Caterpillarwork toolgrapple-contractor

Caterpillar G120B

Maintenance schedule, common problems & OEM parts breakdown

The Caterpillar G120B is a Contractors' Grapple work tool, not a self-powered machine. It is a purely mechanical attachment with no engine, no ECM, no hydraulic cylinders, and no undercarriage of its own; it opens and closes using the carrier excavator's own bucket linkage motion and mounts pin-on or through a Cat Pin Grabber coupler without modification. Operating weight is about 1523 kg (3350 lb), with a maximum jaw opening near 2687 mm (105.8 in) measured per SAE J2754 and a two-over-three interlocking tine layout. It is offered in B-Linkage form for roughly 19-23 ton excavators, CB-Linkage form for roughly 24-35 ton excavators, and a C-Linkage variant for larger carriers; exact tonnage for the C-Linkage version is not consistently documented across sources. The G120B sits inside a shared Contractors' Grapple family running from the G107B up through the G185B, all built and lubricated the same way, sized to different excavator classes. Available documentation does not establish a distinct earlier non-B G120 predecessor or a confirmed later successor; dealer listings still carry the G120B in the current Contractors' Grapple lineup.

What differs across the family and linkage variants is size and mounting geometry, not construction: every version uses AR400 steel tines and wear plates, grease-only lubrication at the pivots, and the same no-hydraulics, linkage-driven operating principle, with an optional extreme-duty wear package for higher-abrasion work. There is no separate engine or fluid-system generation split to track, unlike powered attachments. In the used and parts market the G120B matters because it is a high-wear, low-complexity tool: value and service life track pin, bushing, and tine wear rather than engine hours, and steady demand comes from replacement pins, bushings, and wear tines rather than powertrain parts. Its compatibility with a wide range of 19-35 ton class excavators, and interchangeability across pin-on and Pin Grabber setups, keeps it in active service on demolition, scrap handling, and material-sorting jobs well after the excavator it first shipped with has moved on.

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 G120B specifications

Engine

Power source	None. The G120B is a passive mechanical Contractors' Grapple work tool. It has no engine, ECM, or onboard power source and draws no hydraulic circuit of its own — it operates through the carrier excavator's existing bucket linkage.
Emissions tier	Not applicable — no engine fitted.

Weights

Operating weight (all linkage configurations)	1523 kg (3350 lb) — consistent across the B-Linkage, CB-Linkage, and C-Linkage versions of this grapple.
Shipping weight	Not separately published; matches the listed operating weight since the tool ships assembled and unpowered.
Ground pressure	Not applicable — this is a carried work tool, not a ground-bearing machine.

Dimensions

Maximum jaw opening	2687 mm (105.8 in), capacity figure calculated per SAE J2754 for fabricated grapples.
Tine configuration	Two upper-jaw tines over three lower-jaw tines (interlocking two-over-three pattern) for grasping and retention.
Wear plate thickness	About 20 mm (0.8 in).
Inner wrapper thickness	About 16 mm (0.6 in).
Outer wrapper thickness	About 13 mm (0.5 in).
Transport length/width/height	Not published by the factory or dealer listings reviewed; not typically quoted for pin-on grapple attachments of this type.

Performance

Carrier machine class — B-Linkage	19-23 ton excavator class (for example Cat 320/323/325-size carriers).
Carrier machine class — CB-Linkage	24-35 ton excavator class.
Carrier machine class — C-Linkage	Sized for the same general excavator range, matched with 320D/325C/325D-class carriers depending on pin configuration.
Mounting	Pin-on or pin-grabber coupler mounting, usable without modification; replaceable pins let the same grapple be shared across similar-sized carriers.
Gradeability / travel speed / drawbar figures	Not applicable — the grapple has no independent travel or drive system; its performance is governed entirely by the host excavator.

Service capacities (summary)

Fuel tank	Not applicable — no engine.
Hydraulic system	Not applicable — the grapple is mechanically actuated through the carrier's bucket linkage and needs no dedicated hydraulic lines or hoses.
Engine oil	Not applicable — no engine.
Cooling system	Not applicable — no engine.

Values vary by configuration, region, and serial range — confirm against your machine before planning transport or lifts.

G120B fluids & capacities

System	Capacity	Recommended fluid
Grease - pivot pins and bushings	Not applicable - lubricated through grease fittings, no fluid reservoir or fill capacity specified	Cat Multipurpose Grease (MPGM) for general service, -30 to 40 C (-22 to 104 F) ambient range; Cat Extreme Application Grease (XTM) where higher load, higher temperature, or corrosive/wet conditions apply. No separate winter/summer viscosity split is published for this attachment.

Capacities are refill values from factory literature — always fill to the dipstick/sight gauge, not the number.

Caterpillar G120B maintenance schedule

Service interval	Tasks
Every 50 h	No engine-hour service table applies to this passive attachment; the checks below follow typical dealer guidance for pin-on grapples, not a literal factory hour chart. Each shift: grease all jaw and tine pivot pins and bushings with Cat MPGM or XTM grease until purge is visible at the seals. Each shift: walk around the grapple and visually check tine tips and AR400 wear plates for cracks, chips, or excessive rounding. Each shift: check pin keepers, retaining bolts, and coupler lock hardware for looseness or missing fasteners. Weekly (approx. 50 hours): confirm the Pin Grabber or pin-on coupler locks fully and shows no play against the carrier's quick coupler. Weekly (approx. 50 hours): work grease fully through each pivot to purge contaminants picked up during demolition or sorting work.
Every 250 h	Measure pin-to-bushing clearance at the main jaw pivots and tine mounting points against service limits. Inspect the grapple frame, box-section, and gusset welds for surface cracking, especially near the jaw pivot bosses. Check tine mounting hardware and pins for wear grooves or elongation. Confirm AR400 wear plate and tip thickness has not dropped below the minimum usable range.
Every 500 h	Pull and inspect wear bushings at the jaw and tine pivots; replace any showing measurable bore wear before the mating pin starts to gall. Inspect the extreme-duty wear package (if fitted) and rotate or replace inserts showing uneven wear. Torque-check all tine, frame, and coupler mounting hardware. Grease every fitting to full purge and clear grease of any embedded grit or metal fines.
Every 1,000 h	Remove main jaw pivot pins for full inspection; measure pin diameter and bushing bore, and replace any pair outside service tolerance. Inspect structural welds across the full frame and jaw assembly for stress cracking under magnification or dye check if cracking is suspected. Replace tines worn past the usable wear-line; do not weld build-up cracked AR400 tines in the field. Recheck coupler wear plates and lock mechanism for play that could allow the grapple to shift on the linkage.
Every 2,000 h	Replace all main pivot pins and bushings as a matched set rather than spot-replacing individual worn pins. Strip and inspect the full frame and jaw structure for cumulative fatigue cracking, especially at the two-over-three tine root welds. Recoat exposed bare steel to control corrosion after wear-plate or tine replacement. Reassess the coupler interface (pin-on bores or Pin Grabber lugs) for wear that affects fit to the carrier.
Every 4,000 h	Plan a full pivot rebuild covering every jaw and tine pin, bushing, and thrust washer on the attachment. Evaluate the frame and box-section for cumulative wear or repair welds that may warrant retirement of the grapple rather than further rebuild. Replace the wear-tine set and AR400 wear plates as a group once mixed wear states start affecting jaw closure and material retention. Document accumulated carrier hours against the grapple since it carries no onboard hour meter of its own.

Servicing the G120B beyond the schedule

Predictive Maintenance & Pin-Play Monitoring

The G120B has no fluids to sample and no ECM to log faults, so predictive care means tracking mechanical wear by hand. Measure pin-to-bushing clearance at the main jaw and tine pivots on a set interval and log the trend rather than reacting to a single reading. Watch for grease purge color darkening or turning gritty, a sign of bushing bore wear letting contamination in. Rising play at the jaw pivot before a scheduled interval is the earliest warning of a coming bushing or pin replacement.

Corrective & Common Repairs

Most corrective work on a G120B centers on the tines, wear plates, and pivot hardware, not powertrain parts, since it has none. Cracked or rounded AR400 tine tips and worn wear plates get replaced rather than built up with weld in the field. Elongated pin bores at the jaw or tine pivots call for bushing replacement before the pin itself starts to gall. Loose or sheared coupler lock hardware on the pin-on or Pin Grabber interface is a common field fix that restores secure attachment to the carrier.

Overhaul & Rebuild Points

A full G120B overhaul is a structural and pin rebuild, not an engine teardown. Replace main jaw and tine pivot pins and bushings as matched sets once wear approaches service limits, rather than swapping individual components piecemeal. Inspect the box-section frame and tine-root welds for fatigue cracking that accumulates from repeated demolition and sorting cycles. Reassess the coupler wear plates and lock mechanism at the same time, since coupler-side wear affects how securely the whole grapple sits on the carrier's linkage.

Seasonal & Environment Servicing

With no coolant or fuel system, seasonal care for the G120B is mostly about grease and corrosion control. In cold or wet conditions, grease pivot points more frequently to purge water and prevent it from freezing or corroding pin and bushing surfaces. After wear-plate or tine replacement, recoat exposed bare steel promptly, since demolition and scrap-yard environments accelerate rust on unprotected AR400 surfaces. Salt, mud, or standing water around job sites also warrants more frequent inspection of pin keepers and coupler lock hardware for corrosion-driven looseness.

G120B attachments & work tools

Work tool identity

G120B is itself a Cat Contractors' Grapple work tool, not a host machine. It is a passive, mechanically operated attachment (no ECM, no dedicated hydraulic circuit) built for structural demolition and material handling/sorting of rock, scrap, pipe, and debris.

Contractors' Grapple family range

G120B sits in Cat's Contractors' Grapple lineup that spans G107B through G185B, sized from smaller skid/compact-excavator classes up through large excavator classes. G120B occupies a mid-size slot, matched to excavators from the high-teens up to mid-30-ton range depending on which linkage variant is ordered.

Linkage/mounting configurations

G120B is offered in more than one linkage version matched to the host excavator's bucket-link geometry. The B-Linkage version is rated for roughly 19-23 ton excavators and the CB-Linkage version for roughly 24-35 ton excavators; both share the same 2687 mm (105.8 in) jaw opening and about 1523 kg (3350 lb) weight. A separate C-Linkage version is also sold; its exact excavator fitment varies by series and should be confirmed with a dealer before ordering.

Coupler compatibility

The grapple can be pinned directly to the excavator linkage or mounted through a Pin Grabber quick coupler without modification. Replaceable mounting pins let the same grapple body be matched to different linkages, so one unit can be shared across similar-sized excavators.

Hydraulic requirement

No auxiliary hydraulics or hoses are needed. The jaws open and close using the excavator's existing bucket-cylinder linkage motion, so no extra hydraulic kit or plumbing is required on the host machine for this grapple to function.

Wear and guarding options

Standard build uses AR400 steel tips, wrapper plates, and wear strips (wear plate roughly 20 mm/0.8 in thick, wrappers roughly 12-16 mm/0.5-0.6 in) protecting the base structure in abrasive scrap and demolition work. A field-installable extreme-duty wear package is offered as a factory option for heavier-abrasion applications.

Jaw design and capacity rating

Jaws use a two-over-three interlocking tine layout (two tines on the upper jaw, three on the lower) with a slightly curved lower jaw for easier loading, better penetration into debris piles, and unrestricted release when dumping. Rated capacity is calculated per the SAE J2754 standard used across the fabricated-grapple industry.

All G120B assemblies by section

Every catalogued assembly group for the Caterpillar G120B. Open an assembly to preview the parts inside — full OEM part numbers are available in Heavy Parts AI.

Service Equipment And Supplies

285-3642 Plate & Film Gp

15***44	Film-Warning; (Flying Debris)	1
15***35	Film-Warning; (Crush Hazard, Stay Back)	2
15***36	Film-Warning; (Read Operation Manual)	1
28***42	Plate & Film Group	1

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287-0487 Plate & Film Gp

15***44	Film-Warning; (Flying Debris)	1
15***35	Film-Warning; (Crush Hazard, Stay Back)	2
15***36	Film-Warning; (Read Operation Manual)	1
28***87	Plate & Film Group	1

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285-8093 Plate & Film Gp

15***44	Film-Warning; (Flying Debris)	1
15***35	Film-Warning; (Crush Hazard, Stay Back)	2
15***36	Film-Warning; (Read Operation Manual)	1
28***93	Plate & Film Group	1

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287-8239 Plate & Film Gp

28***39

Plate & Film Group

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280-1490 Plate & Film Gp

15***44	Film-Warning; (Flying Debris)	1
15***35	Film-Warning; (Crush Hazard, Stay Back)	2
15***36	Film-Warning; (Read Operation Manual)	1
28***90	Plate & Film Group	1

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286-5619 Plate & Film Gp

15***44	Film-Warning; (Flying Debris)	1
15***35	Film-Warning; (Crush Hazard, Stay Back)	2
15***36	Film-Warning; (Read Operation Manual)	1
28***19	Plate & Film Group	1

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288-3908 Plate & Film Gp

28***08

Plate & Film Group

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287-5798 Plate & Film Gp

15***44	Film-Warning; (Flying Debris)	1
15***35	Film-Warning; (Crush Hazard, Stay Back)	2
15***36	Film-Warning; (Read Operation Manual)	1
28***98	Plate & Film Group	1

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284-7987 Plate & Film Gp

15***44	Film-Warning; (Flying Debris)	1
15***35	Film-Warning; (Crush Hazard, Stay Back)	2
15***36	Film-Warning; (Read Operation Manual)	1
28***87	Plate & Film Group	1

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Work Tool Arrangement

321-6032 Grapple Ar-Demolition

28***04	Pin Group-Grapple; -G130b, D-Linkage	1
32***58	Grapple Group	1
32***32	Grapple Ar-Demolition	1

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283-5790 Grapple Ar-Mechanical -G112b

13***34	Plate-Identification; (Work Tool)	1
28***90	Grapple Ar-Mechanical; -G112b	1
28***91	Grapple Group; -G112b	1
28***92	Pin Group-Grapple; -G112b, 312-Linkage	1

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285-1264 Grapple Ar-Mechanical -G107b

13***34	Plate-Identification; (Work Tool)	1
28***64	Grapple Ar-Mechanical; -G107b	1
28***15	Grapple Group	1
28***50	Pin Group-Grapple; -G107b	1

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275-2401 Grapple Ar-Mechanical -G130b

13***34	Plate-Identification; (Work Tool)	0
27***01	Grapple Ar-Mechanical; -G130b	1
27***04	Grapple Group; -G130b	1
28***12	Pin Group-Grapple; -G130b	1

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283-7308 Grapple Ar-Mechanical -G185b

13***34	Plate-Identification; (Work Tool)	1
28***08	Grapple Ar-Mechanical; -G185b	1
28***10	Pin Group-Grapple; -G185b	1
28***86	Grapple Group; -G185b	1

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275-2403 Grapple Ar-Mechanical -G130b

13***34	Plate-Identification; (Work Tool)	1
27***03	Grapple Ar-Mechanical; -G130b	1
27***04	Grapple Group; -G130b	1
28***13	Pin Group-Grapple; -G130b, Cb-Linkage	1

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282-8316 Grapple Ar-Mechanical -G115b

13***34	Plate-Identification; (Work Tool)	1
28***16	Grapple Ar-Mechanical; -G115b	1
28***17	Grapple Group; -G115b	1
28***21	Pin Group-Grapple; -G115b	1

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279-7306 Grapple Ar-Mechanical -G120b

13***34	Plate-Identification; (Work Tool)	1
27***06	Grapple Ar-Mechanical; -G120b	1
27***22	Grapple Group; -G120b	1
28***56	Pin Group-Grapple; -G120b, G125b, Cb-Linkage	1

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279-7305 Grapple Ar-Mechanical -G120b

13***34	Plate-Identification; (Work Tool)	1
27***05	Grapple Ar-Mechanical; -G120b	1
27***22	Grapple Group; -G120b	1
28***55	Pin Group-Grapple; -G120b, G125b, C-Linkage	1

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279-7307 Grapple Ar-Mechanical -G120b

13***34	Plate-Identification; (Work Tool)	1
27***07	Grapple Ar-Mechanical; -G120b	1
27***22	Grapple Group; -G120b	1
28***57	Pin Group-Grapple; -G120b, G125b, B-Linkage	1

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275-2400 Grapple Ar-Mechanical -G130b

13***34	Plate-Identification; (Work Tool)	1
27***00	Grapple Ar-Mechanical; -G130b	1
27***04	Grapple Group; -G130b	1
28***04	Pin Group-Grapple; -G130b, D-Linkage	1

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283-7307 Grapple Ar-Mechanical -G185b

13***34	Plate-Identification; (Work Tool)	1
28***07	Grapple Ar-Mechanical; -G185b	1
28***09	Pin Group-Grapple; -G185b	1
28***86	Grapple Group; -G185b	1

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279-7361 Grapple Ar-Mechanical -G145b

13***34	Plate-Identification; (Work Tool)	1
27***61	Grapple Ar-Mechanical; -G145b	1
27***77	Grapple Group; -G145b	1
28***49	Pin Group-Grapple; -G145b, F / T-Linkage	1

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275-6074 Grapple Ar-Mechanical -G125b

13***34	Plate-Identification; (Work Tool)	1
27***74	Grapple Ar-Mechanical; -G125b	1
27***75	Grapple Group; -G125b	1
28***57	Pin Group-Grapple; -G120b, G125b, B-Linkage	1

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275-6073 Grapple Ar-Mechanical -G125b

13***34	Plate-Identification; (Work Tool)	1
27***73	Grapple Ar-Mechanical; -G125b	1
27***75	Grapple Group; -G125b	1
28***56	Pin Group-Grapple; -G120b, G125b, Cb-Linkage	1

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275-6072 Grapple Ar-Mechanical -G125b

13***34	Plate-Identification; (Work Tool)	1
27***72	Grapple Ar-Mechanical; -G125b	1
27***75	Grapple Group; -G125b	1
28***55	Pin Group-Grapple; -G120b, G125b, C-Linkage	1

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282-2576 Grapple Ar-Mechanical

13***34	Plate-Identification; (Work Tool)	1
28***76	Grapple Ar-Mechanical	1
28***77	Grapple Group; -G165b	1
28***83	Pin Group-Grapple; -G165b	1

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282-2575 Grapple Ar-Mechanical -G165b

13***34	Plate-Identification; (Work Tool)	1
28***75	Grapple Ar-Mechanical; -G165b	1
28***77	Grapple Group; -G165b	1
28***82	Pin Group-Grapple; -G165b, V-Linkage	1

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275-2402 Grapple Ar-Mechanical -G130b

13***34	Plate-Identification; (Work Tool)	1
27***02	Grapple Ar-Mechanical; -G130b	1
27***04	Grapple Group; -G130b	1
28***11	Pin Group-Grapple; -G130b, C-Linkage	1

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279-7362 Grapple Ar-Mechanical -G145b

13***34	Plate-Identification; (Work Tool)	1
27***62	Grapple Ar-Mechanical; -G145b	1
27***77	Grapple Group; -G145b	1
28***51	Pin Group-Grapple; -G145b	1

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Work Tools

282-8317 Grapple Gp -G115b

09***48	Nipple, Grease	4
12***90	Bearing-Sleeve	2
19***63	Spacer; (16.5x22.2x13-mm Thk)	1
21***83	Pin As	1

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282-2577 Grapple Gp -G165b

09***48	Nipple, Grease	4
11***81	Bearing-Sleeve	2
12***90	Bearing-Sleeve	2
19***63	Spacer; (16.5x22.2x13-mm Thk)	1

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283-5791 Grapple Gp -G112b

09***48	Nipple, Grease	6
14***38	Bearing-Sleeve	4
16***52	Bearing; (180.45-mm Id)	2
19***63	Spacer; (16.5x22.2x13-mm Thk)	1

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279-7377 Grapple Gp -G145b

09***48	Nipple, Grease	6
14***38	Bearing-Sleeve	4
18***58	Bearing; (190.31-mm Od)	2
19***63	Spacer; (16.5x22.2x13-mm Thk)	1

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321-4358 Grapple Gp

27***09	Bushing	2
27***14	Pin	1
27***17	Bushing	2
28***52	Collar	2

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284-5386 Grapple Gp -G185b

08***97	Washer; (13x50x6-mm Thk)	1
09***30	Seal-Lip Type	4
09***74	Bearing-Sleeve	1
09***48	Nipple, Grease	2

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279-7322 Grapple Gp -G120b

09***48	Nipple, Grease	4
10***29	Bearing-Sleeve	2
12***90	Bearing-Sleeve	2
19***63	Spacer; (16.5x22.2x13-mm Thk)	1

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275-6075 Grapple Gp -G125b

09***48	Nipple, Grease	4
10***29	Bearing-Sleeve	2
19***52	Bracket As-Mounting	1
19***60	Pin As	1

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275-2404 Grapple Gp -G130b

09***48	Nipple, Grease	4
19***52	Bracket As-Mounting	1
19***60	Pin As	1
19***63	Spacer; (16.5x22.2x13-mm Thk)	1

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285-3515 Grapple Gp

27***08	Bushing	2
27***13	Pin	1
27***16	Bearing	2
28***52	Collar	2

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282-2582 Pin Gp-Grapple -G165b, V-Linkage

10***78	Pin	1
28***82	Pin Group-Grapple; -G165b, V-Linkage	1
28***22	Bearing	2
28***24	Pin	1

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281-2051 Pin Gp-Grapple -G145b

19***79	Plate	1
21***88	Pin As	1
28***51	Pin Group-Grapple; -G145b	1
28***59	Collar	2

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283-7310 Pin Gp-Grapple -G185b

26***19	Plate As-Wear	2
26***20	Plate As-Wear	3
26***23	Plate-Wear	4
26***24	Plate-Wear	4

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280-9012 Pin Gp-Grapple -G130b

27***16	Bearing	2
27***79	Bearing	2
27***81	Pin	1
28***12	Pin Group-Grapple; -G130b	1

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282-8521 Pin Gp-Grapple -G115b

19***79	Plate	1
28***59	Collar	2
28***21	Pin Group-Grapple; -G115b	1
28***21	Bearing	2

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285-3550 Pin Gp-Grapple -G107b

26***28	Plate As-Wear	3
26***29	Plate-Wear	4
26***30	Plate-Wear	4
26***69	Plate As-Wear	2

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280-9011 Pin Gp-Grapple -G130b, C-Linkage

09***49	Washer; (22x60x6-mm Thk)	1
23***31	Pin As	1
27***11	Bushing	2
27***13	Pin	1

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281-0357 Pin Gp-Grapple -G120b, G125b, B-Linkage

20***71	Washer; (26x90x8-mm Thk)	1
27***83	Collar	2
27***86	Bushing	2
27***87	Pin	1

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283-5792 Pin Gp-Grapple -G112b, 312-Linkage

19***80	Plate	1
19***84	Pin As	1
28***59	Collar	2
28***92	Pin Group-Grapple; -G112b, 312-Linkage	1

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281-0355 Pin Gp-Grapple -G120b, G125b, C-Linkage

27***80	Bushing	2
27***81	Pin	1
27***84	Bushing	2
28***55	Pin Group-Grapple; -G120b, G125b, C-Linkage	1

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280-9013 Pin Gp-Grapple -G130b, Cb-Linkage

09***49	Washer; (22x60x6-mm Thk)	1
23***31	Pin As	1
27***08	Bushing	2
27***82	Pin	1

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282-2583 Pin Gp-Grapple -G165b

08***23	Pin Bkt To Stk Link To Bkt.	1
09***76	Nut; (M14x2-Thd)	2
24***74	Bolt; (M14x2x160-mm)	1
28***83	Pin Group-Grapple; -G165b	1

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283-7309 Pin Gp-Grapple -G185b

04***12	Pin	2
10***34	Pin	1
28***09	Pin Group-Grapple; -G185b	1
28***51	Bearing	2

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281-2049 Pin Gp-Grapple -G145b, F / T-Linkage

19***79	Plate	1
28***49	Pin Group-Grapple; -G145b, F / T-Linkage	1
28***53	Pin As	1
28***58	Bearing	2

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280-9004 Pin Gp-Grapple -G130b, D-Linkage

09***49	Washer; (22x60x6-mm Thk)	1
25***58	Pin As	1
27***10	Bushing	2
27***15	Pin	1

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281-0356 Pin Gp-Grapple -G120b, G125b, Cb-Linkage

27***82	Bushing	2
27***83	Collar	2
27***84	Pin	1
27***85	Bushing	2

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268-9625 Plate Gp-Wear

26***25	Plate Group-Wear	1
26***74	Plate As-Wear	4
26***76	Plate As-Wear	1
26***77	Plate-Wear	4

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298-5689 Plate Gp-Wear

28***32	Plate-Wear	2
28***33	Plate-Wear	2
28***37	Bar, Bolt,Hex Flange Head Cap M8 X 1.25 X 125mm; Special, Bolt,Hex Flange Head Cap M8 X 1.25 X 125mm	2
29***89	Plate Group-Wear	1

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298-5672 Plate Gp-Wear

29***72	Plate Group-Wear	1
29***92	Plate As-Wear	5
29***93	Plate-Wear	2
29***94	Plate-Wear	3

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268-9631 Plate Gp-Wear

26***31	Plate Group-Wear	1
29***66	Plate As-Wear	4
29***69	Plate As-Wear	1
29***70	Plate-Wear	4

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298-5681 Plate Gp-Wear

27***37	Keeper	1
27***78	Keeper	1
27***00	Plate-Wear	2
27***01	Plate-Wear	2

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268-9617 Plate Gp-Wear

26***17	Plate Group-Wear	1
26***34	Plate As-Wear	2
26***65	Plate As-Wear	3
26***66	Plate-Wear	4

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268-9670 Plate Gp-Wear

26***70	Plate Group-Wear	1
28***14	Plate-Wear	4
28***15	Plate-Wear	4
28***16	Plate As-Wear	3

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268-9679 Plate Gp-Wear

26***79	Plate Group-Wear	1
29***75	Plate As-Wear	4
29***78	Plate As-Wear	1
29***79	Plate As-Wear	4

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288-5713 Plate Gp-Wear

28***13	Plate Group-Wear	1
29***84	Plate As-Wear	4
29***85	Plate-Wear	4
29***86	Plate-Wear	4

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285-1266 Tine As

10***29	Bearing-Sleeve	2
27***07	Tine Group; -Lower	1
28***66	Tine As	1

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275-6076 Tine As -Upper

27***76	Tine As; -Upper	1
28***33	Plate-Wear	3
28***41	Plate-Wear	3

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285-1265 Tine As

27***37	Keeper	1
27***74	Plate-Wear	2
27***75	Plate-Wear	2
27***76	Bar	1

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275-6078 Tine Gp

27***78	Tine Group	1
28***18	Plate-Wear	2
28***19	Plate-Wear	2

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275-2406 Tine Gp -Lower

10***29	Bearing-Sleeve	2
27***06	Tine Group; -Lower	1
27***78	Tine Group	1

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275-2407 Tine Gp -Lower

27***07	Tine Group; -Lower	1
27***01	Plate-Wear	2
27***07	Plate-Wear	1
27***08	Plate-Wear	1

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283-5856 Tine Gp

10***29	Bearing-Sleeve	2
27***06	Tine Group; -Lower	1
28***56	Tine Group	1
28***15	Plate-Wear	4

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285-3538 Tine Gp

27***05	Tine Group	1
28***38	Tine Group	1
28***14	Plate-Wear	4
28***16	Plate As-Wear	2

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279-7378 Tine Gp

25***07	Bearing-Sleeve	2
27***78	Tine Group	1
28***56	Tine Group	1

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321-4360 Tine Gp

15***44	Film-Warning; (Flying Debris)	1
15***35	Film-Warning; (Crush Hazard, Stay Back)	2
15***36	Film-Warning; (Read Operation Manual)	1
29***59	Film-Identification; (Cat G130b)	1

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275-2405 Tine Gp

27***05	Tine Group	1
27***75	Plate-Wear	1
27***76	Bar	2
27***82	Plate-Wear	1

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321-4361 Tine Gp -Heavy Duty

15***44	Film-Warning; (Flying Debris)	1
15***35	Film-Warning; (Crush Hazard, Stay Back)	2
15***36	Film-Warning; (Read Operation Manual)	1
29***57	Film-Identification; (Cat G120b)	1

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283-5794 Tine Gp

22***14	Bearing-Sleeve	2
28***94	Tine Group	1
28***66	Tine As	1

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283-5793 Tine Gp

21***21	Keeper	2
28***93	Tine Group	1
28***19	Plate-Wear	2
28***59	Plate-Wear	1

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275-6077 Tine Gp

27***77	Tine Group	1
27***10	Plate-Wear	2
27***11	Plate-Wear	2
28***45	Keeper	1

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G120B serial number reference

The PIN/serial plate for the G120B is riveted to the grapple frame near the top pivot or mounting ears, the same general location used across the G-series Contractors' Grapple line. Read the first 3 characters as the prefix (GCG for G120B) followed by the sequential unit number; the prefix identifies the attachment model/group, not a build plant, since this is a passive work tool with no engine serial number.

Prefix	Identifies	Notes
GCG	G120B Contractors' Grapple, all linkage configurations (B-Linkage, C-Linkage, CB-Linkage)	Machine serial prefix for the G120B grapple group, S/N GCG1-UP. Same prefix spans the B-linkage, C-linkage, and CB-linkage pin-group part listings, so linkage type is a mounting/pin-kit variant rather than a separate serial series. No engine or added hydraulic circuit on this attachment; it runs off the host excavator's bucket linkage. Fits the 320D-325D excavator class depending on linkage.

Frequently asked questions

What excavator size fits the Cat G120B grapple?

It depends on linkage variant. The B-Linkage G120B is sized for roughly 19-23 ton excavators and the CB-Linkage version for roughly 24-35 ton excavators. A C-Linkage version is also offered for larger carriers, though its exact tonnage range is not consistently documented; confirm fit against your specific excavator's linkage class with your dealer.

How much does the Cat G120B grapple weigh?

Operating weight is about 1523 kg (3350 lb). This figure is consistent across the documented linkage variants; treat small differences between B-Linkage, CB-Linkage, and C-Linkage versions as normal configuration variance rather than a separate spec.

What replaced the Cat G120B grapple?

No documented successor exists. The G120B still appears in current Cat Contractors' Grapple dealer listings alongside its family siblings (G107B through G185B), and available sources do not point to a newer model that has replaced it in the lineup.

What G120B owners discuss

Does the G120B have its own hydraulics or is it purely mechanical?

It is purely mechanical. The grapple has no cylinders, hoses, or valves of its own and needs none added. It works off the carrier excavator's existing bucket linkage geometry, so jaw open/close motion tracks the stick and bucket-curl cylinders exactly like a standard bucket would. If the grapple feels sluggish or uneven on opening/closing, look at the carrier's bucket circuit and linkage pins first, not the tool itself.

What wears out first on a G120B in daily use?

Pins, bushings, and the tine/tip wear package take the abuse. Owners running grapples in demolition and scrap sorting report shanks and tips wearing fastest, with pins and bushings needing periodic replacement too. Caterpillar ships the wear tips, wrappers, and wear plates in AR400 steel specifically so the field-replaceable wear parts absorb the abrasion instead of the box structure. Grease the pivot and linkage pins on a daily interval (roughly every shift) with a lithium-complex or calcium-sulfonate EP grease; skipping this accelerates pin and bushing wear noticeably.

Why does the jaw feel loose or sloppy after a season of hard use?

Play at the jaw pivot is almost always worn pins and bushings, sometimes called a wallowed-out pivot. Operators dealing with this on comparable grapples describe drilling out the worn bore, welding it back up, and re-machining rather than just swapping a pin into an oversized hole. On a G120B, check for play by lifting the jaw off the ground and working it by hand at each pin joint; visible movement beyond a light take-up means the pin/bushing set needs replacing. Have your dealer verify pin and bushing wear limits before returning the tool to service.

Can I run a B-linkage G120B on a bigger or smaller excavator than it was set up for?

Not without matching the linkage. The G120B ships in distinct B, C, and CB linkage variants specifically because bucket-linkage geometry and pin spread differ by carrier size and by OEM, and there's no universal standard for pin spread across manufacturers. Mounting a grapple built for one linkage class on a mismatched carrier stresses pins, ears, and the coupler beyond design intent. A pin-grabber coupler adds flexibility since it can pick up attachments across a range of pin spreads within its own spec, but the grapple's own linkage class still needs to match the carrier's kinematics for the jaw to open and close through its full intended range.

Where should I look for cracks before buying a used G120B?

Focus on weld seams around the jaw pivots and the top/back radius of the box structure where stress concentrates near pin bores; these are the classic hiding spots for fatigue cracks on any pin-linkage attachment. Wipe grease and mud off the pivot areas so hairline cracks aren't hidden by buildup. Also check for elongated or egg-shaped pin bores, weld repairs that look recent or rough, and mismatched pins (wrong diameter or length) that suggest a prior repair cut corners. Any crack near a pivot weld should be evaluated by a qualified welder or your dealer before the tool goes back to work, since a failure here can drop the load or the jaw itself.

What should I check when buying a used G120B?

Work through it like any pin-linkage attachment: confirm the linkage class (B, C, or CB) actually matches the carrier you intend to run it on, since the three aren't interchangeable. Lift the jaw and work each pivot by hand feeling for play that indicates worn pins/bushings. Inspect the AR400 tips, wrappers, and wear plates for remaining material versus base metal showing through — thin or gouged wear plates mean the wear package is due. Look closely at welds around the jaw pivots and box structure for cracks or prior repairs. Verify the coupler interface (pin-on ears or pin-grabber pockets) is not worn oversize, and pull maintenance/greasing records if available since grapples greased on a shift-by-shift schedule hold up noticeably better than ones run dry. Have your dealer verify pin, bushing, and weld condition before the tool returns to service.

How much does grapple wear-and-tear maintenance typically cost compared to a standard bucket?

More than a bucket, by owner accounts. Grapples see heavier cycling on more pin/bushing joints than a fixed bucket, plus a jaw wear package that a bucket doesn't have, so the recurring cost of pins, bushings, and wear tips runs higher over the life of the tool. Budgeting for scheduled pin/bushing swaps and periodic wear-package replacement, rather than waiting for visible failure, is the pattern experienced operators describe for keeping a demolition/sorting grapple like the G120B productive.

Compiled from owner and technician discussions across the industry — experiences vary by serial range and machine history.

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