PDF Shop Manual Komatsu PC400LC-7L Hydraulic Excavator - 4 MB
This is the complete factory shop manual for the Komatsu PC400LC-7L Hydraulic Excavator, covering serial numbers A86001 and up.
It provides in-depth service information, from testing and adjusting to disassembly and assembly procedures.
The manual also includes details for the SAA6D125E-3 engine.
This is an indispensable resource for any technician performing maintenance or major repairs on this machine.
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--- Page 1 ---
CEBM012503
Shop
Manual
PC400LC-7L
HYDRAULIC EXCAVATOR
SERIAL NUMBERS PC400LC-7L A86001 and up
ENGINE SAA6D125E-3
This material is proprietary to Komatsu America Corp. and is not to be reproduced, used, or disclosed except in
accordance with written authorization from Komatsu America Corp.
It is our policy to improve our products whenever it is possible and practical to do so. We reserve the right to
make changes or improvements at any time without incurring any obligation to install such changes on products
sold previously.
Due to this continuous program of research and development, revisions may be made to this publication. It is
recommended that customers contact their distributor for information on the latest revision.
Copyright 2011 Komatsu
Printed in U.S.A.
Komatsu America Corp.
January 2011
--- Page 3 ---
FOREWORD
Mark Page Rev Mark Page Rev Mark Page Rev Mark Page Rev
90-2 90-35
90-3 90-36
90-4 90-37
90-5 90-38
90-6 90-39
90-7 90-40
90-8 90-41
90-9 90-42
90-10 90-43
90-11 90-44
90-12 90-45
90-13 90-46
90-14 90-47
90-15 90-48
90-16 90-49
90-17 90-50
90-18
90-19
90-20
90-21
90-22
90-23
90-24
90-25
90-26
90-27
90-28
90-29
90-30
90-31
90-32
90-33
90-34
PC400LC-7L 00-2-7 D
--- Page 4 ---
FOREWORD STANDARD TIGHTENING TORQUE
12
TIGHTENING TORQUE OF HOSE NUTS 00
Use these torques for hose nuts.
Thread diameter Width across flat Tightening torque
Nominal No.
mm mm Nm lbf ft
02 14 19 24.5 ± 4.9 18.0 ± 3.6
03 18 24 49 ± 19.6 36.1 ± 14.4
04 22 27 78.5 ± 19.6 57.8 ± 14.4
05 24 32 137.3 ± 29.4 101.2 ± 21.6
06 30 36 176.5 ± 29.4 130.1 ± 21.6
10 33 41 196.1 ± 49 144.6 ± 36.1
12 36 46 245.2 ± 49 180.8 ± 36.1
14 42 55 294.2 ± 49 216.9 ± 36.1
TIGHTENING TORQUE OF SPLIT FLANGE BOLTS 00
Use these torques for split flange bolts.
Thread diameter Width across flat Tightening torque
mm mm Nm lbf ft
10 14 65.7 ± 6.8 48.4 ± 5.0
12 17 112 ± 9.8 82.6 ± 7.2
16 22 279 ± 29 205.7 ± 21.3
TIGHTENING TORQUE FOR FLARED NUTS 00
Use these torques for flared part of nut.
Thread diameter Width across flat Tightening torque
mm mm Nm lbf ft
14 19 24.5 ± 4.9 18.0 ± 3.6
18 24 49 ± 19.6 36.1 ± 14.4
22 27 78.5 ± 19.6 57.8 ± 14.4
24 32 137.3 ± 29.4 101.2 ± 21.6
30 36 176.5 ± 29.4 130.1 ± 21.6
33 41 196.1 ± 49 144.6 ± 36.1
36 46 245.2 ± 49 180.8 ± 36.1
42 55 294.2 ± 9 216.9 ± 36.1
PC400LC-7L 00-11
--- Page 5 ---
GENERAL SPECIFICATIONS
12
● “Variable gauge specification” means the machine can extend and retract overall width (C) of the track frame.
“Fixed gauge specification” means the machine cannot extend or retract overall width (C) of the track frame.
01-3 PC400LC-7L
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STRUCTURE AND FUNCTION RADIATOR • OIL COOLER • AFTERCOOLER
12
RADIATOR • OIL COOLER • AFTERCOOLER
1. Oil cooler 7. Radiator inlet hose Specifications
2. Radiator 8. Radiator outlet hose Radiator: ALW-4
3. Radiator cap 9. Aftercooler Oil cooler: CF40-1
4. Reservoir tank 10. Condenser
5. Net 11. Fuel cooler
6. Shroud
PC400LC-7L 10-3
--- Page 7 ---
STRUCTURE AND FUNCTION CARRIER ROLLER
CARRIER ROLLER
Unit: mm
No. Check item Criteria Remedy
Standard size Repair limit
1 Outside diameter of flange
175 ---
2 Outside diameter of tread 148 134
3 Width of tread 50.3 ---
4 Thickness of tread 32 25
5 Width of flange 19 ---
Standard Tolerance Standard Interference Replace
size Shaft Hole interference limit
6 Interference between shaft and bushing
-0.250 +0.099
50 -0.270 -0.032 0.218 - 0.369 ---
Interference between roller and bushing +0.117 +0.040 0.047 -
7 57 +0.087 0 0.177
Axial clearance of roller Standard clearance Clearance limit
8
0.5 - 0.7 ---
PC400LC-7L 10-13
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STRUCTURE AND FUNCTION HYDRAULIC SYSTEM
12
MEMORANDUM
PC400LC-7L 10-23
--- Page 9 ---
STRUCTURE AND FUNCTION HYDRAULIC SYSTEM
12
C. Operation in decrease direction for pump discharge amount
• The following explains the situation if the servo piston (12) moves to the right (the discharge amount becomes
smaller). When LS differential pressure ∆PLS becomes larger (for example, when the area of opening of the
control valve becomes smaller and pump pressure PP rises), pump pressure PP pushes spool (6) to the right.
• When spool (6) moves, main port pressure PP flows from port C and port D and from port K, it enters the large
diameter end of the piston.
• Main pump pressure PP also enters port J at the small diameter end of the piston, but because of the difference in
area between the large diameter end and the small diameter end of servo piston (12), servo piston (12) is pushed
to the right.
• As a result, the swash plate moves in the direction to make angle smaller.
• If LS selection pressure PSIG enters port G, it acts to make the set pressure of spring (4) weaker.
PC400LC-7L 10-33
--- Page 10 ---
STRUCTURE AND FUNCTION HYDRAULIC SYSTEM
12
2. When signal current is very small (coil energized)
• When a very small signal current flows to coil (5), coil (5) is
energized, and a propulsion force is generated which pushes
plunger (6) to the left.
• Push pin (4) pushes spool (2) to the left, and pressurized oil flows
from port PEPC to port PSIG(PM).
• When the pressure at port PSIG(PM) rises and the load of spring
(3) + the force acting on surface a of spool (2) becomes greater
than the propulsion force of plunger (6), spool (2) is pushed to the
right. The circuit between port PEPC and port PSIG(PM) is shut
off, and at the same time, port PSIG(PM) and port PT are
connected.
• As a result, spool (2) is moved up or down until the propulsion
force of plunger (6) is balanced with the load of spring (3) +
pressure of port PSIG(PM).
• Therefore, the circuit pressure between the EPC valve and the LS
valve is controlled in proportion to the size of the signal current.
3. When signal current is maximum (coil energized)
• When the signal current flows to coil (5), coil (5) is energized.
• When this happens, the signal current is at its maximum, so the
propulsion force of plunger (6) is also at its maximum.
• For this reason, spool (2) is pushed fully to the left by push pin
(4).
• As a result, the maximum flow of pressurized oil from port PEPC
flows to port PSIG(PM), and the circuit pressure between the
EPC valve and LS valve becomes the maximum.
At the same time, port PT closes and stops the oil from flowing to
the tank.
PC400LC-7L 10-43
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STRUCTURE AND FUNCTION HYDRAULIC SYSTEM
12
Unit: mm
No. Check item Criteria Remedy
Standard size Repair limit
Free length x OD Installed length Installed load Free length Installed load
18 Regeneration valve spring 6.2 N 4.9 N
31.5 x 10.3 19.5 --- If damaged or
{0.6 kg} {0.5 kg} deformed,
19 Piston return spring 29.4 N 23.5 N replacespring
36.9 x 11.1 28 ---
{3 kg} {2.4 kg}
20 Piston return spring 29.4 N 23.5 N
36.9 x 11.1 28 ---
{3 kg} {2.4 kg}
Item Torque Nm Torque lbf ft
21. Valve 147.1 - 186.3 108.4 - 137.4
22. Valve 137.0 - 157.0 101.0 - 115.7
23. Valve 49.0 - 58.8 36.1 - 43.3
24. Valve 372.7 - 411.9 274.8 - 303.8
PC400LC-7L 10-53
--- Page 12 ---
STRUCTURE AND FUNCTION HYDRAULIC SYSTEM
12
Basic principle
1. Control of pump swash plate
• The pump swash plate angle (pump discharge amount) is
controlled so that LS differential pressure ∆PLS (the
difference between pump pressure PP and control valve
outlet port LS pressure ∆PLS) (load pressure of actuator) is
constant.
(LS pressure ∆PLS = Pump discharge pressure PP – LS
pressure PLS)
• If LS differential pressure ∆PLS becomes lower than the set
pressure of the LS valve (when the actuator load pressure is
high), the pump swash plate moves towards the maximum
position; if it becomes higher than the set pressure of the LS
valve (when the actuator load pressure is low), the pump swash
plate moves towards the minimum position.
PC400LC-7L 10-63
--- Page 13 ---
STRUCTURE AND FUNCTION HYDRAULIC SYSTEM
12
C. Operation of swing lock
i. When swing lock solenoid valve is deactivated
When the swing lock solenoid valve is deactivated, the
pressurized oil from the main pump is shut off and port B is
connected to the tank circuit.
As a result, brake piston (7) is pushed down by brake spring
(1), discs (5) and plates (6) are pushed together, and the
brake is applied.
ii. When swing lock solenoid valve is activated
When the swing lock solenoid valve is activated, the valve
is switched and the pressure oil from the main pump enters
port B and flows to brake chamber a.
The pressure oil entering chamber a overcomes brake spring
(1) and pushes brake piston (7) up. As a result, discs (5) and
plates (6) are separated and the brake is released.
PC400LC-7L 10-73
--- Page 14 ---
STRUCTURE AND FUNCTION HYDRAULIC SYSTEM
12
2. When stopping travel
Operation
When the travel lever is placed in neutral, counterbalance valve spool (13) returns to the neutral position and the
circuit to the parking brake is closed.
The pressurized oil in chamber e of brake piston (19) passes through the throttle of slow return valve (7) until spool
(13) of the counterbalance valve returns to neutral.
When spool (13) of the counterbalance valve returns to the neutral position, the oil is drained inside the case from the
throttle f of brake piston (19) and brake piston (19) is pushed fully to the left by spring (18).
As a result, plate (9) and disc (10) are pushed together, and the brake is applied.
A time delay is provided by having the pressurized oil pass through a throttle in slow return valve (7) when the brake
piston returns, and this ensures that the brake is applied after the machine stops.
PC400LC-7L 10-83
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STRUCTURE AND FUNCTION HYDRAULIC SYSTEM
12
PC400LC-7L 10-93
--- Page 16 ---
STRUCTURE AND FUNCTION HYDRAULIC SYSTEM
12
Torque Nm Torque lbf ft
4. Bolt 28 ±3 20.6 ±2.2
5. Bolt 23.5 ±3.9 17.3 ±2.8
6. Bolt 30.9 ±2.5 22.7 ±2.5
7. Plug 29.4 ±4.9 21.6 ±3.6
PC400LC-7L 10-103
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STRUCTURE AND FUNCTION HYDRAULIC SYSTEM
12
MEMORANDUM
PC400LC-7L 10-113
--- Page 18 ---
STRUCTURE AND FUNCTION HYDRAULIC SYSTEM
12
QUICK RETURN VALVE
Function
When arm OUT is operated, this valve reduces the pressure loss of the large amount of oil returning from the cylinder bottom.
Operation
1. Arm at OUT
When arm OUT is operated, the pilot pressure from the PPC valve pushes pilot spool (1), and the pressure oil from
chamber b inside the poppet is drained through orifice c.
The oil at the bottom end of the arm flows from orifice a to chamber b to orifice c to drain, so the oil pressure in chamber
b drops.
When the pressure in chamber b drops below the pressure at port A, the pressure at port A and acts on ring shaped area C
(= Area of ød1 – Area of ød2) because of the difference in the outside diameter d1 of valve (2) and seat diameter d2.
Valve (2) moves to the left and the pressure oil from port A goes to port B. From port B, the oil is drained directly to the
tank.
PC400LC-7L 10-123
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STRUCTURE AND FUNCTION HYDRAULIC SYSTEM
12 Unit: mm
No. Check item Criteria Remedy
Tolerance Standard Clearance
Cylinder Standard size
Shaft Hole clearance limit
Boom -0.036 +0.261 0.083 -
Clearance 110 0.412
-0.090 +0.047 0.351
1 between piston Replace bushing
rod and bushing Arm -0.036 +0.263 0.084 -
120 0.412
-0.090 +0.048 0.353
Bucket -0.036 +0.257 0.083 -
100 0.447
-0.090 +0.047 0.347
Boom -0.036 +0.169 0.136 -
110 ---
-0.090 +0.100 0.259
Clearance
between piston Arm -0.036 +0.169 0.136 -
2 110 ---
rod support pin -0.090 +0.100 0.259
and bushing
Bucket -0.036 +0.187 0.133 -
100 ---
-0.090 +0.097 0.277 Replace pin or
Boom -0.036 +0.190 0.106 - bushing
100 ---
-0.090 +0.070 0.280
Clearance
between cylinder Arm -0.036 +0.195 0.135 -
3 110 ---
bottom support -0.090 +0.099 0.285
pin and bushing
Bucket -0.036 +0.187 0.133 -
100 ---
-0.090 +0.097 0.277
BOOM CYLINDER
Torque Nm Torque lbf ft
4. 530 ±78.5 390.9 ±57.9
5. 294 ±29.4 216.8 ±21.6
6. 58.9 ±73.6 43.5 ±54.2
ARM CYLINDER
Torque Nm Torque lbf ft
4. Bolt 892 ±137 657.9 ±101.0
5. Piston 294 ±29.4 216.8 ±21.6
6. Set screw 58.9 ±73.6 43.5 ±54.2
BUCKET CYLINDER
Torque Nm Torque lbf ft
4. Bolt 530 ±78.5 390.9 ±57.9
5. Piston 294 ±29.4 216.8 ±21.6
6. Set screw 58.9 ±73.6 43.5 ±54.2
PC400LC-7L 10-133
--- Page 20 ---
STRUCTURE AND FUNCTION ENGINE CONTROL
12
ENGINE CONTROLLER
PC400LC-7L 10-143
--- Page 21 ---
STRUCTURE AND FUNCTION ELECTRONIC CONTROL SYSTEM
12
Mode B / (Mode ❈L)
Mode Mode B Mode L
Partial output point 82% 61%
Mode B 194.9 kW/1,730 rpm
{261 HP / 1,730 rpm}
Mode ❈L 150.8 kW/1,250 rpm
{202 HP / 1,250 rpm}
• At this time, the controller keeps the pump absorption torque along
the constant horsepower curve and lower the engine horsepower by
the composite control of the engine and pump.
By this method, the engine is used in the low fuel consumption area.
❈: The L mode is on the multi-monitor specification machine only.
PC400LC-7L 10-153
--- Page 22 ---
STRUCTURE AND FUNCTION ELECTRONIC CONTROL SYSTEM
12
1. Auto-warm-up function
After the engine is started, if the engine coolant temperature is low, the engine speed is automatically raised to warm the
engine.
2. Overheat prevention function
If the engine coolant temperature rises too high during work, the pump load and engine speed are reduced to prevent
overheating.
This function is turned on when the coolant temperature rises above 95° C (203° F).
PC400LC-7L 10-163
--- Page 23 ---
STRUCTURE AND FUNCTION ELECTRONIC CONTROL SYSTEM
12
Input and output signals
CN-1 CN-2
Pin No. Signal name Input/ Output Pin No. Signal name Input/ Output
1 NC 1 NC
2 R pump pressure sensor Input 2 Swing emergency switch Input
3 NC 3 NC Input
4 NC 4 232C_RxD Input
5 NC 5 NC
6 NC Input 6 NC
7 NC 7 Model selection 4 Input
8 F boom pressure sensor Input 8 Attachment circuit selector signal Output
9 NC 9 NC
10 Signal GND 10 NC
11 Knob SW Input 11 NC
12 NC 12 CAN shield
13 Buchet CURL PPC pressure sensor Input 13 Model selection 5 Input
14 NC 14 232C_TxD Output
15 NC Input 15 NC
16 NC 16 Travel steering signal pressure SW Input
17 Starting switch (Terminal C) Input 17 Model selection 3 Input
18 NC 18 NC
19 Arm IN PPC pressure sensor Input 19 Auto deceleration signal Output
20 NC 20 NC
21 NC 21 S_NET Input/output
22 POT_PWR Output 22 CAN0_L Input/output
23 Starting switch (terminal ACC) Input 23 NC
24 NC 24 FWE_SW Input
25 NC
26 NC
27 Model selection 2 Input
28 NC
29 GND (pulse GND)
30 NC
31 GND (S_NET GND)
32 CAN0_H Input/ output
33 NC
34 GND (232C GND)
35 Service valve pressure switch Input
36 NC
37 Model selection switch 1 Input
38 Swing lock switch Input
39 GND (pulse GND)
40 Engine speed sensor Input
PC400LC-7L 10-173
--- Page 24 ---
STRUCTURE AND FUNCTION MONITOR SYSTEM
12
SWITCHES
1. Selector switch
2. Selector switch
3. Display brightness, contrast adjustment switch
4. Control switch
5. Window washer switch
6. Wiper switch
7. Maintenance switch
8. Travel speed selector switch
9. Auto-deceleration switch
PC400LC-7L 10-183
--- Page 25 ---
STRUCTURE AND FUNCTION MONITOR SYSTEM
12
• While the user code is being displayed, if the input confirmation
switch is pressed, the service code and failure code can be displayed.
• If there is more than one service code or failure code, the display
switches every 2 seconds and displays all the service codes/failure
codes that caused the user code to be displayed. Even if service codes/
failure codes have occurred, if they did not cause the user code to be
displayed, this function does not display them.
• If the telephone number has been set using the telephone number input
on the service menu, it is possible to switch on the service code/failure
code and display the telephone symbol and telephone number.
For details of inputting and setting the telephone number, see
SPECIAL FUNCTIONS OF MONITOR PANEL in the TESTING
AND ADJUSTING section.
PC400LC-7L 10-193
--- Page 26 ---
TESTING AND ADJUSTING STANDARD VALUE TABLE FOR CHASSIS
12
Cate- Item Measurement conditions Unit Standard value Permissible value
gory
Hydraulic drift of travel ●Hydraulic oil temperature: Within mm 0 0
operating range
●Engine stopped
Travel
●Parking machine on slope 12 degrees
with sprocket facing upslope
●Sliding distance for 5 minutes
●Hydraulic oil temperature: Within
operating range
Leakage of travel ●Engine at high idling
L/min Max. 20 Max. 40
motor ●Travel: Lock sprocket.