PDF Service Repair Manual Komatsu PC45MR-3 PC55MR-3 Hydraulic Excavator - 4 MB
This is the complete factory service repair manual for the Komatsu PC45MR-3 and PC55MR-3 hydraulic excavators.
It provides the detailed technical information needed to perform any repair or maintenance task.
The manual covers everything from the engine and hydraulics to the electrical system, with step-by-step instructions and specifications.
It is the most comprehensive resource available for servicing these compact and powerful machines.
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--- Page 1 ---
SEN04597-06
HYDRAULIC PC45MR -3
EXCAVATOR
PC55MR -3
PC45MR- 5001
SERIAL NUMBERS and up
PC55MR- 15001
--- Page 3 ---
SEN04599-06
PC45MR, PC55MR-3 Hydraulic excavator
Form No. SEN04599-06
©2010 KOMATSU
All Rights Reserved
Printed in Japan 10-10
00-100 10
--- Page 4 ---
200 Foreword and general information
SEN04600-01 Explanation of terms for maintenance standard
Explanation of terms for maintenance standard
The maintenance standard chapter explains the criteria for replacing or reusing products and parts in the ma-
chine maintenance work. The following terms are used to explain the criteria.
1. Standard size and tolerance
q To be accurate, the finishing size of parts is a
little different from one to another.
q To specify a finishing size of a part, a tempo-
rary standard size is set and an allowable dif-
ference from that size is indicated.
q The above size set temporarily is called the
"standard size" and the range of difference
from the standard size is called the "toler-
ance".
q The tolerance with the symbols of + or – is in-
dicated on the right side of the standard size.
Example:
Standard size Tolerance
-0.022
120
-0.126
a The tolerance may be indicated in the text
and a table as [standard size (upper limit of
tolerance/lower limit of tolerance)].
Example) 120 (–0.022/–0.126)
q Usually, the size of a hole and the size of the
shaft to be fitted to that hole are indicated by
the same standard size and different toler-
ances of the hole and shaft. The tightness of
fit is decided by the tolerance.
q Indication of size of rotating shaft and hole
and relationship drawing of them
Example:
Tolerance
Standard size
Shaft Hole
-0.030 +0.046
60
-0.076 0
00-200 10 PC45MR-3,PC55MR-3
--- Page 5 ---
200 Foreword and general information
SEN04600-01 Handling of electric equipment and hydraulic component
5. Change hydraulic oil when the temperature is high
When hydraulic oil or other oil is warm, it flows
easily. In addition, the sludge can also be
drained out easily from the circuit together with
the oil, so it is best to change the oil when it is still
warm. When changing the oil, as much as
possible of the old hydraulic oil must be drained
out. (Drain the oil from the hydraulic tank; also
drain the oil from the filter and from the drain plug
in the circuit.) If any old oil is left, the contami-
nants and sludge in it will mix with the new oil
and will shorten the life of the hydraulic oil.
6. Flushing operations
After disassembling and assembling the equip-
ment, or changing the oil, use flushing oil to
remove the contaminants, sludge, and old oil
from the hydraulic circuit. Normally, flushing is
carried out twice: primary flushing is carried out
with flushing oil, and secondary flushing is
carried out with the specified hydraulic oil.
7. Cleaning operations
After repairing the hydraulic equipment (pump,
control valve, etc.) or when running the machine,
carry out oil cleaning to remove the sludge or
contaminants in the hydraulic oil circuit. The oil
cleaning equipment is used to remove the ultra
fine (about 3 m) particles that the filter built in the
hydraulic equipment cannot remove, so it is an
extremely effective device.
00-200 20 PC45MR-3,PC55MR-3
--- Page 6 ---
200 Foreword and general information
SEN04600-01 Method of disassembling and connecting push-pull type coupler
Method of disassembling and connecting push-pull type coupler
k Before carrying out the following work, loosen the oil filler cap of the hydraulic tank gradually to
release the residual pressure from the hydraulic tank.
k Even if the residual pressure is released from the hydraulic tank, some hydraulic oil flows out
when the hose is disconnected. Accordingly, prepare an oil container.
Type 1
1. Disconnection
1) Hold adapter (1) and push hose joint (2) into
mating adapter (3) . (Fig. 1)
a The adapter can be pushed in about 3.5
mm.
a Do not hold rubber cap portion (4).
2) With hose joint (2) pushed into adapter (3),
press rubber cap portion (4) against adapter
(3) until it clicks. (Fig. 2)
3) Hold hose adapter (1) or hose (5) and pull it
out. (Fig. 3)
a Since some hydraulic oil flows out, pre-
pare an oil container.
2. Connection
1) Hold hose adapter (1) or hose (5) and insert
it in mating adapter (3), aligning them with
each other. (Fig. 4)
a Do not hold rubber cap portion (4).
2) After inserting the hose in the mating adapter
perfectly, pull it back to check its connecting
condition. (Fig. 5)
a When the hose is pulled back, the rubber
cap portion moves toward the hose about
3.5 mm. This does not indicate abnormal-
ity, however.
00-200 30 PC45MR-3,PC55MR-3
--- Page 7 ---
200 Foreword and general information
SEN04600-01 Conversion table
kg/cm2 to lb/in2
1 kg/cm2 = 14.2233 lb/in2
0 1 2 3 4 5 6 7 8 9
0 0 14.2 28.4 42.7 56.9 71.1 85.3 99.6 113.8 128.0
10 142.2 156.5 170.7 184.9 199.1 213.4 227.6 241.8 256.0 270.2
20 284.5 298.7 312.9 327.1 341.4 355.6 369.8 384.0 398.3 412.5
30 426.7 440.9 455.1 469.4 483.6 497.8 512.0 526.3 540.5 554.7
40 568.9 583.2 597.4 611.6 625.8 640.1 654.3 668.5 682.7 696.9
50 711.2 725.4 739.6 753.8 768.1 782.3 796.5 810.7 825.0 839.2
60 853.4 867.6 881.8 896.1 910.3 924.5 938.7 953.0 967.2 981.4
70 995.6 1,010 1,024 1,038 1,053 1,067 1,081 1,095 1,109 1,124
80 1,138 1,152 1,166 1,181 1,195 1,209 1,223 1,237 1,252 1,266
90 1,280 1,294 1,309 1,323 1,337 1,351 1,365 1,380 1,394 1,408
100 1,422 1,437 1,451 1,465 1,479 1,493 1,508 1,522 1,536 1,550
110 1,565 1,579 1,593 1,607 1,621 1,636 1,650 1,664 1,678 1,693
120 1,707 1,721 1,735 1,749 1,764 1,778 1,792 1,806 1,821 1,835
130 1,849 1,863 1,877 1,892 1,906 1,920 1,934 1,949 1,963 1,977
140 1,991 2,005 2,020 2,034 2,048 2,062 2,077 2,091 2,105 2,119
150 2,134 2,148 2,162 2,176 2,190 2,205 2,219 2,233 2,247 2,262
160 2,276 2,290 2,304 2,318 2,333 2,347 2,361 2,375 2,389 2,404
170 2,418 2,432 2,446 2,460 2,475 2,489 2,503 2,518 2,532 2,546
180 2,560 2,574 2,589 2,603 2,617 2,631 2,646 2,660 2,674 2,688
190 2,702 2,717 2,731 2,745 2,759 2,773 2,788 2,802 2,816 2,830
200 2,845 2,859 2,873 2,887 2,901 2,916 2,930 2,944 2,958 2,973
210 2,987 3,001 3,015 3,030 3,044 3,058 3,072 3,086 3,101 3,115
220 3,129 3,143 3,158 3,172 3,186 3,200 3,214 3,229 3,243 3,257
230 3,271 3,286 3,300 3,314 3,328 3,343 3,357 3,371 3,385 3,399
240 3,414 3,428 3,442 3,456 3,470 3,485 3,499 3,513 3,527 3,542
00-200 40 PC45MR-3,PC55MR-3
--- Page 8 ---
100 Specification and technical data
SEN04602-00 Specifications
1
PC55MR-3
Machine model
Canopy specification Cab specification
Serial number 15001 and up
Model 4D88E-6
Type 4-cycle, water cooled, in-line direct injection type
No. of cylinders – bore x stroke mm 4 – 88 × 90
Piston displacement l {cc} 2.189 {2,189}
Flywheel horsepower kW/rpm {HP/rpm} 28.5 / 2,400 {38.2 / 2,400}
Performance
Maximum torque Nm/rpm {kgm/rpm} 137 / 1,440 {14.0 / 1,440}
Engine
High idle speed rpm 2,550
Low idle speed rpm 1,175
Starting motor 12 V, 2.3 kW
Alternator 12 V, 40 A
Battery (*1) 12 V, 72 Ah × 1 (115D31L)
Radiator
• Core type CF68-4
Carrier roller 1 on each side
Undercarriage
Track roller 4 on each side
Track shoe (Rubber shoe) Unit-type rubber crawler
Track shoe (Steel shoe) Assembly-type double grouser: 39 each side
Type x no. Variable displacement piston type × 1, gear type × 1
Hydraulic pump
Theoretical capacity cm /rev
3
22.3 × 2 + 14.1 + 5.2
Set pressure
For travel, work equipment MPa {kg/cm2} 26.5 {270}
For swing MPa {kg/cm2} 18.6 {190}
For blade MPa {kg/cm2} 21.6 {220}
Hydraulic system
Control
Type x no. 9-spool type × 1
valve
Control method Hydraulic assist type
Variable-displacement piston motor (with counter-
Travel motor
Hydraulic
balance valve, parking brake) × 2
motor
Fixed-displacement piston motor (with brake
Swing motor
valve, swing shaft brake) × 1
Hydraulic tank Box-shaped, open type
Hydraulic oil filter Tank return side
Hydraulic oil cooler Air cooled (CF40-1)
01-100 8 PC45MR-3, PC55MR-3
--- Page 9 ---
100 Engine and cooling system
SEN04604-00 PTO
PTO 1
1. Boss
2. Spring pin
3. Rubber
4. Cover
5. Hydraulic pump
10-100 2 PC45MR-3, PC55MR-3
--- Page 10 ---
SEN04605-00
PC45MR, PC55MR-3 Hydraulic excavator
Form No. SEN04605-00
©2008 KOMATSU
All Rights Reserved
Printed in Japan 05-08 (01)
10-200 6
--- Page 11 ---
300 Undercarriage and frame
SEN04606-00 Track shoe
Triple grouser shoe
(If equipped)
10-300 10 PC45MR-3, PC55MR-3
--- Page 12 ---
410 Hydraulic system, Part 1
SEN04607-03 Travel motor
Outline
q Swash plate (1) has two rear faces (x) and (y),
and is supported by ball (2).
q The travel speed is switched by pressurized oil
from control chamber (a) acting on control pis-
ton (3). This switches the angle of swash plate
(1) between the maximum angle and minimum
angle to determine the travel speed.
10-410 8 PC45MR-3, PC55MR-3
--- Page 13 ---
410 Hydraulic system, Part 1
SEN04607-03 Solenoid valve
Solenoid valve 1
2-spool solenoid valve
A : To PPC valve
B : To 2nd travel speed selector valve
P : From hydraulic pump
T : To hydraulic tank
1. PPC lock solenoid valve
2. 2nd travel speed selector solenoid valve
3. Control relief valve
Solenoid valve Control relief valve
4. Coil (ON/OFF type) 9. Adjustment screw
5. Push pin 10. Locknut
6. Valve spool 11. Plug
7. Return spring 12. Return spring
8. Valve body 13. Cover
14. Plunger
10-410 18 PC45MR-3, PC55MR-3
--- Page 14 ---
420 Hydraulic system, Part 2
SEN04608-01 Hydraulic pump
Function Structure
q The engine rotation and torque transmitted to q Cylinder block (7) is supported to shaft (1) by
the pump shaft is converted into hydraulic spline (a), and shaft (1) is supported by the
energy, and pressurized oil is discharged front and rear bearings.
according to the load. q The tip of piston (6) is a concave ball, and shoe
q It is possible to change the pump delivery by (5) is caulked to it to form one unit. Piston (6)
changing the swash plate angle. and shoe (5) form a spherical bearing.
q It has two discharge ports and it enables to q Rocker cam (4) has flat surface (A). Shoe (5)
supply the pressure individually to each one. is kept pressed against the flat surface (A) and
it slides circularly on flat surface (A). Rocker
cam (4) slides around ball (11).
q Piston (6) carries out relative movement in the
axial direction inside each cylinder chamber of
cylinder block (7).
q Cylinder block (7) seals the pressure oil to
valve plate (8) and carries out relative rotation.
This surface is designed so that the oil pres-
sure balance is maintained at a suitable level.
q The oil inside each cylinder chamber of cylin-
der block (7) is sucked in and discharged
through valve plate (8).
q Hole number of cylinder block (7) is an even
number. So, it is fitted to two grooves of valve
plate (8) alternately.
10-420 4 PC45MR-3, PC55MR-3
--- Page 15 ---
420 Hydraulic system, Part 2
SEN04608-01 Control valve
(2/4)
10-420 14 PC45MR-3, PC55MR-3
--- Page 16 ---
420 Hydraulic system, Part 2
SEN04608-01 Anti-drop valve
Anti-drop valve 1
PC55MR-3
(For New Zealand)
V : From work equipment control valve
T : To hydraulic tank
CY : To work equipment hydraulic cylinder
PI : From PPC valve
PCY : For pressure pickup port and equalizer oil circuit
10-420 24 PC45MR-3, PC55MR-3
--- Page 17 ---
430 Hydraulic system, Part 3
SEN04609-01 CLSS
Pressure compensation control
q A pressure compensation valve is installed to
the outlet port side of the control valve spool to
balance the load.
q When two actuators are operated together, this
valve acts to make pressure difference (dP)
between the upstream (inlet port) and down-
stream (outlet port) the same, regardless of the
size of the load (pressure).
q The flow of oil from the pump is divided (com-
pensated) in proportion to the area of openings
(S1) and (S2) of each valve when it is oper-
ated.
10-430 4 PC45MR-3, PC55MR-3
--- Page 18 ---
430 Hydraulic system, Part 3
SEN04609-01 Operation for each function and valve
Introduction of LS pressure
Work equipment valve (Boom, arm, bucket, boom swing)
Function q At the same time, reducing valve (3) also
q The LS pressure is the actuator load pressure moves to the right, so pump pressure (PP3) is
at the outlet port end of the control valve. reduced by the pressure loss at notch (c). It
q With the control valve, it actually reduces goes to LS circuit (PLS3), and then goes to
pump pressure (PP3) at reducing valve (3) of spring chamber (PLS').
the pressure compensation valve to the same q When this happens, LS circuit (PLS3) is con-
pressure as actuation circuit pressure (A), and nected to tank circuit (T) from LS bypass valve
sends it to the LS circuit (PLS3). (4) (see the section on the LS bypass valve).
q The actuator circuit pressure (A) acts on the
Operation left end of reducing valve (3). The reduced
q When spool (1) is operated, pump pressure pump pressure (PP3) acts on at the other end.
(PP3) flows from flow control valve (2) and q As a result, reducing valve (3) is balanced at a
notch (a) in the spool through bridge passage position where actuator circuit pressure (A)
(b) to actuator circuit (A). and the pressure of spring chamber (PLS') are
the same. Pump pressure (PP3) reduced at
notch (a) becomes actuator circuit pressure (A)
and is taken to LS circuit (PLS3).
10-430 14 PC45MR-3, PC55MR-3
--- Page 19 ---
430 Hydraulic system, Part 3
SEN04609-01 Operation for each function and valve
Swing holding brake cancel system
Operation
q The left and right swing PPC pressure and the
arm IN PPC pressure each pass through check
valve inside spring case, are output to port
(BR) from port (PS), and the swing holding
brake is canceled. [The highest pressure is
output to port (BR).]
q The arm and swing are connected by the pilot
circuit inside the control valve.
10-430 24 PC45MR-3, PC55MR-3
--- Page 20 ---
430 Hydraulic system, Part 3
SEN04609-01 Swing motor
Modulating relief valve
Function
The relief valve for the swing motor prevents the
relief pressure from rising sharply to reduce shocks
when the machine starts and stops swinging.
Modulating relief valve
Ordinary relief valve
Operation
When circuit pressure is P0
q The relief valve does not operate.
When circuit pressure rises sharply
q When circuit pressure rises to (P1), the
hydraulic pressure acts on the area difference
between (D1) and (D3) (D1 > D3) and pushes
spring (4) to open valve (3).
q At this time, pressure acts on the area differ-
ence between (D1) and (D2) (D2 > D1), so
seat (1) follows valve (3).
q As seat (1) moves, the passage for the pres-
surized oil in chamber (a) to flow into port (S) is
narrowed by ball (2). Accordingly, seat (1)
does not move so fast as valve (3).
q As a result, the relief pressure rises gradually
from (P1) to (P2) while seat (1) is moving to
sleeve (5).
10-430 34 PC45MR-3, PC55MR-3
--- Page 21 ---
430 Hydraulic system, Part 3
SEN04609-01 PPC valve
10-430 44 PC45MR-3, PC55MR-3
--- Page 22 ---
500 Work equipment
SEN04610-00 Dimensions of each part of work equipment
Dimensions of each part of work equipment 1
Arm section (STD)
10-500 6 PC45MR-3, PC55MR-3
--- Page 23 ---
700 Electrical system
SEN04612-02 Engine control system
Engine control system 1
1. Battery
2. Starting switch
3. Fuse box
4. Engine stop solenoid
5. Lock lever
6. PPC lock switch
7. Neutral engine start relay
8. Safety relay
9. Starting motor
10. Fuel control lever
11. KOMTRAX terminal
12. KOMTRAX engine cut-out relay
10-700 2 PC45MR-3, PC55MR-3
--- Page 24 ---
700 Electrical system
SEN04612-02 Auto-deceleration function
Auto-deceleration function 1
General system drawing
(Auto-deceleration specification)
1. Controller (Auto-deceleration) a. Swing holding brake release sensor signal
2. Oil pressure sensor (Input as operation signal of Swing [Left-Right]
3. Oil pressure switch and Arm [in] to controller)
4. Auto-deceleration switch b. Travel control lever, operation oil pressure
5. Fuel control dial switch signal
6. Fuel control motor c. Work equipment control lever, operation oil
7. Starting switch pressure switch signal
8. Fuse box d. Fuel control dial, potentiometer signal
9. Fuel control motor relay (For driving) e. Fuel control motor, potentiometer signal
10. Fuel control motor relay (For acceleration) f. Auto-deceleration switch, ON/OFF signal
11. Fuel control motor relay (For deceleration) g. Fuel control motor, drive signal
12. Travel alarm h. Fuel control motor, acceleration signal
13. Engine i. Fuel control motor, deceleration signal
14. Hydraulic pump j. Fuel control motor, secondary monitor signal of
15. Control valve drive signal
15a. Self-pressure reducing valve
16. PPC lock solenoid valve
17. Swing motor
17a. Swing holding brake
10-700 12 PC45MR-3, PC55MR-3
--- Page 25 ---
700 Electrical system
SEN04612-02 KOMTRAX system
KOMTRAX system 1
q The KOMTRAX terminal transmits various
kinds of machine information wirelessly. The
KOMTRAX operator can refer to the informa-
tion at the office to provide various kinds of ser-
vices for customers.
a To provide the services, a separate
arrangement for setting up the KOMTRAX
terminal is required.
Information transmittable from KOMTRAX ter-
minal system includes the following.
1. Operation information
2. Service meter
3. Location information
4. Fuel level
10-700 22 PC45MR-3, PC55MR-3
--- Page 26 ---
SEN04612-02
PC45MR, PC55MR-3 Hydraulic excavator
Form No. SEN04612-02
©2010 KOMATSU
All Rights Reserved
Printed in Japan 10-10
10-700 32
--- Page 27 ---
100 Standard service value table
SEN04648-01 Standard service value table for chassis related parts
Applicable model: PC55MR-3
Machine model PC55MR-3
Category
Standard value for
Item Measurement conditions Unit Service limit value
new machine
• Hydraulic oil temperature: 45 – 55°C
Speed when 1 pump is relieved • Engine oil pressure: Within operating Min. 2,220 Min. 2,220
Engine speed
range
• Engine coolant temperature: Within
rpm
operating range
• Relief of 1 pump: Relieve bucket circuit.
Speed when 2 pumps are relieved • Relief of 2 pumps: Relieve bucket and Min. 2,150 Min. 2,150
swing circuits.
Boom control valve
Stroke of control valve spool
Arm control valve
Bucket control valve
Swing control valve
a For details, see Fig. A at the end of this l = 30 l = 30
Breaker control valve mm a=6 a=6
section. b=6 b=6
Boom swing control valve
Blade control valve
Left travel control valve
Right travel control valve
Boom control lever N o RAISE, LOWER 85 ± 10 85 ± 10
Arm control lever N o IN, OUT 85 ± 10 85 ± 10
Bucket control lever N o CURL, DUMP 85 ± 10 85 ± 10
Stroke of control lever and pedal
Swing control lever
• Stop engine. N o Swing to LEFT, 85 ± 10 85 ± 10
• Measure at RIGHT
center of lever N o Swing boom to
Boom swing control pedal grip. 25 ± 5 25 ± 5
LEFT, RIGHT
• Measure at
Blade control lever N o RAISE, LOWER mm 50 ± 5 50 ± 5
pedal tip.
• Read max. N o FORWARD,
Travel control lever 100 ± 10 100 ± 10
value to stroke REVERSE
end (excluding SLOW i
o FULL
Fuel control lever neutral play). 160 ± 20 160 ± 20
THROTTLE
Work equipment,
Max. 5 Max. 5
Play of control lever swing
Travel Max. 5 Max. 5
20-100 10 PC45MR-3, PC55MR-3
--- Page 28 ---
SEN04648-01
PC45MR-3, PC55MR-3 Hydraulic excavator
Form No. SEN04648-01
©2010 KOMATSU
All Rights Reserved
Printed in Japan 09-10
20-100 20
--- Page 29 ---
100 Testing and adjusting
SEN04649-01 Testing compression pressure
Testing compression pressure 1 4. Install adapter E2 and joint E3 to the nozzle
holder mounting part and connect compres-
sion gauge E1.
3 Adapter mounting nut:
a Measuring instruments for compression pres-
sure 4.41 ± 0.49 Nm {0.45 ± 0.05 kgm}
Symbol Part No. Part Name
1 795-502-1590 Compression gauge
E 2 795-111-1130 Adapter
3 795-101-1571 Joint
k When measuring the compression pres-
sure, take care not to burn yourself on the