Caterpillarwheel tractor-scraperwheel scraper
Caterpillar 631E
Maintenance schedule, common problems & OEM parts breakdown
The Caterpillar 631E is a self-propelled wheel tractor-scraper engineered for high-volume earthmoving, mining, and large-scale site preparation. Introduced in the 1980s, this machine class excels at handling large capacities of topsoil over medium to long distances more effectively than bulldozers. The standard configuration features a four-stroke 3-series 3408 turbocharged V-8 engine producing 450 flywheel horsepower, capable of reaching speeds up to 30 mph when fully loaded. The unit consists of a tractor and scraper assembly with an empty weight of approximately 95,000 lb (43,091 kg) and a maximum loaded weight exceeding 171,000 lb (77,562 kg).
Across its production generations, the 631E evolved through various series, including the Series II, which offered updated configurations. The lineage continued with the 637E, which introduced a second motor behind the debris bin for increased power and traction. Today, the 6SS/631E remains a significant presence in the used equipment market due to its substantial 75,000 lb (34,019 kg) payload capacity and 31 cubic yard (~23.7 m³) bowl volume. Its durability makes it a primary target for parts reclamation and secondary fleet operations in heavy earthmoving sectors.
Below: full specifications, fluids & capacities, the factory service schedule, common service parts, verified fault codes, what owners discuss, attachment guidance, the complete assembly directory, and a serial-number reference. Complete parts lists with full OEM part numbers, exploded diagrams, quantities, and fitment data are available free in Heavy Parts AI.
Caterpillar 631E specifications
Engine
| Model | 3408TA / 3408E |
| Gross Power | 490 hp |
| Net Power | 450 hp |
| Displacement | 1098.5 - 1099 cu in |
| Configuration | Four-stroke turbocharged V-8 |
Weights
| Operating Weight (Empty) | 96,882.2 - 97,459 lb |
| Operating Weight (Loaded) | 171,883.5 - 172,459 lb |
| Shipping Weight (Total) | 96,182 lb |
| Tractor Shipping Weight | 44,243 lb |
| Scraper Shipping Weight | 51,939 lb |
| Front Axle Weight (Loaded) | 91,097.3 - 91,576 lb |
| Rear Axle Weight (Loaded) | 80,786.2 - 80,884 lb |
Dimensions
| Overall Length | 46.86 - 47.77 ft |
| Overall Width | 12.93 - 155 in |
| Overall Height (Shipping) | 168.75 in |
| Wheelbase | 28.78 ft |
| Ground Clearance (Maximum) | 21.5 in |
| Width - Inside Bowl | 134 in |
| Width - Outside Rear Tires | 143.1 in |
Performance
| Max Speed Forward | 29.9 - 33.2 mph |
| Reverse Speed | 6.2 mph |
| Transmission Gears (Forward) | 7 or 8 gears |
| Rated Payload | 75,000 - 75,001.3 lb |
| Heaped Capacity | 31 yd³ |
| Struck Capacity | 21 - 21.1 yd³ |
| Max Depth of Cut | 17 - 17.3 in |
| Width of Cut | 11.5 - 11.6 ft |
Service capacities (summary)
| Fuel Capacity | 196.9 - 215.1 gal |
| Hydraulic Reservoir | 50 gal |
| Transmission | 33 gal |
| Differential | 36 gal |
| Cooling System | 33 gal |
| Crankcase (Engine Oil) | 11.7 gal |
| Final Drive (Each) | 7 gal |
Values vary by configuration, region, and serial range — confirm against your machine before planning transport or lifts.
631E fluids & capacities
| System | Capacity | Recommended fluid |
|---|---|---|
| Engine Crankcase | 45 l (11.7 gal) | Cat DEO or Cat DEO-ULS (for Tier 4 engines with aftertreatment); SAE 10W-30 is preferred for ambient temperatures between -18°C (0°F) and 40°C (104°F). Use SAE 0W-40 for extreme cold (-40°C) or SAE 50 for hot climates (above 10°C/50°F). |
| Cooling System | 126 l (33 gal) | Cat ELC (not specified by name in source text, but listed under Caterpillar machine fluids) |
| Hydraulic System and Tank | 190 l (50 gal) | Cat HYDO Advanced 10 (SAE 10W for cold to moderate temperatures) or Cat HYDO Advanced 30 (SAE 30W for moderate to hot temperatures) |
| Transmission | 127 l (33 gal) | Cat TDTO (for powershift transmissions) or Cat MTO (multi-purpose tractor oil); SAE 10W/30/50 viscosity available. |
| Differential | 136 l (36 gal) | Cat TDTO |
| Final Drive (each) | 25 l (7 gal) | Cat TDTO |
| Wheel Coolant (each) | 75 l (19.5 gal) | Not specified |
| Grease | Not specified | Cat Multipurpose Grease (low-load/low-speed), Cat Advanced 3Moly Grease (medium-load/medium-speed), or Cat Ultra 5Moly Grease (high-load/high-speed) |
Capacities are refill values from factory literature — always fill to the dipstick/sight gauge, not the number.
Caterpillar 631E maintenance schedule
| Service interval | Tasks |
|---|---|
| Every 10 h |
|
| Every 250 h |
|
| Every 500 h |
|
| Every 1,000 h |
|
| Every 2,000 h |
|
Servicing the 631E beyond the schedule
Predictive Maintenance & Fluid Analysis
Utilize Caterpillar S.O.S Services to monitor engine oil, hydraulic fluid, and coolant. Analyze engine oil for wear metals like iron or copper and contaminants such as silicon from dirt ingestion. Perform hydraulic oil sampling to track particle counts and oxidation levels. Regular coolant analysis is critical to detect pH changes or SCA depletion, preventing internal liner pitting and radiator corrosion before catastrophic failure occurs.
Corrective & Common Repairs
Address frequent hydraulic failures by replacing contaminated return filters promptly. Monitor the 24-volt electric starting system and ether starting aids for cold-weather reliability. Inspect the piston-actuated bowl, apron, and ejector components for leaks or mechanical binding. If engine oil appears milky, immediately investigate for coolant contamination indicative of head gasket failure. Ensure all hydraulic hoses are checked for cracks or abrasion to prevent high-pressure leaks.
Overhaul & Rebuild Points
Plan major component evaluations during 2,000-hour intervals. Focus on the turbocharger inspection and engine valve train integrity. During transmission service, evaluate torque converter performance and gear wear. Structural rebuild points should prioritize inspecting the cushion-hitch gooseneck, frame castings, and bowl welds for fatigue. For high-hour units, assess the 3408 V-8 engine for piston, ring, and bearing wear to determine if a full top-end overhaul is required.
Seasonal & Environment Servicing
In dusty or quarry environments, check air filter restriction daily and clean radiator fins frequently to prevent overheating. For cold-weather operations, verify the functionality of the 24-volt starting system and ether aids. In high-load, downhill slope applications, inspect brake systems and optional retarders to ensure longevity. During summer months, monitor coolant levels closely and consider using specialized Caterpillar Arctic or Desert grease configurations if operating in extreme temperature shifts.
631E common service parts
| Part number | Part | Notes | |
|---|---|---|---|
| 2J-2864 | Plug-Drain | Scheduled service item | Check fitment → |
Always confirm against your machine's serial number — cross-check any part in Heavy Parts AI before ordering.
631E fault codes & troubleshooting
| Code | Meaning | Likely cause | What to do |
|---|---|---|---|
| E360 | Engine Coolant Temperature — High | Low coolant level, failed thermostat, or water pump issue | Diagnose cooling system; do not operate until resolved |
| E361 | Engine Coolant Temperature — Very High (Shutdown) | Severe cooling system failure | Engine shutdown required; perform full cooling system diagnosis |
| 110-0 | Engine Coolant Temp — Above Normal | Low coolant level or thermostat failure | Inspect cooling system, refill coolant, and test thermostat |
| 110-3 | Engine Coolant Temp Sensor — Voltage High | Open circuit or sensor failure | Check wiring and replace sensor if confirmed faulty |
| 174-3 | Engine Fuel Temperature — Voltage Above Normal | Open circuit in sensor wiring | Inspect harness and replace sensor if necessary |
| 190-8 | Engine Speed — Abnormal Frequency | Speed sensor air gap, sensor failure, or tone ring damage | Check sensor gap and test speed sensor and tone ring |
| 2458-2 | DPF #1 Differential Pressure — Erratic | Plugged pressure ports or failing sensor | Clean pressure ports and test sensor; verify DPF soot load |
| 41-3 | 8-Volt DC Supply — Voltage Above Normal | Short to power on 8V reference circuit | Inspect sensors sharing the 8V supply and isolate fault |
| 41-4 | 8-Volt DC Supply — Voltage Below Normal | Short to ground on 8V reference circuit | Disconnect sensors one at a/time to locate short |
| 2348-9 | SAE J1939 Data Link #2 — Abnormal Update Rate | CAN bus wiring damage or termination fault | Check CAN wiring and measure termination resistance |
Codes and remedies are general guidance for this model family — always confirm with diagnostic tooling and your dealer before major repairs.
631E attachments & work tools
Scraper Bowl and Components
The unit features a piston-actuated bowl, apron, and ejector. The scraper is capable of cutting depths up to 17.2" (436.88 mm) with a blade width of nearly 11.5' (3.5056 m). Capacity is rated at approximately 75,000 lb (~31 yd³).
Hitch and Coupling Systems
The machine utilizes an advanced, electronically controlled cushion-hitch design to dampen shocks. This system includes nitrogen-over-oil accumulators to absorb road shocks and provides a smoother ride.
Hydraulic and Steering Arrangements
A hydraulic servo-steering system is used for low-effort maneuverability. The machine features piston-actuated bowl components and includes accurate hydraulic lines as part of the standard configuration.
Factory Configurations and Guarding
Standard configurations include a 24V electric starting system with an ether starting aid for cold temperatures. Notable options include the Work Area Vision System (WAVS) camera arrangement, scraper draft arm packages, and transmission guards.
All 631E assemblies by section
Every catalogued assembly group for the Caterpillar 631E. Open an assembly to preview the parts inside — full OEM part numbers are available in Heavy Parts AI.
Braking System
5t-0569 Actuator Gp-Brake
| 1D***20 | Nut,Plain,Hexagon Gear Mtg | 1 |
| 2K***37 | Nut (National Fine); (3/4-16-Thd) | 2 |
| 3B***01 | Pin,Cotter Bolt | 1 |
8w-3956 Actuator Gp-Brake
| 03***21 | Bolt; (5/16-18x0.625-In) | 20 |
| 1D***20 | Nut,Plain,Hexagon Gear Mtg | 1 |
| 2K***37 | Nut (National Fine); (3/4-16-Thd) | 2 |
5t-8470 Brake Gp-Service
| 13***18 | Guard-Grease | 2 |
| 14***94 | Drum As-Brake | 2 |
| 2D***26 | Seal | 8 |
4t-1833 Control Gp-Service Brake
| 03***17 | Union | 2 |
| 0S***09 | Bolt (3/4") Filler Tube Assembly To Transfer Drive Case | 26 |
| 0S***88 | Bolt,Machine; Hose Assembly Mounting,Hose Assembly To Transmission,And To Torque Converter | 6 |
9d-0400 Slack Adjuster Gp
| 1H***22 | Plug-Expansion | 1 |
| 3D***91 | Steel Ball | 1 |
| 5D***18 | Button | 2 |
9d-0390 Slack Adjuster Gp
| 1H***22 | Plug-Expansion | 1 |
| 3D***91 | Steel Ball | 1 |
| 5D***18 | Button | 2 |
121-0339 Tank Gp-Air
| 12***34 | Reservoir | 1 |
| 12***39 | Tank Group-Air | 1 |
| 3B***64 | Bushing; (Reducing) | 1 |
4d-0487 Valve As-Check
| 4D***87 | Valve As-Check; -Air Supply-Primary Air Tank-Service Brake Control | 1 |
Electrical And Starting System
1m-1882 Lamp Gp-Flood
| 1M***82 | Lamp Group | 1 |
| 1M***98 | Lamp-Sealed Unit; (Flood) | 1 |
| 2M***82 | Ring-Mounting | 1 |
6n-7981 Lamp Gp -Signal-Stop/Tail
| 2P***68 | Moulding | 1 |
| 6N***81 | Lamp Group | 1 |
| 6N***82 | Lamp-Sealed Unit | 1 |
7x-6219 Lamp Gp-Signal
| 2P***68 | Moulding | 1 |
| 6N***88 | Body As-Lamp | 1 |
| 6V***76 | Screw; (Machine) (8-32x0.25 In) | 1 |
8x-7499 Lamp Gp-Flood
| 01***02 | Lockwasher | 2 |
| 03***09 | Screw & Washer As | 1 |
| 2M***82 | Ring-Mounting | 1 |
6v-1108 Lamp Gp-Signal -Stop, Tail, Red
| 10***51 | Screw; (M4x32-mm) | 4 |
| 10***52 | Seal | 1 |
| 10***54 | Body As; (Lamp) | 1 |
6v-1119 Lamp Gp-Signal
| 10***51 | Screw; (M4x32-mm) | 4 |
| 10***52 | Seal | 1 |
| 10***54 | Body As; (Lamp) | 1 |
5t-0763 Lighting Gp-Flood
| 01***02 | Lockwasher | 1 |
| 03***35 | Bolt-Self Locking; 2.22cm(.875 In.) Lg | 4 |
| 1M***82 | Lamp Group | 1 |
5t-6093 Lighting Gp-Roading
| 2B***52 | Washer .047 In. (1.19 mm) Thick | 4 |
| 3H***81 | Nut,Plain,Hexagon Terminal Assembly | 2 |
| 4D***94 | Clip-- Compressor Clutch Wire To Compressor Body | 1 |
8x-5926 Lighting Gp-Roading
| 3D***79 | Grommet-Install In Hole In Platform | 1 |
| 4D***94 | Clip-- Compressor Clutch Wire To Compressor Body | 1 |
| 5M***62 | Bolt; (3/8-16x0.75-In) | 2 |
6g-8175 Wiring Gp-Scraper
| 01***02 | Lockwasher | 1 |
| 1M***82 | Lamp Group | 1 |
| 3D***54 | Spacer; (47.8mm Thk) | 1 |
Frame And Body
4t-8934 Fender Gp
| 1K***70 | Nut (National Coarse) | 8 |
| 1K***72 | Locknut Horn To Guard | 24 |
| 4T***83 | Fender As | 1 |
4t-3971 Frame Gp-Draft
| 0S***09 | Bolt (3/4") Filler Tube Assembly To Transfer Drive Case | 4 |
| 0S***21 | Bolt --Brace To Starting Engine Mounting Pad; Bolt-- Brace To Starting Engine Mounting Pad | 4 |
| 1D***29 | Bolt (7/8-9x3.5in); (7/8-9x3.5-In) | 24 |
105-8897 Frame Gp-Draft
| 10***97 | Frame Group-Draft | 1 |
| 10***05 | Frame As-Draft | 1 |
| 10***09 | Frame As-Draft | 1 |
8x-6931 Frame Gp-Draft
| 0S***09 | Bolt (3/4") Filler Tube Assembly To Transfer Drive Case | 4 |
| 0S***73 | Bolt (102mm Long); (1/2-13x4-In) | 6 |
| 0S***21 | Bolt --Brace To Starting Engine Mounting Pad; Bolt-- Brace To Starting Engine Mounting Pad | 4 |
8w-5304 Liner Gp-Body
| 8W***04 | Liner Group-Body | 1 |
| 8W***88 | Liner Group-Body | 1 |
| 8W***90 | Plate Group-Wear | 1 |
8x-1839 Liner Gp-Body
| 4T***05 | Plate; (16mm Thk) | 1 |
| 7J***60 | Reinforcement; (0 Holes) | 2 |
| 8W***70 | Reinforcement; (1 Hole) | 2 |
8w-6088 Liner Gp-Body
| 7J***60 | Reinforcement; (0 Holes) | 2 |
| 8W***70 | Reinforcement; (1 Hole) | 2 |
| 8W***71 | Reinforcement; (2 Holes) | 2 |
8w-1492 Lines Gp-Central Lubrication
| 03***30 | Bolt-Self Locking; (5/16unc X 3/4) | 2 |
| 1S***93 | Strap; (Cable) (0.62in Dia) | 3 |
| 2D***83 | Fitting | 2 |
8w-9846 Lines Gp-Central Lubrication
| 2R***22 | Connector | 4 |
| 3B***85 | Fitting-Hydraulic; Fitting 45 Degrees Angle--Used As Required | 12 |
| 3S***93 | Strap-Cable-To Tie Harnesses Together | 6 |
121-5406 Reflector Gp
| 11***22 | Reflector-Red | 2 |
| 12***03 | Bracket | 2 |
| 12***06 | Reflector Group | 1 |
8x-7498 Step Gp
| 8T***99 | Bolt-Plt; Bolt (3/4 X 10 X 2.25in) | 2 |
| 8W***58 | Cable As | 1 |
| 8X***98 | Step Group | 1 |
8w-6394 Step Gp
| 4V***38 | Boss | 2 |
| 5P***82 | Bolt-Self Locking; 57.15mm(2.25in.)Lg. | 2 |
| 8W***58 | Cable As | 1 |
Fuel System
5t-5217 Adapter Gp-Fast Fill Fuel
| 2G***00 | Valve As-Tank | 1 |
| 3J***03 | Cover | 1 |
| 4J***27 | Seal-O-Ring -Pipe As. To Hydraulic Tank | 2 |
8x-4259 Adapter Gp-Fast Fill Fuel
| 1S***33 | Clip | 3 |
| 21***03 | Receiver; (Fast Fill Fuel) | 1 |
| 27***95 | Kit-Vent; (Fuel)(Plastic) | 1 |
8w-9060 Adapter Gp-Fast Fill Fuel
| 1S***33 | Clip | 3 |
| 2G***00 | Valve As-Tank | 1 |
| 3B***00 | Elbow | 2 |
8w-4969 Lines Gp-Fuel
| 3J***07 | Seal Valve Assembly To; Seal- Tube Assembly To Logic Valve | 1 |
| 3K***60 | Seal Pilot Manifold On; Seal To Boom Check Valve Drain | 7 |
| 4D***71 | Clip 25.4 cm(10 In.) Long | 2 |
4t-1835 Lines Gp-Fuel
| 00***01 | Elbow (To Serial No 1md225) | 2 |
| 00***63 | Elbow, 90 Deg Street, 3/4in. N.P.T. | 2 |
| 03***42 | Elbow Hose Assembly To | 1 |
8x-4455 Lines Gp-Fuel
| 3J***07 | Seal Valve Assembly To; Seal- Tube Assembly To Logic Valve | 1 |
| 3K***60 | Seal Pilot Manifold On; Seal To Boom Check Valve Drain | 2 |
| 4D***71 | Clip 25.4 cm(10 In.) Long | 1 |
8w-0401 Pump Gp-Fuel Tfr & Priming
| 03***35 | Bolt-Self Locking; 2.22cm(.875 In.) Lg | 1 |
| 1W***79 | Pump Group-Fuel Tfr & Priming | 1 |
| 3K***60 | Seal Pilot Manifold On; Seal To Boom Check Valve Drain | 2 |
8w-4970 Pump Gp-Fuel Tfr & Priming
| 1W***79 | Pump Group-Fuel Tfr & Priming | 1 |
| 3K***60 | Seal Pilot Manifold On; Seal To Boom Check Valve Drain | 2 |
| 5S***79 | Hex Head Capscrew, 3/8 Nc X 7/8 In. (22 mm) | 1 |
1w-4279 Pump Gp-Fuel Tfr & Priming
| 1J***71 | Seal (10.52 Degrees I.D.); Seal-O-Ring -- To Adapter | 1 |
| 1W***79 | Pump Group-Fuel Tfr & Priming | 1 |
| 1W***39 | Can As | 1 |
2g-9000 Valve As-Tank -Fast Fill Fuel
| 2G***00 | Valve As-Tank | 1 |
Hydraulic System
4t-1819 Control Ar-Scraper Hydraulic
| 1U***48 | Lines Group-Steering | 1 |
| 3G***07 | Cylinder Group-Steer | 1 |
| 4T***19 | Control Ar-Scraper Hydraulic | 1 |
6j-5824 Cylinder Gp-Ejector
| 16***28 | Seal As-Buffer | 1 |
| 16***46 | Seal-U-Cup | 1 |
| 17***08 | Head | 1 |
8j-5931 Cylinder Gp-Apron
| 16***08 | Seal As-Buffer | 1 |
| 16***19 | Seal-U-Cup | 1 |
| 1D***27 | Bolt,Machine Head Mtg Uoc:Bsv,Bsx | 8 |
6e-0905 Cylinder Gp-Ejector
| 0L***78 | Bolt,Machine Governor And Decelerator Control | 6 |
| 16***28 | Seal As-Buffer | 1 |
| 16***46 | Seal-U-Cup | 1 |
9t-3595 Cylinder Gp-Ejector
| 1A***76 | Bolt 11.43cm (4.50 In.) Long | 2 |
| 1D***25 | Bolt 7/8" Unc X 2 1/2" | 6 |
| 1U***08 | Wiper-Rod | 1 |
6e-0897 Cylinder Gp-Ejector
| 16***28 | Seal As-Buffer | 1 |
| 16***46 | Seal-U-Cup | 1 |
| 17***08 | Head | 1 |
9t-4887 Cylinder Gp-Ejector
| 0L***78 | Bolt,Machine Governor And Decelerator Control | 6 |
| 1A***76 | Bolt 11.43cm (4.50 In.) Long | 2 |
| 1D***25 | Bolt 7/8" Unc X 2 1/2" | 6 |
9j-0409 Cylinder Gp-Bowl -Lh
| 16***07 | Seal As-Buffer | 1 |
| 16***17 | Seal-U-Cup | 1 |
| 1D***31 | Bolt 4.25 In. (1.08 Dm) Long | 2 |
9j-0408 Cylinder Gp-Bowl -Rh
| 16***07 | Seal As-Buffer | 1 |
| 16***17 | Seal-U-Cup | 1 |
| 1D***31 | Bolt 4.25 In. (1.08 Dm) Long | 2 |
4t-4699 Lines Gp-Draft Frame
| 03***06 | .. Bearing.; Cushion, Bolt-Locking; (2.5cm Lg) | 2 |
| 06***08 | Bulkhead Tee | 2 |
| 0L***29 | Bolt- 7.63 cm(3 In.) Long - Location "H" | 8 |
8w-4702 Lines Gp-Draft Frame
| 14***80 | Elbow As | 2 |
| 14***34 | Tee As-Orfs | 2 |
| 18***65 | Union As-Bhd | 2 |
4t-1828 Lines Gp-Ejector
| 0S***09 | Bolt (3/4") Filler Tube Assembly To Transfer Drive Case | 8 |
| 0S***85 | Bolt; 12.7 mm (1/2") Diameter X 38.1 mm (1 1/2") Length Generator To Engine | 8 |
| 0S***87 | Bolt-Bracket Assembly To Timing Gear | 18 |
8x-2804 Lines Gp-Ejector
| 0S***85 | Bolt; 12.7 mm (1/2") Diameter X 38.1 mm (1 1/2") Length Generator To Engine | 8 |
| 0S***87 | Bolt-Bracket Assembly To Timing Gear | 18 |
| 0S***94 | Bolt (1 In. Long 3/8 In. Dia.); Plate Assembly To Support Assembly | 1 |
4j-2280 Valve Gp-Ejector
| 0S***90 | Bolt; (3/8-16x2in)(Clip Thru Spacer To Bracket As) | 2 |
| 0S***95 | Bolt 1.25 In. (31.75 mm) Long Guard Assemblies To Radiator Guard | 4 |
| 0V***75 | Screw,Cap,Hexagon H Shaft Mtg,Accessory Drive | 2 |
8j-8840 Valve Gp-Check
| 16***20 | Retainer-Valve | 1 |
| 1P***74 | Flange-Half | 4 |
| 1P***78 | Flange; (To 5v***09 Tube Assembly) | 8 |
4j-9349 Valve Gp-Sequence & Press Cont
| 0S***71 | Screw,Cap,Hexagon; Tube Assembly To Turbocharger And Elbow Mounting | 6 |
| 0S***87 | Bolt-Bracket Assembly To Timing Gear | 3 |
| 0S***88 | Bolt,Machine; Hose Assembly Mounting,Hose Assembly To Transmission,And To Torque Converter | 2 |
Implements
1u-4965 Apron Gp
| 1U***65 | Apron Group | 1 |
| 1U***74 | Apron As | 1 |
| 3G***34 | Trunnion | 2 |
8w-6089 Apron Gp
| 0S***92 | Bolt--Cover To Flywheel Housing | 1 |
| 1A***35 | Bolt 2.00 In. (5.08 cm) Long | 16 |
| 1A***76 | Bolt 11.43cm (4.50 In.) Long | 4 |
4t-1829 Bowl Gp-Scraper
| 0L***29 | Bolt- 7.63 cm(3 In.) Long - Location "H" | 1 |
| 0S***26 | Bolt, Hex. Hd., 3/4in.-10 N.C. X 1 1/2in. | 4 |
| 1A***60 | Capscrew, Hex Head (1/2 - 13 X 2 G5); (Hex Head) (1/2-13x2 Gd 8 Z) | 1 |
8w-6086 Bowl Gp-Scraper
| 0L***29 | Bolt- 7.63 cm(3 In.) Long - Location "H" | 1 |
| 0S***26 | Bolt, Hex. Hd., 3/4in.-10 N.C. X 1 1/2in. | 4 |
| 1A***60 | Capscrew, Hex Head (1/2 - 13 X 2 G5); (Hex Head) (1/2-13x2 Gd 8 Z) | 1 |
8x-1640 Bowl Gp-Scraper
| 0L***29 | Bolt- 7.63 cm(3 In.) Long - Location "H" | 1 |
| 0S***26 | Bolt, Hex. Hd., 3/4in.-10 N.C. X 1 1/2in. | 4 |
| 1A***60 | Capscrew, Hex Head (1/2 - 13 X 2 G5); (Hex Head) (1/2-13x2 Gd 8 Z) | 1 |
8w-1193 Bowl Gp-Scraper
| 4T***05 | Plate; (16mm Thk) | 1 |
| 4T***06 | Plate | 2 |
| 7J***60 | Reinforcement; (0 Holes) | 2 |
4t-1838 Ejector Gp
| 03***38 | Bolt 69.85 mm(2.75 In.) Long | 8 |
| 0S***09 | Bolt (3/4") Filler Tube Assembly To Transfer Drive Case | 12 |
| 1A***58 | Gasket | 2 |
1u-4101 Guard Gp-Overflow
| 1U***01 | Guard Group-Overflow | 1 |
| 2A***85 | Guard As | 1 |
| 4T***70 | Bracket | 4 |
4t-8941 Lift Gp-Apron
| 0L***95 | Washer .25 In.(6.35 mm)Thick | 2 |
| 1J***20 | Washer 3.175 mm (.125 In.) Thick | 2 |
| 1J***69 | Washer 1.588 mm (.0625 In.) Thick | 6 |
8w-6090 Plate Gp-Wear
| 4T***05 | Plate; (16mm Thk) | 1 |
| 8W***83 | Plate; (10mm Thk) | 1 |
| 8W***90 | Plate Group-Wear | 1 |
144-7289 Roller Gp-Ejector Guide
| 03***24 | Bolt-Self Locking; 19mm(.75in.)Dia. | 1 |
| 14***89 | Roller Group-Ejector Guide | 1 |
| 14***90 | Roller As | 1 |
Machine Arrangement
8w-9850 Chassis Ar
| 1U***65 | Apron Group | 1 |
| 4T***19 | Control Ar-Scraper Hydraulic | 1 |
| 4T***29 | Bowl Group-Scraper | 1 |
8x-1639 Chassis Ar
| 10***97 | Frame Group-Draft | 1 |
| 1U***65 | Apron Group | 1 |
| 4T***19 | Control Ar-Scraper Hydraulic | 1 |
128-2634 Conversion Ar-Certification
| 12***39 | Tank Group-Air | 1 |
| 12***06 | Reflector Group | 1 |
| 12***34 | Conversion Ar-Certification | 1 |
8w-8651 Cylinder Ar-Auger Scraper
| 6E***05 | Cylinder Group-Ejector | 1 |
| 8W***51 | Cylinder Ar-Auger Scraper | 1 |
8x-1655 General Ar-Scraper
| 7X***58 | Plate & Film Group | 1 |
| 8W***45 | Wheel & Brake Ar | 1 |
| 8X***39 | Chassis Ar | 1 |
8x-9398 Scraper Ar
| 8X***98 | Step Group | 1 |
| 8X***99 | Lamp Group-Flood | 1 |
| 8X***98 | Scraper Ar | 1 |
8w-5990 Scraper Ar
| 8W***90 | Scraper Ar | 1 |
| 8W***86 | Bowl Group-Scraper | 1 |
| 8W***89 | Apron Group | 1 |
8w-9840 Scraper Ar
| 7X***58 | Plate & Film Group | 1 |
| 8W***40 | Scraper Ar | 1 |
| 8W***45 | Wheel & Brake Ar | 1 |
4t-1817 Scraper Ar
| 1U***65 | Apron Group | 1 |
| 4T***17 | Scraper Ar | 1 |
| 4T***19 | Control Ar-Scraper Hydraulic | 1 |
Power Train
5t-5914 Tire Gp
| 5T***14 | Tire Group | 1 |
5t-5912 Tire Gp
| 5T***12 | Tire Group | 1 |
5t-5913 Tire Gp
| 5T***13 | Tire Group | 1 |
5t-5656 Tire Gp
| 5T***56 | Tire Group | 1 |
8w-9845 Wheel & Brake Ar
| 5T***33 | Wheel Group-Rear | 1 |
| 5T***56 | Tire Group | 1 |
| 5T***70 | Brake Group-Service | 1 |
5t-4633 Wheel Gp-Rear
| 1A***37 | Bolt Clutch Assembly To Bracket (Fan Support) | 16 |
| 1B***74 | Plug,Pipe Base Assembly,Engine Oil Filter Assembly | 2 |
| 2G***81 | Sealant-Pellet | 0 |
Service Equipment And Supplies
4t-8276 Bracket Gp-Shipping
| 06***57 | Elbow-Flared | 1 |
| 0S***90 | Bolt; (3/8-16x2in)(Clip Thru Spacer To Bracket As) | 4 |
| 0S***20 | Bolt--Customer Grounding Bolt | 14 |
6v-6729 Film Gp
| 1P***80 | Film; (Cat)(Cat) | 0 |
| 6V***29 | Film Group | 1 |
| 6V***30 | Film | 0 |
6v-5742 Plate & Film Gp
| 03***60 | Rivets | 10 |
| 1H***68 | Plate-Serial Number-Scraper On Left | 1 |
| 1S***88 | Film-- Drain Valve; --On Each Side Of Radiator Support | 1 |
7x-7759 Plate & Film Gp
| 03***60 | Rivets | 2 |
| 1H***68 | Plate-Serial Number-Scraper On Left | 1 |
| 7X***59 | Plate & Film Group | 1 |
7x-7758 Plate & Film Gp
| 03***60 | Rivets | 10 |
| 10***42 | Film Group | 1 |
| 10***43 | Film-Stripe; (Cat-Rh) | 1 |
Steering System
3g-7607 Cylinder Gp-Steering
| 16***07 | Seal As-Buffer | 1 |
| 16***17 | Seal-U-Cup | 1 |
| 19***04 | Kit-Seal; (Steering Cylinder) | 1 |
8x-4054 Cylinder Gp-Steering
| 3G***07 | Cylinder Group-Steer | 1 |
| 5P***72 | Seal (Cylinder) | 2 |
| 8X***54 | Cylinder Group-Steering | 1 |
8x-7137 Lines Gp-Steering
| 1P***77 | Flange-Half (For Tilt Ports On Valve) | 20 |
| 1S***45 | Plate .312 In. (7.9 mm) Thick | 9 |
| 4J***20 | Seal (For Tilt Ports On Valve) | 8 |
1u-3048 Lines Gp-Steering
| 0L***52 | Capscrew (3/8 - 16 Nc X 3 1/4 Gd8, Hex) | 16 |
| 1P***77 | Flange-Half (For Tilt Ports On Valve) | 20 |
| 1S***45 | Plate .312 In. (7.9 mm) Thick | 9 |
Work Tools
9j-4370 Edge Gp-Bit & Cutting -35-Mm Thk
| 2J***07 | Nut-Full; (1-8 X38.1 Thd) | 32 |
| 4F***42 | Bolt 7.62 cm(3 In.) Long | 22 |
| 4J***58 | Bolt--Per Change 1 To 7j***85 | 10 |
9j-0566 Edge Gp-Bit & Cutting -35-Mm Thk
| 2J***07 | Nut-Full; (1-8 X38.1 Thd) | 32 |
| 4F***42 | Bolt 7.62 cm(3 In.) Long | 32 |
| 4J***65 | Bit (Routing) | 2 |
9j-5904 Edge Gp-Cutting -35-Mm Thk
| 2J***07 | Nut-Full; (1-8 X38.1 Thd) | 32 |
| 4F***42 | Bolt 7.62 cm(3 In.) Long | 22 |
| 4J***58 | Bolt--Per Change 1 To 7j***85 | 10 |
4t-5493 Protector & Bit Gp
| 1U***05 | Retainer-G.E.T. | 2 |
| 2J***07 | Nut-Full; (1-8 X38.1 Thd) | 10 |
| 4F***42 | Bolt 7.62 cm(3 In.) Long | 10 |
Frequently asked questions
What engine powers the 631E?
The 631E is standard with a four-stroke 3408 turbocharged V-8 engine generating 450 flywheel horsepower.
What is the operating weight of the machine?
The tractor and scraper together weigh approximately 95,000 lb (43,091 kg) when empty, reaching over 171,000 lb (77,562 kg) at maximum load capacity.
What model replaced the 631E?
The 637E succeeded the 631E, featuring an additional motor situated behind the debris bin for improved traction and speed.
What 631E owners discuss
What are the primary causes for a 631E losing both forward and reverse movement while manual gear shifting at the transmission remains functional?
Inspect the transmission control linkage and hydraulic system. Potential issues include worn or disconnected shift linkages, low hydraulic fluid levels, or faulty solenoids controlling gear engagement.
What engine is standard on the Caterpillar 631E wheel tractor-scraper?
The machine comes standard with a four-stroke 3408 turbocharged V-8 engine generating 450 flywheel horsepower.
What should be checked regarding electrical wiring if the transmission loses movement suddenly?
Check fuses and the wiring harness. Inspect the harness where it is clamped or routed near hot or vibrating components; performing a wiggle test while monitoring diagnostic data can identify intermittent breaks.
What are the typical weight and capacity specifications for a fully loaded 631E?
The tractor and scraper together weigh 95,000 lb (43,091 kg) when empty. When the 75,000 lb (34,019 kg) capacity load is maxed, the total weight exceeds 171,000 lb (77,562 kg).
What hydraulic system features are noted for the 631E Series II configuration?
The system utilizes a hydraulic servo-steering system for low-effort maneuverability. Wiring harness and hose assemblies run down the draft arms to eliminate 'jump-over' lines, which improves hydraulic efficiency.
What is critical to verify when purchasing a used 631E?
Confirm the exact serial-prefix specification sheet and installed attachment package. Verify the machine build date through a dealer using the official SIS database to ensure accuracy regarding original configuration and destination records.
Compiled from owner and technician discussions across the industry — experiences vary by serial range and machine history.
Serial-range & configuration variants
This page covers the Caterpillar 631E. Related factory variants of the same model family:
631E
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