Title: Daewoo Doosan DX420LC-5 Excavator Service Repair Manual Instant Download
1Shop Manual
DX420LC-5 Excavator
Serial Number 10001 and Up
DOOSAN and the DOOSAN logo are registered
trademarks of DOOSAN Corporation in the United
States and various other countries around the
world.
950106-01020E April 2014
Original Instructions
Copyright DOOSAN 2014
2Table of Contents
1 Safety
1 Track Excavator Maintenance Safety
2 Specifications
1 Specifications
3 General Maintenance
- General Maintenance Instructions
- Standard Torques
4 Engine
1 Engine
2 Engine Coolant Heater (Option)
5 Upper Structure
1 Cabin
2 Counterweight
- Oil Tank
- Fuel Tank
- Main Pump
- Drive Coupling (Main Pump)
- Main Control Valve
- Swing Device
- Fan Pump for Oil Cooler
- Fan Motor for Oil Cooler
- Gear Pump (Rotation)
- Joystick Valve (Work Lever)
- Travel Control Valve (with Damper)
- Solenoid Valve
- EPPR Valve
- Accumulator
Table of Contents Page I
36 Lower Structure and Chassis
1 Swing Bearing
- Center Joint
- Travel Device
- Track Assembly
7 Front
1 Boom and Arm
- Bucket
- Cylinders
8 Hydraulic System
1 Hydraulic System
- Hydraulic System Testing and Adjustment
- Hydraulic System Troubleshooting
9 Electrical System
1 Electrical System
2 Electrical System Troubleshooting
10 Options
1 One Way
- Two-way
- Rotating
- Quick Coupler
11 Schematic
1 Hydraulic Schematic/Electrical Schematic
Table of Contents Page II
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5Track Excavator Maintenance
Safety
Edition 1
Track Excavator Maintenance Safety 1-1-1
DX420LC-5
6Table of Contents Track Excavator Maintenance
Safety Safety Instructions .......................
...................1-1-5 Safety Messages
............................................1-1-5
General...........................................
................1-1-6 Transportation
..............................................1-1-
19 Operation......................................
................1-1-21 Maintenance
.................................................1
-1-38 Environment and Circumstances...............
...1-1-55
Track Excavator Maintenance Safety 1-1-3
DX420LC-5
7SAFETY INSTRUCTIONS
WARNING
AVOID DEATH OR SERIOUS INJURY Instructions are necessary before operating or servicing machine. Read and understand the Operation Maintenance Manual and signs (decals) on machine. Follow warnings and instructions in the manuals when making repairs, adjustments or servicing. Check for correct function after adjustments repairs or service. Untrained operators and failure to follow instructions can cause death or serious injury.
SAFETY MESSAGES Replace with Safety Messages
Section on pages III and IV in the Doosan
Operation Maintenance Manual.
Track Excavator Maintenance Safety 1-1-5
DX420LC-5
8GENERAL
- Safe Operation is Operator's Responsibility
- Only trained and authorized personnel should
operate and maintain the machine. - Follow all safety rules, regulations and
instructions when operating or performing
maintenance on machine. - Do not operate machine if you are under the
influence of drugs or alcohol. An operator who
is taking prescription drugs must get medical
advice to determine if he or she can safely
operate a machine. - When working with other personnel on a work site,
be sure that all personnel know nature of work
and understand all hand signals that are to be
used. - Be sure that all guards and shields are installed
in their proper location. Have guards and
shields repaired or replaced immediately if
damaged. - Be sure that you understand the use and
maintenance of all safety features such as
safety lever and seat belt. Use them properly. - Never remove, modify or disable any safety
features. Always keep them in good operating
condition. - Always check for and know the location of
underground and overhead utility lines before
excavating. - Failure to use and maintain safety features
according to instructions in this manual, Safety
Manual and Shop Manual can result in death or
serious injury. - Know Your Machine
- Know how to operate your machine. Know the
purpose of all controls, gauges, signals,
indicators and monitor displays. Know the rated
load capacity, speed range, braking and steering
characteristics, turning radius and operating
clearances. Keep in mind that rain, snow, ice,
loose gravel, soft ground, slopes etc., can
change operating capabilities of your machine.
DX420LC-5
Track Excavator Maintenance Safety 1-1-6
9Proper Work Tools and Attachments Only use work
tools and attachments that are recommended by
DOOSAN for use on DOOSAN machines. When
installing and using optional attachments, read
instruction manual for attachment, and general
information related to attachments in this
manual. Because DOOSAN cannot anticipate,
identify or test all attachments that owners may
want to install on their machines, contact
DOOSAN for written authorization and approval of
attachments, and their compatibility with
optional kits. Attachments and attachment control
systems that are compatible with the machine are
required for safe and reliable machine
operation. Do not exceed maximum operating weight
(machine weight plus attachment) that is listed
on ROPS certification plate. Make sure that all
guards and shields are in place on machine and
on work tool. Depending on type or combination of
work equipment, there is a potential that work
equipment could interfere with the cabin or
other parts of machine. Before using unfamiliar
work equipment, check if there is any potential
of interference, and operate with caution. While
you are performing any maintenance, testing, or
adjustments to attachments, stay clear of the
following areas cutting edges, pinch points,
and crushing surfaces. Never use attachment as a
work platform or manlift. Contact your DOOSAN
distributor about auxiliary hydraulic kits for
attachments installation. If you are in doubt
about compatibility of a particular attachment
with a machine, consult your DOOSAN distributor.
Pressurized Fluids Pressurized air or fluids can
cause debris and/or fluids to be blown out. This
could result in death or serious
injury. Immediately after operations are stopped,
coolant, engine oil, and hydraulic oil are at
their highest temperatures and the radiator and
hydraulic tank are still under pressure. Always
wait for temperature to cool down. Follow
specified procedures when attempting to remove
caps, drain oil or coolant, or replacing
filters. Always wait for temperature to cool
down, and follow specified procedures when
performing these operations. Failure to do so
can result in death or serious injury. When
pressurized air and/or pressurized water is used
for cleaning, wear protective clothing,
protective shoes, and eye protection. Eye
protection includes goggles or a protective face
shield. Pressure can be trapped in a hydraulic
system and must be relieved before maintenance
is started. Releasing trapped pressure can cause
sudden machine movement or attachment movement.
Use caution if you disconnect hydraulic lines or
fittings.
FG018457
Figure 1
Track Excavator Maintenance Safety 1-1-7
DX420LC-5
10High-pressure oil that is released can cause a
hose to whip or oil to spray. Fluid penetration
can result in death or serious injury. If fluid
enters skin or eyes, get immediate medical
attention from a physician familiar with this
injury. Obey all local laws and regulations for
disposal of liquids. To prevent hot coolant from
spraying out, stop engine and wait for coolant
to cool. Using gloves, slowly loosen cap to
relieve pressure.
Flying or Falling Objects On work sites where
there is a potential hazard that flying or
falling objects can hit operator's cabin, select
and use a guard to match operating conditions
for additional operator protection. Working in
mines, tunnels, deep pits, and loose or wet
surfaces, could produce hazard of falling rocks
or flying objects. Additional protection for
operator's cabin could be required such as an
Operator Protection Guard (OPG) or window guards.
Contact your DOOSAN distributor for information
on available protective guards. To prevent
personnel from being struck by flying objects,
keep personnel out of work area.
HAOA110L
Figure 2
HAOA100L
Figure 3
DX420LC-5
Track Excavator Maintenance Safety 1-1-8
11Engine
Edition 1
DX420LC-5
Engine 4-1-1
12- Removal Cylinder Head
- Remove water-cooled EGR cooler as instructed in
the work description for "Removing the EGR
Cooler" on page 4-1-267. - Remove brackets for the water-cooled EGR cooler.
- Remove bolts for the exhaust manifold on the
relevant cylinder and slacken the bolts on the
adjacent cylinders so the relevant part of the
exhaust manifold comes loose. - Remove cooling system bleeder hose, separate the
quick release coupling at the front lifting eye. - Remove cable duct from the intake.
- Remove cable ties for the cable harness from the
engine control unit.
IMPORTANT
The fuel system components are extremely
sensitive to dirt. Clean thoroughly before
dismantling and plug all connections with
lint-free rags and tape.
- Depressurize the fuel system and detach the fuel
pipe (1, Figure 29) running between the
accumulator and fuel manifold. - Detach the fuel manifold and remove bolts on the
relevant cylinder. - Detach the intake manifold and remove bolts on
the relevant cylinder. To remove fuel and intake
manifold, see "Fuel Manifold" and "Intake
Manifold".
1
IMPORTANT All parts in the fuel injection
system and valve mechanism must be
marked. Everything must be reinstalled in the
same position.
EX1401040
Figure 29
9. Remove injectors as instructed in the work
description for "Removing Injector" on page
4-1-311. Also remove high-pressure pipes and
connection on the cylinder head at the back
viewed from the coolant pump.
Engine 4-1-57
DX420LC-5
13IMPORTANT
If work is done on the 6th cylinder of an engine
with an EGR system, the EGR valve control
cylinder must be detached at the damper and
removed.
10. Remove upper rocker cover and then the rocker
arm housing, valve bridges and pushrods.
FG020251
Figure 30 11. Pull the cable harness out of the
lower rocker cover and remove it.
NOTE
Take care when pulling the cable harness out of
the rocker cover the cable terminals can be
damaged which can cause the nut securing the
cable harness to the injector to come loose.
- Work on the adjacent cylinders. Remove upper
rocker cover, release the cable harness and the
lower rocker cover so it can be moved. - Remove relevant cylinder head. Be careful with
the adjacent rocker covers.
FG020252
Figure 31
NOTE
Mark the cylinder heads if more than one is
being removed at the same time. If all cylinder
heads are removed at the same time, the
turbocharger must be removed or supported
against the frame.
NOTE
Installing Cylinder Head
- Check the liner height.
- Clean the cylinder head and cylinder block.
Lubricate the threads and below the heads of the
cylinder head bolts. - Install a new cylinder head gasket.
- Install the cylinder head.
- Tighten the cylinder head as shown in the
illustration and according to specification. - Cylinder head bolts can only be reused three
times. Make a mark with a center punch on the
head of the bolt. If any of the bolts already
has three marks, it must be replaced.
1
5
3
4
6
2
FG020253
Figure 32
DX420LC-5
Engine 4-1-58
141
2
3
4
FG020254
- Figure 33
- Tighten the intake manifold. Use a new gasket.
Tighten the bolts in the order 1 - 24 as
illustrated. Tighten the bolts in the same order
again. - Tighten the intake manifold and the exhaust
manifold. Use new gaskets. - Install the cable bracket bolt in the lower
rocker cover and install the following parts
- Lower rocker cover.
- Pushrods.
- Valve bridge.
- Rocker arm housing.
Figure 34
IMPORTANT
- Lubricate the valve bridge and rocker arm housing
with engine oil. - Install the injector, high-pressure pipe
connection and high-pressure pipe as instructed
in the work description. - Reset adjacent cylinders.
- Adjust the valve clearance.
- Install the upper rocker covers.
- Install the cooling system vent
- Install the brackets for the water-cooled EGR
cooler. - Install the water-cooled EGR cooler as described
in the work description for "Installing the EGR
Cooler" on page 4- 1-268.
Engine 4-1-59
DX420LC-5
15Removing and Installing Valves
WARNING
AVOID DEATH OR SERIOUS INJURY Wear protective
goggles for eye protection. 1. Removing Valves
- Remove split collets, valve spring collars,
springs and valves. Press down the spring using
tool 99 322 in a press so the collets can be
removed. - Place the valves in a stand so they can be
reinstalled in the same position in the cylinder
head.
99 322
FG020258
Figure 35
2. Installing Valves
99 322
NOTE
There are different versions of the combination
valve valve spring collar split collet. Parts
from the different versions must not be mixed
on the same valve.
- Lubricate all parts well with engine oil before
assembly. - Insert the valve in the guide. C.
- D.
Install the valve springs and the valve spring
collar. Press together the springs in a press
with tool 99 322 and install the collets. Ensure
that collets are installed in their correct
positions.
FG020259
Figure 36
- Replacing a Valve Stem Seal
- Remove valve according to the work description
for "Removing Valves" on page 4-1-75. - Remove valve stem seal with a pair of pliers.
- Install the valve.
FG020261
Figure 37
DX420LC-5
Engine 4-1-60
164. Carefully tap a new valve stem seal into place
using tool 99 323 and a hammer.
99 323
FG020262
Figure 38
Replacing the Valve Seats
1. Remove valve seat inserts with an expanding
sleeve from the kit with puller 587 270 (1,
Figure 39). NOTE Insert, for example, an
aluminum sheet between the cylinder head and
counterhold to protect against damage.
1
2
WARNING
FG020266
AVOID DEATH OR SERIOUS INJURY Wear protective
goggles for eye protection from flying metal
parts.
Figure 39
2. Press in new valve seat inserts. Use drift 99
384 (2, Figure 39) and shank 99 385. Cool the
drift and valve seat insert to about -80C with
dry ice or liquid air. Pressing must be done
rapidly.
99 385
99 384
WARNING
AVOID DEATH OR SERIOUS INJURY
Prevent frost injuries. Be careful when handling
very cold parts and refrigerant.
FG020267
Figure 40
Oversize valve seat inserts can be installed if
the valve seat insert position has been
damaged. The position is then machined using tool
587 277.
Engine 4-1-61
DX420LC-5
17Replacing the Valve Guides 1. Press out the valve
guides using drift 99 383.
99 383
FG020268
Figure 41
2. Press in the new valve guides using drift 99
382. Press the guide down as far as the drift
allows, i.e. until it contacts the spring seat
in the cylinder head.
99 382
FG020269
Figure 42
Replacing the Injector Sleeves The cylinder head
must be removed when replacing the unit injector
sleeve. The valves do not need removing. The
illustrations show the cylinder head with valves
removed to demonstrate clearly the work
described. NOTE Guide and pilot tap on
extension piece 99 397.
FG020272
Figure 43
DX420LC-5
Engine 4-1-62
18- Thread the lower part of the sleeve using the
pilot tap and guide from tool kit 99 574. - Knock out the pilot tap and sleeve from
underneath. Use a 100 mm long metal rod of
diameter 9 mm. - Degrease and check the contact surfaces of the
sleeve and cylinder head. Smooth off any burrs
and irregularities that may score the sleeve. - Degrease the new injector sleeve and apply a thin
film of sealant 561 200 on the sleeve and
cylinder head contact surfaces. - Press in the sleeve using the drift and guide
from tool kit 99 574.
FG020273
Figure 44
Engine 4-1-63
DX420LC-5
19Replacing the Valve Bridge Guide Pins The
cylinder head must be removed when replacing the
guide pins. 1. Remove Outlet valves and Intake
valves.
1
2
Reference Number Description
1 Outlet Valves
2 Intake Valves
FG020276
Figure 45 2. Install shrink sleeve number 10
from tool kit 587 470.
FG020277
Figure 46
3. Use pin extractor 587 470 to remove guide pins.
587 470
FG020278
Figure 47
FG020279
Figure 48
DX420LC-5
Engine 4-1-64
204. Press in the new guide pins using drift 99
015. Maximum press force 15 kN.
99 015
NOTE
Check before pressing in that tool is not
deformed. Check after pressing in that valve
bridge slides easily on the guide pin.
5. Install all the parts in the cylinder head.
FG020280
Figure 49
- Machining the Valve Seat Position
- Check that contact surface on the cylinder head
is level and clean. Also check that magnetic
stand on the valve seat cutter is clean. Clean
the valve guides. - Zero the micrometer.
FG020282
Figure 50 3. Assemble the micrometer with a
suitable spindle on the valve seat cutter and
adjust the cutter. It is very important that tip
of the cutter is in the center of the micrometer
spindle.
FG020283
Figure 51
Engine 4-1-65
DX420LC-5
21- Select the largest control spindle that moves
easily in the valve guide. Install the valve
seat cutter and turn the feed screw to its upper
position. - Turn off the magnet (position 2). Insert the
guide spindle into the valve guide. Adjust the
pivot plate so the distance between the cutter
and the valve seat is approximately 1 mm. - Center the valve seat cutter precisely.
- Turn on the magnet (position 1).
FG020284
Figure 52 7. Apply the quick-action lock. Make
sure the crank can be turned easily. If not,
redo the centering.
FG020285
Figure 53 8. Machine the valve seat by cranking
clockwise while turning the screw clockwise.
Lubricate with cutting oil while machining.
IMPORTANT
The cutter must never be cranked counterclockwise.
- When the surface of the valve seat has been
machined, reduce the cutting pressure by turning
2-3 revolutions without any feed. Continue
turning clockwise while turning the screw
counterclockwise until cutter is free. Disconnect
the solenoid by briefly pressing switch position
2. - The valve seat cutter is now ready for the next
valve seat.
FG020286
Figure 54
DX420LC-5
Engine 4-1-66
22- Removing the Valve Seat Insert
- Remove cylinder head. According to the word
description for "Removal Cylinder Head" on page
4-1-57. - Remove intake and exhaust valves. According to
the word description for "Removing and
Installing Valves" on page 4-1-60.
NOTE
Insert, for example, an aluminium sheet between
the cylinder head and counterhold to protect
against damage.
IMPORTANT
Wear protective goggles. There is a risk that
loose slivers of metal can cause personal injury
when pulling out the valve seats.
Figure 55
Remove valve seat inserts with an expanding
sleeve from the kit with puller 587 270.
- Machining the Reducer Chamfer
- Check that contact surface on the cylinder head
is level and clean. Also check that magnetic
stand on the valve seat cutter is clean. Clean
the valve guides. - Adjust the cutting blade for a 51 reducer
chamfer on the valve seat cutter and set the
distance to approximately 21 mm as illustrated.
Figure 56 3. Select the largest control spindle
that moves easily in the valve guide. Install
the valve seat cutter and turn the feed screw to
its upper position.
Figure 57 4. Lubricate the control spindle and
insert it in the valve guide.
Engine 4-1-67
DX420LC-5
235. Adjust the pivot plate so distance between
the cutter and the reducer chamfer is
approximately 1 mm. Center the valve seat cutter
precisely.
- Figure 58
- Turn on the magnet (position 1).
- Apply the quick-action lock. Make sure the crank
can be turned easily. If not, redo the centering.
Figure 59
IMPORTANT
The cutter must never be cranked
counterclockwise. 8. Mill the reducer chamfer by
cranking clockwise while turning the feed screw
clockwise. Make sure you do not make the outer
diameter of the reducer chamfer larger, as shown
in the illustration.
- Figure 60
- When the surface of the reducer chamfer has been
machined, reduce the cutting pressure by turning
2 3 revolutions without any feed. Continue
turning clockwise while turning the screw
counterclockwise until cutter is free. Disconnect
the solenoid by briefly pressing switch position
2. - Continue with the next reducer chamfer as
described in the steps above.
DX420LC-5
Engine 4-1-68
24- Installing a New Valve Seat Insert
- Clean the cylinder head.
- Tap/press in new valve seat inserts. Use drift 99
384 and shank 99 695. Cool the drift and valve
seat insert to about - 80C with dry ice or
liquid air. The tapping/pressing in must be done
very rapidly.
WARNING
AVOID DEATH OR SERIOUS INJURY Be careful when
handling the cold parts and refrigerant
mentioned above. Risk of frost injuries.
Oversize valve seat inserts can be installed if
the valve seat insert position has been damaged.
The position must then be machined with tool 587
277.
Figure 61
- Machining the Valve Seat Insert Sealing Surface
- Check that contact surface on the cylinder head
is level and clean. Also check that magnetic
stand on the valve seat cutter is clean. Clean
the valve guides. - Adjust the cutting blade for a 30 valve seat
position on the valve seat cutter and set the
distance to approximately 17 mm as illustrated.
Figure 62 3. Lubricate the control spindle and
insert it in the valve guide.
Engine 4-1-69
DX420LC-5
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264. Adjust the pivot plate so distance between
the cutter and the valve seat insert is
approximately 1 mm. Center the valve seat cutter
precisely.
- Figure 63
- Turn on the magnet (position 1).
- Apply the quick-action lock. Make sure the crank
can be turned easily. If not, redo the centering.
Figure 64
IMPORTANT
The cutter must never be cranked
counterclockwise. 7. Perform minimal machining
of the valve seat insert sealing surface by
cranking clockwise while turning the feed screw
clockwise. Continue until it can be seen that
entire sealing surface is machined.
Figure 65
DX420LC-5
Engine 4-1-70
27- When the sealing surface of the valve seat insert
has been machined, reduce the cutting pressure
by turning 2 3 revolutions without any feed.
Continue turning clockwise while turning the
screw counterclockwise until cutter is free. - Disconnect the solenoid by briefly pressing
switch position 2. - Continue with the next valve seat insert as
described in the steps above. - Height Check of Valve Seat Insert
- 1. Make sure that cylinder head is clean.
NOTE
Use the same exhaust valve for the measurement
below to avoid measurement errors.
2. Install the exhaust valve in the first valve
guide. Measure the height of the exhaust valve.
Figure 66 3. Install the same exhaust valve in
the second valve guide. Measure the height of
the exhaust valve.
Figure 67 4. The height tolerance between
exhaust valves is 0.05 mm. If the difference is
greater, machine the valve seat insert which is
highest until height tolerance is obtained. Also
check that distance between the valve disk and
the bottom of the cylinder head is not less than
0.71 mm as shown in the illustration.
Figure 68
Engine 4-1-71
DX420LC-5
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the link into your browser. The full manual is
available for immediate download. https//www.eb
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