service repair manual

1. K1009096AE Shop Manual
Copyright 2008 Doosan
Doosan reserves the right to improve our products in a continuing process to provide the best possible
product to the market place. These improvements can be implemented at any time with no obligation to
change materials on previously sold products. It is recommended that consumers periodically contact their
distributors for recent documentation on purchased equipment.
This documentation may include attachments and optional equipment that is not available in your
machine's package. Please call your distributor for additional items that you may require.
Illustrations used throughout this manual are used only as a representation of the actual piece of
equipment, and may vary from the actual item.
Shop Manual
K1009096AE
Serial Number 5327 and Up
DX420LC

2. Table of Contents
Page I
1Table of Contents
Safety
Track Excavator Safety......................................................................... SP000907
Specifications
Specification for DX420LC.................................................................... SP001755
General Maintenance
General Maintenance Procedures........................................................ SP000016
Standard Torques................................................................................. SP000813
Upper Structure
Cabin .................................................................................................... SP001737
Counterweight....................................................................................... SP001756
Fuel Tank.............................................................................................. SP001757
Fuel Transfer Pump (Opt)..................................................................... SP000021
Swing Bearing....................................................................................... SP001856
Swing Reduction Gear.......................................................................... SP001740
Lower Structure and Chassis
Track Assembly .................................................................................... SP000263
Engine and Drive Train
Drive Coupling (Main Pump)................................................................. SP000026
Hydraulics
Hydraulic System Troubleshooting, Testing and Adjustment ............... SP001758
Accumulator.......................................................................................... SP000028
Center Joint (Swivel)............................................................................. SP000181
Cylinders............................................................................................... SP000030

3. Table of Contents
Page II
Swing Motor.......................................................................................... SP000261
Travel Motor (With Gearbox) ................................................................ SP000266
Main Pump............................................................................................ SP000186
Gear Pump (Fan Cooling Drive) ........................................................... SP000208
Main Control Valve ............................................................................... SP000187
Remote Control Valve (Work Lever / Joystick)..................................... SP000189
Travel Control Valve (With Damper)..................................................... SP001743
Fan Motor (Vane Type)......................................................................... SP000209
Fan Cooling Flow In-Out Change Valve ............................................... SP000207
Solenoid Valve Assembly ..................................................................... SP001622
Breaker EPPR Valve (Opt) ................................................................... SP000192
Hydraulic Schematic (DX420LC).......................................................... SP001769
Electrical System
Electrical System .................................................................................. SP001759
Electrical Schematic DX420LC............................................................. SP001857
Attachments
Boom and Arm...................................................................................... SP001851
Bucket................................................................................................... SP001852

4. SP000186
Page 5
Main Pump
SAFETY PRECAUTIONS
APPLICABLE MODELS
The contents of this section apply to the following models and
serial number ranges.
CAUTION!
Follow all safety recommendations and safe shop practices
outlined in the front of this manual or those contained
within this section.
Always use tools and equipment that are in good working
order.
Use lifting and hoisting equipment capable of safely
handling load.
Remember, that ultimately safety is your own personal
responsibility.
MODEL SERIAL NUMBER RANGE
DX340LC 5980 and Up
DX350LC 5980 and Up
DX420LC 5327 and Up
DX480LC 5221 and Up
DX520LC 5117 and Up

5. SP000186Main Pump
Page 6
ECTIONAL VIEW
A8VO200LA1KH1/63
ASS0010L
Figure 1

6. SP000186
Page 7
Main Pump
ASS0020L
Figure 2

7. SP000186Main Pump
Page 8
GENERAL REPAIR GUIDELINES
NOTE: Observe the following cautions when carrying
out repairs on hydraulic units.
1. Close off all openings of hydraulic unit.
2. Replace all seals.
Use only original spare parts
3. Check all sealing and sliding surfaces for wear.
NOTE: Rework of sliding surfaces using crocus cloth or
other similar materials, can damage the
surface.
ASS1140L
Figure 3
ASS0030L
Figure 4
ASS0040L
Figure 5
ASS0050L
Figure 6

8. SP000186
Page 9
Main Pump
4. Fill hydraulic unit with hydraulic oil before putting into
operation.
ASS0060L
Figure 7

9. SP000186Main Pump
Page 10
SEAL KITS AND SUB-
ASSEMBLIES
1. Seal kit for drive shaft.
2. Peripheral seal kit.
3. Rotary group 1, ready to install.
ASS0070L
Figure 8
ASS0080L
Figure 9
ASS0090L
Figure 10

10. SP000186
Page 11
Main Pump
4. Rotary group 2, ready to install.
5. Rotary group, hydraulic component (order rotary groups 1
and 2 separately).
NOTE: Adjustment is necessary. Pay attention to
direction of rotation.
6. Rotary group 1, mechanical section, ready to install.
7. Rotary group 2, mechanical section, ready to install.
ASS0100L
Figure 11
ASS0110L
Figure 12
ASS0120L
Figure 13
ASS0130L
Figure 14

11. SP000186Main Pump
Page 12
8. Control, pre-adjusted.
9. Gear pump, complete.
10. Intermediate gear.
ASS0140L
Figure 15
ASS0150L
Figure 16
ASS0160L
Figure 17

12. SP000186
Page 13
Main Pump
11. Auxiliary drive.
12. Valve plate with valves.
13. Pipe, complete with fittings.
ASS0170L
Figure 18
ASS0180L
Figure 19
ASS0190L
Figure 20

13. SP000186Main Pump
Page 14
SEALING THE DRIVE SHAFT
1. Protect drive shaft. (e.g. with tape).
2. Remove retaining ring and shim.
ASS0200L
Figure 21
ASS0210L
Figure 22
ASS0220L
Figure 23

14. SP000186
Page 15
Main Pump
3. Screw sheet metal screw(s) into holes fitted with rubber.
Pull out seal with pliers.
4. Press in shaft seal ring and shim with bushing to stop.
NOTE: Take note of press-in depth. Install mark for
press-in depth of safety ring.
ASS0230L
Figure 24
ASS0240L
Figure 25

15. SP000186Main Pump
Page 16
GEAR PUMP SEALING
Remove gear pump.
Visually check:
1. O-ring (1, Figure 27).
ASS0250L
Figure 26
1 ASS0260L
Figure 27

16. SP000186
Page 17
Main Pump
2. Sealing surface of housing (2, Figure 28).
2
ASS0270L
Figure 28

17. SP000186Main Pump
Page 18
REMOVE THE CONTROL
HOUSING
ASS0280L
Figure 29

18. SP000186
Page 19
Main Pump
1. Place pump into a disassembly / assembly device with a
crane and secure it into position.
2. Remove screws holding port plate.
3. Using a suitable lifting device, remove port plate.
NOTE: Mark installation position.
NOTE: Be careful, control lenses can fall out.
ASS0290L
Figure 30
ASS0300L
Figure 31

19. SP000186Main Pump
Page 20
4. Remove paper seal, and clean sealing surface.
ASS0310L
Figure 32
2
3
2
3
1
1 ASS0320L
Figure 33
Number Description
1 Setting Screw: Qmax
2 Setting Screw: Hydraulic Stroke Limitation
3 Setting Screw: Power Characteristic (Begin of Regulation)

20. SP000186
Page 21
Main Pump
NOTE: Before carrying out setting or disassembly of
regulator, measure distance "X" of adjustment
screw and record value.
X
ASS0330L
Figure 34

21. SP000186Main Pump
Page 22
CONTROL MODULE
Control Module LR
Remove and disassemble control module LR.
ASS0340L
Figure 35
* *
ASS0350L
Figure 36

22. Thank you very much for
your reading. Please Click
Here. Then Get COMPLETE
MANUAL. NO WAITING
NOTE:
If there is no response to
click on the link above,
please download the PDF
document first and then
click on it.

23. SP000186
Page 23
Main Pump
Control Module H
Remove and disassemble control module H.
ASS0360L
Figure 37
ASS0370L
Figure 38

24. SP000186Main Pump
Page 24
REMOVING THE CONTROLLER
1. Remove cover.
NOTE: Do not change the setting of adjustment screw
(1, Figure 39).
*
*
(1)
ASS0380L
Figure 39
ASS0390L
Figure 40

25. SP000186
Page 25
Main Pump
2. Remove screws.
NOTE: Install control lens - torque support.
3. Remove locking screw and replace with a new one.
NOTE: Loosen adhesive with a "gentle" flame
(approximately 120°C).
4. Remove swivel pin.
ASS0400L
Figure 41
ASS0410L
Figure 42
ASS0420L
Figure 43
ASS0430L
Figure 44