Caterpillar 320B S
Maintenance schedule, common problems & OEM parts breakdown
The Caterpillar 320B S is a severe-duty configuration of the 320B medium hydraulic excavator class, built with a reinforced, narrower-gauge undercarriage for demanding underfoot conditions such as mountainous or mining terrain. It carries the Cat 3116T turbocharged diesel, a mechanically governed inline-six of 6.6 L (402.8 cu in) displacement rated around 95.5 kW (128 hp), controlled by an electronic speed-control actuator rather than a full engine ECM. Operating weight runs about 22.5 t (49,670 lb), heavier than the base 320B's roughly 20.6 t due to the added undercarriage reinforcement, with a narrower track gauge of about 1.92 m (6.24 ft) versus roughly 2.2 m on the standard machine. The 320B S was built through the 1990s as part of Cat's 320B family, which followed the original 320/320 L excavators and was itself succeeded by the 320C generation. Cat offered the base 320B chassis in several undercarriage and frame configurations for different jobs: standard, L (long), LL, LN (long/narrow), N (narrow), and S (severe-duty reinforced), each suited to different ground conditions and lift requirements.
Across the 320B lineage, the letter suffixes mark undercarriage and frame changes more than powertrain changes. The S variant's main difference from a standard 320B is its reinforced frame and narrower track gauge for tougher ground, not a different design philosophy, though in practice Cat paired it with the 3116T rather than the 3066T used across the rest of the 320B family. The next-generation 320C moved the whole line to updated cooling and electronics, and later 320D, E, F, GC, and Next Gen generations shifted to electronic, common-rail fuel systems under Tier emissions rules. That makes the 320B S a pre-electronic, pre-emissions machine: mechanically simple, no ECM fault codes, and serviceable without a diagnostic laptop. On the used and parts market today, that simplicity plus shared undercarriage and drivetrain components across the 320B family keep demand steady for used and aftermarket parts, particularly undercarriage, hydraulic, and mechanical fuel-system components, on machines still working in regions without strict emissions enforcement.
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 320B S specifications
Engine
| Engine model | Cat 3116T turbocharged diesel, inline-6 |
| Rated power | 95.5 kW (128 hp) — spec sheets label this figure inconsistently as gross vs. net; treat as the machine's single published rating |
| Displacement | 6.6 L (402.8 cu in / 6,600 cc) |
| Cylinders | 6, inline |
| Emissions tier | Predates EPA/EU nonroad emissions-tier regulation (pre-Tier, 1990s production) |
Weights
| Operating weight (S severe-duty undercarriage) | approx. 22,530 kg (49,670 lb) — heavier than the standard 320B due to the S model's reinforced, narrow-gauge undercarriage |
| Ground pressure | Not documented in available spec sheets for this configuration — verify with your dealer |
| Transport weight | Not separately published; operating weight is the standard shipping reference figure |
Dimensions
| Height to top of cab | 3.11 m (10 ft 2 in) |
| Width over tracks (narrow transport gauge) | 2.50 m (8 ft 2 in) |
| Tail swing radius | 2.77 m (9 ft 1 in) |
| Track shoe width | 551 mm (21.7 in), standard grouser shoe |
| Track gauge | 1.92 m (6 ft 4 in) |
| Length of track on ground | 3.51 m (11 ft 6 in) |
| Ground clearance | approx. 0.49–0.52 m (1 ft 7 in–1 ft 8 in), minor variance across spec sheets |
| Transport length/width (overall shipping dimensions) | Not separately documented for this configuration; track-on-ground length and transport width above are the closest published figures |
Performance
| Max digging depth | 6.49 m (21 ft 3 in) on the recorded boom/stick configuration |
| Max reach at ground level | 9.68 m (31 ft 9 in) on the recorded boom/stick configuration |
| Max cutting height | 9.47 m (31 ft 1 in) on the recorded boom/stick configuration |
| Max vertical wall digging depth | 5.48 m (18 ft 0 in) on the recorded boom/stick configuration |
| Max dump height | Not separately documented — cutting height figure above is the closest published reach dimension |
| Swing speed | Not documented in available spec sheets — verify with your dealer |
| Max travel speed | approx. 5.5–5.6 km/h (3.4–3.5 mph), minor variance across spec sheets |
| Gradeability | Not documented in available spec sheets for this configuration — verify with your dealer |
| Drawbar pull | 177 kN (39,800 lbf / 18,053 kgf) |
Forces
| Bucket digging force | Not documented for this configuration in available spec sheets — verify with your dealer |
| Stick digging force | Not documented for this configuration in available spec sheets — verify with your dealer |
Service capacities (summary)
| Fuel tank | 290 L (76.7 gal) |
| Hydraulic system | Pump flow capacity 370 L/min (97.8 gpm) at 34.3 MPa (4,980 psi) relief pressure; hydraulic tank capacity not separately documented |
| Engine oil | Not documented in available spec sheets — verify with your dealer |
| Cooling system | Not documented in available spec sheets — verify with your dealer |
Values vary by configuration, region, and serial range — confirm against your machine before planning transport or lifts.
320B S fluids & capacities
| System | Capacity | Recommended fluid |
|---|---|---|
| Engine crankcase (with filter) | approx. 19.3–20.5 L (5.1–5.5 US gal) | Cat DEO (Diesel Engine Oil), multigrade diesel engine oil. Viscosity by ambient temperature per the Cat chart: SAE 10W-30 or 15W-40 in temperate range, dropping to 0W-20/0W-30 in sub-zero cold-start conditions. |
| Cooling system | approx. 25 L (6.6 US gal) | Cat coolant/antifreeze meeting Cat EC-1 spec — factory-era fill is Cat DEAC (conventional, requires supplemental coolant additive on interval); Cat ELC (extended-life, no SCA needed) is the accepted long-life alternative for refill. |
| Fuel tank | approx. 340–341 L (89.9–90 US gal) | No. 2-D diesel fuel meeting ASTM D975 (or equivalent EN 590), minimum cetane number 40. No. 1-D or a winter blend recommended below freezing to prevent fuel waxing. |
| Hydraulic system total (including tank) | approx. 219.5–220 L (58 US gal) | Cat HYDO (multigrade hydraulic oil) as first choice; Cat TDTO is an accepted second-choice fluid in this system. Viscosity by climate: SAE 10W in cold ambient temperatures, SAE 30 (or 10W-30) in temperate-to-hot conditions. |
| Hydraulic tank (reservoir only) | Not published as a separate figure — the OMM's Service Refill Capacities table lists only the combined "hydraulic system including tank" figure above for this family | Same fluid as hydraulic system total (Cat HYDO, second choice Cat TDTO). |
| Final drive (each) | approx. 9.8 L (2.6 US gal) per side | Cat TDTO (TO-4 drivetrain oil) — historically the factory spec for final drive and swing-drive compartments on this era of machine. Viscosity SAE 10W, 30, or 50 selected by ambient temperature per the Cat chart. |
| Swing drive | approx. 6.0–6.1 L (1.6 US gal) | Cat TDTO (TO-4 drivetrain oil), same viscosity-by-temperature selection as the final drives. |
| Grease (all lubrication points) | Spec only — no reservoir capacity applies | Cat Multipurpose Grease (MPGM), NLGI grade 2 for normal ambient temperatures; NLGI grade 1 or 0 recommended in sustained sub-zero cold climates. |
Capacities are refill values from factory literature — always fill to the dipstick/sight gauge, not the number.
Caterpillar 320B S maintenance schedule
| Service interval | Tasks |
|---|---|
| Every 10 h |
|
| Every 250 h |
|
| Every 500 h |
|
| Every 1,000 h |
|
| Every 2,000 h |
|
| Every 4,000 h |
|
| Every 6,000 h |
|
Servicing the 320B S beyond the schedule
Predictive Maintenance & Fluid Analysis
Sample engine oil at every oil change to track soot and fuel dilution typical of the mechanically governed 3116T; without an ECM to log fault codes, oil analysis is the main early warning for turbocharger wear (rising boost lag, oil in the intake) or injection pump wear. Pull hydraulic oil samples at the 500 and 2000 hour intervals to catch pump wear before the roughly 370 L/min (97.8 gpm) pump and 34.3 MPa (4,980 psi) relief circuit lose output. Track undercarriage wear readings more closely than on a standard 320B, since the S's reinforced frame usually works harder ground.
Corrective & Common Repairs
Rough idle and hard starting on a high-hour 3116T usually trace to worn mechanical injectors or a sticking governor linkage, not electronics. Turbocharger seal leaks and boost loss are common by mid-life; check the electronic speed-control actuator linkage for corrosion and free movement. On the undercarriage, watch track adjuster and idler mounting bolts for loosening, more frequent on the S's reinforced but narrower-gauge frame under sustained severe-duty loads than on a standard-gauge 320B. Swing bearing play also shows up earlier on units run hard in this configuration.
Overhaul & Rebuild Points
Judge swing gear and bearing condition on wear and backlash rather than a fixed hour count. The 3116T's mechanical injection pump and turbocharger are the major mid-life rebuild items on this engine, both serviceable without diagnostic tools. Hydraulic pump and main control valve wear shows up as slower cycle times against the roughly 370 L/min flow spec. Undercarriage components (rollers, idlers, sprockets, track chain) wear faster on the reinforced S frame under mountainous or severe-duty ground and are the most common full-rebuild items on used units.
Seasonal & Environment Servicing
In cold climates, protect the mechanical 3116T fuel system from gelling with the correct diesel blend, and verify the cold-start aid works, since there is no ECM-managed cold-start strategy on this engine. On the hot, dusty, or rocky severe-duty sites the S configuration is built for, check the air intake and turbocharger inlet for dust ingestion more often and keep the hydraulic oil cooler clear to protect the 34.3 MPa (4,980 psi) relief circuit. Inspect undercarriage seals for grit intrusion on rocky-terrain jobs.
320B S fault codes & troubleshooting
| Code | Meaning | Likely cause | What to do |
|---|---|---|---|
| 1302 | Engine oil pressure low | Low oil level, worn oil pump, plugged filter, or a failed oil pressure sending unit | Shut engine down if the warning lamp is active, check oil level and filter condition, verify the sender before replacing parts |
| 1303 | Engine coolant temperature too high | Low coolant level, clogged radiator core, failed thermostat, or a slipping/failed fan drive | Reduce load and let the engine idle down, check coolant level and radiator fins, inspect fan belt and drive before restart |
| 1304 | Hydraulic oil temperature too high | Low hydraulic oil level, clogged oil cooler fins, failed cooling fan, or sustained relief-valve operation from a stuck or overloaded circuit | Reduce load, idle to cool, check oil level and cooler for debris, confirm the cooling fan is turning |
| 1305 | Engine air intake filter element restricted | Dirty or clogged primary air filter element, or a faulty restriction indicator | Inspect and service the air filter element, check the restriction indicator for a false signal |
| 2201 | System (battery) voltage abnormal | Weak or failing battery, loose or corroded battery cable, faulty alternator or voltage regulator | Check battery state of charge and terminal condition, test alternator output, inspect charging harness |
| 2301 | Governor actuator feedback sensor circuit shorted to ground | Chafed or pinched harness wiring near the governor motor, corroded connector | Inspect governor actuator wiring and connector for a short to frame ground, repair or replace the harness as needed |
| 2302 | Governor actuator feedback signal unstable (biased, does not track commanded position) | Worn or misadjusted governor actuator linkage, or a failing feedback potentiometer inside the actuator motor | Check the governor linkage for binding or wear, verify feedback sensor voltages at the connector against the test procedure, recalibrate or replace the actuator |
| 2303 | Governor actuator feedback signal deviates from the commanded position | Linkage binding, worn actuator gear train, or a drifted calibration | Inspect linkage for free movement, recalibrate the governor actuator, replace the actuator if deviation persists |
| 2304 | Governor actuator not responding to command (no movement detected) | Seized actuator motor, broken or disconnected linkage, blown fuse, or open wiring to the actuator | Check power supply and fuse to the actuator, inspect linkage for mechanical seizure, replace the actuator motor if confirmed failed |
Codes and remedies are general guidance for this model family — always confirm with diagnostic tooling and your dealer before major repairs.
320B S attachments & work tools
Buckets
General-purpose buckets for this 20-23 t class run about 0.8-1.36 m³ (1.0-1.8 yd³), with widths from roughly 900 mm to 1.4 m (36-54 in). Heavy-duty buckets give up some capacity for reinforced sides and extra wear plate, and rock buckets narrow further to about 0.8-1.0 m³ in 400-900 mm (16-36 in) widths for better breakout control in abrasive ground. Buckets mount on 80 mm pins, either pin-on direct to the stick or through a coupler; pin spacing and ear width should be checked against the specific boom/stick option fitted, since this machine was offered with several stick lengths.
Hydraulic hammers
This machine falls in the mid-size breaker class built for roughly 19-32 t carriers, matching a service-weight-near-1.7 t hammer class. Typical demand is about 120-220 L/min (32-58 gpm) at roughly 155-235 bar (2,250-3,400 psi) working pressure, with impact rates around 320-600 bpm depending on model. Breakers from other brands sized to the same 20-23 t carrier class, flow, and pressure bands are equally compatible.
Quick couplers
A hydraulic pin-grabber coupler was available for this size class, using an 80 mm pin with a wedge-type primary lock, spring-loaded secondary latch, and in-cab visual lock confirmation. Manual (mechanical pin) couplers with the same 80 mm pin geometry are also common on machines of this vintage; either type accepts buckets, thumbs, and light work tools sized to the 320-class pin and ear dimensions.
Thumbs/grapples
Hydraulic thumbs for this class run about 1.5-1.8 m (60-72 in) long, pin-on to the stick with an 80 mm pin, and need a dedicated two-way auxiliary hydraulic circuit to open and close the cylinder. Demolition and sorting grapples sized for carriers in the low-20-tonne range run roughly 0.4-1.0 m³ jaw capacity; larger grapples in the same product family are built for heavier carriers and don't suit this weight class.
Rippers
A single-shank pin-on ripper is available for this class, roughly 1.4 m (55 in) long with a shank around 1.05-1.1 m (42-43 in), mounting on the same 80 mm stick pin. It suits light rock ripping, frost breaking, and root or pavement work rather than dozer-class mass ripping; service weight runs near 490 kg (1,080 lb).
Hydraulic-kit notes
Running a hammer needs a one-way auxiliary circuit sized to the breaker's flow/pressure window (roughly 120-220 L/min at 155-235 bar); a thumb or grapple needs a two-way circuit for cylinder return. As a mechanically governed, pre-electronic-flow-select machine, tool flow and pressure are set by a fixed relief/orifice circuit rather than an in-cab adjustable multi-tool menu, so match the auxiliary kit's rated flow to the specific tool at install time.
All 320B S assemblies by section
Every catalogued assembly group for the Caterpillar 320B S. Open an assembly to preview the parts inside — full OEM part numbers are available in Heavy Parts AI.
Electrical And Starting System
1761784 (V00) Lighting Gp - Boom
| 17***84 | Lighting Group; Lighting Gp-Boom | 1 |
1415998 (V00) Magnet
| 14***98 | Magnet | 1 |
166638 (V00) Magnet As
| 16***38 | Magnet As | 1 |
1475000 (V01) Special Ar - Generator
| 12***59 | Frame Group-Upper | 1 |
| 13***05 | Gear & Bearing Group-Swing | 1 |
| 14***00 | Special Ar | 1 |
1482245 (V03) Wiring Gp
| 14***45 | Wiring Group; Wiring Gp-Riser | 1 |
1760146 (V01) Wiring Gp
| 17***46 | Wiring Group | 1 |
1482245 (V01) Wiring Gp - Riser
| 14***45 | Wiring Group; Wiring Gp-Riser | 1 |
Frame And Body
1856068 (V00) Counterweight As.
| 18***68 | Counterweight As. | 1 |
1856070 (V00) Counterweight Gp
| 18***70 | Counterweight Group | 1 |
1856069 (V00) Counterweight Gp (Basic)
| 18***69 | Counterweight Group (Basic) | 1 |
1724148 (V00) Frame Ar - Upper
| 12***59 | Frame Group-Upper | 1 |
| 13***05 | Gear & Bearing Group-Swing | 1 |
| 15***28 | Counterweight Group | 1 |
1642952 (V01) Frame Ar - Less Off U/C
| 10***04 | Bolt; (Socket Head) (M10x1.5x30mm) | 16 |
| 11***79 | Flange-Special | 2 |
| 11***42 | Gear & Bearing Group-Swing | 1 |
1593755 (V01) Frame Ar - Less Off U/C
| 10***04 | Bolt; (Socket Head) (M10x1.5x30mm) | 16 |
| 11***79 | Flange-Special | 2 |
| 11***42 | Gear & Bearing Group-Swing | 1 |
2018776 (V00) Frame Gp - Upper Hd
| 20***76 | Frame Group; Frame Gp-Upper | 1 |
1761874 (V00) Frame Gp - Upper
| 17***74 | Frame Group; Frame Gp-Upper | 1 |
1745530 (V00) Guard Ar
| 17***84 | Walkway Group | 1 |
| 17***29 | Guard Group-Swing | 1 |
| 17***30 | Guard Ar | 1 |
1487309 (V01) Guard Gp - Bottom
| 14***09 | Guard Group; Guard Gp-Bottom | 1 |
Hydraulic System
1517841 (V00) Control Ar - Aux.
| 12***85 | Lines Group-Front | 1 |
| 12***66 | Film Group; Film Gp-Combined Function | 1 |
| 13***72 | Control & Mtg Group-Auxiliary Flow; Control & Mounting Gp-Electronic | 1 |
1763989 (V00) Cylinder & Lines Gp - Boom
| 11***03 | Lines Group-Boom Cylinder; -Rh | 1 |
| 17***89 | Cylinder & Lines Group; Cylinder & Lines Gp-Boom | 1 |
| 17***90 | Cylinder & Seal Group; Cylinder & Seal Gp-Boom | 1 |
1763988 (V00) Cylinder & Lines Gp - Boom
| 11***02 | Lines Group-Boom Cylinder; -Lh | 1 |
| 17***88 | Cylinder & Lines Group; Cylinder & Lines Gp-Boom | 1 |
| 17***90 | Cylinder & Seal Group; Cylinder & Seal Gp-Boom | 1 |
1763990 (V00) Cylinder & Seal Gp - Boom
| 17***90 | Cylinder & Seal Group; Cylinder & Seal Gp-Boom | 1 |
1760584 (V01) Cylinder Gp-Boom
| 17***84 | Cylinder Group | 1 |
1883783 (V00) Hydraulic Ar
| 12***85 | Lines Group-Front | 1 |
| 16***06 | Installation Group-Harvester Head | 1 |
| 16***46 | Lines Group-Front | 1 |
1482242 (V02) Lines Gp - Pilot
| 14***42 | Lines Group; (Riser 700mm) | 1 |
1482242 (V00) Lines Gp - Pilot
| 14***42 | Lines Group; (Riser 700mm) | 1 |
1723643 (V00) Lines Gp - Boom
| 17***43 | Lines Group; Lines Gp-Boom | 1 |
1750310 (V00) Lines Gp - Boom
| 17***10 | Lines Group; Lines Gp-Boom | 1 |
1759090 (V02) Lines Gp - Stick
| 17***90 | Lines Group; Lines Gp-Stick | 1 |
1723644 (V02) Lines Gp - Stick
| 17***44 | Lines Group; Lines Gp-Stick | 1 |
1716066 (V00) Valve Ar - Tlcd
| 17***66 | Valve Ar | 1 |
| 17***43 | Lines Group; Lines Gp-Boom | 1 |
| 17***44 | Lines Group; Lines Gp-Stick | 1 |
1966698 (V01) Valve Ar - Tlcv
| 19***98 | Valve Ar Tlcv | 1 |
1957731 (V01) Valve Ar - Tlcv
| 19***31 | Valve Ar Tlcv | 1 |
Implements
1745568 (V00) Boom Ar
| 11***96 | Boom Group; Boom Gp -B | 1 |
| 11***97 | Lines Group-Grease; (Grease) | 1 |
| 11***62 | Cylinder & Lines Group-Stick | 1 |
1761780 (V00) Boom Ar - Forestry
| 11***97 | Lines Group-Grease; (Grease) | 1 |
| 11***58 | Cylinder & Lines Group-Boom | 1 |
| 11***60 | Cylinder & Lines Group-Boom; -Rh | 1 |
1761781 (V00) Boom Gp - Forestry
| 17***81 | Boom Group | 1 |
1605079 (V00) Bracket As
| 16***79 | Bracket As | 1 |
1743555 (V00) Coupler Gp - Quick
| 17***55 | Coupler Group | 1 |
1760588 (V00) Front Ar - Super Long Reach
| 11***15 | Lock Group-Transport | 1 |
| 11***90 | Cylinder & Lines Group-Stick | 1 |
| 12***21 | Lines Group-Boom; (Boom) | 1 |
1608597 (V00) Special Ar - Super Long Reach Front
| 14***70 | Special Ar-Ditch Cleaning; Special Ar-Super Long Reach Front | 1 |
| 16***97 | Special Ar | 1 |
1761787 (V00) Stick Ar - Forestry
| 17***90 | Lines Group; Lines Gp-Stick | 1 |
| 17***87 | Stick Ar; Stick Ar-Forestry | 1 |
| 17***88 | Stick Group | 1 |
1761788 (V00) Stick Gp - Forestry
| 17***88 | Stick Group | 1 |
Machine Arrangement
1368991 (V00) Conversion Ar
| 13***91 | Conversion Ar | 1 |
| 15***01 | Alternator Group-Charging | 1 |
| 15***03 | Pulley Group-Fan Drive | 1 |
2008079 (V00) Conversion Ar.
| 11***08 | Lines Group-Front | 1 |
| 12***85 | Lines Group-Front | 1 |
| 13***72 | Control & Mtg Group-Auxiliary Flow; Control & Mounting Gp-Electronic | 1 |
1759089 (V00) Forestry Ar - Boom & Stick Only
| 17***89 | Forestry Ar | 1 |
| 17***80 | Boom Ar; Boom Ar-Forestry | 1 |
| 17***87 | Stick Ar; Stick Ar-Forestry | 1 |
1760131 (V02) Forestry Ar
| 13***91 | Conversion Ar | 1 |
| 16***06 | Installation Group-Harvester Head | 1 |
| 16***42 | Hydraulic Ar | 1 |
1782274 (V00) Forestry Ar.
| 13***91 | Conversion Ar | 1 |
| 16***06 | Installation Group-Harvester Head | 1 |
| 16***42 | Hydraulic Ar | 1 |
1997489 (V00) Special Ar
| 11***15 | Lock Group-Transport | 1 |
| 11***90 | Cylinder & Lines Group-Stick | 1 |
| 12***21 | Lines Group-Boom; (Boom) | 1 |
Operator Station
1600405 (V00) Hex Ar-Less Off Cab
| 12***12 | Bonnet; (Rain) | 1 |
| 16***05 | Hex Ar | 1 |
1482246 (V01) Lines Gp-A/C
| 14***46 | Lines Group; (Riser 700mm) | 1 |
1482246 (V00) Lines Gp-A/C
| 14***46 | Lines Group; (Riser 700mm) | 1 |
1482244 (V01) Lines Gp-Heater
| 14***44 | Lines Group; (Riser 700mm) | 1 |
1482244 (V00) Lines Gp-Heater
| 14***44 | Lines Group; (Riser 700mm) | 1 |
1481327 (V03) Riser Ar-Cab (700mm)
| 12***12 | Bonnet; (Rain) | 1 |
| 14***27 | Riser Ar; Riser Ar-Cab | 1 |
| 14***42 | Lines Group; (Riser 700mm) | 1 |
1508146 (V00) Riser Ar - Cab
| 12***59 | Frame Group-Upper | 1 |
| 13***05 | Gear & Bearing Group-Swing | 1 |
| 15***46 | Riser Ar | 1 |
1486272 (V00) Riser Gp-Cab
| 14***72 | Riser Group; (700mm) | 1 |
1486271 (V00) Riser Gp-Cab
| 14***71 | Riser Group; (Proc.) | 1 |
1486272 (V02) Riser Gp-Cab
| 14***72 | Riser Group; (700mm) | 1 |
1486271 (V01) Riser Gp-Cab
| 14***71 | Riser Group; (Proc.) | 1 |
1766710 (V00) Tool Box Gp-Overhead
| 17***10 | Tool Box Group | 1 |
1482243 (V00) Washer Gp-Riser
| 14***43 | Washer Group; (700mm) | 1 |
1482243 (V01) Washer Gp-Riser
| 14***43 | Washer Group; (700mm) | 1 |
Service Equipment And Supplies
1883785 (V00) Lubricant Gp B
| 18***85 | Lubricant Group B | 1 |
Undercarriage
1601516 (V00) Frame Ar - Undercarriage
| 11***42 | Gear & Bearing Group-Swing | 1 |
| 11***19 | Idler Group-Front | 1 |
| 12***18 | Step Group | 1 |
1601517 (V00) Frame As - Undercarriage
| 16***17 | Frame As; Frame As-Undercarriage | 1 |
1766405 (V00) Guard Gp - Track Guide
| 17***05 | Guard Group | 1 |
1605089 (V01) Guard Gp - Track Guide
| 16***89 | Guard Group; Guard Gp-Track Guide | 1 |
1614315 (V03) Link As Track
| 16***15 | Link As Track; (Lubricated Pins) | 1 |
1614315 (V03) Link As - Track
| 09***63 | Pin; (Cotter) | 1 |
| 11***71 | Bushing - Track | 44 |
| 11***72 | Bushing-Track Master | 1 |
1593754 (V00) Ring As
| 15***54 | Ring As | 1 |
1605014 (V01) Roller Ar - Track & Carrier
| 16***14 | Roller Ar; Roller Ar-Track & Carrier | 1 |
1790879 (V00) Track Gp - 500mm Triple Grouser Shoe
| 17***79 | Track Group | 1 |
| 17***80 | Track Group; Track Gp-500mm Tg | 2 |
1919125 (V00) Track Gp (700 Triple)
| 10***45 | Step As | 2 |
| 11***21 | Track Group | 1 |
| 19***25 | Track Group | 1 |
2054567 (V00) Track Gp
| 10***45 | Step As | 2 |
| 19***11 | Track Group; -2-Required | 1 |
| 20***67 | Track Group | 1 |
1613164 (V02) Track Gp - 800 Mm Triple Grouser Shoe
| 16***64 | Track Group | 1 |
1631117 (V00) Track Gp - 600 Mm Triple Grouser Shoe
| 16***17 | Track Group; (Lubricated Pins) | 1 |
2064908 (V00) Track Gp
| 10***15 | Shoe; (Track) | 49 |
| 19***08 | Link As-Track; (Track) | 1 |
| 20***08 | Track Group | 1 |
1580485 (-00) Track Gp
| 15***85 | Track Group | 1 |
4q4356 (V00) Track Gp - 850mm Triple Grouser Shoe
| 13***16 | Track Group; Track Gp-850mm Tg Offset | 1 |
| 13***17 | Track Group; Track Gp-850mm Tg Offset | 1 |
| 4Q***56 | Track Group | 1 |
1600027 (V00) Track Gp
| 16***27 | Track Group | 1 |
| 16***43 | Step As | 2 |
| 9W***58 | Track Group; Track Gp-900mm Tg | 1 |
1613164 (V02) Track Gp
| 12***62 | Shoe; (Track) | 45 |
| 16***64 | Track Group | 1 |
| 16***15 | Link As Track; (Lubricated Pins) | 1 |
1307617 (-00) Track Gp - 850 Mm Triple Grouser Shoe
| 13***17 | Track Group; Track Gp-850mm Tg Offset | 1 |
1631116 (V01) Track Gp - 600 Mm Triple Grouser Shoe
| 16***16 | Track Group | 1 |
1790880 (V00) Track Gp
| 17***80 | Track Group; Track Gp-500mm Tg | 1 |
1307616 (-00) Track Gp-850 Mm Triple Grouser Shoe
| 13***16 | Track Group; Track Gp-850mm Tg Offset | 1 |
1784797 (V00) Track Gp - 500mm Triple Grouser Shoe
| 17***97 | Track Group | 1 |
320B S serial number reference
The PIN/serial plate on a 320B-family excavator is a riveted metal tag on the upper frame, typically front-right near the base of the cab (or on the cab's right-side exterior below the window); the number is also stamped directly into the frame at the same spot so it stays readable if the plate is lost. These are pre-2001 machines, so the plate shows a plain 8-character serial number rather than a full 17-character PIN: read the first 3 letters/digits as the prefix, which identifies the model and configuration block, and the last 5 digits as the sequential unit number within that block.
| Prefix | Identifies | Notes |
|---|---|---|
| 5MS | 320B S (severe-duty, narrow-gauge undercarriage configuration) | Block 5MS00001-UP. Dedicated serial-prefix directories list 5MS under the 320B S heading only, separate from plain 320B, 320B L, 320B LL, 320B LU, and 320B N blocks. Runs the 3116T turbocharged engine (about 128 hp gross, 6.6 L / 402.8 cu in); the base 320B used the earlier 3066 on its own separate prefix blocks. The S designation is a heavier, reinforced narrow-gauge undercarriage (about 2.5 m shipping width) built for severe underfoot/mountainous-terrain work, not a length variant like the L/LL/LN suffixes. |
Frequently asked questions
What engine does the Caterpillar 320B S excavator use?
The 320B S is fitted with the Cat 3116T turbocharged diesel, a mechanically governed inline-six of 6.6 L (402.8 cu in) displacement rated around 95.5 kW (128 hp), controlled by an electronic speed-control actuator rather than a full engine ECM. This differs from the 3066T shared across the rest of the base 320B family. Confirm the exact engine against the machine's own serial and engine plate, since the factory Operation & Maintenance Manual for this range covers several 320B undercarriage configurations in one book.
What is the operating weight of the Caterpillar 320B S excavator?
Operating weight runs about 22.5 t (49,670 lb), heavier than the standard 320B's roughly 20.6 t because of the S configuration's reinforced, narrower-gauge undercarriage frame. Exact weight varies with bucket, counterweight, and attachment selection, so treat this as a class figure rather than a fixed number.
What replaced the Caterpillar 320B S excavator?
The 320B S was part of Cat's 320B family built through the 1990s, alongside 320B L, LL, LN, and N undercarriage variants. Caterpillar's next 320-series generation, the 320C, succeeded the 320B line with updated electronics and cooling. Later 320D, E, F, GC, and Next Gen generations carried the 320 lineage forward with electronic, common-rail, emissions-compliant engines.
What 320B S owners discuss
What engine does the Cat 320B S actually have, and does it matter for parts and service?
Are there known problems with the 3116-family engine that a 320B S owner should watch for?
What hydraulic behavior do owners commonly report on 320B-family excavators?
What undercarriage wear pattern is typical of the 320B S specifically?
Do these machines drift or creep in swing, and is it serious?
What electrical or monitor issues come up on the 320B family?
What should a buyer check on a used 320B S beyond the usual excavator checklist?
Compiled from owner and technician discussions across the industry — experiences vary by serial range and machine history.
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