the best service manual

1. BULLDOZER
SEN01128-05
D68ESS-12
SERIAL NUMBERS
D68ESS- 1001
D68ESS-J10001
and up

2. SEN01130-05 00 Index and foreword
4 D68ESS-12
Table of contents 1
00 Index and foreword
Index SEN01130-05
Composition of shop manual ................................................................................................... 2
Table of contents...................................................................................................................... 4
Foreword and general information SEN01131-02
Safety notice............................................................................................................................ 2
How to read the shop manual.................................................................................................. 7
Explanation of terms for maintenance standard ...................................................................... 9
Handling of electric equipment and hydraulic component ....................................................... 11
Handling of connectors newly used for engines ...................................................................... 20
How to read electric wire code................................................................................................. 23
Precautions when carrying out operation ................................................................................ 26
Method of disassembling and connecting push-pull type coupler ........................................... 29
Standard tightening torque table.............................................................................................. 32
Conversion table...................................................................................................................... 36
01 Specification
Specification and technical data SEN01133-00
Specification and technical data.................................................................................................. 2
Specification drawing............................................................................................................... 2
Specifications........................................................................................................................... 4
Weight table............................................................................................................................. 8
Table of fuel, coolant and lubricants ........................................................................................ 10
10 Structure, function and maintenance standard
Engine and cooling system SEN01135-00
Engine and cooling system ......................................................................................................... 2
Radiator, power train, oil cooler ............................................................................................... 2
Engine control.......................................................................................................................... 4
Power train, Part 1 SEN01136-00
Power train, Part 1....................................................................................................................... 2
Power train system .................................................................................................................. 2
Power train skeleton ................................................................................................................ 3
Power train unit........................................................................................................................ 4
Power train hydraulic piping diagram....................................................................................... 5
Damper, universal joint ............................................................................................................ 6
Torque converter and PTO....................................................................................................... 9
Transmission control................................................................................................................ 14
Transmission............................................................................................................................ 15
Transmission control valve ...................................................................................................... 24
Main relief valve....................................................................................................................... 30
Lubrication relief valve............................................................................................................. 33
Steering and brake control....................................................................................................... 34
Power train, Part 2 SEN01137-00
Power train, Part 2....................................................................................................................... 2
Bevel gear shaft, steering clutch and brake............................................................................. 2
Brake valve.............................................................................................................................. 12
Scavenging pump strainer....................................................................................................... 17
Power train oil strainer............................................................................................................. 18
Power train oil filter .................................................................................................................. 19
Final drive ................................................................................................................................ 20

3. 00 Index and foreword SEN01130-05
D68ESS-12 5
Undercarriage and frame SEN01138-00
Undercarriage and frame ............................................................................................................ 2
Main frame............................................................................................................................... 2
Suspension.............................................................................................................................. 4
Track frame.............................................................................................................................. 7
Recoil spring............................................................................................................................ 8
Idler.......................................................................................................................................... 10
Track roller............................................................................................................................... 11
Carrier roller............................................................................................................................. 12
Track shoe............................................................................................................................... 14
Hydraulic system, Part 1 SEN01139-00
Hydraulic system, Part 1 ............................................................................................................. 2
Work equipment hydraulic piping diagram .............................................................................. 2
PPC control piping diagram..................................................................................................... 6
Work equipment control........................................................................................................... 7
Hydraulic tank and filter ........................................................................................................... 10
Hydraulic pump........................................................................................................................ 12
Power train lubrication pump................................................................................................... 13
PPC valve (for steering) .......................................................................................................... 14
PPC charge valve.................................................................................................................... 19
Hydraulic system, Part 2 SEN01140-01
Hydraulic system, Part 2 ............................................................................................................. 2
1-spool valve
Main control valve.................................................................................................................... 2
CLSS ....................................................................................................................................... 8
Functions, operation of valve................................................................................................... 10
Suction valve ........................................................................................................................... 18
3-spool valve
Main control valve.................................................................................................................... 20
CLSS ....................................................................................................................................... 27
Functions, operation of valve................................................................................................... 29
Suction valve ........................................................................................................................... 38
Work equipment SEN01141-00
Work equipment .......................................................................................................................... 2
Work equipment ...................................................................................................................... 2
Cutting edge, end bit ............................................................................................................... 12
Work equipment cylinder ......................................................................................................... 14
Electrical system SEN01142-00
Electrical system ......................................................................................................................... 2
Engine control.......................................................................................................................... 2
Machine monitor system.......................................................................................................... 3
Sensors ................................................................................................................................... 6
20 Standard value table
Standard service value table SEN01499-01
Standard service value table ....................................................................................................... 2
Standard value table for engine............................................................................................... 2
Standard value table for chassis.............................................................................................. 3
Standard value table for electrical system ............................................................................... 8

4. SEN01130-05 00 Index and foreword
6 D68ESS-12
30 Testing and adjusting
Testing and adjusting SEN01501-01
Testing and adjusting................................................................................................................... 2
Tools for testing, adjusting, and troubleshooting...................................................................... 2
Measuring blow-by pressure.................................................................................................... 3
Measuring exhaust color.......................................................................................................... 4
Measuring engine oil pressure................................................................................................. 5
Measuring engine speed ......................................................................................................... 6
Testing fan belt tension............................................................................................................ 7
Measuring speed at torque converter stall............................................................................... 8
Adjusting fuel control linkage................................................................................................... 9
Adjusting steering/directional lever, gearshift lever, and parking brake lever .......................... 11
Adjusting brake pedal linkage.................................................................................................. 14
Adjusting work equipment lock lever ....................................................................................... 15
Measuring power train hydraulic pressure............................................................................... 16
Measuring and adjusting work equipment oil pressure............................................................ 19
Measuring leakage inside cylinder........................................................................................... 20
Bleeding air from hydraulic cylinder......................................................................................... 20
40 Troubleshooting
General information on troubleshooting SEN01503-01
General information on troubleshooting ...................................................................................... 2
Points to remember when troubleshooting .............................................................................. 2
How to proceed troubleshooting.............................................................................................. 3
Connector types and mounting locations................................................................................. 5
Connector pin arrangement diagram....................................................................................... 6
How to distinguish wire code ................................................................................................... 8
Wiring table for connector pin numbers ................................................................................... 12
T-adapter box and T-adapter table .......................................................................................... 45
How to follow the troubleshooting flow diagrams..................................................................... 48
Troubleshooting of electrical system (E-mode) SEN01504-01
Troubleshooting of electrical system (E-mode) ........................................................................... 2
Table of failure modes and causes (Electrical system)............................................................ 2
Electrical circuit diagram for each system ............................................................................... 4
E-1 Starting motor is not cranked when starting switch is turned to ON.................................. 12
E-2 Lamps do not light up........................................................................................................ 18
Troubleshooting of hydraulic and mechanical system (H-mode) SEN01505-00
Troubleshooting of hydraulic and mechanical system (H-mode)................................................. 4
Table of failure modes and causes (hydraulic, mechanical system)........................................ 4
H-1 Brake does not work ......................................................................................................... 6
H-2 Machine does not turn (can travel in a straight line) ......................................................... 7
H-3 Overruns when turning...................................................................................................... 8
H-4 Can turn in only one direction (when steering lever is operated)...................................... 8
H-5 Excessive time lag ............................................................................................................ 9
H-6 Machine can travel in only one direction (forward or reverse) .......................................... 9
H-7 Machine does not move (when engine is started and lever is shifted to 2nd or 3rd) ........ 10
H-8 Machine does not move in any speed range .................................................................... 12
H-9 Power train oil temperature rises too high ........................................................................ 14
H-10 Drawbar pull is weak, travel speed is slow ..................................................................... 16
H-11 Abnormal noise is generated from around hydraulic pump............................................. 18
H-12 Work equipment speed is slow or lacks power............................................................... 18
H-13 No work equipment moves ............................................................................................. 19
H-14 Blade lift or tilt cylinder speed is slow or lacks power ..................................................... 19
H-15 Blade angle cylinder speed is slow or lacks power......................................................... 20
H-16 Hydraulic drift of blade lift is excessive ........................................................................... 20
H-17 Hydraulic drift of blade tilt is excessive ........................................................................... 21
H-18 Hydraulic drift of blade angle is excessive ...................................................................... 21

5. 00 Index and foreword SEN01130-05
D68ESS-12 7
Troubleshooting of machine monitor system (M-mode) SEN01506-01
Troubleshooting of machine monitor system (M-mode).............................................................. 2
Table of failure modes and causes (machine monitor system)................................................ 2
Electrical circuit diagrams for each system ............................................................................. 4
M-1 Caution item lights up....................................................................................................... 12
M-2 Gauge is abnormal ........................................................................................................... 16
M-3 Service meter does not move after engine is started ....................................................... 24
M-4 Monitor panel lighting does not light up (front lamps are normal)..................................... 25
50 Disassembly and assembly
General information on disassembly and assembly SEN01508-00
General information on disassembly and assembly.................................................................... 2
How to read this manual.......................................................................................................... 2
Coating materials list ............................................................................................................... 4
Special tool list......................................................................................................................... 7
Sketches of special tools......................................................................................................... 11
Engine and cooling system SEN01509-00
Engine and cooling system ......................................................................................................... 2
Removal and installation of engine assembly ......................................................................... 2
Removal and installation of radiator and guard assembly....................................................... 4
Removal and installation of radiator assembly ........................................................................ 6
Removal and installation of hydraulic oil cooler assembly ...................................................... 9
Removal and installation of fuel tank assembly....................................................................... 10
Removal and installation of damper assembly ........................................................................ 11
Power train SEN01510-02
Power train.................................................................................................................................. 3
Removal and installation of PTO, torque converter and transmission assembly..................... 3
Disconnection and connection of PTO, torque converter and transmission assembly............ 7
Disassembly and assembly of PTO assembly......................................................................... 9
Disassembly and assembly of torque converter assembly...................................................... 14
Disassembly and assembly of TORQFLOW transmission assembly...................................... 18
Removal and installation of torque converter main relief valve assembly ............................... 35
Disassembly and assembly of torque converter main relief valve assembly........................... 36
Removal and installation of transmission control valve assembly........................................... 37
Disassembly and assembly of transmission control valve assembly ...................................... 38
Removal and installation of steering clutch and brake assembly ............................................ 40
Disassembly and assembly of steering clutch and brake assembly........................................ 41
Removal and installation of bevel gear and bevel gear shaft (Clutch and brake model)......... 48
Removal and installation of brake valve assembly.................................................................. 54
Disassembly and assembly of brake valve assembly ............................................................. 55
Removal and installation of scavenging pump assembly ........................................................ 58
Removal and installation of power train and lubricating oil pump assembly ........................... 59
Removal and installation of final drive assembly..................................................................... 61
Disassembly and assembly of final drive assembly ................................................................ 62
Undercarriage and frame SEN01511-01
Undercarriage and frame ............................................................................................................ 2
Removal and installation of track frame assembly .................................................................. 2
Removal and installation of recoil spring assembly................................................................. 4
Disassembly and assembly of recoil spring assembly ............................................................ 5
Removal and installation of idler assembly ............................................................................. 8
Disassembly and assembly of idler assembly ......................................................................... 9
Removal and installation of track roller assembly ................................................................... 13
Disassembly and assembly of track roller assembly ............................................................... 14
Removal and installation of carrier roller assembly ................................................................. 17
Disassembly and assembly of carrier roller assembly............................................................. 18
Removal and installation of track shoe assembly.................................................................... 20

6. SEN01130-05 00 Index and foreword
8 D68ESS-12
Overall disassembly and assembly of track shoe assembly.................................................... 21
Field disassembly and assembly of one link............................................................................ 37
Removal and installation of pivot shaft assembly .................................................................... 44
Removal and installation of equalizer bar assembly................................................................ 46
Removal and installation of equalizer bar side bushing........................................................... 48
Removal installation of segment teeth..................................................................................... 49
Hydraulic system SEN01512-01
Hydraulic system......................................................................................................................... 2
Removal and installation of work equipment pump assembly ................................................. 2
Removal and installation of work equipment control valve assembly...................................... 3
Disassembly and assembly of work equipment control valve assembly ................................. 5
Removal and installation of steering PPC valve assembly...................................................... 9
Disassembly and assembly of steering PPC valve assembly ................................................. 10
Removal and installation of suction valve assembly................................................................ 13
Removal and installation of blade angle cylinder assembly .................................................... 14
Removal and installation of blade tilt cylinder assembly.......................................................... 15
Removal and installation of blade lift cylinder assembly.......................................................... 16
Disassembly and assembly of hydraulic cylinder assembly .................................................... 17
Work equipment SEN01513-01
Work equipment .......................................................................................................................... 2
Removal and installation of work equipment assembly ........................................................... 2
Disassembly and assembly of work equipment assembly....................................................... 8
Cab and its attachments SEN01514-00
Cab and its attachments.............................................................................................................. 2
Removal and installation of floor frame assembly ................................................................... 2
Removal and installation of sweep guard ................................................................................ 6
Electrical system SEN01515-01
Electrical system ......................................................................................................................... 2
Removal and installation of dashboard assembly ................................................................... 2
Removal and installation of panel assembly............................................................................ 3
90 Diagrams and drawings
Hydraulic diagrams and drawings SEN01144-00
Hydraulic diagrams and drawings ............................................................................................... 3
Power train hydraulic circuit diagram....................................................................................... 3
Work equipment hydraulic circuit diagram (1-spool valve (angle dozer)) ................................ 5
Work equipment hydraulic circuit diagram (3-spool valve (angle tilt dozer)) ........................... 7
Work equipment hydraulic circuit diagram (2-spool valve (trimming dozer)) ........................... 9
Electrical diagrams and drawings SEN01145-01
Electrical diagrams and drawings................................................................................................ 3
Forestry specification, general construction specification
Electrical circuit diagram (Serial No. 1001 – 1002, J10001 – J10010).................................... 3
Electrical circuit diagram (Serial No. 1003 and up, J10011 and up) ........................................ 5
Trimming dozer
Electrical circuit diagram.......................................................................................................... 7

7. D68ESS-12 1
SEN01131-02
BULLDOZER 1SHOP MANUAL
D68ESS-12
Machine model Serial number
D68ESS-12 1001 and up
J10001 and up
00 Index and foreword 1
Foreword and general information
Safety notice ................................................................................................................................................... 2
How to read the shop manual......................................................................................................................... 7
Explanation of terms for maintenance standard ............................................................................................. 9
Handling of electric equipment and hydraulic component .............................................................................11
Handling of connectors newly used for engines ........................................................................................... 20
How to read electric wire code...................................................................................................................... 23
Precautions when carrying out operation...................................................................................................... 26
Method of disassembling and connecting push-pull type coupler................................................................. 29
Standard tightening torque table ................................................................................................................... 32
Conversion table ........................................................................................................................................... 36

8. SEN01131-02 00 Index and foreword
2 D68ESS-12
(Rev. 2007/03)Safety notice 1
Important safety notice
Proper service and repair are extremely important for safe machine operation. The service and repair
techniques recommended by Komatsu and described in this manual are both effective and safe.
Some of these techniques require the use of tools specially designed by Komatsu for the specific
purpose.
To prevent injury to workers, the symbol k is used to mark safety precautions in this manual. The
cautions accompanying these symbols should always be followed carefully. If any dangerous situa-
tion arises or may possibly arise, first consider safety, and take the necessary actions to deal with
the situation.
1. General precautions
k Mistakes in operation are extremely
dangerous. Read the Operation and
Maintenance Manual carefully before
operating the machine.
1) Before carrying out any greasing or
repairs, read all the safety plates stuck to
the machine. For the locations of the
safety plates and detailed explanation of
precautions, see the Operation and Main-
tenance Manual.
2) Decide a place in the repair workshop to
keep tools and removed parts. Always
keep the tools and parts in their correct
places. Always keep the work area clean
and make sure that there is no dirt, water,
or oil on the floor. Smoke only in the areas
provided for smoking. Never smoke while
working.
3) When carrying out any operation, always
wear safety shoes and helmet. Do not
wear loose work clothes, or clothes with
buttons missing.
q Always wear safety glasses when hit-
ting parts with a hammer.
q Always wear safety glasses when
grinding parts with a grinder, etc.
4) When carrying out any operation with 2 or
more workers, always agree on the oper-
ating procedure before starting. Always
inform your fellow workers before starting
any step of the operation. Before starting
work, hang UNDER REPAIR warning
signs in the operator's compartment.
5) Only qualified workers must carry out work
and operation which require license or
qualification.
6) Keep all tools in good condition, learn the
correct way to use them, and use the
proper ones of them. Before starting work,
thoroughly check the tools, machine, fork-
lift, service car, etc.
7) If welding repairs are needed, always
have a trained and experienced welder
carry out the work. When carrying out
welding work, always wear welding
gloves, apron, shielding goggles, cap and
other clothes suited for welding work.
8) Before starting work, warm up your body
thoroughly to start work under good condi-
tion.
2. Preparations for work
1) Before adding oil or making any repairs,
park the machine on hard and level
ground, and apply the parking brake and
block the wheels or tracks to prevent the
machine from moving.
2) Before starting work, lower the work
equipment (blade, ripper, bucket, etc.) to
the ground. If this is not possible, insert
the lock pin or use blocks to prevent the
work equipment from falling. In addition,
be sure to lock all the control levers and
hang warning signs on them.
Safety points
1 Good arrangement
2 Correct work clothes
3 Following work standard
4 Making and checking signs
5
Prohibition of operation and handling by
unlicensed workers
6 Safety check before starting work
7
Wearing protective goggles
(for cleaning or grinding work)
8
Wearing shielding goggles and protectors
(for welding work)
9 Good physical condition and preparation
10
Precautions against work which you are
not used to or you are used to too much

9. 00 Index and foreword SEN01131-02
D68ESS-12 3
3) When disassembling or assembling, sup-
port the machine with blocks, jacks, or
stands before starting work.
4) Remove all mud and oil from the steps or
other places used to get on and off the
machine. Always use the handrails, lad-
ders or steps when getting on or off the
machine. Never jump on or off the
machine. If it is impossible to use the
handrails, ladders or steps, use a stand to
provide safe footing.
3. Precautions during work
1) Before disconnecting or removing compo-
nents of the oil, water, or air circuits, first
release the pressure completely from the
circuit. When removing the oil filler cap, a
drain plug, or an oil pressure pickup plug,
loosen it slowly to prevent the oil from
spurting out.
2) The coolant and oil in the circuits are hot
when the engine is stopped, so be careful
not to get scalded. Wait for the oil and
coolant to cool before carrying out any
work on the oil or water circuits.
3) Before starting work, stop the engine.
When working on or around a rotating
part, in particular, stop the engine. When
checking the machine without stopping
the engine (measuring oil pressure,
revolving speed, temperature, etc.), take
extreme care not to get rolled or caught in
rotating parts or moving parts.
4) Before starting work, remove the leads
from the battery. Always remove the lead
from the negative (–) terminal first.
5) When raising a heavy component (heavier
than 25 kg), use a hoist or crane. Before
starting work, check that the slings (wire
ropes, chains, and hooks) are free from
damage. Always use slings which have
ample capacity and install them to proper
places. Operate the hoist or crane slowly
to prevent the component from hitting any
other part. Do not work with any part still
raised by the hoist or crane.
6) When removing a cover which is under
internal pressure or under pressure from a
spring, always leave 2 bolts in diagonal
positions. Loosen those bolts gradually
and alternately to release the pressure,
and then remove the cover.
7) When removing components, be careful
not to break or damage the electrical wir-
ing. Damaged wiring may cause electrical
fires.
8) When removing piping, stop the fuel or oil
from spilling out. If any fuel or oil drips
onto the floor, wipe it up immediately. Fuel
or oil on the floor can cause you to slip
and can even start fires.
9) As a general rule, do not use gasoline to
wash parts. Do not use it to clean electri-
cal parts, in particular.
10) Be sure to assemble all parts again in their
original places. Replace any damaged
parts and parts which must not be reused
with new parts. When installing hoses and
wires, be sure that they will not be dam-
aged by contact with other parts when the
machine is operated.
11) When installing high pressure hoses,
make sure that they are not twisted. Dam-
aged tubes are dangerous, so be
extremely careful when installing tubes for
high pressure circuits. In addition, check
that connecting parts are correctly
installed.
12) When assembling or installing parts,
always tighten them to the specified
torques. When installing protective parts
such as guards, or parts which vibrate vio-
lently or rotate at high speed, be particu-
larly careful to check that they are
installed correctly.
13) When aligning 2 holes, never insert your
fingers or hand. Be careful not to get your
fingers caught in a hole.
14) When measuring hydraulic pressure,
check that the measuring tools are cor-
rectly assembled.
15) Take care when removing or installing the
tracks of track-type machines. When
removing the track, the track separates
suddenly, so never let anyone stand at
either end of the track.
16) If the engine is operated for a long time in
a place which is not ventilated well, you
may suffer from gas poisoning. Accord-
ingly, open the windows and doors to ven-
tilate well.

10. D68ESS-12 1
SEN01133-00
BULLDOZER 1SHOP MANUAL
D68ESS-12
Machine model Serial number
D68ESS-12 1001 and up
J10001 and up
01 Specification 1
Specification and technical data
Specification and technical data...................................................................................................................... 2
Specification drawing ........................................................................................................................... 2
Specifications ....................................................................................................................................... 4
Weight table ......................................................................................................................................... 8
Table of fuel, coolant and lubricants................................................................................................... 10

11. SEN01133-00 01 Specification
2 D68ESS-12
Specification and technical data 1
Specification drawing 1
Forestry specification
Angle dozer (Mechanical angle)
Angle tiltdozer (Power angle)

12. 01 Specification SEN01133-00
D68ESS-12 3
General construction specification
Angle dozer (Mechanical angle)
Trimming dozer

13. SEN01133-00 01 Specification
4 D68ESS-12
Specifications 1
Machine name and type
Forestry
specification
General
construction
specification
Trimming
dozer
Serial number
1001 and up
J10001 and up
1005 and up
Weight
Operating weight
kg
• Bare tractor 14,280 14,150 —
• With angle tiltdozer, sweep guard, winch 18,800 — —
• With angle dozer, sweep guard, winch 19,100 — —
• With angle dozer — 17,350 —
• With trimming dozer — — 17,600
• With trimming dozer, ROPS cab — — 17,860
Performance
Min. turning radius m 2.8 2.7 2.7
Gradeability deg 30 30 30
Stability (front, rear, left, right) deg 35 35 35
Speedranges
Forward 1st 3.4 3.4 3.4
Forward 2nd km/h 5.8 5.8 5.8
Forward 3rd 9.0 9.0 9.0
Reverse 1st 4.4 4.4 4.4
Reverse 2nd km/h 7.6 7.6 7.6
Reverse 3rd 11.3 11.3 11.3
Groundpressure
Bare tractor
kPa
{kg/cm2
}
39 {0.40} 45 {0.46} —
Angle tiltdozer, winch, sweep guard 52 {0.53} — —
Angle dozer, winch, sweep guard 52 {0.53} — —
With angle dozer — 56 {0.57} —
With trimming dozer — — 61.4 {0.63}
With trimming dozer, ROPS cab — — 62.3 {0.64}
Dimensions
Overalllength
• Bare tractor
mm
4,100 4,100 —
• With angle tiltdozer, winch 6,120 — —
• With angle dozer, winch 6,280 — —
• With angle dozer — 5,415 —
• With trimming dozer — — 5,855
Overallwidth
• Bare tractor
mm
2,535 2,535 —
• With angle tiltdozer 3,275 — —
• With angle dozer 3,970 3,970 —
• With trimming dozer — — 3,020
Overallheight
• To tip of exhaust pipe
mm
2,780 2,715 —
• To top of operator’s compartment 2,305 2,305 —
• To top of sweep guard 3,135 3,140 —
• With trimming dozer, ROPS cab (excluding antenna) — — 3,070
• With trimming dozer, cab (excluding antenna) — — 2,990
Track gauge
mm
1,925 1,925 1,925
Length of track on ground 2,930 2,725 2,725
Width of track shoe (standard) 610 560 510
Min. ground clearance (To bottom of undercover) 390 390 390

14. 01 Specification SEN01133-00
D68ESS-12 5
Machine name and type
Forestry
specification
General construction
specification
Trimming dozer
Serial number
1001 and up
J10001 and up
1005 and up
Engine
Model S6D114E-1A
Type
4-cycle, water cooled, inline vertical type
direct injection with turbocharger
No. of cylinder – bore × stroke mm 6 – 114 × 135
Piston displacement l {cc} 8.27 {8,270}
Performance
Rated horsepower
kW/rpm
{HP/rpm}
116/1,850
{155/1,850}
Max. torque
Nm/rpm
{kgm/rpm}
824/1,300
{84/1,300}
High idle rpm 2,000
Low idle rpm 890
Min. fuel consumption ratio
g/kWh
{g/HPh}
220 {163}
Starting motor 24 V, 7.5 kW
Alternator 24 V, 35 A
Battery 12 V, 200 Ah × 2
Radiator core type D-6
Powertrainsystem
Torque converter
3-element,
1-stage, 1 phase
Transmission
Planetary gear type, multiple disc clutch, hydraulically actuated, lubri-
cation gear pump, force feed, forward 3-speed, reverse 3-speed,
manual mechanical type
Bevel gear shaft Spiral bevel gear, force feed lubrication gear pump
Steering clutch
Wet type multiple disc, spring boosted, hand operated, hydraulically
actuated
Steering brake
Wet type, multiple disc, spring boosted, hand and foot operated,
hydraulically actuated
Final drive 2-stage spur gear reduction, splash type lubrication
Undercarriage
Suspension Semi-rigid, floating beam
Carrier roller (each side) 2
Track roller (each side) 7 6
Track shoe 610 mm
Assembly type, single
grouser, on each side,
pitch: 203.2 mm
— —
Track shoe 560 mm —
Assembly type, single
grouser, on each side,
pitch: 203.2 mm
—
Track shoe 510 mm — —
Assembly type, triple
grouser, on each side,
pitch: 203.2 mm
Power train, lubrication pump Gear type (SAL(2)–040+040)
PPC pump
Gear type (SBR(1)-08)
Max. discharge pressure: 3.0 MPa {31 kg/cm2
}
Theoretical discharge amount:
17.3 l/min/2,164 rpm

15. SEN01133-00 01 Specification
6 D68ESS-12
Machine name and type
Forestry
specification
General
construction
specification
Trimming dozer
Serial number
1001 and up
J10001 and up
1005 and up
Workequipmenthydraulicsystem
Hydraulic pump
Gear type (SAL 63)
Permissible peak pressure: 24 MPa {250 kg/cm2
}
Maincontrolvalve
Type
1 spool type —
• For blade lift
Type
3-spool type
(1 spool type for
angle dozer)
— —
• For blade lift
• For blade tilt
• For blade angle
Type
— — 2-spool type• For blade lift
• For blade incline
Hydrauliccylinder
Type Reciprocal type
Dimensionsof
bladeliftcylinder
Cylinder bore
mm
110 110
Outside diameter of piston rod 55 55
Piston stroke 469 505
Max. distance between pins 1,322 1,394
Min. distance between pins 853 889
Dimensionsof
bladetiltcylinder
Cylinder bore
mm
130
— —
Outside diameter of piston rod 70
Piston stroke 190
Max. distance between pins 1,226
Min. distance between pins 1,036
Dimensionsof
bladeanglecylinder
Cylinder bore
mm
100
— —
Outside diameter of piston rod 60
Piston stroke 469
Max. distance between pins 1,349
Min. distance between pins 880
Dimensionof
trimmingcylinder
Cylinder bore
mm — —
110
Outside diameter of piston rod 55
Piston stroke 460
Max. distance between pins 1,334
Min. distance between pins 874
Hydraulic tank Box type (externally installed control valve)
Workequipment
(angletiltdozer)
Type Hydraulic angle tiltdozer
Blade support method Frame type —
Perfor-
mance
Max. lifting height (from ground) mm 1,055
— —Max. lowering depth (from ground) mm 560
Max. tilt mm 510
Dimen-
sions
Blade width mm 3,275
— —Blade height mm 1,200
Blade cutting angle deg 57

16. 01 Specification SEN01133-00
D68ESS-12 7
Machine name and type
Forestry
specification
General
construction
specification
Trimming dozer
Serial number
1001 and up
J10001 and up
1005 and up
Workequipment
(angledozer)
Type Mechanical angle
Blade support method Frame type —
Perfor-
mance
Max. lifting height (from ground) mm 1,205 1,130
—Max. lowering depth (from ground) mm 535 540
Max. tilt mm 400
Dimen-
sions
Blade width mm 3,970
—Blade height mm 950
Blade cutting angle deg 55
Workequipment
(trimmingdozer)
Type Trimming dozer
Blade support method — — Frame type
Performance
Max. lifting height (from ground) mm
— —
1,655
Max. lowering depth (from ground) mm 735
Degree of blade
inclining
Front direction
deg
45
Rear direction 26
Dimen-
sions
Blade width mm 3,020
Blade height mm 960

17. SEN01133-00 01 Specification
8 D68ESS-12
Weight table 1
k This weight table is a guide for use when transporting or handling components.
Unit: kg
Machine Model Forestry specification
General construction
specification
Trimming dozer
Serial Numbers
1001 and up
J10001 and up
1005 and up
Engine, damper assembly 840
• Engine assembly 797
• Damper assembly 35
• Parts mounted to engine (wiring) 8
Radiator assembly (including oil cooler) 140
• Oil cooler assembly (for hydraulic oil) 5
• Fuel tank assembly 151
Transmission assembly 465
• Transmission valve assembly 15
• Main relief valve assembly 7
Torque converter, PTO assembly 320
• Steering clutch and brake assembly 1,235
Final drive assembly (each side) 741
Sprocket assembly (each side) 15 × 5
Hull frame assembly 1,010
Track group assembly (each side) 1,398 1,398
• Track frame 534 510
• Idler assembly (each side) 172 172
• Track roller assembly (single: 1) 54 × 5 54 × 5
• Track roller assembly (double: 1) 61 × 2 61 × 2
• Carrier roller assembly (1) 27 × 2 27 × 2
Track shoe assembly (each side)
(single) (610 mm, wet type)
1,493 — —
Track shoe assembly (each side)
(single) (560 mm, wet type)
— 1,365 —
Track shoe assembly (each side)
(triple) (510 mm, wet type)
— — 2,770
Pivot shaft (each side) 78
Equalizer bar 85
Hydraulic tank assembly 44 44
Main control valve
• Lift 16 16
• Lift + tilt + angle 32 —
Engine underguard 45
Transmission underguard 22
Operator's seat 27

18. 01 Specification SEN01133-00
D68ESS-12 9
Angle tiltdozer assembly 2,355
— —
• Blade 1,010
• U-frame 1,005
• Tilt cylinder assembly 78
• Angle cylinder 52 × 2
Blade lift cylinder assembly 48 × 2
Power train pump assembly 20
Hydraulic pump assembly 11
Floor frame assembly 310
Sweep guard assembly 548
Winch assembly (with wire) 1,520 —
Angel dozer assembly 2,660
—• Blade 910
• C-frame 1,012
Trimming dozer
— —
2,550
• Trimming dozer cylinder assembly 48 x 2
Unit: kg
Machine Model Forestry specification
General construction
specification
Trimming dozer
Serial Numbers
1001 and up
J10001 and up
1005 and up

19. SEN01133-00 01 Specification
10 D68ESS-12
Table of fuel, coolant and lubricants 1
a For details of notes (Notes 1 and 2...) in the table, see Operation and Maintenance Manual.
a Although SAE10W30DH and SAE15W40DH are specified to be used as engine oil for engine oil pan,
SAE10W30 (API CH4, CI-4) and SAE15W40 (API CH4, CI-4) can be used instead respectively.

20. 01 Specification SEN01133-00
D68ESS-12 11
Unit: l
Supply point Specified capacity Refill capacity
Engine oil pan 23 19
Damper case 1.3 1.3
Idler (each of right and left) 0.22 0.22
Hydraulic oil system 73 48
Power train case 100 75
Final drive case (each of right and left) 32 28.5
Fuel tank 315 —
Cooling system (including sub-tank) 44 —

21. 12
SEN01133-00
D68ESS-12 Bulldozer
Form No. SEN01133-00
© 2006 KOMATSU
All Rights Reserved
Printed in Japan 06-06 (01)

22. D68ESS-12 1
SEN01135-00
BULLDOZER 1SHOP MANUAL
D68ESS-12
Machine model Serial number
D68ESS-12 1001 and up
J10001 and up
10 Structure, function and
maintenance standard 1
Engine and cooling system
Engine and cooling system............................................................................................................................. 2
Radiator, power train, oil cooler............................................................................................................ 2
Engine control ...................................................................................................................................... 4

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24. SEN01135-00 10 Structure, function and maintenance standard
2 D68ESS-12
Engine and cooling system 1
Radiator, power train, oil cooler 1
Outline
q A reservoir tank has been installed for the radi-
ator to make it possible to check the radiator
coolant level.
q The power train oil cooler is built into the lower
tank.
Radiator
Power train oil cooler
(built into the lower tank)
Core type D-6 PTO-LS
Fin pitch (mm) 4.0 —
Heat dissipation capacity (kcal/h) 88,500 25,900
Heat dissipation area (m2
) 46.19 1.829

25. 10 Structure, function and maintenance standard SEN01135-00
D68ESS-12 3
1. Radiator core assembly
2. Fan guard
3. Inlet hose
4. Reservoir tank
5. Outlet hose
6. Lower tank (with built-in power train oil cooler)
7. Fan
8. Coolant filler cap
9. Drain plug
10. Power train oil cooler
11. Boss
12. Cushion
A. Power train oil cooler inlet port
B. Power train oil cooler outlet port

26. SEN01135-00 10 Structure, function and maintenance standard
4 D68ESS-12
Engine control 1
1. Decelerator pedal
2. Throttle lever
3. Clutch
4. Cable
5. Fuel injection pump
Lever positions
[1] Low idle
[2] High idle
Outline
q The engine speed is controlled by throttle lever
(2) or decelerator pedal (1).