Case 120 User manual

120
Crawler
Service Manual
S406208M2

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TABLE OF CONTENTS
GENERAL
SafetyPrecautions ............................................................................. 3,4
Introduction
..................................................................................... 5
Nomenclatureand MachineGeneral Description
................................................. 6,7
Directional Reference
............................................................................ 8
Partsand Service
................................................................................ 8
SECTION 1 • SCHEDULED PREVENTIVE MAINTENANCE
Lubricantand Fluid Recommendations ............................................................ 9
ComponentCapacities
.......................................................................... 10
PressureSettings
............................................................................... 10
MaintenanceSchedule
.......................................................................... 11
Service Chart ................................................................................ 12, 13
Pictorial Listing
of Grease Fitting Locations ................................................... 14, 15
SECTION 2• THE UNDERCARRIAGE
Description, Maintenanceand Troubleshooting ............................................ 16 thru 26
Carbodyand Turntable Bearing ................................................................ 17
Track Assemblies
...................................................................... 18 thru 22
Track Drive Assemblies ................................................................ 22 thru 26
Disassemblyand Repair .................................................................. 27 thru 42
General Cleaning Instructions ................................................................. 27
UpperTrack Rollers
........................................................................ 28,29
LowerTrack Rollers
........................................................................ 30,31
IdlerWheel Assembly .................................................................. 31 thru 33
Digging
Brake ............................................................................ 34-35B
Track DriveTransmission
.............................................................. 36 thru 42
SECTION 3• THE UPPERSTRUCTURE
Description, Maintenanceand Troubleshooting ............................................ 43 thru 54
Pump Drive System
.................................................................... 43 thru 48
Swing System
......................................................................... 49 thru 53
Boom
Assembly. . ... . .. .. . .. .. ... .. . .. ... .. . .. ... .. . ... .. .. ... . .. .. . .. . .. .. . ... . . . .......... 54
Disassemblyand Repair . ................................................................. 55 thru 67
Pump Drive Transmission and Clutch
................................................... 56 thru 59
House
Brakes ................................................................................ 59
Swing Gearbox ........................................................................ 59 thru 65
Turntable Bearing Replacement
........................................................ 65 thru 67
Boom Removal
..........................................................•.................... 67
SECTION 4• THE ELECTRICAL SYSTEM
Description, MaintenanceandTroubleshooting ............•..•.•.............••....•.....• 68 thru 79
The Charging System .................................................................. 69thru 74
Control Circuits .•........•..............................................•...•...•..•.. 74 thru 77
Lightsand Instrument Circuits .........................................•...................... 78
Disassembly and Repair . ........................................................................ 79
1
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CONTENTS
MODEL 12 0 CRAWLER
SECTION 5• THE HYDRAULIC SYSTEM
Description, Maintenanceand Troubleshooting ........................................... 80 thru 127
Introduction
to Hydraulics .................................................................... 80
General Descriptionand System Maintenance
........................................... 81 thru 89
Hydraulic Reservoirand Supercharge System
........................................... 82 thru 86
HydraulicSystem Flushing and Troubleshooting
........................................ 87 thru 89
Main HydraulicSystem
............................................................... 90 thru 100
Pilot Control System ................................................................. 101 thru 107
AuxiliarySystem
........................................................................ 107,108
Track Drive Circuit
................................................................... 108 thru 114
Tool CylinderCircuit.
........................................................................ 115
Swing Circuit.
...................................................................... 116 thru 118
Crowd Cylinder Circuit.
.................................................................. 119,120
Hoist CylinderCircuit (includes Fast Hoist Circuit) .................................... 120 thru 124
Pump Drive Clutch Circuit.
................................................................... 125
CounterweightSystem
................................................................... 126,127
Disassemblyand Repair
................................................................ 128thru 173
Hydraulic Reservoir
...................................................................... 128,129
Main Pumps
........................................................................ 129thru 137
Main Control Valves
................................................................. 138 thru 140
PowerSensing Valve
........................................................................ 141
Hydraulic Filters(In-line) ..................................................................... 142
Charging Pump
...................................................................... 143 thru 145
ModulatorValves
.................................................................... 146thru 150
Swing Cushion Valve
........................................................................ 151
Swing Motors ....................................................................... 152 thru 156
Tool, Crowd and
Hoist Cylinders ...................................................... 157thru 161
Fast Hoist Control Valve ..................................................................... 161
Track Drive Motors .. :. .............................................................. 162 thru 165
Hydraulic Swivel.
........................................................................ 166, 1-67
CounterweightControl Valve ............................................................. 168,169
CounterweightCylinders
............................................................ 170 thru 172
Clutch Cylinder
.............................................................................. 173
TORQUE CHARTS AND SCHEMATICS . ...................................................... 174 thru 179
2
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MODEL 12 D CRAWLER
SAFETY PRECAUTIONS
THIS
SAFETY ALERT SYMBOL IND/CA TES
A
IMPORTANT
SAFETY MESSAGES
IN THIS
MANUAL WHEN YOU
SEE
THIS SYMBOL,
CAREFULLY READ THE
MESSAGE
THAT
FOL-
LOWS AND
BE ALERT
TO THE
POSSIBILITY
OF PERSONAL INJURY OR DEA TH.
\1 ,lir 11 sr•rvrcrrllJ tl1,· llldr l1111t· tdr] 111drl
A 1111° Iqr11tI11I1 ,\\'il( 11 t,1 <1lr•1t CJfh,-•r
~ rrp/ r-,·,Jr, ,J11rl Irrr•1 r rrt ,r< c1rl1•11tc1I
lr1I1 Ill''.
A
CAUTION [NCilfJE FAr\J Af'JD REL TS
T() 1irI•v,·rIt [Hl'.,
1
,1I ,J,-, Sf"fll •us lflJLHY J\ "'' I
C0lild( 1 .vrtli IUld1II1/I fdrl ,Hlii hf-'lts
h. tl< f"11· c.t 1IlrrIq ,11qrr1, rP,il ,, ',lli'' rll
~ 1,
1
11•1 i1II1
11
r ,11111"1,. JII' 111 rH:UTRAL
A I< r"PIJ f111· 1•xtir1q111c.l1t0I•, diirl frr•,t ,ir<I ~ rt
~ l1,111ily IIHI ~ IIU'.V l1i1W tr, LI'.<' tlir•1r1
A
\VJ--\I-n\Jlf'J(; r,J,•vr0I Sllrrd,
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\lirl,·
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0
l111q '.I IVl/llllj tlw l110I •,v,II•III 1)1
VJ1,rl II1q ,vrtli l1c1tt1 r 11",
A
WARNlf'JC Thrc; macl1111c ,,, r•qu,
th,124vultelectr1 stvnI Spdrk111q
wrll occur dt· qI1•c11(1r clrst,-111ces tlrdtl
wrtlr a co11v1_'11t1011dl 12 vult tern
r1 JEVER \NEAR Rlr\JCS OR OfHf,R
MET.AL OBJE'CTS th,n III.iv qr,11111<I
' Cl rCl J 11
A \ 'J A RrJf rj ( 1 [Jr l r J( )l ,f II I < 11 r I 1111 ' I II,,
~ 1rl111,t111111l11·rl1
3
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SAFETY PRECAUTIONS
A
\',Af-::~Jl1J(1 T,1 [ll' Pill ''\I' illjlliiPS
,\1l JI (,dfl'tv qlz1'>SI"; \,\~11'r1 ')f'r
1
I( lfllj th1l.,
1111( 11111,,
A
\\ARNl1\Jli 81•fure c1tte11111t111q to
cl1s<JssP111bll' tlw sh()( k Jhsor her ''\ l111cler
rnc1I, slllP dll 1ircssur,· rs relre",l'ci frrst
4
A \\11pP
rnl sprlls rmniedratPly ,rnd kePp
work dlPd dS clP,111 ,1s possrhlE A
(
lutH·r eel wr JI~ c11 Pr1 111vr tes c11 c rderits
A
C/\lJTI( H•J i'rJr·.r r I,· f\t 1·nq111P 1111111111/J
'11, I• llld( iil')I I', ,Jlldl (>'11<1,,i]
MODEL 12 D CRAWLER
LJ1,,c111111/"I I lrotli f,, 11]', 1111111 tliP IJc1llr•11Ps
A
\Vl11•11 1vr,rl 1111] ()II 1111 ('ll((lllf' Ill PIP( tllldi
',,•,11·111 Al1.\,IVS dr'.(llll'll'Ct 1hr• Ci1"11r1d
l<-',1(1 trr st
A
CAUTION WIH'ri I lw1 krrHt 1 ""I 1111 IPu•I
remove 1,Fl1c1tr1r \,ii) r,l1Ji:,ly Ir) fr llt'\f'
pressur1° ,v1tli111 th,• syst1·111
A
When bleecl111g brakes, loosen hleecler
plug approxrrnatelv orilv crne half to
three quarter turn or u1111I orl 1ust stc1rts
to flow If pluq rs loosened too far rt
may he hlowri out urider pressure
WAR~~li'r~G Us,· extr1·r1w , ,11e vvlwn
A hdrHll111q thr· tld[k NP\Pr 1r1•,P11 f1r1qers
~ ln·twe,•11 tr dCK ,;l1oes •vh,·n r ernrl\ 1r1g the
trcid
A\',/\,fi[\Jff\1(1
Tr) J/()ld [H'IS(lflcil llijlJf\/
l,H'fJ 11111rlc ( lr•,11 ril t11111t.drlr• lilllj ']•'di
I 1111 t rr r r1 I ii ,Ir• r, I ll'l llll 11 ,I II f-il
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INTRODUCTION
This manual is designed to serve as a guide in maintaining and servicing the
120 CRAWLER. All components and systems are covered, with the
exception
of the engine which is covered in the engine manufacturer's
manual.
The book
is basically divided into five sections, preceded by a general section
on safety. nomenclature and Parts & Service information.
Section 1
gives the Scheduled Preventive Maintenance needed to keep the
machine
in top operating condition. It includes a maintenance schedule,
component capacities, service chart, lubricant and fluid recommendations,
and a pictorial listing
of all grease fitting locations. If more detailed
maintenance information
is required, it can be found in the individual service
sections.
Section 2 covers
the undercarriage. It includes the turntable bearing, the
tracks and
the track drives.
Section 3 covers
the mechanical components of the upperstructure. Included
are
the engine, pump drive transmission, the swing assemblies and the boom
assembly.
Section 4 covers
the Electrical System. It is divided into the charging system,
lights and instrumentcircuits, and
the control circuits.
Section 5 covers
the Hydraulic System. It includes the main system, the pilot
control system,
the counterweight system, the supercharge system, and the
auxiliary hydraulic system.
The sections are divided into two subdivisions. The first part covers
description, maintenance and troubleshooting. The second part covers
disassembly and repair.
Torque Charts and Schematics
of the hydraulic and electrical systems are
located
in back of this manual. These should be used as aids in
troubleshooting.
5
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NOMENCLATURE
M0D ■ L 12 0 CRAWLER
6
NOMENCLATURE
TOOL CYLINDER r DIPPERSTICK
f ,,,..,,./ .. _ [ CROWD CYLINDER
, ......... "-
LOCATION OF
FUEL TANK
AND SWING
MOTORS
LOCATION OF TURNTABLE
BEARING
MAIN BOOM
LOCATION OF
HOIST CYLINDERS
ENGINE COMPARTMENT
WITH PUMPS, VALVES,
HYDRAULIC RESERVOIR
AND BATTERIES
LOCATION OF TRACK
IDLER WHEEL ASSEMBLY
LOCATION OF TRACK
DRIVE MOTORS, DIGGING LOCATION OF
BRAKES AND TRACK DRIVE--'
TRANSMISSIONS
MODULATOR CONTROLS
(Shown in DIGGING position with Track Drives to the Front)
Figure 1. Nomendature
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_,
MODEL 12 0 CRAWLER GENERAL
GENERAL DESCRIPTION
General Description
The 120 is a fully hydraulic unit. Power for operation
is supplied by a Detroit Diesel 12V-71 engine. Engine
power
is converted to hydraulic energy by two main
pumps and a two-section pump located at the rear
of
the engine.
Hydraulic systems include:
1) the Main System, 2)
the Pilot System, 3) the Counterweight system, and
4) the
Auxiliary System.
1) The Main System powers the work functions
(track drive, swing, hoist, crowd and
tool). Its
pumps
are driven off the engine through a
transmission and clutch which
can be either
manually
or hydraulically disengaged from the
engine. The
two main pumps supply oil to two
main control valve banks where it is available to
operate the individual work functions.
LEFT TRACK TOOL
SWING
2) The Pilot System supplies oil to the Modulator
Controls. The Modulator controls replace the
conventional mechanical linkage
to the main
valves and provide precise hydraulic control of
the main valve spools. The pilot system also
supplies oil
for release of the digging and house
brakes,
for release of the hoist and crowd anti-
drift valves, and for clutch engagement or dis-
engagement.
3) The Counterweight System allows the 14
ton
counterweight to be easily removed or installed.
4) The
Auxiliary System is connected directly into
the pilot system. Its pump is driven by an
electric motor, independent of the engine, and
can be used in case of engine failure to
pressurize the pilot system.
Figure 2 shows the power distribution
from the
engine
to the various machine functions.
MAIN
CONTROL
VALVE PUMP
BANK
MAIN
CONTROL PUMP
VALVE
:G
I
BANK
__ .,
CROWD
DRIVE MOTOR
CYLINDER MOTORS CYLINDER
CWT.
BRAKE
GEAR BOX
&
SPROCKET
BRAKE
GEARBOX
&
SPROCKET
PLANETARY
DRIVE
GEARBOXES
CLUTCH
CYLINDER
Figure 2. Block Diagram
MODULATOR
CONTROL VALVES
HOUSE BRAKE
CONTROL VALVE
DIGGING BRAKE
CONTROL VALVE
CLUTCH"CYL.
SOL. VALVES
CONTROL
VALVE
CWT.
CYLINDERS
CIRCUIT
AUXILIARY
i-----1 PUMP
(l).C. MOTOR)
7
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DIRECTIONAL
REFERENCE
F
R
0
N
T
DIRECTION
OF
TRAVEL
R
E
A
R
TRACK
DRIVES
Figure 3.
Direc.-tional
Reference
The turntable on the
DROTT
120
CRAWLER
will
rotate through a complete 360
degrees.
The normal
driving position
is
with
the Boom over the
front
of
the undercarriage (track drive transmissions
to
the
rear),
as
shown in figure
2.
In
th
is
position,
directional callouts
for
both
the turntable and the
undercarriage
are
the
same.
All
references
to
Front,
Rear, Right and
Left
will
be
made
with
respect
to
this
position.
RIGHT
is
the Operator's right;
LEFT
is
the
Operator's left.
PARTS
AND
SERVICE
When
writing
or calling the dealer or manufacturer
about
your
DROTT
machine, always refer
to
the
model and serial number,
as
well
as
the part name and
location. The machine identification plate
is
located
at lower right corner
of
the Operator's
Cab.
Figure 4. Machine Identification
INTERNATIONAL
SYMBOLS
The International Symbols shown here are
used
in
the
Service Chart
to
help
identify
areas
and
components which require periodic maintenance.
C!J
©
~
HYDRAULIC
RESERVOIR TRANSMISSION
GEAR BOX
8
Engine identification
is
found on the
Option
Plate
located on the engine valve cover. Major components
such
as
the pumps, motors, etc.
are
equipped
with
a
serial plate located on the component housing.
OPTION PLATE
Figure
5.
Engine
Identification
~
♦
_.......__.
cJ
•
...
LUBRICATE with
FILTER, AIR FILTER Multipurpose Grease
© s
Ii)
ENGINE OIL
COOLANT
DIESEL FUEL
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SECTION 1
SCHEDULED PREVENTIVE MAINTENANCE
INTRODUCTION
Scheduled preventive maintenance is essential to
keeping the machine in top operating condition.
Decide from the start upon a maintenance schedule
that
will best suit your particular needs. The type of
work being done, the size of loads, ground and
weather
conditions should all be taken into
consideration when establishing a schedule.
Use the hourmeter, along with a calendar and
checklist
to ensure that all recommended
maintenance
is performed at prescribed intervals. Our
recommendations are based upon average operating
conditions, and should be considered
as the
MINIMUM requirements.
Depart
from the recommended intervals only when
conditions warrant shortening them, or when changes
in
ambient temperature require it. The recommended
intervals should
be shortened whenever the machine
is operated under extreme conditions, such as on a
dusty
job site, in extreme heat or cold, under
intermittent operation or extremely heavy loads.
LUBRICANTS
It is not the policy of DROTT Manufacturing to
publish lists of approved lubricants or to guarantee
lubricant performance. The responsibility for the
quality of any lubricant rests solely with the
distributor or manufacturer of the lubricant.
In various paragraphs of this manual, you will find
the statement "Use (lubricant brand name) or
functional equivalent". This statement does not
constitute an unconditional guarantee of the
performance of the brand of oil mentioned; it is
intended only as a guide to the type of lubricant
recommended for a given application.
SPARK ARRESTORS
Laws of some states or provinces may require that
this unit be equipped with a SPARK ARRESTOR or
SPARK ARRESTING MUFFLERS. The State of
California, as an example, is one state which has such
regulations
for agricultural and forestry applications,
plus a regulation
for construction applications in
forest-covered, brush-covered
or grass-covered lands.
Typically, such laws and regulations require spark
arresting devices
to be maintained in good working
order and typically to be attached to the exhaust
system on
naturally aspirated engines (engines
without a turbo-charger).
CLEANING SOUNDPROOFING INSULATION
Care must be taken when cleaning Cab interiors
which have soundproofing insulation installed. To
clean the insulating material, use only a vacuum
cleaner,
or damp cloth with plain water, or mild
detergent solution.
DO NOT steam clean, wash, or rinse with a water
hose, etc., since
only a slight wetting of the insulation
will substantially reduce its soundproofing ability.
PREVENTIVE
MAINTENANCE
IS
THE LEAST
EXPENSIVE
MAINTENANCE
9

SCHEDULED PREVENTIVE MAINTENANCE
MODEL 12 0 CRAWLER
HYDRAULIC OIL RECOMMENDATIONS
Drott DHF Fluid is recommended for year-around
use in the hydraulic system; or as alternate, use oils
listed below:
SYSTEM
OIL WEIGHT OPERATING TEMPERATURE
SAE 20-20W
50° to 210° F (10° to 99° C)
SAE 10W o0 to 180° F (-18° to 82° C)
SAE 5W or 5W-20
Arctic Conditions
Viscosity: The viscosity of the oil at starting should
not exceed 4000 SSU or drop below 60 SSU for
sustained high temperature operation. The optimum
operating conditions are between 80 SSU and 180
SSU. The viscosity index should not be less than 90
(for this service).
Arctic Conditions: The use of an auxiliary heater, a
warm-up period avoiding high
speed operation of
hydraulic components until the system is warm, and
the
use of SAE 5W or SAE 5W-20 oils may be
necessary, provided the viscosity requirements for
sustained high temperature operation are not ~
exceeded at maximum operation temperatures. See
paragraph on Viscosity above.
COMPONENT CAPACITIES
Item Lubricant/Fluid Capacity
Engine Crankcase
See Enlline Manufacturer's Manual 38 qts. (36L) +
2/w filter
Engine Cooling System 1
/2 ethylene glycol base anti-freeze, 1 /2 water 30 Gal. (115L)
Fuel Tank
Diesel Fuel 182 Gal. (690L)
Track Drive Transmission SAE 80-90 Gearlube
Pump Drive Transmission
Swinll. Gearbox 6 qts. (5.6L)
Col'nplete Hydraulic
Drott DHF or alternate (see Hydraulic 240 Gal. (908L)
System Oil Recommendations above)
Hydraulic 108 Gal. (400L)
Reservoir
Turntable
Open
Spray-on open gear lubricant such as !\Jlobiltac E,
-
Gear Texaco Crater Compound or equivalent.
Pressure grease
Multi-purpose lithium base
-
fittings EP No. 2
HYDRAULIC SYSTEM OPERATING PRESSURES
VALVE/CIRCUIT PRESSURE SETTING
VALVE/CIRCUIT PRESSURE SETTING
Main Reliefs 3000-3200
psi
Track Drive Port Reliefs 3400
psi (23 440 kPa)
(20 685-22 060 kPa)
Hoist Up Port Relief 3400
psi (23 440 kPa)
Hoist Down Port Relief 1250
psi (8620 kPa)
Crowd Port Reliefs 3400
psi (23 440 kPa)
Tool Port Reliefs 3400
psi (23 440 kPa)
Power Sensing Reliefs 2500
psi (17 200 kPa)
Swing Cushion Reliefs 1950
psi (13 450 kPa)
Pilot Systern Relief 750 psi (5175
kPa)
Counterweight Sys. Relief 2500
psi (17 200 kPa)
Auxiliary Sys. Relief 500
psi (3440 kPa)
10

MODEL I2 D CRAWLER SCHEDULED PREVENTIVE MAINTENANCE
PREVENTIVE MAINTENANCE SCHEDULE
Hydraulic Filters . . .
Engine1 ....... .
Turntable Capscrews'. . . . . .
Hydraulic Reservoir
Fuel Tank
Engine Crankcase
Radiator
....
Operator's Cab
Operator's Controls
Engine
Air Cleaner .
Tracks and Track Frames
Turntable Open
Gear . .
Boom, Dipper and Bucket
Batteries . . . . . . .
Engine
....... .
Pump Drive Transmission
Track
... .
Radiator
.. .
Overall machine
Swing Gearbox
Track Drive Transmission
Filters
with visual indicators
Turntable capscrews
Controls
.....
END OF FIRST DAY OR 10 HOURS
Replace paper elements, clean screen-type elements
Check engine oil and filters; refer
to engine manufacture's literature
f:ND OF Fl RST WEEK . . . . . . . Check
for proper torque
DAILY OR EVERY 10 HOURS
Check fluid level and fill; bleed off air pressure at end of work
Fill at end of shift to prevent condensation
. . . Check
oil level and fill
. Check coolant level and fill
. . . . . Clean thoroughly
. . . . . Check
for binding
Check dust
cap for ·excessive dust
.
........... Clean
. Lubricate with spray-on open gear lube
.Grease (See PICTORIAL LISTING, Page 14)
WEEKLY OR EVERY 50 HOURS
. . . . . . . . . . . . . . . . . . .Check electrolyte level and fill
.Refer to engine manual; check V-belt deflection, clean or replace fuel strainer
Check
oil level and fill, check breather
. . . . . . . . . . . . Check tension and adjust
. . . . . . . . . . . Check fins
for obstructions
Lubricate (Refer
to PICTORIAL LISTING, Page 14)
.Clean, check for leaks, proper oil level, check breather
.Clean, check
for leaks, proper oil level, check breather
. . . . . . . . . . . . . . Check visual indicators
MONTHLY OR EVERY 250 HOURS . . . . . Check
for proper torque
. . . . . . . . . . . . . . . . Inspect
for wear and proper adjustment
EVERY 2 MONTHS OR 500 HOURS
Engine Air Cleaner . . . . . . .
Hydraulic Filters (externally accessible) ·
Radiator
...
Remove and clean or replace elements
.Replace paper elements
Add corrosion inhibitor
. Lubricate top bearing
Swing Gearbox ...... .
Batteries
...... .
Hydraulic System
Pump Drive Transmission
Engine Cooling System .
Swing Gearbox
....
Track Drive Transmission
Clutch
....... .
EVERY 6 MONTHS OR 1500 HOURS . . . . . . Clean connecting posts
Drain and refill -clean in-tank
filter screens
.Drain and refill, clean breather
. Drain and flush
. . Drain and refill
. . Drain and refill
. Check adjustment
11

SCHEDULED PREVENTIVE MAINTENANCE MODEL 12D CRAWLER
®-
12
SERVICE CHART
C1J--.j o
t-------1 ► ~--? /
◄ ,,~- 0
0
0
11
Figure 6. Service Points on Turntable and Undercarriage

MODEL
120
CRAWLER
SCHEDULED
PREVENTIVE
MAINTENANCE
SERVICE
CHART
1.
ENGINE -
Daily
or
every 10 hours check
crankcase oil level. Refer
to
Engine
Manufacturer's literature
for
other
maintenance
information.
2. RADIATOR -
Daily
or
every
10
hours check
coolant level. Every 6 months
or
1500 hours
drain and flush cooling system
(see
page
43).
, 3.
OIL
COOLER -
Weekly
or
every 50 hours check
for
obstructions, clean fins.
4.
TRACK
DRIVE
TRANSMISSION -
Weekly
or
every 50 hours check oil level. Check breather
and clean
if
required. Every 6 months
or
1500
hours drain and refill.
See
page
25.
5. BATTERIES -
Weekly
or
every 50 hours check
electrolyte level.
At
least every 6 months
or
1500 hours clean terminals.
See
page
71.
6. FUEL
TANK
-
Fill at end
of
shift
to
prevent
condensation. Weekly
or
every 50 hourse check
breather, clean
or
replace
if
required.
7. SWING GEARBOXES -
Weekly
or
every 50
hours check oil level. Every 2 months
or
500
hours lubricate
top
bearing. Every 6 months
or
1500 hours drain and refill units. Inspect
breathers; clean
if
required.
See
page
52.
8. TURNTABLE OPEN GEAR -
Daily
or
every 10
hours lubricate
with
spray-on open
gear
lubricant.
See
page
52.
9. TRACK COMPONENTS -
Daily
or
every 10
hours clean tracks and track frames. Clean more
frequently
when
working
in wet
or
muddy
areas.
Weekly
or
every 50 hours check track tension
and adjust
if
required. Check rollers
for
leakage.
See
page
18.
10. PRESSURE GREASE
FITTINGS
-
Use
Lithium
base
EP
No. 2 bearing
grease
or
functional
equivalent.
See
PICTORIAL
LISTING
on
page
14.
11. TURNTABLE BOLTS -
After
1st week
of
operation and
monthly
or
every 250 hours
thereafter, retorque.
See
page
52.
12. CAB -
Daily
or
every 10 hours clean
thoroughly.
Weekly
or
every 50 hours check controls
for
binding.
Monthly
or
every 250 hours inspect
controls
for
wear and proper adjustment.
13.
HYDRAULIC
FILTERS -
Weekly
or
every 50
hours check visual indicators. Every 2 months
or
500 hours replace paper elements and clean
Power Sensing Valve screens.
See
page
83.
14.
HYDRAULIC
RESERVOIR -
Daily
or
every 10
hours check oil level. Bleed
off
air pressure at
end
of
shift
to
prevent oil
loss.
Every 6 months
or
1500 hours drain and refill system, clean
in-tank filters.
See
page
82.
15. PUMP
DRIVE
TRANSMISSION -
Weekly
or
every 50 hours check oiI level. Check breather
and clean
if
required. Every 6 months
or
1500
hours drain and
refill.
See
page
48.
16. AIR CLEANER -
Daily
or
every 10 hours check
air restriction
indicator
and dust cup. Every 2
months
or
500 hours remove and clean
(or
replace) primary element.
See
page
44.
17. BOOM, DIPPERSTICK
and
BUCKET -
Daily
or
every 10 hours
grease
all pressure fittings.
Inspect levers, links and pins
for
binding
or
wear.
See
Pictorial Listing and figure 7.
Figure
7.
Service
Points
on
Boom, Dipperstick
and
Bucket
13

SCHEDULED PREVENTIVE MAINTENANCE
MDD&L 12 0 CRAWLER
Ref.
8
9,10
11,12
13
12,14
14
15
14
16
·17
1
E!'
19
14
PICTORIAL LISTING OF LUBRICATION FITTINGS
Location/Title Quantity Interval
Main Boom Pivot Point 2 Daily
or 10 hours
Hoist Cylinders 4 Daily
or 10 hours
Crowd Cylinder 2 Daily
or 10 hours
Dipper-to-Boom Pivot 2 Daily
or 10 hours
Tool Cylinder 2 Daily
or 10 hours
Bucket Paddle
Link 1 Daily
or 10 hours
Bucket
t<1ii.Dipper Pivot 1 Daily
or 10 hours
Upper Bucket
to Dipper Link 1 Daily or 10 hours
Turntable Bearing Lube
line 1 Weekly
or 50 hours
Pump Drive Clutch
Throwout
2 Weekly
or 50 hours
Bearing and Clutch Handle
Counterweight Valve Handle 1 Weekly
or 50 hours
Control
Pedals 2 Weekly or 50 hours
NOTE:
The following pictures illustrate all lube fittinglocations. Quantity of fittings
at each location and lubrication intervals are shown in the chart above.
Figure 8. Figure 9. Figure 10.

MODEL 12 D CRAWLER SCHEDULED PREVENTIVE MAINTENANCE
PICTORIAL LISTING OF LUBRICATION FITTINGS
Figure 11. Figure 12. Figure 13.
I ,1"
:; /7"
{/ /
•
-= '
(1
I~
I I
~ ''-_-
I rJ--
-----/~
, I
\ 0\ I
rl
/ .
~ I
---~ /
-I
V'
.. ·- . ---=---===---
Figure 14. Figure 15. Figure 16.
Figure 17. Figure 18. Figure 19.
15

SECTION
2
THE
UNDERCARRIAGE
DESCRIPTION,
MAINTENANCE
AND
TROUBLESHOOTING
General Description
The Undercarriage includes
the
carbody, turntable
bearing,
the
track drives and
the
track assemblies.
The carbody and turntable bearing are welded
together and
will
be considered
as
one unit.
Each track assembly consists
of
the
track frame,
rollers, chain, pads, guides, ider wheel assembly and
the
drive sprocket.
The track drive includes
the
drive motor,
the
brake,
and
the
double planetary gear reducer.
:~.---
IDLER WHEEL
ASSEMBLY
.....
......._
___
-
.....
______
.____
g---~
Operation
The tracks are driven
by
tandem
hydraulic motors.
When hydraulic fluid
is
directed
to
the
drive
motor
(with brake released),
it
creates driving
torque
which
is
transmitted through
the
planetary transmission
to
the
drive sprocket.
As
the
sprocket turns, it causes
the
track, supported by
the
rollers and idler wheel
to
walk around
the
track frame.
Component Listing:
1.
Carbody and Turntable Bearing
2. Track Assemblies
3. Track Drive Assemblies
..
~_
-
DRIVE
SPROCKET
TRACK
CHAIN
GUIDES
TRACK
ROLLERS
Figure
20. The
Undercarriage
16

MODEL
12
0
CRAWLER
UNDERCARRIAGE
1.
Carbody
and
Turntable
Bearing
RING
GEAR (INNER
RACE)
OUTER
RACE............
~
0
BOLTS
TO
0~
TURNTABLE
r
I
ID
I
~
I
1
l
.,,c.-----::.,
I I
CARBODY
Figure 21. Carbody and Bearing
The Carbody and Turntable Bearing
The Carbody
is
the
welded steel structural which
Joins
the
track frames and supports
the
upperstructure. It
is
fastened
to
the
track frames by
twenty-four bolts and
is
adjustable
to
two
traek
widths.
The turntable bearing consists
of
an inner and an
outer
race, with a single row
of
steel balls
at
its
center. The inner race
is
welded
to
the
carbody and
remains stationary. The
outer
race
is
bolted
to
the
upperstructure and rotates with it.
A large ring gear forms
the
inner race
of
the
bearing.
The teeth of
the
ring gear mesh with
the
Swing
Gearbox
output
pinions, and as
the
pinions rotate,
they· walk around
the
ring gear and cause
the
turntable
to
rotate.
Scheduled Maintenance
Periodically check
the
carbody for loose bolts. When
retracting
or
extending
the
tracks,
all
twenty-four
bolts must be re-installed,
then
torqued
1800
lb-ft
(2450
Nm).
IMPORTANT:
Remove track motor
guards
before extending or
retracting track frames to prevent damage to
drive motors.
Lubricate
the
Turntable Open Gear daily
or
every 10
hours. Lubricate
the
Turntable Bearing once a week
or
every 50 hours. Apply grease
to
the
Bearing
through
the
Central Lube fitting
in
Cab
(see
Pictorial
Listing
of
Lubrication Fittings) while slowly rotating
the
Turntable through several revolutions.
17

UNDERCARRIAGE
MODEL 12 D CRAWLER
2. Track Assemblies
Track Frames
Periodically check the track frames for loose bolts.
The entire assembly should
be steam cleaned to allow
for aclose inspection.
The track assembly may
be removed from the
undercarriage
by removing the twelve mounting
capscrews and the
two stop brackets which fasten it
to the carbody.
NOTE:
Each track assembly weighs approximately
20,000
lbs. (9000 kg). Use a hoist or crane
capable of supporting this weight.
Track Rollers
Both the upper and lower track rollers are sealed and
require no periodic lubrication. They should,
however,
be checked regularly for leakage, free
rotation and wear.
Periodically check the torque on the roller mounting
capscrews.
Keep lower roller capscrews torqued to
560 lb-ft (760 Nm). To extend the life of the rollers,
if excessive wear is noted in one particular location,
the rollers may
be rotated. Switch the rollers that
show the least wear with those
that show the most
wear.
NOTE:
The roller nearest the drive sprocket end is larger
in diameter than the rest, and
can not be
re-located.
The upper carrier rollers
are held suspended by
clamp-type mounts welded to the track frame. The
clamp bolts should be kept torqued
to 65 lb-ft (88
Nm).
18
Track Chain and Pads
A total of 50 links are used per track. Each link will
accept one track pad. The pads are made of cast
alloy, and
bolt to the track links with four bolts each.
The
pads can be removed from the chain without
removing the track. Simply remove the four
mounting bolts.
NOTE:
When replacing or switching pads, make sure the
pads are installed with the lower lip facing in the
normal direction of travel.
The track pad mounting bolts should be kept torqued
to 560 lb-ft (760Nm). Loose mounting bolts will
cause unnecessary vibrations and pad wear.
Each track chain consists of forty-eight standard links
and
two master links. The master links can be
identified by the indentation on the end of the link
pin. The master link is equipped with an extra set of
spacers which allows it to be removed more easily
than the standard links. A portable
press is required
to remove the track pins.
MASTER PIN
Figure 22. Master Link and
Pin
Track Tension
Proper track tension is important. If the track is too
loose, it will tend to jump the drive sprocket and kink
between the rollers. If it is too tight, it will cause
excess wear on the track link pins and bushings.