631K (Tier 2/Stage II)

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631K Wheel Tractor-Scraper


  • 180° Curb-to-Curb Turning Width 40.12 ft 12.23 m
  • Fuel Tank Refill Capacity - Scraper 231.0 gal (US) 874.0 l
  • Maximum Depth of Cut 17.7 in 450.0 mm
  • Maximum Depth of Spread 21.1 in 535.0 mm
  • Overall Shipping Height 12.75 ft 3.89 m
  • Overall Width 12.93 ft 3.94 m
  • Rated Load 37 200 kg (82,200 lb); 37.2 tonnes (41.1 tons) 37 200 kg (82,200 lb); 37.2 tonnes (41.1 tons)
  • Scraper Capacity - Heaped 34.0 yd³ 26.0 m³
  • Scraper Capacity - Struck 24.0 yd³ 18.3 m³
  • Tires - Scraper 37.25R35**E3 37.25R35**E3
  • Tires - Tractor 37.25R35**E3 37.25R35**E3
  • Top Speed - Loaded 34.7 mile/h 55.8 km/h
  • Width - Cut 11.5 ft 3.51 m


  • Emissions Cat C18 ACERT engine meets U.S. EPA Tier 2/EU Stage II Equivalent emission standards. Cat C18 ACERT engine meets U.S. EPA Tier 2/EU Stage II Equivalent emission standards.
  • Engine Model - Tractor Cat C18 ACERT™ Cat C18 ACERT™
  • Flywheel Power - Tractor 570.0 HP 425.0 kW
  • Rated Engine RPM - Tractor 1900.0 r/min 1900.0 r/min

Tractor Engine

  • Flywheel Power - Tractor/Scraper 570.0 HP 425.0 kW

Scraper Bowl

  • Scraper Capacity - Heaped 34.0 yd³ 26.0 m³


  • Top Speed - Loaded 34.7 mile/h 55.8 km/h

Service Refill Capacities

  • Cooling System 19.8 gal (US) 75.0 l
  • Crankcase - Tractor 13.7 gal (US) 52.0 l
  • Fuel Tank 231.0 gal (US) 874.0 l
  • Hydraulic System 37.5 gal (US) 142.0 l
  • Transmission System 29.0 gal (US) 110.0 l


  • Front of Tractor to Front Axle 142.2 in 3612.0 mm
  • Axle to Vertical Hitch Pin 20.0 in 509.0 mm
  • Wheel Base 346.8 in 8808.0 mm
  • Rear Axle - Rear of Machine 108.0 in 2744.0 mm
  • Ground Clearance - Tractor 26.1 in 664.0 mm
  • Height - Overall Shipping 153.2 in 3892.0 mm
  • Height - Scraper Blade Maximum 20.0 in 510.0 mm
  • Height - Top of Cab 147.0 in 3733.0 mm
  • Length - Maximum (Push-Pull) 655.1 in 16640.0 mm
  • Length - Overall Machine - Standard 597.0 in 15164.0 mm
  • Width - Inside of Bowl 134.0 in 3404.0 mm
  • Width - Outside Rear Tires 143.2 in 3636.0 mm
  • Width - Overall Machine 155.0 in 3937.0 mm
  • Width - Rear Tire Centers 96.9 in 2462.0 mm
  • Width - Tractor 137.8 in 3499.0 mm

Non Push-Pull

  • Operating Weight - Empty 102750.0 lb 46600.0 kg
  • Overall Length 49.34 ft 15.04 m


  • Operating Weight - Empty 106430.0 lb 48275.0 kg
  • Overall Length - With Bail Down 54.59 ft 16.64 m


  • Exterior Sound Level The exterior sound power level for the standard machine (ISO 6393) is 111.5 dB(A). The exterior sound power level for the standard machine (ISO 6393) is 111.5 dB(A).
  • ROPS/FOPS ROPS/FOPS meet “ISO Standards.” ROPS/FOPS meet “ISO Standards.”

Safety Criteria Compliance Standards

  • Brakes Brakes ISO 3450:2011 Brakes ISO 3450:2011
  • Falling Object Protective Structure (FOPS) ISO 3449:2005 Level II ISO 3449:2005 Level II
  • Reverse Alarm ISO 9533:2010 ISO 9533:2010
  • Rollover Protection Structure (ROPS) ISO 3471:2008 for up to 21 282 kg (46,919 lb) ISO 3471:2008 for up to 21 282 kg (46,919 lb)
  • Seat Belt SAE J386:FEB2006 SAE J386:FEB2006
  • Steering System ISO 5010:2007 ISO 5010:2007

Travel Speeds - Runout

  • Transmission Gear - Eighth 34.7 mile/h 55.8 km/h
  • Transmission Gear - Fifth 14.1 mile/h 22.7 km/h
  • Transmission Gear - First 3.4 mile/h 5.5 km/h
  • Transmission Gear - Fourth 10.5 mile/h 16.9 km/h
  • Transmission Gear - Reverse 6.2 mile/h 9.9 km/h
  • Transmission Gear - Second 6.2 mile/h 10.0 km/h
  • Transmission Gear - Seventh 25.7 mile/h 41.4 km/h
  • Transmission Gear - Sixth 19.0 mile/h 30.6 km/h
  • Transmission Gear - Third 7.7 mile/h 12.4 km/h

Implement Cycle Times

  • Apron Lower 3.8 s 3.8 s
  • Apron Raise 4.0 s 4.0 s
  • Bail Lower 2.1 s 2.1 s
  • Bail Raise 1.5 s 1.5 s
  • Bowl Lower 3.5 s 3.5 s
  • Bowl Raise 3.5 s 3.5 s
  • Ejector Extend 8.5 s 8.5 s
  • Ejector Retract 8.5 s 8.5 s

Tractor Serviceability Improvement

The fuel, water and engine oil are relocated at ground level on the right hand side of the machine for easy access.


Have been changed from an air actuated drum shoe brake to a hydraulic actuated tractor wet disc brake and a scraper dry caliper.

Tire Spin Reduction

This feature will allow the machine to control the slip of the tractor tires only.

Engine Over Speed Protection

In the event of an engine over speed situation, the compression brake or brakes will automatically engage with no operator input. The machine determines the over speed condition based on rate of acceleration and applies compression brakes automatically.

Advanced Cushion Hitch

With similar technology as the Cat® Advanced Ride Management seat suspension, this software allows the cushion hitch to prevent end stroke by having the ability to predict end stroke events and manage the rate of dampening. Resulting in reduced hitch maintenance and improved operator ride in rough conditions.

High Pressure Steering

K Series steering system design requires significantly less steering effort. The reduced steering effort will allow for decreased operator fatigue and a more efficient operator resulting in possible higher rates of production late in the work cycle.

Differential Lock Engagement Protection

This standard feature allows the machine to prevent the operator from engaging the differential lock when damage could occur.

Cab Improved

The K Series cab interior improves operator comfort and visibility. The overall interior is 21% larger than the G Series cab.

Machine Speed Limit

This feature is designed to take the place of top gear selection. If the machine top speed needs to be limited the operator can select the top speed through the display or the top speed can be set in ET. This will allow the machine to find the correct gear that works best for the engine and transmission. Allowing the engine and transmission to select the correct gear to pull the load in most cases resulting in a lower engine load factor and lower fuel burn verses using top gear selection that required the machine to run at engine speeds at or close to high idle.

Ground Speed Control

Ground Speed Control sets the desired top speed by the operator if job site conditions or segment speed limits require a speed less than full run out. Machine Speed Limit is intended for use when top speed needs to be limited for longer durations and Ground Speed Control is intended for use when the top speed needs to be reduced for shorter segments or intermediate periods of time. The operator can set the desired top speed and the machine will find the correct gear that works best for the engine and transmission.

Sequence Assist (Optional Attachment)

This option uses cylinder position sensors to automate bowl, apron and further implement controls throughout the four core work cycles: Dig, Haul, Unload and Return. When utilized this can reduce up to 14 individual operator commands per cycle. Sequence Assist simplifies control over the implements, reduces joystick usage, automatically controls cushion hitch, transmission hold and ejector.

Payload Estimator (Optional Attachment)

The Payload Estimator will calculate the payload of the machine in tonnes or tons by measuring the bowl lift cylinder pressures at the beginning of the loaded haul segment. This feature works best when using Sequence Assist. Using Payload Estimator during testing has achieved better than 95% accuracy when compared to actual scale weights. The Payload Estimator feature comes automatically when a machine is ordered with Sequence Assist.

Load Assist (Optional Attachment)

Is designed to help shorten the learning curve of inexperienced operators to ensure consistency and faster loading of material while reducing effort of the operator. Based on the speed of the machine, Load Assist automatically adjusts the cutting edge height to manage wheel slip and to ensure consistent and efficient loading in bulk earthmoving applications.

Cat Grade Control (Optional Attachment)

Intelligently ensures the machine does not cut below grade in the cut area or over fill in the fill area – avoiding rework and moving unnecessary material.

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