PDF Shop Manual Komatsu PC1250-8R PC1250SP-8R Hydraulic Excavator - 6 MB
This is the official shop manual for the Komatsu PC1250-8R and PC1250SP-8R Hydraulic Excavators.
It provides comprehensive, factory-authorized procedures for testing, adjusting, troubleshooting, and disassembly/assembly.
This manual is the ultimate guide for mechanics and technicians, enabling them to perform any repair or service with precision.
Ensure your excavator is maintained to the highest standards.
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--- Page 1 ---
SEN02048-26
HYDRAULIC PC1250 -8R
EXCAVATOR
PC1250SP -8R
PC1250- 35001
SERIAL NUMBERS and up
PC1250SP- 35001
--- Page 3 ---
SEN02050-26 00 Index and foreword
Removal and installation of front window assembly .................................................................... 15
Remove and install work equipment control lever assembly....................................................... 21
Electrical system SEN02793-02
Removal and installation of air conditioner unit assembly........................................................... 2
Removal and installation of monitor assembly ............................................................................ 5
Removal and installation of pump controller assembly ............................................................... 6
Removal and installation of Orbcomm terminal assembly for VHMS .......................................... 7
Removal and installation of VHMS controller assembly .............................................................. 8
Removal and installation of engine controller assembly ............................................................. 9
90 Diagrams and drawings
Hydraulic circuit diagrams SEN02069-03
Hydraulic circuit diagram (1/2) Serial number 35001 – 35016 .................................................... 3
Hydraulic circuit diagram (2/2) Serial number 35001 – 35016 .................................................... 5
Hydraulic circuit diagram (1/3) Serial number 35017 and up ...................................................... 7
Hydraulic circuit diagram (2/3) Serial number 35017 and up ...................................................... 9
Hydraulic circuit diagram (3/3)..................................................................................................... 11
Electrical diagrams and drawings SEN02070-06
Electrical circuit diagram (1/7) Serial number 35001 - 36050 ..................................................... 3
Electrical circuit diagram (2/7) Serial number 35001 - 36050 ..................................................... 5
Electrical circuit diagram (3/7) Serial number 35001 - 36050 ..................................................... 7
Electrical circuit diagram (4/7) Serial number 35001 - 36050 ..................................................... 9
Electrical circuit diagram (5/7) Serial number 35001 - 36050 ..................................................... 11
Electrical circuit diagram (6/7) Serial number 35001 - 36050 ..................................................... 13
Electrical circuit diagram (7/7) Serial number 35001 - 36050 ..................................................... 15
Electrical circuit diagram (1/8) Serial number 36051 and up....................................................... 17
Electrical circuit diagram (2/8) Serial number 36051 and up....................................................... 19
Electrical circuit diagram (3/8) Serial number 36051 and up....................................................... 21
Electrical circuit diagram (4/8) Serial number 36051 and up....................................................... 23
Electrical circuit diagram (5/8) Serial number 36051 and up....................................................... 25
Electrical circuit diagram (6/8) Serial number 36051 and up....................................................... 27
Electrical circuit diagram (7/8) Serial number 36051 and up....................................................... 29
Electrical circuit diagram (8/8) Serial number 36051 and up....................................................... 31
Connector arrangement diagram ................................................................................................ 33
12 PC1250-8R
--- Page 4 ---
00 Index and foreword SEN02051-03
Handling of electric equipment and hydraulic component 1
To maintain the performance of the machine over a long period, and to prevent failures or other troubles
before they occur, correct “operation“, “maintenance and inspection“, “troubleshooting“, and “repairs” must
be carried out. This section deals particularly with correct repair procedures for mechatronics and is aimed at
improving the quality of repairs. For this purpose, it gives sections on “Handling electric equipment” and
“Handling hydraulic equipment” (particularly gear oil and hydraulic oil).
Points to remember when handling electric
equipment
1. Handling wiring harnesses and connectors
Wiring harnesses consist of wiring connecting
one component to another component, con-
nectors used for connecting and disconnecting
one wire from another wire, and protectors or
tubes used for protecting the wiring.
Compared with other electrical components fit-
ted in boxes or cases, wiring harnesses are
more likely to be affected by the direct effects
of rain, water, heat, or vibration. Furthermore,
during inspection and repair operations, they
are frequently removed and installed again, so
they are likely to suffer deformation or damage.
For this reason, it is necessary to be extremely
careful when handling wiring harnesses.
2. Main failures occurring in wiring harness
1) Defective contact of connectors (defec-
tive contact between male and female)
Problems with defective contact are likely
to occur because the male connector is
not properly inserted into the female con-
nector, or because one or both of the con-
nectors is deformed or the position is not
correctly aligned, or because there is cor-
rosion or oxidization of the contact sur-
faces. The corroded or oxidized contact
surfaces may become shiny again (and
contact may become normal) by connect-
ing and disconnecting the connector about
10 times.
2) Defective crimping or soldering of connec-
tors
The pins of the male and female connec-
tors are in contact at the crimped terminal
or soldered portion, but if there is exces-
sive force brought to bear on the wiring,
the plating at the joint will peel and cause
improper connection or breakage.
PC1250-8R 11
--- Page 5 ---
SEN02051-03 00 Index and foreword
2. Dimensions
(Table 2)
Nominal No. 0.5f (0.5) 0.75f (0.85) 1.25f (1.25) 2f 2 3f 3 5
Number of
strands/Diam- 20/0.18 7/0.32 30/0.18 11/0.32 50/0.18 16/0.32 37/0.26 26/0.32 58/0.26 41/0.32 65/0.32
eter of strand
Conductor
Sectional
0.51 0.56 0.76 0.88 1.27 1.29 1.96 2.09 3.08 3.30 5.23
area (mm2)
d (approx.) 1.0 1.2 1.5 1.9 1.9 2.3 2.4 3.0
AVS Standard 2.0 2.2 2.5 2.9 2.9 3.5 3.6 –
Cov-
AV Standard – – – – – – – 4.6
er D
AEX Standard 2.0 2.2 2.7 3.0 3.1 – 3.8 4.6
Nominal No. 8 15 20 30 40 50 60 85 100
Number of
strands/Diam- 50/0.45 84/0.45 41/0.80 70/0.80 85/0.80 108/0.80 127/0.80 169/0.80 217/0.80
eter of strand
Conductor
Sectional
7.95 13.36 20.61 35.19 42.73 54.29 63.84 84.96 109.1
area (mm2)
d (approx.) 3.7 4.8 6.0 8.0 8.6 9.8 10.4 12.0 13.6
AVS Standard – – – – – – – – –
Cov-
AV Standard 5.5 7.0 8.2 10.8 11.4 13.0 13.6 16.0 17.6
er D
AEX Standard 5.3 7.0 8.2 10.8 11.4 13.0 13.6 16.0 17.6
“f” of nominal No. denotes flexible”.
24 PC1250-8R
--- Page 6 ---
00 Index and foreword SEN02051-03
Millimeters to inches
1 mm = 0.03937 in
0 1 2 3 4 5 6 7 8 9
0 0 0.039 0.079 0.118 0.157 0.197 0.236 0.276 0.315 0.354
10 0.394 0.433 0.472 0.512 0.551 0.591 0.630 0.669 0.709 0.748
20 0.787 0.827 0.866 0.906 0.945 0.984 1.024 1.063 1.102 1.142
30 1.181 1.220 1.260 1.299 1.339 1.378 1.417 1.457 1.496 1.536
40 1.575 1.614 1.654 1.693 1.732 1.772 1.811 1.850 1.890 1.929
50 1.969 2.008 2.047 2.087 2.126 2.165 2.205 2.244 2.283 2.323
60 2.362 2.402 2.441 2.480 2.520 2.559 2.598 2.638 2.677 2.717
70 2.756 2.795 2.835 2.874 2.913 2.953 2.992 3.032 3.071 3.110
80 3.150 3.189 3.228 3.268 3.307 3.346 3.386 3.425 3.465 3.504
90 3.543 3.583 3.622 3.661 3.701 3.740 3.780 3.819 3.858 3.898
Kilogram to pound
1 kg = 2.2046 lb
0 1 2 3 4 5 6 7 8 9
0 0 2.20 4.41 6.61 8.82 11.02 13.23 15.43 17.64 19.84
10 22.05 24.25 26.46 28.66 30.86 33.07 35.27 37.48 39.68 41.89
20 44.09 46.30 48.50 50.71 51.91 55.12 57.32 59.53 61.73 63.93
30 66.14 68.34 70.55 72.75 74.96 77.16 79.37 81.57 83.78 85.98
40 88.18 90.39 92.59 94.80 97.00 99.21 101.41 103.62 105.82 108.03
50 110.23 112.44 114.64 116.85 119.05 121.25 123.46 125.66 127.87 130.07
60 132.28 134.48 136.69 138.89 141.10 143.30 145.51 147.71 149.91 152.12
70 154.32 156.53 158.73 160.94 163.14 165.35 167.55 169.76 171.96 174.17
80 176.37 178.57 180.78 182.98 185.19 187.39 189.60 191.80 194.01 196.21
90 198.42 200.62 202.83 205.03 207.24 209.44 211.64 213.85 216.05 218.26
Liters to U.S. Gallons
1 l = 0.2642 U.S.Gal
0 1 2 3 4 5 6 7 8 9
0 0 0.264 0.528 0.793 1.057 1.321 1.585 1.849 2.113 2.378
10 2.642 2.906 3.170 3.434 3.698 3.963 4.227 4.491 4.755 5.019
20 5.283 5.548 5.812 6.076 6.340 6.604 6.869 7.133 7.397 7.661
30 7.925 8.189 8.454 8.718 8.982 9.246 9.510 9.774 10.039 10.303
40 10.567 10.831 11.095 11.359 11.624 11.888 12.152 12.416 12.680 12.944
50 13.209 13.473 13.737 14.001 14.265 14.529 14.795 15.058 15.322 15.586
60 15.850 16.115 16.379 16.643 16.907 17.171 17.435 17.700 17.964 18.228
70 18.492 18.756 19.020 19.285 19.549 19.813 20.077 20.341 20.605 20.870
80 21.134 21.398 21.662 21.926 22.190 22.455 22.719 22.983 23.247 23.511
90 23.775 24.040 24.304 24.568 24.832 25.096 25.361 25.625 25.889 26.153
PC1250-8R 37
--- Page 7 ---
SEN02053-04 01 Specification
Backhoe specification
PC1250-8R Serial number 35017 and up
Machine model PC1250-8R
Bucket capacity m 3
5.0
Weight of machine kg 113,400
Max. digging depth mm 9,350
Working range
Max. vertical wall depth mm 7,610
Max. digging reach mm 15,350
Max. reach at ground level mm 15,000
Max. digging height mm 13,400
Performance
Max. dumping height mm 8,680
Max. digging force kN {kg} 479 {48,800}
Swing speed rpm 5.8
Swing max. slope angle deg. 12
Travel speed km/h Lo: 2.1 Hi: 3.2
Gradeability deg. 35
Ground pressure
kPa {kg/cm2} 144 {1.47}
[standard double grouser shoe width: 700 mm]
Overall length mm 16,020
Overall width mm 5,600
Overall width of track mm 4,965
Overall height (for transport) mm 6,040
Overall height to top of machine mm 5,180
Dimensions
Ground clearance of upper structure mm 1,790
Min. ground clearance mm 990
Tail swing radius mm 4,870
Min. swing radius of work equipment mm 7,965
Height of work equipment at min. swing radius mm 11,390
Length of track on ground mm 4,995
Track gauge mm 3,900
Height of machine cab mm 4,075
8 PC1250-8R
--- Page 8 ---
01 Specification SEN02053-04
Unit: kg
Machine model PC1250-8R PC1250SP-8R
Serial number 35017 and up 35017 and up
Bucket cylinder top pin 37.9 37.9
Bucket cylinder foot pin 37.9 37.9
Arm-bucket connecting pin 120.4 120.4
Link assembly 817 878
Link connecting pin 103 103
PC1250-8R 21
--- Page 9 ---
SEN02055-02 10 Structure, function and maintenance standard
Radiator and oil cooler 1
6 PC1250-8R
--- Page 10 ---
10 Structure, function and maintenance standard SEN02056-02
Unit: mm
No. Check Item Criteria Remedy
Backlash between No. 3 plane- Standard clearance Clearance limit
21
tary carrier and case 0.08 – 0.27 —
Backlash between No. 2 sun
22 0.47 – 0.97 —
gear and No. 2 planetary gear
Backlash between No. 3 sun
23 0.47 – 0.97 —
gear and No. 2 planetary carrier
Backlash between No. 3 sun
24 0.25 – 0.82 —
gear and No. 3 planetary gear
Backlash between No. 3 plane-
25 0.29 – 0.82 —
tary gear and No. 3 ring gear
Backlash between No. 1 plane-
26 0.38 – 0.72 —
tary carrier and No. 2 sun gear Replace
Backlash between No. 1 ring
27 0.08 – 0.26 —
gear and case
Backlash between No. 1 sun
28 0.07 – 0.85 —
gear and travel motor coupling
Backlash between No. 1 sun
29 0.15 – 0.53 —
gear and No. 1 planetary gear
Backlash between No.1 ring
30 0.19 – 0.62 —
gear and No. 1 planetary gear
Backlash between No.2 ring
31 0.19 – 0.62 —
gear and No. 2 planetary gear
32 Wear of sprocket tooth shape Repair limit: 6
Standard size Repair limit Rebuild or
33 Sprocket tooth width
114 108 replace
PC1250-8R 11
--- Page 11 ---
SEN02057-00 10 Structure, function and maintenance standard
Unit: mm
No. Check item Criteria Remedy
Tightening torque Additional tightening
a. Regular link (Nm {kgm}) angle (deg.)
1,372 ± 137 {140 ± 14} 150 ± 10
Shoe bolt Retighten
20 Tightening torque Additional tightening Lower limit torque
b. Master link (Nm {kgm}) angle (deg.) (Nm {kgm})
— — —
No. of shoes (each side) 48 —
Standard Tolerance Standard Interference
Interference between bushing size Shaft Hole interference limit
21
and link +0.622 +0.087 0.435 –
98 1.5
+0.522 +0.087 0.622
Interference between regular +0.042 –0.126 0.452 –
22 60 —
pin and link +0.326 –0.200 0.626
Standard Tolerance Standard Clearance
Clearance between regular pin size Shaft Hole clearance limit
23
and bushing –0.174 +0.666 0.340 – Adjust or
60.5 —
–0.074 +0.166 0.740 replace
Standard Tolerance Standard Interference
Interference between master size Shaft Hole interference limit
*24
pin and link +0.228 –0.126 0.324 –
60 —
+0.198 –0.200 0.428
Standard Tolerance Standard Clearance
Clearance between master pin size Shaft Hole clearance limit
*25
and bushing –0.51 +0.666 0.676 –
60.5 —
–0.61 +0.166 1.276
*Dry type track link
10 PC1250-8R
--- Page 12 ---
10 Structure, function and maintenance standard SEN02059-02
1. Front shaft 11. Rear end cap
2. Front cradle 12. Valve plate
3. Front case 13. Cylinder block
4. Rocker cam 14. Piston
5. Piston 15. Rear case
6. Cylinder block 16. Rocker cam
7. Valve plate 17. Rear cradle
8. Front end cap 18. Rear shaft
9. Coupling 19. Servo piston
10. Impeller
PC1250-8R 11
--- Page 13 ---
SEN02059-02 10 Structure, function and maintenance standard
5. No. 1 pump front CO + NC valve
PA1I : Main pump pressure input port
PE1 : TVC valve output pressure front, rear inter-
connection port
PC : CO selector pilot port
PD : Jet sensor downstream pressure input port
PDR2 : Servo valve drain output port
PE2 : TVC valve output pressure pick-up port
PECN : CO + NC valve output pressure output port
PT : Jet sensor upstream pressure input port
24 PC1250-8R
--- Page 14 ---
10 Structure, function and maintenance standard SEN02059-02
3. No. 2 pump rear servo
P2 : Main pump pressure input port 1. Servo valve
PAC : Servo actuator port
PDR : Servo valve drain output port
PECN : CO + NC valve output pressure input port
PSV : Servo basic pressure input port
PC1250-8R 37
--- Page 15 ---
SEN02059-02 10 Structure, function and maintenance standard
Return oil filter 1
1. Cover Outline
2. Spring There are two return oil filters installed to the rear
3. Bypass valve face of the hydraulic tank. They remove the dirt and
4. Bypass valve spring dust in the return oil.
5. Element
6. Housing Specifications
q Bypass valve set pressure:
A: From control valve 1.15 ± 0.03 MPa {1.5 ± 0.3 kg/cm2}
B: To hydraulic tank
50 PC1250-8R
--- Page 16 ---
10 Structure, function and maintenance standard SEN02059-02
3. EPC valve
C : To PC valve
P : From pilot relief valve
T : To tank
1. Connector
2. Coil
3. Body
4. Spring
5. Spool
6. Rod
7. Plunger
PC1250-8R 63
--- Page 17 ---
SEN02059-02 10 Structure, function and maintenance standard
Safety valve Function
q When the engine is started, the pressure in
port (P) of the motor is heightened in some
cases.
q Safety valve (1) is installed to protect the fan
system circuit.
Operation
q If the pressure in port (P) rises above the
cracking pressure of safety valve (1), valve (2)
of safety valve (1) opens to release the pres-
surized oil into port (T).
q By this operation, generation of abnormal pres-
sure in port (P) is prevented.
76 PC1250-8R
--- Page 18 ---
10 Structure, function and maintenance standard SEN02060-02
A1 : To boom cylinder
A2 : To swing motor MB
A3 : To bucket cylinder
A4 : To arm cylinder
B1 : Plug
B2 : To swing motor MA
B3 : Plug
B4 : To arm cylinder
NCA : To NC valve at front of No. 3 main pump
NCB : To NC valve at front of No. 3 main pump
P : From No. 3 main pump
PA1 : From control pump
PA2 : From L.H. work equipment, swing PPC valve
PA3 : From R.H. work equipment, swing PPC valve
PA4 : From L.H. work equipment, swing PPC valve
PB1 : From R.H. work equipment, swing PPC valve
PB2 : From L.H. work equipment, swing PPC valve
PB3 : From R.H. work equipment, swing PPC valve
PB4 : From L.H. work equipment, swing PPC valve
PI : From pilot valve
PR : From 2-stage main relief solenoid valve
T : To hydraulic tank
PC1250-8R 11
--- Page 19 ---
SEN02060-02 10 Structure, function and maintenance standard
Swing holding brake
1. When solenoid valve is de-energized 2. When solenoid valve is energized
Operation Operation
q As the swing brake solenoid valve is de-ener- q As the swing brake solenoid valve is ener-
gized, the pressurized oil from the pump is gized, the valve is switched.
shut off. q The pressurized oil from the pump is con-
q Port (B) is connected to tank circuit (T). ducted brake chamber (a) through port (B).
q Brake piston (7) is pushed down by brake q After entering chamber (a), the pressurized oil
spring (1). compresses brake spring (1) and pushes
q Disc (5) and plate (6) are pushed together, and brake piston (7) up.
the brake is applied. q Disc (5) is separated from plate (6), releasing
the brake.
24 PC1250-8R
--- Page 20 ---
10 Structure, function and maintenance standard SEN02060-02
PPC control relief valve 1
A : From PPC valve 1. Relief valve
B : From solenoid valve 2. Valve body
C : From pilot valve 3. Check valve spring
D : To PPC valve 4. Check valve
E : To accumulator
F : To solenoid valve Specifications
P : From control pump Set pressure: 3.1 +0.3 +3 2
+0.3 MPa {32 +0 kg/cm }
T : To tank (at 182 l/min)
Unit: mm
No. Check item Criteria Remedy
Standard size Repair limit
Free length ×
Installed Installed Installed
outside Free length
3 Check valve spring length load load Replace
diameter
6.9 N 3.9 N
56 × 21.4 37 —
{0.7 kg} {0.4 kg}
PC1250-8R 37
--- Page 21 ---
SEN02060-02 10 Structure, function and maintenance standard
Solenoid valve 1
For CO cancel, straight-travel, heavy lift, machine push-up, travel speed
A1 : To No. 1 pump (CO valve) 1. CO cancel solenoid valve
A2 : To straight-travel valve 2. Straight-travel solenoid valve
A3 : To main valve (Relief valve) 3. Heavy lift solenoid valve
A4 : To boom LOWER 2-stage safety valve 4. Machine push-up solenoid valve
A5 : To left and right travel motor 5. Travel speed solenoid valve
ACC : Blind
P1 : From control pump
PPC : Blind
T : To tank
50 PC1250-8R
--- Page 22 ---
SEN02061-01
HYDRAULIC EXCAVATOR 1SHOP MANUAL
PC1250-8R
PC1250SP-8R
Machine model Serial number
PC1250-8R 35001 and up
PC1250SP-8R 35001 and up
10 Structure, function and
maintenance standard 1
Work equipment
Work equipment .............................................................................................................................................. 2
Dimensions of work equipment....................................................................................................................... 6
PC1250-8R 1
--- Page 23 ---
SEN02062-01
PC1250-8R, PC1250SP-8R Hydraulic excavator
Form No. SEN02062-01
© 2007 KOMATSU
All Rights Reserved
Printed in Japan 05-07 (01)
4
--- Page 24 ---
10 Structure, function and maintenance standard SEN02063-03
Operation
Control levers at neutral When control lever is operated
q If the engine is running at above the decelera- q If any control lever is operated when the
tion actuation speed (approx. 1300 rpm), and engine speed is at No. 2 deceleration, the
all the control levers are returned to neutral, engine speed will immediately rise to the
the engine speed drops immediately to approx. speed set by the fuel control dial.
100 rpm below the set speed to the No. 1
deceleration position.
q If another 4 seconds passes, the engine speed
is reduced to the No. 2 deceleration position
(approx. 1300 rpm), and is kept at that speed
until a lever is operated.
PC1250-8R 13
--- Page 25 ---
SEN02063-03 10 Structure, function and maintenance standard
Travel speed selector function
1. Travel pressure rise function
26 PC1250-8R
--- Page 26 ---
10 Structure, function and maintenance standard SEN02063-03
q Upon receiving the signal from the machine
monitor, the pump controller outputs the fan
reverse signal, which drives the fan reverse
solenoid valve of the fan motor to change the
fan reverse valve and reverse the fan rotation
direction.
Note) Since the fan reverse function is for
cleaning the cooling devices, the fan
speed in reverse direction is not con-
trolled by the temperature (hydraulic oil
temperature and coolant temperature)
but controlled by only the engine speed.
1. Cooling fan 7. Servo
2. Fan motor 8. EPC valve
3. Fan reverse valve 9. Fan pump flow control signal