PDF Shop Manual Komatsu PC138USLC-10 Hydraulic Excavator - 3 MB
This is the complete factory shop manual for the Komatsu PC138USLC-10 Hydraulic Excavator.
It contains comprehensive information on testing, adjusting, troubleshooting, and repair procedures.
Technicians will find detailed specifications and step-by-step instructions for all major systems, including the engine and hydraulics.
This manual is the definitive guide for servicing your Komatsu excavator.
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--- Page 1 ---
SEN06062-04
HYDRAULIC PC138USLC -10
EXCAVATOR SERIAL NUMBERS 40001 and up
--- Page 3 ---
00 Index and foreword
Foreword, safety and general information
Foreword, safety and general information (ALL-0370-001-A-00-A)
Important safety notice (ALL-1120-012-A-01-A)
(Rev. 2014/08)
âĒ Appropriate servicing and repair are extremely important to ensure safe operation of the machine. The
shop manual describes the effective and safe servicing and repair methods recommended by Komatsu.
Some of these methods require the use of the special tools designed by Komatsu for the specific purpose.
âĒ The symbol mark k is used for such matters that require special cautions during the work. The work
indicated by the caution mark should be performed according to the instructions with special attention to
the cautions. Should hazardous situation occur or be anticipated during such work, be sure to keep safe
first and take every necessary measure.
Safety points before starting. While working, always keep
âĒ Good arrangement conversations of the work between your fellow
âĒ Correct work clothes workers and your self on any step of the work.
âĒ Observance of work standard During the work, hang the warning tag of
âĒ Practice of making and checking signals "UNDER WORKING" in the operator's
âĒ Prohibition of operation and handling by compartment.
unlicensed workers âĒ Only qualified workers must perform the work
âĒ Safety check before starting work and operation which require license or
âĒ Wearing protective goggles (for cleaning or qualification.
grinding work) âĒ Keep the tools in good condition. And learn the
âĒ Wearing shielding goggles and protectors (for correct way to use the tools, and use the proper
welding work) ones among them. Before starting the work,
âĒ Good physical condition and preparation thoroughly check the tools, lift truck, service
âĒ Precautions against work which you are not vehicle, etc.
used to or you are used to too much âĒ If welding repairs is required, always have a
trained and experienced welder with good
General precautions knowledge of welding perform the work. When
k Inappropriate handling causes an extreme
performing welding work, always wear welding
danger. Read and understand what is gloves, apron, shielding goggles, cap, etc.
described in the operation and maintenance âĒ Before starting work, warm up your body
manual before operating the machine. Read thoroughly to start work under good condition.
and understand what is described in this âĒ Avoid continuing work for long hours and take
manual before starting the work. rests with proper intervals to keep your body in
good condition. Take a rest in a specified safe
âĒ Before performing any greasing or repairs, read place.
all the safety labels stuck to the machine. For
Preparation
the locations of the safety labels and detailed
âĒ Before adding oil or making any repairs, place
explanation of precautions, see the operation
the machine on a firm and level ground, and
and maintenance manual.
apply the parking brake and chock the wheels or
âĒ Locate a place in the repair workshop to keep
tracks to prevent the machine from moving.
the tools and removed parts. Always keep the
âĒ Before starting work, lower the work equipment
tools and parts in their correct places. Always
(blade, ripper, bucket, etc.) to the ground. If it is
keep the work area clean and make sure that
not possible to lower the equipment to the
there is no dirt, water or oil on the floor. Smoke
ground, insert the lock pin or use blocks to
only in the areas provided for smoking. Never
prevent the work equipment from falling. And be
smoke while working.
sure to lock all the work equipment control levers
âĒ When performing any work, always wear the
and hang a warning tag on them.
safety shoes and helmet. Do not wear loose
âĒ When performing the disassembling or
work cloths, or clothes with buttons missing.
assembling work, support the machine securely
1. Always wear the protective eyeglasses when with blocks, jacks, or stands before starting the
hitting parts with a hammer. work.
2. Always wear the protective eyeglasses when âĒ Remove all of mud and oil from the steps or
grinding parts with a grinder, etc. other places used to get on and off the machine
âĒ When performing any work with 2 or more completely. Always use the handrails, ladders of
workers, always agree on the working procedure steps when getting on or off the machine. Never
PC138USLC-10 00-13
--- Page 4 ---
00 Index and foreword
Foreword, safety and general information
Flushing operations
âĒ After disassembling the equipment or when
changing the hydraulic oil with new one, flush
the system to remove the contaminant and
sludge left in the hydraulic circuit as well as the
oil which includes them. Normally, flushing is
performed twice. Primary flushing is performed
by use of the flushing oil and the secondary
flushing is performed by use of the specified
hydraulic oil.
Cleaning operations
âĒ After repairing the hydraulic equipment (pump,
control valve, etc.) or when the machine is in
operation, perform oil cleaning to remove the
sludge or contaminant in the hydraulic oil circuit.
The oil cleaning equipment can remove the ultra
fine (approximately 3 Ξm) particles that the filter
built in the hydraulic equipment can not remove.
So, it is an extremely effective device.
PC138USLC-10 00-27
--- Page 5 ---
00 Index and foreword
Foreword, safety and general information
Color codes table
(Table 3)
Color Code Color of wire Color Code Color of wire
B Black LgW Light green & White
Br Brown LgY Light green & Yellow
BrB Brown & Black LR Blue & Red
BrR Brown & Red LW Blue & White
BrW Brown & White LY Blue & Yellow
BrY Brown & Yellow O Orange
Ch Charcoal P Pink
Dg Dark green R Red
G Green RB Red & Black
GB Green & Black RG Red & Green
GL Green & Blue RL Red & Blue
Gr Gray RW Red & White
GR Green & Red RY Red & Yellow
GW Green & White Sb Sky Blue
GY Green & Yellow Y Yellow
L Blue YB Yellow & Black
LB Blue & Black YG Yellow & Green
Lg Light green YL Yellow & Blue
LgB Light green & Black YR Yellow & Red
LgR Light green & Red YW Yellow & White
a Remarks: In a color code consisting of 2 colors, the first color is the color of the background and the
second color is the color of the marking.
Examples)
GW means that the background is "Green" and marking is "White".
Types of circuits and color codes
Type of wire AVS, AV, CAVS AEX
Charge R WG â â â â R â
Ground B â â â â â B â
Start R â â â â â R â
Light RW RB RY RG RL â D â
Instrument Y YR YB YG YL YW Y Gr
Signal G GW GR GY GB GL G Br
L LW LR LY LB â L â
Type of â â â
Br BrW BrR BrY BrB
circuit
Lg LgR LgY LgB LgW â â â
O â â â â â â â
Others Gr â â â â â â â
P â â â â â â â
Sb â â â â â â â
Dg â â â â â â â
Ch â â â â â â â
PC138USLC-10 00-41
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00 Index and foreword
Foreword, safety and general information
Purpose of use (major
Abbrevia- Actual word spelled applicable machine (*), or Explanation
tion out equipment/device)
Transmission Proportional electromagnetic valve that
Electronic Control
ECMV gradually increases oil pressure to engage
Modulation Valve (D, HD, WA, etc.)
clutch and reduces transmission shock.
Electronically This system ensures smooth high-speed
Travel travel by absorbing vibration of machine
ECSS Controlled Suspension
System (WA) during travel with hydraulic spring effect of
accumulator.
Electronic control device uses the signals
from the sensors on the machine. This signal
ECU Electronic Control Unit Electronic control system indicates the optimum actuation to the
actuators. (Same as E.C.M.)
This function recirculates part of exhaust gas
Exhaust Gas Engine to combustion chamber in order to reduce
EGR
Recirculation combustion temperature, controls emission of
NOx.
Equipment This system allows data (filter, oil replacement
Management interval, malfunctions on machine, failure
EMMS Machine monitor
Monitoring System code, and failure history) from each sensor on
the machine to be checked on the monitor.
Electromagnetic This mechanism allows actuators to be
EPC Hydraulic system
Proportional Control operated in proportion to the current supplied.
This structure protects the operator's head
from falling objects. (Falling Object Protective
Falling Object Cab and canopy Structure)
FOPS
Protective Structure
This performance is standardized as ISO
3449.
Forward-Neutral- Operation
F-N-R Forward-Neutral-Reverse
Reverse
Global Navigation A general term for positioning system using
GNSS Satellite System Communication satellites such as GPS, GALILEO, etc.
Communication
Global Positioning This system uses satellites to determine the
GPS System (KOMTRAX, KOMTRAX current location on the earth.
Plus)
This function uses a combination of hydraulic
Steering motor and bevel shaft to control difference in
Hydrostatic Steering
HSS travel speed of right and left tracks.
System (D) Accordingly machine can turn without using
steering clutch.
Transmission This function uses a combination of hydraulic
Hydro Static pump and hydraulic motor to shift the speed
HST
Transmission (D, WA) range steplessly without using gears.
Information and A general term for the engineering and its
Communication Intelligent Machine socially applied technology of information
ICT
Technology Control processing and communication.
This valve is installed at inlet port of pump,
Inlet Metering Actuator Engine and it adjusts fuel intake amount in order to
IMA
control fuel discharge of supply pump. Same
as I.M.V.
This is a device to detect the angular velocity
Inertial Measurement Intelligent Machine
IMU and acceleration of the 3 axes that control
Unit Control
motions.
This valve is installed at inlet port of pump,
and it adjusts fuel intake amount in order to
IMV Inlet Metering Valve Engine
control fuel discharge of supply pump. Same
as I.M.V. (I.M.A.)
This mechanism separates oil in blowby gas
Komatsu Closed Engine and returns it to the intake side to afterburn it
KCCV
Crankcase Ventilation there. It primarily consists of filters.
PC138USLC-10 00-55
--- Page 7 ---
01 Specification
Specifications
Specifications (ALL-2111-001-A-01-A)
PC138USLC-10 (PC138_10-2111-931-A-00-A)
PC138USLC-10
Machine model Blade mountable Reinforced blade
Unit specification specification
Serial No. 40001 and up
Bucket capacity m3 0.50 0.50
Machine weight kg 14,600 15,450
Performance
Working ranges
Max. digging depth mm 5,480 5,480
Max. vertical wall digging depth mm 4,900 4,900
Max. digging reach mm 8,300 8,300
Max. digging reach at ground level mm 8,180 8,180
Max. digging height mm 9,340 9,340
Max. dumping height mm 6,840 6,840
Max. blade lift above ground mm â 470
Max. blade drop below ground mm â 490
Max. digging force (bucket) kN {kg} 93.2 {9,500} 93.2 {9,500}
Continuous swing speed min-1 {rpm} 11.0 {11.0} 11.0 {11.0}
Swing operation max. slope angle deg. 20 20
Travel speed (Lo/Hi) km/h 2.9/5.1 2.9/5.1
Gradeability deg. 35 35
Ground pressure (standard shoe) kPa {kg/cm2} 35.3 {0.36} 37.3 {0.38}
Dimensions
Overall length (for transport) mm 7,390 8,040
Overall width mm 2,590 2,590
Overall height (for transport) mm 2,850 2,850
Overall height (for operation) mm 2,830 2,830
Ground clearance of upper structure (*1) mm 900 900
Min. ground clearance mm 395 395
Tail swing radius mm 1,545 1,545
Min. swing radius of work equipment mm 1,980 1,980
Max. height of work equipment in min.
mm 6,770 6,770
swing radius posture
Overall width of track mm 2,590 2,590
Overall length of track mm 3,870 3,870
Distance between tumbler centers mm 3,140 3,140
Track gauge mm 1,990 1,990
Machine cab height mm 2,140 2,140
Blade width x height mm â 2,590 x 590
*1: The values are for machines with triple grouser shoes.
PC138USLC-10 01-5
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10 Structure and function
Variable flow turbocharger
1. Variable flow turbocharger motor
2. Flange bolt
3. Bracket
4. Thrust sleeve
PC138USLC-10 10-7
--- Page 9 ---
10 Structure and function
KDOC muffler
KDOC muffler (ENG95-A9H2-041-K-00-A)
a KDOC: Abbreviation for Komatsu Diesel Oxidation Catalyst
a The shape is subject to machine models.
1. DOC unit
2. Silencer unit
3. Exhaust gas outlet piping
4. Exhaust gas inlet piping
5. Drain piping
Structure
âĒ The KDOC muffler consists of inlet piping (4) to lead in the exhaust gas from the engine, DOC unit (1) to
store the oxidation catalyst, silencer unit (2) having silencing function and containing a "dam" to prevent
rain water from flowing into the DOC unit from exhaust gas outlet piping, outlet piping (3) to discharge the
exhaust gas, and drain piping (5) to drain water from the silencer unit. Those components are welded
together into one unit.
âĒ DOC unit (1) consists of ceramic honeycomb with oxidation catalyst.
âĒ The ceramic honeycomb is protected with a mat made of special fibers to prevent breakage of the ceramic
under the vibrations from the engine and chassis.
PC138USLC-10 10-21
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10 Structure and function
Hydraulic tank
Hydraulic tank (PC138-PM30-041-K-00-A)
1. Hydraulic tank
2. Oil filler cap with breather
3. Sight gauge
4. Drain plug
5. Filter element
6. Bypass valve
7. Suction strainer
Specifications (PC138-PM30-030-K-00-A)
Hydraulic tank capacity (l) 99
Hydraulic oil in tank (l) 69
Bypass valve set pressure (MPa {kg/cm2}) 0.15 Âą 0.03 {1.53 Âą 0.3}
PC138USLC-10 10-35
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10 Structure and function
Main pump
LS valve (PC138-C2J0-041-K-00-A)
a LS: Abbreviation for Load Sensing
PA: Pump port
PDP: Drain port
PLP: LS control pressure output port
PLS: LS pressure input port
PP: Pump port
PPL: Control pressure input port
1. Sleeve
2. Piston
3. Spool
4. Spring
5. Seat
6. Sleeve
7. Plug
8. Lock nut
Function (PC138-C2J0-042-K-00-A)
âĒ The LS valve detects the load and controls the pump discharge.
âĒ This valve controls pump discharge (Q) according to differential pressure (dPLS) [ = (PP) â (PLS)] (called
LS differential pressure) between pump discharge pressure (PP) and control valve outlet port pressure
(PLS).
âĒ This valve receives main pump pressure (PP) and pressure (PLS) (called the LS pressure) coming from
the control valve output.
PC138USLC-10 10-49
--- Page 12 ---
10 Structure and function
Main pump
PC-EPC valve (D65-C2E5-041-P-00-A)
a PC: Abbreviation for Pressure Compensation
a EPC: Abbreviation for Electromagnetic Proportional Control
C: To PC valve
P: From pump
T: To tank
1. Connector
2. Coil
3. Body
4. Spring
5. Spool
6. Rod
7. Plunger
Function (D65-C2E5-042-P-00-A)
âĒ The EPC valve consists of the proportional solenoid and the hydraulic valve.
âĒ When signal current (i) from the controller is received, an EPC output pressure proportional to the
amperage of current is generated and output to the PC valve.
PC138USLC-10 10-63
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10 Structure and function
Control valve
PC138USLC-10 10-77
--- Page 14 ---
10 Structure and function
Control valve
Operation
When work equipment valve is operated
(including simultaneous operation of work equipment and travel)
âĒ Since merge-divider spool (1) is located at the merge position, the pressurized oil in LS circuits (PLS1),
(PLS2), and (PLS3) flows from filter (a) at the end of LS bypass plug (2) through orifice (b) into tank circuit
(T).
PC138USLC-10 10-91
--- Page 15 ---
10 Structure and function
Control valve
Self-pressure reducing valve (PC138-PL30-042-K-00-A)
Function
âĒ It reduces the main pump discharge pressure and provides it as control pressure to the solenoid valves,
EPC valves, etc.
Operation
If normal
âĒ When pressure (PR) exceeds the set pressure, poppet (1) opens.
âĒ The pressurized oil flows from port (PR) to orifice (a) in spool (4), and then flows through the opening of
poppet (1) to seal drain port (TS).
âĒ Differential pressure is generated over orifice (a) in spool (4) and spool (4) moves to close the opening
between ports (P) and (PR).
âĒ Pressure (P) is reduced and adjusted to constant pressure (set pressure) by the opening area at this time
and supplied as pressure (PR).
When abnormal high pressure occurs
âĒ If pressure (PR) of the self-pressure reducing valve becomes abnormal, ball (6) compresses spring (5)
and separates from the seat.
âĒ The pressurized oil flows through port (PR) to (TS) to reduce pressure (PR).
âĒ Thus, the hydraulic components such as the PPC valves and solenoid valves are protected from abnormal
pressure.
PC138USLC-10 10-105
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10 Structure and function
Swing motor
When stopping swing
âĒ When the control lever is returned from "Swing RIGHT" to "NEUTRAL", the pressurized oil from the pump
is not supplied to port (MA).
âĒ Since the return circuit to the tank for the pressurized oil from the motor outlet is closed by control valve (6),
the pressure in port (MB) increases.
âĒ Rotation resistance is generated in the motor and the brake starts to work.
âĒ When the pressure in port (MB) exceeds that in port (MA), it pushes shuttle valve (4).
âĒ The pressure in chamber (C) becomes the same with port (MB) and increases to the set pressure of relief
valve (1).
âĒ High braking torque is applied to the motor to stop.
âĒ While relief valve (1) is in operation, the relieved pressurized oil and the pressurized oil from port (S) are
supplied to port (MA) through check valve (3).
âĒ Cavitation in port (MA) is prevented.
PC138USLC-10 10-119
--- Page 17 ---
10 Structure and function
Travel motor
When traveling downhill
âĒ If the machine runs away during downhill travel, the hydraulic motor rotates idle and the oil pressure in port
(C) drops, and the oil pressure in port (G) also drops through orifice (f).
âĒ When the oil pressure in chamber (G) decreases below the set pressure of spring (3), counterbalance
valve (2) moves to the left.
âĒ When the oil in chamber (J) flows through orifice (h) to port (B), the throttle effect of orifice (h) generates
back pressure, which controls the speed of counterbalance valve (2) moving to the right.
âĒ When ports (D) and (B) are throttled and the oil pressure in port (D) increases, resistance is applied to the
rotation of the hydraulic motor to prevent running away of the machine.
âĒ Counterbalance valve (2) moves to a position where the pressure generated by the machine weight and
the pressure in port (A) are balanced with the pressure in port (B). As a result, the outlet circuit is throttled
to control the rotation speed according to the pump discharge.
PC138USLC-10 10-133
--- Page 18 ---
10 Structure and function
Travel PPC valve
When valve is in fine control range
(when control lever is returned)
âĒ When lever (5) begins to return, spool (1) is pushed up by the force of centering spring (3) and the
pressure in port (P1).
âĒ Fine control hole (f) is connected to drain chamber (D), and the pressurized oil in port (P1) is released.
âĒ When the pressure in port (P1) decreases too much, spool (1) is pushed down by metering spring (2).
âĒ Fine control hole (f) is disconnected from drain chamber (D) and connected to pump pressure chamber
(PP) almost at the same time.
âĒ The pump pressure is supplied until the pressure in port (P1) recovers to the pressure corresponding to
the lever position.
âĒ When the spool of control valve returns, the pressurized oil in drain chamber (D) flows in through fine
control hole (f') in the valve on the side that is not operated. The oil passes through port (P2) and flows into
chamber (B) to replenish the port with pressurized oil.
PC138USLC-10 10-147
--- Page 19 ---
10 Structure and function
Solenoid valve
For machine(s) ready for installation of attachment
PC138USLC-10 10-161
--- Page 20 ---
10 Structure and function
Anti-drop valve for arm
Anti-drop valve for arm (PC138-LA1B-041-K-01-A)
(Machine with anti-drop valve for arm)
a General view
CY: To work equipment cylinder
PC138USLC-10 10-175
--- Page 21 ---
10 Structure and function
ROPS cab
Take wiring harness out of cab (PC138-K16F-520-K-00-A)
1. Grommet
Structure
âĒ 2 grommets (1) are installed to take the wiring out of the cab.
PC138USLC-10 10-189
--- Page 22 ---
10 Structure and function
Electrical control system
Engine automatic warm-up function (PC138-AP13-042-K-00-A)
1. Battery disconnect switch
2. Battery
3. Battery relay
4. Fusible link
5. Fuse box
6. Resister for PC-EPC valve
7. Pump controller
8. Engine controller
9. Machine monitor
10. Emergency pump drive switch
11. Fuel control dial
12. Fuel supply pump
13. Various sensors
14. Hydraulic oil temperature sensor
15. Main pump
15a. Servo
15b. LS valve
15c. PC valve
16. Control valve
16a. Merge-divider valve
16b. Self-pressure reducing valve
17. PC-EPC valve
Input/output signal
a. CAN signal
PC138USLC-10 10-203
--- Page 23 ---
10 Structure and function
Electrical control system
System operating lamp function (PC138-AW1Q-042-K-00-A)
1. Battery disconnect switch
2. Battery
3. System operating lamp
4. Machine monitor
5. Engine controller
6. Pump controller
7. KOMTRAX terminal
Function
âĒ You can prevent an abnormal end due to cut-off of the battery power supply circuit while the controllers are