) Frame (2, arch)
(10) Bolt (M14, arch)
(11) Collar (arch)

(a) Place in the frame (arch)

guide

(b) 30 °

RY9212001MBS0082US0

Assembling the Arch

There is a counter bore in the arch mounting area on the swivel

frame and it has a structure where a collar (arch) (4) is inserted and
joined with the arch.

Be careful not to lose the collar (arch) (4) when disassembling

and reassembling and tighten using the following torque.

123.6 to 147.1 N·m

Tightening torque Bolt (3)

12.6 to 15.0 kgf·m

91.17 to 108.4 lbf·ft

Apply thread lock compound (Loctite 271).

(1) Frame (arch)
(2) Frame (2, arch)

(3) Bolt (M14, arch)
(4) Collar (arch)

RY9212050MBS0027US0

1-S15

U48-4,U55-4, WSM

KiSC issued 03, 2010 A

(4) Radiator

[A] Assembling of the Radiator

MACHINE BODY

(1) Radiator, ASSY
(2) Rubber (radiator mount)
(3) Bracket (1, radiator)
(4) Bracket (2, radiator)

(5) Shroud (fan)
(6) Hose (upper, WP)
(7) Hose (lower, WP)
(8) Coupler (drain)

(9) Hose (drain)
(10) Clamp
(11) Cord band
(12) Tray (engine oil)

Assembling the Shroud (fan)

Tightening torque Bolt (A)

(1) Radiator, ASSY
(2) Rubber (radiator mount)
(3) Bracket (1, radiator)
(4) Bracket (2, radiator)
(5) Shroud (fan)

(A) Bolt (M6 x 16)

(a) Pass through hole

RY9212001MBS0084US0

4.5 to 5.5 N·m

0.46 to 0.56 kgf·m

3.4 to 4.0 lbf·ft

(a) Tolerance from shroud (fan) to

fan : 30 ± 3 mm, 1.2 ± 0.1 in.

(b) Gap between fan and shroud

(fan) at least 10 mm, 0.4 in.

(c) Be sure that the tab is fully

inserted into the hole in the
bracket.

RY9212001MBS0085US0

1-S16

U48-4,U55-4, WSM

KiSC issued 03, 2010 A

(5) Oil cooler

[A] Assembling of the Oil Cooler

MACHINE BODY

(1) Oil cooler
(2) Bracket (oil cooler)
(3) Bolt (M8 x 20)
(4) Flat metal washer

(5) Bolt (M8 x 25)
(6) Bolt (M8 x 20)

(7) Pipe joint (oil cooler, L)
(8) Pipe joint (oil cooler, R)

Oil cooler assembly procedure

1. Lightly tighten bolts (3), (5), and (6).

2. Tighten bolt (6).

Tightening torque Bolt (6)

3. Tighten bolt (3).

Tightening torque Bolt (3)

4. Tighten bolt (5).

Tightening torque Bolt (5)

(3) Bolt (M6 x 14)
(5) Bolt (M8 x 25)

(6) Bolt (M8 x 20)

(9) Guide (hose, PP)
(10) Cooler (fuel)

RY9212032MBS0029US0

17.7 to 20.6 N·m

1.8 to 2.1 kgf·m

13.1 to 15.1 lbf·ft

9.8 to 11.3 N·m

1.0 to 1.15 kgf·m

7.3 to 8.3 lbf·ft

23.5 to 27.5 N·m

2.4 to 2.8 kgf·m

17.4 to 20.2 lbf·ft

RY9212032MBS0030US0

1-S17

U48-4,U55-4, WSM

KiSC issued 03, 2010 A

(6) Accelerator cable

MACHINE BODY

(1) Motor ASSY (AI)
(2) Cable (accelerator)
(3) Sensor (accelerator)
(4) Bracket (sensor, AI)
(5) Washer head machine

screw
(6) Machine screw (taptite)
(7) Spring Pins
(8) Rod (AI motor)

(1) Motor ASSY (AI)
(2) Cable (accelerator)
(3) Sensor (accelerator)
(4) Bracket (sensor, AI)
(5) Washer head machine

screw
(6) Machine screw (taptite)

(9) Flat metal washer
(10) Snap pin (6, with bleed

prevention)
(11) Bracket (AI motor)
(12) Bolt (M10 x 20)
(13) Bolt (M6 x 16)
(14) Flat metal washer
(15) Cotter pin

RY9212001MBS0088US0

(a) Gap of at least 1 mm

(0.04 in.) at max engine

speed

RY9212001MBS0089US0

Motor, assy (AI) tightening torque

Tightening torque Bolt (12)

Sensor (accelerator) tightening torque

Tightening torque Bolt (5)

1-S18

2.45 to 3.92 N·m

0.25 to 0.40 kgf·m

1.81 to 2.89 lbf·ft

RY9212050MBS0028US0

1.47 to 1.96 N·m

0.15 to 0.20 kgf·m

1.09 to 1.94 lbf·ft

RY9212050MBS0029US0

U48-4,U55-4, WSM

KiSC issued 03, 2010 A

[5] ASSEMBLING OF OPERATING LEVERS

(1) Travel lever

MACHINE BODY

(1) Lever (travel, left)
(2) Lever (travel, right)
(3) Bolt (M8 x 20)
(4) Grip (travel)

(a) 193 ± 5 mm, 7.6 ± 0.2 in.
(b) When in neutral
(c) To-and-fro difference between

left and right levers should be
within 2 mm, 0.08 in.

(d) Gap between left and right levers

: 11 to 22 mm, 0.43 to 0.87 in.

RY9212032MBS0031US0

Lever (travel, left), lever (travel, right) assembly

The pilot valve side is aluminum die cast so be careful not to

over tighten; tighten to the torques indicated below.

Tightening torque Bolt (3)

(1) Lever (travel, left)
(2) Lever (travel, right)
(3) Bolt (M8 x 20)
(4) Grip (travel)
(5) Washer head bolt
(6) Valve, assy (PV, travel)
(7) Damper (HST)
(8) Headed pin
(9) Snap pin 8

(10) Flat metal washer
(11) Pedal assy (travel left)
(12) Pedal (travel 2)
(13) Pedal assy (travel right)
(14) Headed pin
(15) Flat metal washer
(16) Snap pin
(17) Bolt (M10 x 25)

17.7 to 20.6 N·m

1.8 to 2.1 kgf·m

13.1 to 15.1 lbf·ft

RY9212032MBS0032US0

1-S19

U48-4,U55-4, WSM

KiSC issued 03, 2010 A

(2) Blade lever

MACHINE BODY

(1) Plate (blade)
(2) Bolt (M10 x 30)
(3) Lever (blade)
(4) Bolt (M8 x 16)
(5) Bolt (M10 x 25)
(6) Grip (two gears)

Assembling the lever (blade)

Tightening torque Lever (blade) (3)

(1) Plate (blade)
(2) Bolt (M10 x 30)
(3) Lever (blade)
(4) Bolt (M8 x 16)
(5) Bolt (M10 x 25)

(a) 60 mm, 2.4 in.
(b) 65 °

RY9212001MBS0094US0

23.5 to 27.5 N·m

2.4 to 2.8 kgf·m

17.4 to 20.2 lbf·ft

(6) Grip (two gears)
(7) Button (switch, green)
(8) Pan head machine screw
(9) Plate spring (capacitor)
(10) Washer head machine screw

RY9212001MBS0095US0

Assembling the plate (blade)

Tightening torque Plate (blade) (1)

1-S20

39.2 to 45.1 N·m

4.0 to 4.6 kgf·m

29.0 to 33.2 lbf·ft

RY9212001MBS0096US0

U48-4,U55-4, WSM

KiSC issued 03, 2010 A

3. TRACK FRAME

[1] ASSEMBLING OF SWIVEL BEARING

(1) Swivel bearing assembly procedure

1. Component names

No. in

Figure

(1) Bearing (swivel) 1 1
(2) Bolt (M16 x 60) 22 24
(3) Diaphragm spring 44 48
(4) Bolt (M16 x 55) 22 24

2. Assembly position

Mount the inner tire soft zone ('S' mark) (d) on the right side of
the body.

3. Swivel bearing tightening torque
After lightly tightening, tighten to the torque indicated below
from a diagonal angle.

Tightening torque Swivel bearing (1)

Component names

MACHINE BODY

Q'ty

U48-4 U55-4

259.9 to 304 N·m

26.5 to 31 kgf·m

191.7 to 224 lbf·ft

Apply thread lock compound. (Loctite 271)

4. Apply grease to the tooth surfaces
Apply grease so that it covers the entire bearing teeth surfaces.

(a) Ball insert groove (external tire

soft zone)

(b) Tooth surface grease application

zone

(c) Port for applying grease to the

ball (mate with hole in swivel
frame)

(d) 'S' Mark

A : Rear of vehicle
B : Front of vehicle

RY9212052MBS0004US0

(2) Swivel bearing external dimensions

No. in

Figure

A 60 mm, 2.4 in. 60 mm, 2.4 in.
B 50 mm, 2.0 in. 47 mm, 1.8 in.
C 694 mm, 27.3 in. 770 mm, 30.3 in.
D P.C.D. 662 mm, 26.1 in. P.C.D. 742 mm, 29.2 in.

E 605 mm, 23.8 in. 689 mm, 27.1 in.

F P.C.D. 552 mm, 21.7 in. P.C.D. 638 mm, 25.1 in.
G 529 mm, 20.8 in. 610 mm, 24 in.
H P.C.D. 507 mm, 20.0 in. P.C.D. 588 mm, 23.1 in.

I 495.5 mm, 19.5 in. 574 mm, 22.6 in.

U48-4 U55-4

Size

RY9212052MBS0005US0

1-S21

U48-4,U55-4, WSM

CAUTION

KiSC issued 03, 2010 A

MACHINE BODY

(3) Measuring the swivel bearing play

1. Attach the dial gauge and the dial gauge fixture on the machine
front. (Measurement position differs with the machine model.)

2. Fully stretch the arm and place the bucket in the crowded
position. Set the dial gauge to the zero point.

3. Using the attachment, tilt up the machine body, and take the dial
gauge reading. Make this measurement several times and take
their average as the final measurement.

• Perform the measurement three times, determine the
average value, and take this as the measured value.

U48-4

U55-4

(L) Measurement position

(L) : 50 mm (2.0 in.)

away from swivel race

(L) : 20 mm (0.8 in.)
away from swivel race

Factory
spec..

Allowable
limit

Factory
spec..

Allowable
limit

2.36 mm

0.1 in.

4.72 mm

0.19 in.

1.28 mm

0.05 in.

2.56 mm

0.10 in.

RY9212052MBS0007US0

1-S22

U48-4,U55-4, WSM

CAUTION

WARNING

KiSC issued 03, 2010 A

MACHINE BODY

[2] TRACK

(1) Assembly / disassembly of rubber track

• The pressure in the grease cylinder is high so if loosened quickly, the nipple may pop off and the highly
pressurized grease in the cylinder may fly out so do not get your face nea r the nipple nor place your body
in front of the nipple and loosen the nipple gradually.

RY9212001MBS0008US0

• The excavator is equipped with an overload warning system.
When changing from rubber crawlers to steel crawlers or vice versa it is necessary to change the
overload warning setting.
Overload warning doesn't operate normally, and it could result in death or serious injury if Pre-set code
is not correctly set.
After setting, confirm overload warning operates normally based on Boom Overload Alarm Check
Method. (Refer to "Overload Warning System" at "ELECTRICAL SYSTEM" Section)

RY9212052MBS0013US0

Removing the grease nipple

1. Remove one bolt (2) and then the cover (1).

2. Place a wrench (socket) at the base of the grease nipple and
loosen slowly.
If there is a rock etc. caught in the sprocket, remove the rock
first.

98 to 107.8 N·m

Tightening torque Grease nipple

(1) Cover
(2) Bolt (M10)

(3) Grease nipple

10 to 11 kgf·m
73 to 79.5 lbf·ft

RY9212001MBS0016US0

Loosen track

1. Jack up the body using the front end and blade, expel grease
from inside the grease cylinder, and fully loosen up the track.
When the track loosens up, attach the grease nipple.

RY9212032MBS0008US0

1-S23

U48-4,U55-4, WSM

CAUTION

CAUTION

CAUTION

WARNING

KiSC issued 03, 2010 A

MACHINE BODY

Removing the rubber tracks

1. Lift the body slightly and move the track in the forward direction

A.
Slide the track in the sideways direction at the front idler to
remove it.
Weight of rubber track : approximately 240 kg (529 lbs)

A : Forward direction B : Slide direction

RY9212032MBS0033US0

Assembling rubber tracks

1. Jack up the mini-excavator with the front-end and the blade and
assemble the track starting at the sprocket.

• Make sure to assemble the rubber track in the correct
orientation.

2. With the mini-excavator lifted slightly, hold the rubber track with
your hand on the outside, slowly turn it in the forward direction,
and set it on the stepped area of the front idler.

• Watch carefully to prevent your hands and legs from
getting caught.

• Lower the mini-excavator, drive it backwards to make sure
the tracks are on securely.

RY9212032MBS0034US0

(2) Assembly / disassembly of iron tracks

• The pressure in the grease cylinder is high so if loosened quickly, the nipple may pop off and th e highly
pressurized grease in the cylinder may fly out so do not get your face near the nipple no r place your body
in front of the nipple and loosen the nipple gradually.

RY9212001MBS0008US0

• The excavator is equipped with an overload warning system.
When changing from rubber crawlers to steel crawlers or vice versa it is necessary to change the
overload warning setting.
Overload warning doesn't operate normally, and it could result in death or serious injury if Pre-set code
is not correctly set.
After setting, confirm overload warning operates normally based on Boom Overload Alarm Check
Method. (Refer to "Overload Warning System" at "ELECTRICAL SYSTEM" Section)

RY9212052MBS0013US0

1-S24

U48-4,U55-4, WSM

KiSC issued 03, 2010 A

MACHINE BODY

Removing the grease nipple

1. Remove one bolt (2) and then the cover (1).

2. Place a wrench (socket) at the base of the grease nipple and
loosen slowly.
If there is a rock etc. caught in the sprocket, remove the rock
first.

(1) Cover
(2) Bolt (M10)

(3) Grease nipple

RY9212001MBS0009US0

Loosen track

1. Jack up the body using the front end and blade, expel grease
from inside the grease cylinder, and fully loosen up the track.
When the track loosens up, attach the grease nipple.

RY9212032MBS0008US0

Removing the locking pin

1. Turn the track until the master pin (1) is in front of the front idler.

2. Remove the locking pin (3) from the master pin.

(1) Master pin
(2) Master link

(3) Locking pin

RY9212001MBS0103US0

Removing the master pin

1. Place a jig on the master pin and tap it out with a hammer.
Use a jig as shown in the diagram to the left for removing the
pin.

(1) Hammer
(2) Jig

(3) Block

RY9212001MBS0104US0

1-S25

U48-4,U55-4, WSM

DANGER

KiSC issued 03, 2010 A

MACHINE BODY

Removing the shoe

1. Slowly move the travel lever to the backup position and back up
the mini-excavator.

2. Jack up the mini excavator using the front end and blade and
pull off the shoe.

• Do not place feet under the mini excavator.

• Weight of iron track : approximately 285 kg (628 lbs)

RY9212001MBS0105US0

Mounting an iron track

1. Jack up the mini excavator using the front end and blade and
place the track so that the end of the track meshes with the
sprocket under the mini excavator.
Make sure the track is placed in the correct orientation.

(1) Master link (a) Sprocket side

(b) Front idler side

RY9212001MBS0106US0

2. Raise the track using a crane and mesh it with the sprocket
teeth.

(4) Sprocket

RY9212001MBS0107US0

3. Slowly move the travel lever to the forward travel position to
mesh the track with the shoe (6).
When the track is sufficiently pulled on to where the track link
joint is at the front idler, lower the mini-excavator, and place a
block (7) under the shoe to support the shoe.
Match up both ends of the shoe, insert the master pin from the
outside of the body, insert the locking pin and bend the tip.

(5) Idler
(6) Shoe

(7) Block

RY9212001MBS0108US0

1-S26

U48-4,U55-4, WSM

KiSC issued 03, 2010 A

[3] FRONT IDLER

(1) Assembly / disassembly of front idler

Removing the idler

1. Remove the track.
(Refer to the chapter "Track Assembly/Disassembly".)
Jack up the mini-excavator with the front-end and the blade and
place timbers etc. under the frame.

2. Using a bar, remove the front idler from the track frame along
with the yoke.

• Front idler assy weight : approximately 46 kg (100 lbs)

(1) Block

MACHINE BODY

RY9212032MBS0035US0

(2) Front idler structural components

No. Component names Q'ty

(1) Spring Pins 1
(2) Bracket (R) 4
(3) Shaft (idler) 1
(4) Idler 1
(5) Floating Seal 2
(6) Bushing 1
(7) External circlip 2
(8) O-Ring 2

(9) Bracket (L) 1
(10) Plate (yoke) 1
(11) Bolt 1
(12) Plug (R1/8) 1

RY9212001MBS0112US0

1-S27

U48-4,U55-4, WSM

KiSC issued 03, 2010 A

[4] SPRING ASSY

(1) Assembly / disassembly of spring assy

Removing the spring assy

1. Remove the track and the front idler.
(Refer to the "Track and Front Idler" chapters for
assembly/disassembly of the track and front idler.)
After removing the front idler assy, pull out the spring assy (1)
from the track frame.

• Spring assy weight : approximately 17 kg (37 lbs)

(1) Spring assy

Rubber track specification

MACHINE BODY

RY9212001MBS0113US0

No. Component names Q'ty

(1) Bolt (spring) 1
(2) Spring 1
(3) Retainer (spring) 1
(4) Slotted nut 1
(5) Cotter pin 1

Iron track specifications

(a) Set length for rubber track : 227.5 mm, 8.96 in.
(b) Make sure the cotter pin is set in the groove of

the slotted nut

(c) Set position for iron track specifications

RY9212001MBS0114US0

No. Component names Q'ty

(1) Bolt (spring) 1
(2) Spring 1
(3) Retainer (spring) 1
(4) Slotted nut 1
(5) Cotter pin 1

(a) Set length for iron track : 242.5 mm, 9.55 in.
(b) Make sure the cotter pin is set in the groove of

the slotted nut

(c) Set position for rubber track specification

RY9212001MBS0115US0

1-S28

U48-4,U55-4, WSM

KiSC issued 03, 2010 A

[5] CYLINDER ASSEMBLY

(1) Assembly / disassembly of cylinder assy

Removing the cylinder assy

1. Remove the track, front idler, and spring assy.
(Refer to the spring idler chapter for assembly/disassembly of
the track, front idler, and spring assy.)
After removing the spring assy, pull out the cylinder assy (1)
from the track frame.

• Cylinder assy weight : approximately 14 kg (31 lbs)

(1) Cylinder Assembly

(2) Cylinder assembly structural components

No. Component names Q'ty

(1) Rod 1
(2) Rod seal 1
(3) Backup ring 1
(4) O-Ring 1
(5) Cylinder tube 1
(6) Nipple, assy 1

MACHINE BODY

RY9212001MBS0116US0

98 to 107.8 N·m

Tightening torque Nipple, assy (6)

10 to 11 kgf·m
73 to 79.5 lbf·ft

RY9212001MBS0117US0

Rubber track specification structural components

No. Component names

(1) Idler assy
(2) Spring assy
(3) Cylinder assembly

(a) 227.5 mm, 8.96 in.

RY9212001MBS0126US0

Iron track specification structural components

No. Component names

(1) Idler assy
(2) Spring assy
(3) Cylinder assembly

(a) 242.5 mm, 9.55 in.

RY9212001MBS0127US0

1-S29

U48-4,U55-4, WSM

KiSC issued 03, 2010 A

MACHINE BODY

Mounting an iron track guide

Tightening torque for iron track guide mounting bolt (2)

103.0 to 117.7 N·m

Tightening torque Guide (1)

10.5 to 12.0 kgf·m

76.0 to 86.8 lbf·ft

Apply thread lock compound (Loctite 271).

(1) Guide (2) Bolt (diaphragm spring flat washer)

RY9212001MBS0128US0

1-S30

U48-4,U55-4, WSM

CAUTION

KiSC issued 03, 2010 A

MACHINE BODY

[6] TRACK ROLLER

(1) Assembly / disassembly of track roller

• The pressure in the grease cylinder is high so if loosened quickly, the nipple may pop off and the highly
pressurized grease in the cylinder may fly out so do not get your face nea r the nipple nor place your body
in front of the nipple and loosen the nipple gradually.

RY9212001MBS0008US0

Removing the grease nipple

1. Remove one bolt (2) and then the cover (1).

2. Place a wrench (socket) at the base of the grease nipple and
loosen slowly.
If there is a rock etc. caught in the sprocket, remove the rock
first.

(1) Cover
(2) Bolt (M10)

(3) Grease nipple

RY9212001MBS0009US0

Loosen track

1. Jack up the body using the front end and blade, expel grease
from inside the grease cylinder, and fully loosen up the track.
When the track is loose, attach the grease nipple and place a
block under the track frame.

RY9212032MBS0036US0

Removing the track roller

1. Loosen the track roller mounting bolt, and remove the track
roller.
Track roller weight : 10 kg (22 lbs)

RY9212001MBS0118US0

1-S31

U48-4,U55-4, WSM

KiSC issued 03, 2010 A

Mounting the track roller

MACHINE BODY

(1) Track roller, assy (2) Bolt (3) Flat metal washer (a) Less than 1.5 mm (0.06 in.)

(gap between working
surfaces)

Please perform the procedure in reverse for assembly.

259.9 to 304.0 N·m

Tightening torque Track roller assy

26.5 to 31.0 kgf·m

191.7 to 224.2 lbf·ft

Thread locking compound : Three Bond 1305P
Apply the thread locking compound to the female threads.

RY9212001MBS0119US0

(2) Track roller structural components

No. Component names Q'ty No. Component names Q'ty

1 Shaft assy 1 7 Track roller (body) 1
2 Shaft (track roller) 1 8 Seal (floating) 2
3 Bracket (track roller) 1 9 O-Ring 1
4 Plug (R1/8) 1 10 Bracket (track roller) 1
5 Track roller 1 11 Wire 1
6 Bushing 2

RY9212001MBS0120US0

1-S32

U48-4,U55-4, WSM

CAUTION

KiSC issued 03, 2010 A

MACHINE BODY

[7] CARRIER ROLLER

(1) Assembly / disassembly of carrier roller

• The pressure in the grease cylinder is high so if loosened quickly, the nipple may pop off and the highly
pressurized grease in the cylinder may fly out so do not get your face nea r the nipple nor place your body
in front of the nipple and loosen the nipple gradually.

RY9212001MBS0008US0

Removing the grease nipple

1. Remove one bolt (2) and then the cover (1).

2. Place a wrench (socket) at the base of the grease nipple and
loosen slowly.
If there is a rock etc. caught in the sprocket, remove the rock
first.

(1) Cover
(2) Bolt (M10)

(3) Grease nipple

RY9212001MBS0009US0

Loosen track

1. Jack up the body using the front end and blade, expel grease
from inside the grease cylinder, and fully loosen up the track.
When the track is loose, attach the grease nipple and place a
block under the track frame.

RY9212032MBS0036US0

1-S33

U48-4,U55-4, WSM

KiSC issued 03, 2010 A

MACHINE BODY

Removing the carrier roller

1. Insert a block (2) into the gap between the carrier roller and the
track.

2. Loosen the nut (3) and remove the carrier roller (1).
Carrier weight : approximately 4 kg (9 lbs)

(1) Carrier roller
(2) Block

(3) Nut

RY9212032MBS0037US0

Mounting the carrier roller

Please perform the procedure in reverse for assembly.

77.5 to 90.2 N·m

Tightening torque Carrier roller assy

7.9 to 9.2 kgf·m

57.2 to 66.5 lbf·ft

Apply thread locking compound : (Loctite 271)

(1) Carrier roller, assy
(2) Bolt

(2) Carrier roller structural components

No. Component names Q'ty

1Roller 1
2Shaft 1
3 Shaft seal 1
4 Ball bearing 2
5 Ring stopper 1
6 Cap seal 1
7Spacer 1
8Plug 1

(3) Spring washer
(4) Nut

RY9212001MBS0122US0

RY9212001MBS0123US0

1-S34

2 ENGINE

KiSC issued 03, 2010 A

GENERAL

KiSC issued 03, 2010 A

CONTENTS

1. ENGINE...................................................................................................................................... 2-G1

[1] ENGINE SPECIFICATIONS................................................................................................. 2-G1

[2] PERFORMANCE CURVE .................................................................................................... 2-G3

[3] DIMENSIONS....................................................................................................................... 2-G4

2. SPECIAL TOOLS ....................................................................................................................... 2-G5

U48-4,U55-4, WSM

KiSC issued 03, 2010 A

1. ENGINE

[1] ENGINE SPECIFICATIONS

ENGINE

U48-4

(Air conditioner type)

U48-4 Remarks

Model V2607-DI-E3-BH-4 V2607-DI-E3-BH-6
Number of cylinder 4

Bore x Stroke

Displacement 2615 cc, 159.59 in

29.5 / 2200 kW/rpm

Max. output / rpm

40.1 / 2200 PS/rpm

39.5 / 2200 HP/rpm

87 x 110 mm

3.43 x 4.33 in.

30.0 / 2200 kW/rpm

40.8 / 2200 PS/rpm

40.2 / 2200 HP/rpm

3

ISO 9249 NET
SAEJ 9249 NET

Compression ratio 20

Max. torque/rpm

Dimensions : L x W x H

Dry weight

149.6 / 1300 ± 200 N·m

15.3 / 1300 ± 200 kgf·m

110.3 / 1300 ± 200 lbf·ft
687 x 497 x 653 mm

27.0 x 19.6 x 25.7 in.

225 kg

496.0 lbs

150.3 / 1300 ± 200 N·m

15.3 / 1300 ± 200 kgf·m

110.9 / 1300 ± 200 lbf·ft

225 kg

496.0 lbs
Valve clearance 0.15 mm, 0.01in. Cold condition
Firing sequence 1-3-4-2
Combustion chamber (Direct Injection)

Compression pressure

3.20 MPa

32.6 kgf/cm
464 psi

2

Ref. valve at 150 rpm
starter speed

Fan belt Bando RPF3355 Bando RPF3350

Fuel consumption ratio

234.0 g/kWh

172.1 g/PSh

0.385 lbs/HPh

230.1 g/kWh

169.2 g/PSh

0.378 lbs/HPh

Net value

Engine speed with idling 1050 to 1200 rpm On the machine

Engine oil pressure with rated
engine rpm

Fuel injection pressure
1st stage / 2nd stage

1st stage : 18.6 MPa (190 kgf/cm

2nd stage : 21.6 MPa (220 kgf/cm

245 to 441 kPa

2.50 to 4.50 kgf/cm

35.6 to 64.0 psi

2

2

, 2700 psi)

2

, 3130 psi)

0.68 g/kWh

Engine oil consumption ratio

0.50 g/PSh

0.00112 lbs/HPh
Alternator 12 V – 720 w DENSO Co.
Charging current 60 A
Regulation voltage 14.2 ~ 14.8 V
Battery 105D31L
Electrolyte gravity 1.26 ≤
Starter 12 V – 2.0 kW DENSO Co.
Glow plug 0.95 Ω

RY9212052END0001US0

2-G1

U48-4,U55-4, WSM

KiSC issued 03, 2010 A

ENGINE

U55-4

(Air conditioner type)

U55-4 Remarks

Model V2607-DI-E3-BH-3 V2607-DI-E3-BH-5
Number of cylinder 4

Bore x Stroke

Displacement 2615 cc, 159.59 in

33.8 / 2200 kW/rpm

Max. output / rpm

46.0 / 2200 PS/rpm

45.4 / 2200 HP/rpm

87 x 110 mm

3.43 x 4.33 in.

34.3 / 2200 kW/rpm

46.6 / 2200 PS/rpm

46.0 / 2200 HP/rpm

3

ISO 9249 NET
SAEJ 9249 NET

Compression ratio 20

Max. torque/rpm

Dimensions : L x W x H

Dry weight

169.7 / 1300 ± 200 N·m

17.3 / 1300 ± 200 kgf·m

125.2 / 1300 ± 200 lbf·ft
687 x 497 x 653 mm

27.0 x 19.6 x 25.7 in.

225 kg

496.0 lbs

170.4 / 1300 ± 200 N·m

17.4 / 1300 ± 200 kgf·m

125.7 / 1300 ± 200 lbf·ft

225 kg

496.0 lbs
Valve clearance 0.15 mm, 0.01in. Cold condition
Firing sequence 1-3-4-2
Combustion chamber (Direct Injection)

Compression pressure

3.20 MPa

32.6 kgf/cm
464 psi

2

Ref. valve at 150 rpm
starter speed

Fan belt Bando RPF3355 Bando RPF3350

Fuel consumption ratio

232.7 g/kWh

171.2 g/PSh

0.383 lbs/HPh

229.3 g/kWh

168.7 g/PSh

0.377 lbs/HPh

Net value

Engine speed with idling 1050 to 1200 rpm On the machine

Engine oil pressure with rated
engine rpm

Fuel injection pressure
1st stage / 2nd stage

1st stage : 18.6 MPa (190 kgf/cm

2nd stage : 21.6 MPa (220 kgf/cm

245 to 441 kPa

2.50 to 4.50 kgf/cm

35.6 to 64.0 psi

2

2

, 2700 psi)

2

, 3130 psi)

0.68 g/kWh

Engine oil consumption ratio

0.50 g/PSh

0.00112 lbs/HPh
Alternator 12 V – 720 w DENSO Co.
Charging current 60 A
Regulation voltage 14.2 ~ 14.8 V
Battery 105D31L
Electrolyte gravity 1.26 ≤
Starter 12 V – 2.0 kW DENSO Co.
Glow plug 0.95 Ω

RY9212052END0003US0

2-G2

U48-4,U55-4, WSM

KiSC issued 03, 2010 A

[2] PERFORMANCE CURVE

ENGINE

(a) Brake Horse Power (kW) (b) Engine Speed (rpm) (c) Torque (N·m) (A) U48-4

(B) U55-4

RY9212052END0002US0

2-G3

U48-4,U55-4, WSM

KiSC issued 03, 2010 A

[3] DIMENSIONS

Dimension Dimension Dimension
A 686.59 mm (27.03 in.) E 262.47 mm (10.33 in.) I 145 mm (5.71 in.)
B 389.3 mm (15.33 in.) F 234.5 mm (9.23 in.) J 145 mm (5.71 in.)
C 160 mm (6.30 in.) G 652.5 mm (25.69 in.)
D 496.97 mm (19.57 in.) H 233.1 mm (9.18 in.)

ENGINE

Component layout

No. Part name No. Part name No. Part name

(1) Injection pump (6) Oil cooler (11) Starter
(2) Governor (7) Oil filter (12) Revolution sensor
(3) Glow plug (8) Oil switch (13) Water temperature sensor
(4) Stops (9) Drain plug (oil) (14) Belt tensioner
(5) Alternator (10) Oil filter plug (15) V-belt

RY9212050END0003US0

2-G4