electronic controls

®®

EngineEngine Model 3408ENet Power - Gears 1-2 336 kW 450 hpNet Power - Gears 3-8 365 kW 490 hpGross Power - Gears 1-2 358 kW 480 hpGross Power - Gears 3-8 384 kW 515 hp

631GWheel Tractor-Scraper

2

631G Wheel Tractor-ScraperHighly productive earthmoving machines, built to last.

Quick loading, high travel speeds and theability to load and dump on the run yieldfast cycle times, allowing Caterpillar WheelTractor-Scrapers to consistently deliver highproductivity at the lowest cost per ton.

Auger Arrangement

Provides self-loading capability with aCaterpillar designed and manufacturedauger system. pg. 12

Scraper Bowl

Cellular construction which features awide cutting edge and a low profiledesign to optimize loads. pg. 11

Power Train Features

The power train features an integratedelectronic control system whichprovides continuous communicationbetween the engine, transmission, andoperator.

pg. 7

Electronic Controls

The electronic controls respond tooperator commands and input from on-board sensors to optimize machineperformance. In addition, the electroniccontrols provide advanced diagnosticcapabilities that result in better machineavailability. pg. 6

Operator Station

Standard enclosed ROPS which featuresa redesigned cab interior that deliversenhanced operator comfort, efficiency,and productivity. Features includestandard air-conditioning, greaterlegroom, a single lever joystick control,and a redesigned control layout.pg. 4

✔

✔ New Feature

3

Serviceability

Simplified service means moreproductive uptime. pg. 14

Electronically Controlled Cushion Hitch

Accumulator system dampens roadshocks, and helps prevent loping, andlock down for precise control.pg. 13

Advanced Modular Cooling System(AMOCS)

Caterpillar exclusive technologyimproves serviceability and coolingcapability. pg. 10

✔

Transmission

Caterpillar planetary powershifttransmission design offers greater loadcarrying capacity than competitivedesigns by providing a larger contactarea between gears. Individual clutchmodulation provides fast, smooth shiftsand improved serviceability. pg. 9

Power Train

The Caterpillar® 3408E engine withhydraulically actuated, electronicallycontrolled unit injector fuel system andeight-speed power shift transmissioncombine to form a responsive, highlyfuel efficient power train. pg. 8

4

Operator StationHas been redesigned for enhanced operator comfort, efficiency, and productivity.

Legroom. A new design increaseslegroom 11%, a full 88.9 mm (3.5 in),and eliminates knee contact points.

Standard Enclosed ROPS. Standardenclosed ROPS with air conditioningenhances operator comfort as well asefficiency.

Multi-Adjustable Seat. The Cat®

Comfort Cloth Seat offers comfort withmulti-adjustable seat and armrests.

• Swivels and locks in four positions (0ºto 30º) providing the optimum operatingposition in the cut or on the haul.

• Fore/aft and vertical height adjustmentto accommodate various sizedoperators.

Seat Suspension. The new standard seatsuspension redefines the ride ofscrapers. It features a self contained aircompressor with a high performance airshock absorber.

Joystick Controller. Simple and easy tooperate, the joystick enhances theproductivity of operators of all skilllevels. Requires less force to control thecritical scraper functions and requiresless lever travel.

1) Bowl (forward & back)

2) Ejector (side to side)

3) Apron (thumb rocker switch)

4) Transmission Hold

5) Cushion Hitch

6) Trigger - Auger on/off (not shown -is on front of joystick)

* Standard open bowl does not have atrigger.

Instrument Display Panel.Instrumentation has been relocated foroptimal viewing. Real-timeperformance and diagnostic informationis provided through the display panel.

Electronic Monitoring System (EMS).Monitors the machine status andprovides real-time informationincluding warnings of problemsidentified by the EMS.

Ergonomic Switch Layout. Enhancesconvenience by placing the frequentlyused switches and indicator lights onthe instrument panel, and lessfrequently used switches on theoverhead console.

Throttle Lock Controller. Enhancesoperation during long haul cycles byallowing the operator to maintain adesired engine speed withoutmaintaining pressure on the throttle.

Standard Air Conditioning. Standard airconditioning system with improvedventilation location enhances airflow inthe cab.

Storage And Amenities. Convenientstorage location includes space for alunch box and first aid kit. The cab alsohas a cup holder as well as an ashtray.

Visibility. The redesigned hood hassloped corners to maintain visibility.The exhaust has been moved to the backof the hood to increase visibility to theright side.

5

14

5

3

(Down)

1 (Up)

2 (Forward) 2 (Return)

Air Filter Restrictor Indicator.Electronic control module monitors airfilter restriction and sends a warningmessage to the electronic monitoringsystem to alert the operator if therestriction exceeds the allowable limit.

Automatic Ether Injection. Electroniccontrol module activates the etherinjection system during engine crankingto enhance cold weather starting.

Automatic Altitude Compensation. Athigh altitudes the system automaticallyde-rates fuel delivery as a function ofbarometric pressure sensed by thesystem’s atmospheric pressure sensor.

Easy Access Diagnostics. ElectronicTechnician displays real-time pressures,temperatures, fuel settings anddiagnostic messages as well ashistorical information such as engineover-speeds, overheating, low oilpressure, and air filter restriction events.

Fuel Economy. Electronic controls yielda fuel savings by optimizing the timingsetting for varying conditions.

Greater Reliability. Caterpillar’sHEUI™ fuel system uses hydraulicelectronic unit injectors, has fewermoving parts than mechanical unitinjection, and requires few adjustments.

Maintenance. With fewer mechanicallycontrolled parts to wear or adjust, theelectronic controls reduce maintenancecosts and increase machine availability.

Reduced Exhaust Smoke. Utilizingelectronic sensors, the optimum air/fuelratio is precisely controlled by theelectronic control module during allsegments of the haul cycle. This resultsin a reduction of smoke and particulatesduring cranking, starting, andacceleration.

Low Battery Elevated Idle. Electroniccontrol module automaticallycompensates for low alternator output atlow idle to keep the batteries fullycharged.

6

Electronic ControlsThe electronic controls respond to operator commands and input from on-board sensors tooptimize machine performance. In addition, the electronic controls provide advanceddiagnostic capabilities that result in better machine availability.

Integrated Electronics. Electroniccontrols integrated into the power trainmonitors the engine, transmission, andoperator input.

• Electronic control provides smooth,consistent shifts through thesynchronization of engine andtransmission speeds.

• Planetary design provides largercontact area between gears thancountershaft transmissions for greaterload-carrying capacity.

Controlled Throttle Shifting.Automatically synchronizes enginespeed to transmission speed duringshifting to reduce power train stress,increase component life, and provide asmoother ride for the operator.

Programmable Top Gear Selection. Topgear selection may be either selected bythe operator or downloaded into theMAC-14 controller. Provides theflexibility to match the hauling speed ofthe fleet to specific job-site needs.

Differential Control. Electronicdifferential lock on the tractor helpsprevent the drive wheels from spinningin poor underfoot conditions. Theoperator engages the differential lock,prior to wheelspin, with either the leftor right foot controls located on thefloor of the cab.

Transmission Hold. Allows the operatorto maintain the current gear forenhanced control.

Neutral Coast Inhibitor. Prevents thetransmission from shifting into neutralif the operator selects neutral whilemoving faster than 8 kmph (5 mph).Maintains oil to transmission to preventdamage.

Directional Shift Management. Reducesdriveline torque and transmission clutchenergy when directional shifts areattempted while the engine is at highrpms.

Final Drives. Outboard-mounted,planetary design final drives reducetorque loads on other drivetraincomponents while deliveringexceptional reliability in the toughestapplications.

Braking System. Provides cam-operatedexpanding-shoe type brakes,independent front and rear circuits, lowair pressure audible and visual actionalert indicators, and a push-buttonoperated parking brake.

7

Power Train FeaturesElectronic controls have been integrated into the power train to provide optimal powerdelivery, expanded monitoring capabilities, more efficient fuel usage, and reduced emissions.

3408E Tractor Engine. The engine hasthe HEUI™ fuel system which useshydraulically actuated electronicallycontrolled unit injectors. The 3408Ediesel engine has dual horsepowercapability for the tractor, and providesthe power and torque rise for excellentlugging in tough loading conditions.

Dual Horsepower Capability. Theelectronic engine provides dualhorsepower settings, which increaseshorsepower and provides quickeracceleration on the haul road.

HEUI™ Fuel System. Yields improvedfuel economy through more precise fueldelivery and cleaner, more efficientcombustion.

Advanced Diesel Engine Management(ADEM) . Utilizes advanced enginemanagement software to monitor,control and protect the engine.

Air To Air After Cooling (ATAAC).Reduces air inlet temperature forenhanced combustion efficiency,reduced emission levels, higher altitudecapability, and more power.

8

Power TrainProven components combine to deliver the most durable, reliable power train in the industry,keeping cost low and production high.

Tractor Transmission. Theelectronically controlled Caterpillarplanetary powershift transmission usesproven components electronicallyintegrated to achieve new levels ofperformance and efficiency.

• Eight forward and one reverse speed.

• Gears one and two operate inconverter drive for increased torquecapability during cut and fill operations.

• Gears three through eight operate indirect-drive for drivetrain efficiencyduring the haul and return.

• Reverse gear operates in converterdrive.

Retarder. Reduces wear on the servicebrakes and enhances machine control.The hydraulic retarder is internal to thepower train and acts as an internal brakewhen going down a grade. It is engagedbefore going down a grade.

9

TransmissionIntegrated electronics allows the machine to monitor the power train which reduces stress aswell as provide a better ride to the operator.

Increased Performance. Dual stagecoolant flow process improves coolingcapability by allowing coolant to passon the air side of the radiator as well asthe fan side. The coolant travels:

• Into the air side of the bottom tank;

• Up the air side of the core;

• Down the fan side of the core;

• To the fan side of the bottom tank;

• Then back to the engine.

Basic Construction. A modular designradiator that is less prone to pluggingdue to a lower fin density of nine finsper inch versus thirty-three of theprevious folded core radiator.

Improved Serviceability. Modulardesign allows one module to bereplaced instead of replacing the entireradiator.

• Shunt tank incorporates a sight gaugefor quick, accurate checks of coolantlevel.

• No longer necessary to remove the toptank to swap out modules.

• Unique service tool facilitates coreremoval and allows one-person servicejob.

10

Advanced Modular Cooling System (AMOCS)Caterpillar exclusive technology improves serviceability and cooling capability.

Low-profile Design. Offers lessresistance to incoming materials.

Cat Bulldozer Ejection. Systemcombines constant spreading controlwhile minimizing carryback material.

Overflow Guard. Optional attachment,helps retain material and keep it fromspilling over onto the rear of thescraper.

Cellular Construction. Adds strengthand dent resistance to bowl sides andfloor.

Cutting Edge. May be adjustedaccording to job conditions. The stinger(drop down) position provides goodpenetration and efficient flow ofmaterial into the bowl while the levelcutting edge is used for finish work. Forefficient loading the thinnest edge thatprovides satisfactory wear life should beused.

Caterpillar Ground Engaging Tools(G.E.T.). To optimize scraper loading invarious materials a wide range ofG.E.T. are available.

11

Scraper BowlDesigned for optimum loading, material retention and ejection.

Material Application. Work alonecapability with a wide material appetiteranging from overburden to laminatedrock. Conditions material whichpromotes compaction in the fill andsignificantly reduces dust duringloading.

Dual Horsepower. Provides increasedpower to the auger for improvedloading performance.

Auger Mechanism. The auger liftsmaterial off of the cutting edge for trueself-loading capability. Material isdistributed evenly throughout the bowl,resulting in consistent loads.

Apron. Prevents material spillage andretains fine material far better than anelevating scraper.

.

Additional Auger Features. Caterpillardesign provides top performance.

• Two-speed auger motor shiftsautomatically from high speed to lowspeed to enhance loading capability.

• Dual horsepower tractor engineautomatically reverts to the highersetting when the auger motor isengaged.

• Single hydraulic system for entiremachine with separate implementpumps and valves.

12

Auger ArrangementExcellent self-loading capability in a wide range of material. Optional attachment availablefor the 631G and the 637G.

Cushion Hitch. Electrically actuatedhydraulic damper absorbs haul roadshocks for increased operator comfort.

Cushion Hitch Features. Designed forprecise control.

• Can be locked down when loading orspreading.

• Vertically mounted hydraulic cylindertransfers road shocks to nitrogenaccumulators.

• Controlled oil flow dampens reboundoscillation.

• Leveling valve automatically centerspiston in cylinder for all loads.

• Extensive use of steel castingseliminates many welded joints, andincreases strength.

• Double-kingbolt design withstandshigh external forces and enhancesinstallation and removal.

Steering. Full hydraulic power steeringprovides automotive feel with positive,modulated flow control for constantsteering response.

13

Electronically Controlled Cushion HitchDelivers a smoother ride for enhanced operator comfort.

Service Points. Service points for theengine are grouped on the right-hand-side for easy access.

Floor Rollers. Sealed floor rollerseliminate lubrication.

Electro-Hydraulic Control. Simplifiesserviceability by removing the cab pilotvalve and associated line from the cab,which provides increased cab space andreduces noise. The high efficiencyelectro-hydraulic pilot oil filter providescleaner oil for the pilot system.

Wiring Harness. Incorporates color-coded and numbered circuits for quickidentification and simplifiedtroubleshooting.

Cantilever Wheels. Provide greaterparts commonality and ease ofserviceability to the wheels and brakes.

Electronic Monitoring System (EMS).Monitors the machine status andprovides real-time information to theoperator including warnings ofproblems identified by the ElectronicControl Modules.

14

ServiceabilitySimplified service means more productive uptime.

15631G Wheel Tractor-Scraper specifications

Transmission

1 Forward 4.7 kph 2.9 mph2 Forward 8.4 kph 5.2 mph3 Forward 11.9 kph 7.4 mph4 Forward 16.1 kph 10 mph5 Forward 21.6 kph 13.4 mph6 Forward 29.3 kph 18.2 mph7 Forward 39.4 kph 24.5 mph8 Forward 53.5 kph 33.2 mphReverse 9.9 kph 6.2 mph

Steering

Width Required for Curb-to-Curb 180 Degree Turn 12.2 m 40.08 ftSteering Angle - Right 90 DegreesSteering Angle - Left 85 DegreesHydraulic Output 370 L/min 96.2 gal/minGround-Driven Secondary Steering System 192 L/min 51 gal/min• Ratings at 2000 rpm

Service Refill Capacities

Fuel Tank 814 L 215 galCrankcase 45 L 11.7 galTransmission 127 L 33 galDifferential 136 L 36 galFinal Drive (each side) 25 L 7 galCooling System 122 L 32 galHydraulic Reservoir 190 L 50 galWheel Coolant (each) 75 L 19.5 galWindshield Washer 1.5 L 6 gal

Engine

Engine Model 3408ENet Power - Gears 1-2 336 kW 450 hpNet Power - Gears 3-8 365 kW 490 hpGross Power - Gears 1-2 358 kW 480 hpGross Power - Gears 3-8 384 kW 515 hpCaterpillar Net Power 365 kW 490 hpISO 9249 365 kW 490 hpEEC 80/1269 365 kW 490 hpSAE J1349 365 kW 490 hpBore 137 mm 5.4 inStroke 152 mm 6 inDisplacement 18 L 1,099 in3

• Ratings at 2000 rpm

Scraper Bowl

Heaped Capacity, SAE Rated 23.7 m3 31 yd3

Rated Payload 34 020 kg 75,000 lbStruck Capacity, SAE Rated 16.1 m3 21 yd3

Maximum Depth of Cut 437 mm 17 inWidth of Cut, Outside Router Bits 3512 mm 11.5 inMaximum Ground Clearance 545 mm 21 inThickness of Optional Cutting Edge 42 mm 1.62 inMaximum Hydraulic Penetration Force 255 kN 57,375 lbMaximum Depth of Spread 480 mm 18.9 inApron Opening 2007 mm 79 inApron Closure Force 170 kN 38,250 lb

Weights

Total Shipping 45 362 kg 100,006 lbTractor Shipping 20 866 kg 46,002 lbScraper Shipping 24 496 kg 54,004 lbTotal Operating - Empty 46 475 kg 102,460 lbFront Axle 31 138 kg 68,648 lbRear Axle 15 337 kg 33,812 lbTotal Operating - Loaded 80 495 kg 177,460 lbFront Axle 42 662 kg 94,054 lbRear Axle 37 833 kg 83,406 lb

16 631G Wheel Tractor-Scraper specifications

Hydraulics

Bowl Cylinder Bore 184 mm 7.2 inBowl Cylinder Stroke 813 mm 34.4 inApron Cylinder Bore 210 mm 8.2 inApron Cylinder Stroke 727 mm 28.6 inEjector Cylinder Bore 210 mm 8.2 inEjector Cylinder Stroke 1880 mm 74 inSteering Circuit 389 L/min 103 gal/minScraper Circuit 344 L/min 91 gal/minCushion Hitch Circuit 34.5 L/min 9 gal/minOptional Supplemental Steering Circuit 291 L/min 77 gal/minRelief Valve Setting - Steering Circuit 13 700 kPa 1,987 psiRelief Valve Setting - Implement Circuit 14 000 kPa 2,030 psiCompensator Setting - Cushion Hitch Circuit 16 000 kPa 2,320 psi

Standards

Cab Meets ANSI, SAEROPS/FOPS Meets SAE, ISOBrakes Meets ISO• The operator sound exposure Leq (equivalent sound

pressure level) measured according to the work cycleprocedures specified in ANSI/SAE J1166 OCT 98 is 81 dB(A),for cab offered by Caterpillar, when properly installed andmaintained and tested with the doors and windows closed.Hearing protection may be needed when operating with anopen operator station and cab (when not properlymaintained or doors/windows open) for extended periods orin noisy environment.

• The exterior sound pressure level for the standard machinemeasured at a distance of 15 meters according to the testprocedures specified in SAE J88 JUN 86, mid-gear-movingoperation, is 84 dB(A).

• Standard air conditioning system contains R134a refrigerant.

• ROPS (Rollover Protective Structure) meets SAE J320a, SAEJ1040 MAY 94, and ISO 3471-1994.

• FOPS (Falling Object Protective Structure) meets SAE J231JAN 81 and ISO 3449-1992.

• Brakes meet ISO 3450: 1996 standard.


Retarding

To determine retarding performance:Read from gross weight down to thepercent effective grade. (Effective gradeequals actual percent grade minus 1%for each 9 kg/t (20 lb/ton) of rollingresistance). From this weight-effectivegrade point, read horizontally to thecurve with the highest obtainable speedrange, then down to maximum descentspeed the retarder can properly handle.

Gradeability/Speed/Rimpull

To determine gradeability performance:Read from gross weight down to thepercent of total resistance. Totalresistance equals actual percent gradeplus 1% for each 9 kg/t (20 lb/ton) ofrolling resistance. From this weight-resistance point, read horizontally to thecurve with the highest obtainable gear,then down to maximum speed. Usablerimpull will depend upon tractionavailable and weight on drive wheels.

0 5 10 15 20 25 30 35 40 45 50 55

30 40 50 60 80 100 120 160 200 lb x 1000

6555

45

35

25

20

15

10

8

6

4

2

12

5

10

15

20

30

40

50

70

100

120

150

lb x1000

kg x1000

0 5 10 15 20 25 30 35 mph

km/h

30%

25%

20%

15%

12%

10%

8%

6%

5%

4%

3%

2%

605040302015 70 90 kg x 1000

E L

1

2

3

45

6

7

8

631G Gross Weight37.25R35 Tires

Speed

Tota

l Res

ista

nce

(Gra

de p

lus

Rolli

ng R

esis

tanc

e)

Rim

pull

1— 1st Gear Torque Converter Drive2—2nd Gear Torque Converter Drive3—3rd Gear Direct Drive4—4th Gear Direct Drive5—5th Gear Direct Drive6—6th Gear Direct Drive7—7th Gear Direct Drive8—8th Gear Direct Drive

E—Empty 46 475 kg (102,460 lb)L—Loaded 80 495 kg (177,460 lb)

55 75 100 125 150 175 lb x 1000

km/h0 5 10 15 20 25 30 35 40 45 50 55

mph0 5 10 15 20 25 30 35

E L3

4

5

6

7

8

30 kg x 100040 50 60 70 80

30%

22%

16%

10%

5%

1%

631G RetardingGross Weight

Speed

Effe

ctiv

e G

rade

(Gra

de m

inus

Rol

ling

Resi

stan

ce)

3—3rd Gear Direct Drive4—4th Gear Direct Drive5—5th Gear Direct Drive6—6th Gear Direct Drive7—7th Gear Direct Drive8—8th Gear Direct Drive

E—Empty 46 475 kg (102,460 lb)L—Loaded 80 495 kg (177,460 lb)


DimensionsAll dimensions are approximate.

Dimensions 631G1 Overall machine width 3938 mm 12’11"

2 Tractor width 3481 mm 11’5"

3 Width to center of rear tires 2464 mm 8’1"

4 Width to inside of bowl 3405 mm 11’2"

5 Width to outside of tires 3636 mm 11’11"

6 Overall shipping height 4286 mm 14’1"

7 Height to top of cab 3715 mm 12’2"

8 Tractor ground clearance 665 mm 2’2"

9 Length from front axle to front 3359 mm 11’0"

10 Axle to vertical hitch pin 548 mm 1’10"

11 Maximum scraper blade height 545 mm 1’9"

12 Wheelbase 8769 mm 28’9"

13 Overall machine length 14 565 mm 47’9"

14 Length from rear axle to rear 2437 mm 8’0"

21 53

76

9

11

12 14

13

8

10

4


ElectricalAlarm, BackupAlternator, 75 amp - Tractor EngineBatteries (4), 12V Maintenance Free, High OutputElectrical System, 24VLighting System - (directional signals, hazard lights,halogen headlights with dimmer, cutting edge floodlight)Starting Receptacle - Tractor Engine

Operator EnvironmentAir Conditioner (includes heater and defroster)Cigarette Lighter and AshtrayCoat HookDiagnostic Connection Port (12V)Dome Courtesy LightGauge Group

Actual Transmission Gear IndicatorCoolant TemperatureElectronic Monitoring System (EMS II)Fuel GaugeSpeedometerSystem Air PressureTachometerTransmission/Torque Converter Oil Temperature

HornImplement Control JoystickRadio Ready (two radio openings, speakers, and 5-ampconverter)Rearview MirrorsROPS Cab - Sound Suppression and PressurizationStatic Seatbelt - Seat MountedSeat, Cloth with Air SuspensionSteering Wheel - Tilt and TelescopingStorage CompartmentThrottle LockTransmission HoldWindows - Sliding SideWindshield - Laminated GlassWindshield Wiper/Washer - Front and Rear

Power Train3408E Diesel EngineGuard, CrankcaseHEUI™ Fuel System8-speed Automatic Powershift Transmission

Control Throttle ShiftingDifferential-LockupDownshift InhibitorNeutral Coast InhibitorProgrammable Top-Gear SelectionRetarder, Hydraulic

Power Train FeaturesAir Cleaner, Dry Type with Pre-cleanerBraking System

Parking / Primary / SecondaryShields - Brake

Electric Start, 24VFan, SuctionGround Level Engine ShutdownMufflerStarting Aid, Ether

Other Standard EquipmentAdvanced Modular Cooling System (AMOCS) RadiatorAir DryerEngine Door, Right SideExtended Life Coolant, -36°C (-33°F)Fast Oil ChangeFenders, TractorProduct Link ReadyTires, 37.25-R35 Radial ** E3Tow PinsThermo-Shield, Laminated

Standard EquipmentStandard equipment may vary. Consult your Caterpillar dealer for specifics.


TractorCoolant, Extended Life -50°C (-58°F)Cooler, Hydraulic OilGuard, Crankcase Heavy DutyGuard, Power TrainHeater, Engine Coolant, 120 VLights, Side VisionRear Auxiliary Defrost FanRetarder, HydraulicSeat Belt, RetractableSecondary Steering

Special ArrangementsStandard Bowl with Auger

ScraperGuard, OverflowFast Fuel SystemFendersLiner, Bowl

Optional EquipmentOptional equipment may vary. Consult your Caterpillar dealer for specifics.


Notes

R

For more complete information on Cat products, dealer services, and industrysolutions, visit us on the web at www.CAT.com

© 2001 CaterpillarPrinted in U.S.A.

Materials and specifications are subject to change without notice.Featured machines in photos may include additional equipment.

See your Caterpillar dealer for available options.AEHQ5424 (4-01)

631G Wheel Tractor-Scraper

electronic controls

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