Caterpillarwork toolcold planer

Caterpillar PC204

Maintenance schedule, common problems & OEM parts breakdown

The Caterpillar PC204 is a standard-flow cold planer, a hydraulically driven work-tool attachment used to mill asphalt and light concrete rather than a self-propelled machine. It carries a 450 mm (18 in) wide cutting drum, weighs about 690 kg (1,521 lb), and measures roughly 1180 x 1720 x 840 mm (46 x 68 x 33 in). It has no engine, no ECM, and no undercarriage of its own: a gerotor motor mounted directly on the drum draws hydraulic power from the host carrier's standard-flow auxiliary circuit, rated 55-100 L/min at 160-240 bar (14-26 gal/min at 2,320-3,480 psi). It mounts through Cat's mechanical/hydraulic quick-coupler interface onto skid steer, multi-terrain, and compact wheel loaders, and the drum oscillates up to ±16 degrees for angled cuts. The PC204 sits in the middle of the legacy standard-flow/high-flow cold planer line-up: the PC203 (350 mm/14 in) is the smaller standard-flow sibling, while the PC205, PC206, and PC210 are wider high-flow versions built for larger carriers. No PC204B or later-lettered version was released; Caterpillar's current cold-planer catalog uses a renumbered PC1xx/PC3xx/PC4xx line that occupies a similar market slot today.

Across the PC203-PC210 family the main split is standard-flow versus high-flow: the PC203/PC204 run on skid-steer-class hydraulic circuits with mechanical depth control, while the PC205/PC206/PC210 need higher-flow carriers and wider drums for bigger milling jobs. Caterpillar has since retired this numbering in favor of the current PC1xx-PC4xx line, so the PC204 no longer appears in active Specalog literature, but it remains a common find in the used-attachment and parts market. Its appeal is practical: it is an inexpensive way to add milling capability to an older skid steer, track loader, or wheel loader, its hydraulic-only drivetrain has far fewer failure points than a self-propelled planer, and the gerotor motor, bearings, bits, and coupler wear parts are simple, commodity-style items that stay available well after the attachment itself has left the new-equipment lineup.

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 PC204 specifications

Engine

Power source	No onboard engine. Passive work tool driven entirely by the carrier machine's auxiliary hydraulic circuit through a direct-drive gerotor motor on the drum.
Drive type	Gerotor motor, direct drive to cutting drum
Required carrier hydraulic flow	55-100 L/min (14-26 gpm), standard-flow circuit
Required carrier hydraulic pressure	160-240 bar (2,320-3,480 psi)
Emissions tier	Not applicable — no engine or ECM on the tool itself

Weights

Tool weight	690 kg (1,521 lb)
Ground pressure	Not published — not applicable to a carrier-mounted work tool

Dimensions

Overall length	1180 mm (46 in)
Overall width	1720 mm (68 in)
Overall height	840 mm (33 in)
Maximum drum (cutting) width	450 mm (18 in)
Ground clearance	Not published for this work tool

Performance

Carrier compatibility	Sized for standard-flow Cat skid steer and multi-terrain loaders; utility milling duty
Maximum depth of cut	150 mm (6 in)
Drum speed at max flow	202 rpm
Drum torque at max pressure	1250 N·m
Tilt (oscillation) angle range	±16 degrees, for angled cuts
Hydraulic sideshift travel	650 mm (26 in), for close planing along curbs and walls
Travel/propulsion speed	Not applicable — tool has no self-propulsion; ground speed is set by the carrier

Service capacities (summary)

Fuel tank	Not applicable — no independent fuel system
Hydraulic system	No dedicated reservoir; runs off the carrier's hydraulic oil supply at 55-100 L/min, 160-240 bar
Engine oil	Not applicable — no engine
Cooling system	Not applicable — no engine; heat is managed through the carrier's hydraulic cooling circuit

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

PC204 fluids & capacities

System	Capacity	Recommended fluid
Engine crankcase (with filter)	Not applicable	PC204 carries no engine of its own. It is a carrier-mounted cold planer work tool driven off the host skid steer/CTL/wheel loader's hydraulic system, so there is no engine oil to check or change on the attachment.
Cooling system	Not applicable	No coolant system exists on the attachment. With no onboard engine there is nothing to cool independently of the carrier machine.
Fuel tank	Not applicable	No fuel tank. The cold planer has no combustion engine or fuel system of its own.
Transmission / drum drive	No gear case or oil reservoir on the attachment	The cutting drum is turned directly by a uni-directional gerotor-style hydraulic motor in direct drive, not through a gearbox. With no gear case, there is no drive-train oil fill or drain point on the PC204 itself.
Final drives	Not applicable	No final drive units. Drum torque comes straight from the direct-drive hydraulic motor.
Hydraulic system and tank	No dedicated reservoir on the attachment; runs on the carrier's standard-flow circuit, roughly 55-100 L/min (14-26 US gal/min) at 160-240 bar (2320-3480 psi)	PC204 has no hydraulic tank of its own. Supply and return run through the host loader's hydraulic system, so oil type, viscosity grade, and refill capacity follow that carrier machine's own operation and maintenance manual rather than a chart specific to this attachment.
Axles / differentials	Not applicable	No axle or differential assemblies on this attachment.
Grease (spec only)	Spec only - no fill volume published for drum-end bearings, depth-skid pivots, side-shift wear points, and cylinder pins	Routine greasing of the drum bearings and moving pivot/wear points is called out on the maintenance interval schedule. A general-purpose Cat lithium-complex multipurpose grease, chosen for the ambient temperature range, is the typical fit for this class of work tool, but no dedicated grease-brand callout specific to the PC204 could be confirmed in available documentation - verify the current spec with your dealer.

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

Caterpillar PC204 maintenance schedule

Service interval	Tasks
Every 10 h	Inspect conical bits for wear, breakage, and free rotation before starting work; grinding dust can seize a bit within a single shift. Check skid shoes and depth-control plates for wear and secure mounting. Inspect hydraulic hoses, quick-couplers, and fittings for leaks, abrasion, or loose connections at the coupler frame. Confirm coupler mounting pins and locks are fully engaged and free of play before lifting a load. Grease depth-control cylinder pin ends and control-shaft pivots on the weekly cycle. Inspect the drum frame and side-shift wear plates for cracks or excess clearance.
Every 250 h	Grease drum bearing points and the gerotor drive motor coupling per the standard work-tool lube chart. Inspect the drum drive motor shaft seal for leakage. Check bit-holder wear and replace holders showing loose bits or rounded retaining pins. Inspect hydraulic hose assemblies fully for chafing against the frame and re-route or re-clamp as needed. Torque-check coupler mounting bolts and wear-plate fasteners.
Every 500 h	Replace bits worn past the carbide wear line even if not yet broken. Inspect drum bearing seals and repack if the grease purge shows contamination. Check oscillation-frame bushings and pivot pins for play. Inspect quick-coupler wear plates and hooks for wear and shim or adjust as needed.
Every 1,000 h	Remove and inspect drum bearing assemblies for pitting or play; replace if out of tolerance. Inspect the gerotor drive motor for internal wear; check output speed against the 202 rpm baseline if a flow meter is available. Inspect drum shaft splines and keys for wear. Replace hydraulic hoses showing age-cracking regardless of visible leakage.
Every 2,000 h	Rebuild or replace the drum drive motor if a flow/pressure test shows output below the 55-100 L/min, 160-240 bar design range. Replace drum bearings and seals as a set. Inspect and recondition or replace the drum shell and tool-holder pockets if wear approaches the base weldment. Inspect the coupler frame weldment for cracks at the pivot lugs.
Every 3,000 h	Perform a full teardown inspection of the drum, bearings, drive motor, and coupler frame at major overhaul. Replace all wear bushings and pins as a set rather than individually. Recondition or replace the drum shell assembly if base metal is exposed. Verify frame squareness and coupler alignment before returning the attachment to service.

Servicing the PC204 beyond the schedule

Predictive Maintenance & Fluid Analysis

The PC204 has no engine oil or coolant to sample; predictive care centers on the carrier's hydraulic fluid. Track oil-cleanliness or particle-count results from the host's standard-flow circuit (55-100 L/min, 160-240 bar) feeding the drum's gerotor motor, since contaminated oil wears the motor and drum bearings long before bits show damage. Watch drum speed and cutting rate for gradual drop-off against the roughly 202 rpm baseline; a slowing drum under normal carrier flow signals internal motor leakage before it fails outright.

Corrective & Common Repairs

The most common PC204 repairs are bit and bit-holder replacement, since worn conical bits are the first failure point on any milling job, followed by skid-shoe and depth-plate wear from constant ground contact. Hydraulic hose and quick-coupler leaks are the next most frequent complaint, usually traced to chafing where hoses route across the coupler frame rather than to the gerotor motor itself. Drum bearing failure is rarer but shows up as radial play or discolored grease purge, and calls for bearing and seal replacement before the shaft or housing is damaged.

Overhaul & Rebuild Points

Overhaul on a PC204 centers on the drum assembly and its direct-drive gerotor motor rather than a powertrain teardown. Rebuild points include the drum bearings and shaft seals, the motor's internal gerotor set once flow/pressure testing shows output below the 55-100 L/min, 160-240 bar design range, and the tool-holder pockets once repeated bit changes have opened the retaining bores. The oscillation-frame pivots and coupler-mounting lugs are the other wear points worth checking at a full rebuild, since play there affects cut quality as much as drum condition.

Seasonal & Environment Servicing

Because the PC204 carries no coolant or crankcase, seasonal prep is mostly about the abrasive environment it works in. Wash accumulated asphalt or concrete slurry off the drum, bearings, and coupler pins after each job so grinding paste doesn't work into the seals. Before cold-weather storage, verify hydraulic couplers and quick-disconnects are capped and dry to prevent moisture freeze-lock, and grease all exposed cylinder pins and control shafts so they don't seize between paving seasons.

PC204 attachments & work tools

Model identity and class

PC204 is a cold planer (asphalt/concrete milling) work tool for skid steer loaders, compact track loaders, compact wheel loaders, and backhoe loaders, not a machine that itself takes attachments. It carries a 450 mm (18 in) working width drum and sits in the standard-flow segment of the legacy PC203/PC204/PC205/PC206/PC210 cold planer lineup, alongside the 350 mm (14 in) PC203 and larger high-flow PC205/PC206/PC210 siblings.

Hydraulic requirement

Runs on the carrier's standard auxiliary hydraulic circuit rather than a high-flow package. Reported flow and pressure figures vary by source and by which generation of spec sheet is cited, with flow in roughly the 55-100 L/min (14-26 gpm) range and pressure around 160-280 bar depending on configuration; confirm the exact window against the specific carrier's auxiliary circuit rating before sizing.

Mounting and coupler system

Mounts via the carrier's integrated mechanical and hydraulic quick-coupler interface used across the skid steer/compact track loader/compact wheel loader work-tool range, allowing tool changes without separate brackets. Backhoe loader applications use the same coupler family scaled to that machine class.

Bit and drum options

Ships with all-purpose conical bits as the standard cutting configuration. Optional bit types for the family include concrete bits, heavy-duty concrete bits, and heavy-duty asphalt bits, with the tools needed to swap bit sets supplied with the unit.

Depth and leveling control

Uses a self-leveling drum frame that settles flat on the ground regardless of coupler orientation, with independent left/right depth control handled mechanically through adjustable, wear-resistant skid shoes on this standard-flow class (hydraulic independent depth control is reserved for the larger high-flow models in the range).

Tilt and side-shift

Spring-controlled tilt allows angled cuts on standard-flow planers in this class (hydraulic tilt is limited to high-flow models), and hydraulic side-shift lets the drum plane close to curbs, walls, and other obstructions.

Dust suppression / water kit

An optional water-sprinkler kit for dust suppression during dry cutting is offered across the cold-planer work-tool line for this size class; verify current kit availability and tank capacity for this specific model with the dealer, since integrated-tank capacity is documented mainly for the larger current-generation planers.

Guarding and operator aids

Wear-resistant skid plates and side frame plates shield the drum housing and carry cutting loads, while a cut-mark indicator and drum-center indicator on the housing help the operator and a ground assistant judge cut position without added guarding hardware.

Lineage note

Cat has since renumbered its skid steer/CTL/CWL cold planer range (current lineup runs PC104, PC105, PC305/306/310, PC406/408/412); the PC204's 18 in standard-flow specification is closest to the current PC105 slot, but treat the PC204 as the legacy-family model and do not substitute current-generation PC105 figures for it without a source tying them together.

All PC204 assemblies by section

Every catalogued assembly group for the Caterpillar PC204. Open an assembly to preview the parts inside — full OEM part numbers are available in Heavy Parts AI.

Frame And Body

219-5450 Frame Ar

21***10	Frame Group-Cold Planer; -Rear	1
21***15	Control Group-Cold Planer	1
21***20	Drum Group-Cold Planer	1
21***25	Drive Group-Cold Planer	1

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224-7394 Frame Ar

22***60	Drum Group-Cold Planer	1
22***61	Control Group-Cold Planer	1
22***62	Frame Group-Cold Planer; -Rear	1
22***63	Drive Group-Cold Planer	1

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224-7388 Frame Ar

22***82	Frame Group-Cold Planer; -Rear	1
22***83	Control Group-Cold Planer	1
22***84	Drum Group-Cold Planer	1
22***86	Drive Group-Cold Planer	1

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224-7393 Frame Ar

22***67	Drive Group-Cold Planer	1
22***68	Control Group-Cold Planer	1
22***69	Frame Group-Cold Planer; -Front	1
22***33	Adjustment Group-Depth	1

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224-7365 Frame Ar

22***67	Drive Group-Cold Planer	1
22***68	Control Group-Cold Planer	1
22***69	Frame Group-Cold Planer; -Front	1
22***33	Adjustment Group-Depth	1

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220-4769 Frame Gp-Cold Planer -Front

09***70	Bolt-Socket Hd; (M12 X 1.75 X 45)	6
09***16	Ring-Retaining	2
21***03	Plate	2
22***69	Frame Group-Cold Planer; -Front	1

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219-5410 Frame Gp-Cold Planer -Rear

21***90	Frame As	1
21***94	Plate-Guide	4
21***95	Plate-Clamp	2
21***96	Plate-Spacer	2

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219-5430 Frame Gp-Cold Planer -Front

09***70	Bolt-Socket Hd; (M12 X 1.75 X 45)	6
17***11	Locknut; (M16x2-Thd)	10
21***85	Frame As	1
21***86	Cover	1

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224-7387 Frame Gp-Cold Planer -Front

09***70	Bolt-Socket Hd; (M12 X 1.75 X 45)	6
09***16	Ring-Retaining	2
21***03	Plate	2
21***14	Plate-Indicator	1

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224-7364 Frame Gp-Cold Planer -Front

09***70	Bolt-Socket Hd; (M12 X 1.75 X 45)	6
09***16	Ring-Retaining	2
21***03	Plate	2
21***14	Plate-Indicator	1

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224-7362 Frame Gp-Cold Planer -Rear

21***90	Frame As	1
21***16	Spacer; (21x65x5-mm Thk)	2
22***15	Plate-Guide	4
22***16	Plate-Clamp	2

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224-7382 Frame Gp-Cold Planer -Rear

21***90	Frame As	1
21***16	Spacer; (21x65x5-mm Thk)	2
22***19	Plate-Clamp	1
22***70	Plate-Guide	4

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232-2327 Spring & Mtg Gp-Leveler -Mounting

23***64	Spring Group-Leveler	1
23***27	Spring & Mtg Group-Leveler; -Mounting	1
6V***06	Fitting-Grease	2
6V***54	Ring; (Retaining)	2

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Hydraulic System

219-5433 Cylinder & Mtg Gp-Cold Planer -Depth

21***21	Cylinder Group-Hydraulic	2
21***23	Pin	3
21***24	Bushing	6
21***26	Pin	1

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219-5432 Cylinder & Mtg Gp-Cold Planer

21***18	Cylinder Group-Hydraulic; -Rotate	1
21***32	Cylinder & Mtg Group-Cold Planer	1
6V***54	Ring; (Retaining)	2

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219-5434 Cylinder & Mtg Gp-Cold Planer -Sideshift

21***91	Locknut	2
21***29	Cylinder Group-Hydraulic; -Sideshift	1
21***34	Cylinder & Mtg Group-Cold Planer; -Sideshift	1

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224-7401 Cylinder & Mtg Gp-Cold Planer -Rotate

21***18	Cylinder Group-Hydraulic; -Rotate	1
22***01	Cylinder & Mtg Group-Cold Planer; -Rotate	1
6V***54	Ring; (Retaining)	2

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230-6433 Cylinder & Mtg Gp-Cold Planer -Sideshift

21***91	Locknut	2
23***51	Cylinder Group-Hydraulic; -Sideshift	1
23***33	Cylinder & Mtg Group-Cold Planer; -Sideshift	1

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224-7402 Cylinder & Mtg Gp-Cold Planer -Depth

21***21	Cylinder Group-Hydraulic	2
21***23	Pin	2
21***24	Bushing	4
21***26	Pin	2

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224-7403 Cylinder & Mtg Gp-Cold Planer -Sideshift

21***91	Locknut	2
22***03	Cylinder & Mtg Group-Cold Planer; -Sideshift	1
23***51	Cylinder Group-Hydraulic; -Sideshift	1

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219-5429 Cylinder Gp-Hydraulic -Sideshift

21***29	Cylinder Group-Hydraulic; -Sideshift	1
21***31	Kit-Seal	1

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230-6051 Cylinder Gp-Hydraulic -Sideshift

21***31	Kit-Seal	1
23***51	Cylinder Group-Hydraulic; -Sideshift	1

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219-5421 Cylinder Gp-Hydraulic

21***19	Kit-Seal	1
21***21	Cylinder Group-Hydraulic	1

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219-5418 Cylinder Gp-Hydraulic -Rotate

21***18	Cylinder Group-Hydraulic; -Rotate	1
21***19	Kit-Seal	1

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248-3076 Hydraulic Ar

21***32	Cylinder & Mtg Group-Cold Planer	1
21***33	Cylinder & Mtg Group-Cold Planer; -Depth	1
21***34	Cylinder & Mtg Group-Cold Planer; -Sideshift	1
22***34	Manifold Group-Control	1

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224-7409 Hydraulic Ar

22***01	Cylinder & Mtg Group-Cold Planer; -Rotate	1
22***02	Cylinder & Mtg Group-Cold Planer; -Depth	1
22***09	Hydraulic Ar	1
22***34	Manifold Group-Control	1

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248-6490 Hydraulic Ar

22***01	Cylinder & Mtg Group-Cold Planer; -Rotate	1
22***02	Cylinder & Mtg Group-Cold Planer; -Depth	1
22***34	Manifold Group-Control	1
22***17	Valve Group-Check	1

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224-7366 Hydraulic Ar

22***66	Hydraulic Ar	1
22***01	Cylinder & Mtg Group-Cold Planer; -Rotate	1
22***02	Cylinder & Mtg Group-Cold Planer; -Depth	1
22***34	Manifold Group-Control	1

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249-0580 Hydraulic Ar

22***01	Cylinder & Mtg Group-Cold Planer; -Rotate	1
22***02	Cylinder & Mtg Group-Cold Planer; -Depth	1
22***34	Manifold Group-Control	1
22***17	Valve Group-Check	1

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224-7392 Hydraulic Ar

19***12	Seal-O-Ring	2
22***66	Manifold Group-Control	1
22***92	Hydraulic Ar	1
22***03	Cylinder & Mtg Group-Cold Planer; -Sideshift	1

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219-5455 Hydraulic Ar

21***32	Cylinder & Mtg Group-Cold Planer	1
21***33	Cylinder & Mtg Group-Cold Planer; -Depth	1
21***34	Cylinder & Mtg Group-Cold Planer; -Sideshift	1
21***55	Hydraulic Ar	1

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231-4185 Lines Gp-Connecting

13***98	Connector	1
14***18	Connector As	2
14***27	Connector Group	4
15***94	Coupler As-Quick Disconnect; (Female)(Quick Disconnect)	1

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231-4242 Lines Gp-Connecting

14***15	Connector As	4
15***94	Coupler As-Quick Disconnect; (Female)(Quick Disconnect)	1
15***95	Fitting As; (Quick Disconnect, Male)	1
23***41	Hose As	2

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249-0581 Lines Gp-Connecting

13***98	Connector	1
14***48	Fitting As; (Quick Disconnect, Male)	1
14***49	Fitting As; (Quick Disconnect, Female)	1
14***18	Connector As	2

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231-6146 Lines Gp-Connecting

14***18	Connector As	2
14***27	Connector Group	4
15***94	Coupler As-Quick Disconnect; (Female)(Quick Disconnect)	1
15***95	Fitting As; (Quick Disconnect, Male)	1

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248-6491 Lines Gp-Connecting

14***48	Fitting As; (Quick Disconnect, Male)	1
14***49	Fitting As; (Quick Disconnect, Female)	1
14***18	Connector As	2
14***25	Connector As.	2

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231-9853 Lines Gp-Connecting

14***18	Connector As	1
14***27	Connector Group	4
15***94	Coupler As-Quick Disconnect; (Female)(Quick Disconnect)	1
15***95	Fitting As; (Quick Disconnect, Male)	1

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248-3077 Lines Gp-Connecting

14***48	Fitting As; (Quick Disconnect, Male)	1
14***49	Fitting As; (Quick Disconnect, Female)	1
14***18	Connector As	2
14***25	Connector As.	2

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231-4378 Lines Gp-Cylinder

14***18	Connector As	2
23***78	Lines Group-Cylinder	1
23***79	Hose As	1
23***74	Hose As	1

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231-5255 Lines Gp-Cylinder

14***18	Connector As	2
23***52	Hose As	1
23***53	Hose As	1
23***55	Lines Group-Cylinder	1

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231-9855 Lines Gp-Cylinder

11***60	Strap	2
14***18	Connector As	7
14***74	Elbow As	1
23***73	Hose As	2

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231-9854 Lines Gp-Motor

12***86	Flange-Split	4
14***27	Connector Group	2
23***71	Hose As	2
23***54	Lines Group-Motor	1

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231-5221 Lines Gp-Motor

09***19	Connector	2
13***98	Connector	2
14***27	Connector Group	2
14***70	Elbow, 90°,-8 Orb Swiv. /-8 Orfs	1

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231-4018 Lines Gp-Motor

14***15	Connector As	2
14***41	Connector Group	2
23***17	Hose As	2
23***18	Lines Group-Motor	1

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231-4186 Lines Gp-Motor

09***19	Connector	2
14***18	Connector As	1
14***27	Connector Group	2
16***76	Adapter As	1

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220-4766 Manifold Gp-Control

22***66	Manifold Group-Control	1
22***20	Valve As	2
23***95	Connector	2
23***77	Manifold	1

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227-7034 Manifold Gp-Control

22***20	Valve As	4
22***34	Manifold Group-Control	1
22***98	Valve Group-Solenoid	3
23***32	Bolt-Socket Head	4

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227-7036 Motor Gp-Gerotor -Basic

22***14	Screw	6
22***36	Motor Group-Gerotor; -Basic	1
25***28	Kit-Seal; (Conveyor Motor)	1

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224-7398 Motor Gp-Piston

11***70	Bearing Assembly	1
1T***68	Seal-O-Ring; (Fuel Injection Pump)	1
22***98	Motor Group-Piston	1
22***07	Stud	10

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224-7399 Motor Gp-Piston

22***91	Kit-Seal	1
22***99	Motor Group-Piston	1
22***06	Stud	6
22***07	Nut-Flange	6

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227-9398 Valve Gp-Solenoid

21***13	Seal-O-Ring	1
21***14	Seal-O-Ring	1
21***73	Cartridge As-Valve	1
21***74	Seal & Retainer As	1

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Service Equipment And Supplies

232-2453 Film Gp

12***56	Film; (Warning) (No Step) (On Top Of Hood Behind Cab On Each Side) (On Each Fender Flare)	1
15***62	Film-Information; (Tie-Down Location)	2
15***35	Film-Warning; (Crush Hazard, Stay Back)	2
15***36	Film-Warning; (Read Operation Manual)	1

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232-3554 Film Gp

12***56	Film; (Warning) (No Step) (On Top Of Hood Behind Cab On Each Side) (On Each Fender Flare)	1
15***62	Film-Information; (Tie-Down Location)	2
15***35	Film-Warning; (Crush Hazard, Stay Back)	2
15***36	Film-Warning; (Read Operation Manual)	1

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232-3553 Film Gp

12***56	Film; (Warning) (No Step) (On Top Of Hood Behind Cab On Each Side) (On Each Fender Flare)	1
15***62	Film-Information; (Tie-Down Location)	2
15***35	Film-Warning; (Crush Hazard, Stay Back)	2
15***36	Film-Warning; (Read Operation Manual)	1

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232-3552 Film Gp

12***56	Film; (Warning) (No Step) (On Top Of Hood Behind Cab On Each Side) (On Each Fender Flare)	1
15***62	Film-Information; (Tie-Down Location)	2
15***35	Film-Warning; (Crush Hazard, Stay Back)	2
15***36	Film-Warning; (Read Operation Manual)	1

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232-3555 Film Gp

12***56	Film; (Warning) (No Step) (On Top Of Hood Behind Cab On Each Side) (On Each Fender Flare)	1
15***62	Film-Information; (Tie-Down Location)	2
15***35	Film-Warning; (Crush Hazard, Stay Back)	2
15***36	Film-Warning; (Read Operation Manual)	1

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Work Tool Arrangement

224-7390 Cold Planer Ar

15***70	Kit-Connecting Plug; (2-Pin)(Engine Sensor Wiring Harness)	6
22***88	Frame Ar	1
22***90	Cold Planer Ar	1
22***09	Hydraulic Ar	1

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224-7397 Cold Planer Ar

15***70	Kit-Connecting Plug; (2-Pin)(Engine Sensor Wiring Harness)	6
22***66	Hydraulic Ar	1
22***94	Frame Ar	1
22***97	Cold Planer Ar	1

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246-7313 Cold Planer Ar

15***70	Kit-Connecting Plug; (2-Pin)(Engine Sensor Wiring Harness)	13
21***50	Frame Ar	1
22***14	Harness As-Work Tool; (Power)	1
23***55	Film Group	1

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224-7396 Cold Planer Ar

22***92	Hydraulic Ar	1
22***93	Frame Ar	1
22***96	Cold Planer Ar	1
23***52	Film Group	1

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224-7395 Cold Planer Ar

22***65	Frame Ar	1
22***92	Hydraulic Ar	1
22***95	Cold Planer Ar	1
23***53	Film Group	1

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219-5400 Cold Planer Ar

15***70	Kit-Connecting Plug; (2-Pin)(Engine Sensor Wiring Harness)	6
21***00	Cold Planer Ar	1
21***50	Frame Ar	1
21***55	Hydraulic Ar	1

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246-7314 Cold Planer Ar

15***70	Kit-Connecting Plug; (2-Pin)(Engine Sensor Wiring Harness)	13
22***88	Frame Ar	1
22***14	Harness As-Work Tool; (Power)	1
23***53	Film Group	1

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246-7315 Cold Planer Ar

15***70	Kit-Connecting Plug; (2-Pin)(Engine Sensor Wiring Harness)	13
22***94	Frame Ar	1
22***14	Harness As-Work Tool; (Power)	1
23***54	Film Group	1

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Work Tools

224-7333 Adjustment Gp-Depth

09***91	Pin - Spring	2
21***23	Pin	2
21***24	Bushing	4
22***33	Adjustment Group-Depth	1

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224-7383 Control Gp-Cold Planer

13***45	Spacer; (50.8x60x4.8-mm Thk)	4
21***11	Plate-Indicator	1
21***12	Plate-Indicator	1
21***38	Bearing	6

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219-5415 Control Gp-Cold Planer

13***45	Spacer; (50.8x60x4.8-mm Thk)	4
21***99	Pin As; (Lh)	1
21***04	Plate	2
21***09	Pin As; (Rh)	1

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220-4768 Control Gp-Cold Planer

13***45	Spacer; (50.8x60x4.8-mm Thk)	4
21***38	Bearing	6
21***41	Ring-Retainer	2
22***68	Control Group-Cold Planer	1

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224-7361 Control Gp-Cold Planer

13***45	Spacer; (50.8x60x4.8-mm Thk)	4
21***11	Plate-Indicator	1
21***12	Plate-Indicator	1
21***38	Bearing	6

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224-7386 Drive Gp-Cold Planer

22***86	Drive Group-Cold Planer	1
22***99	Motor Group-Piston	1
7X***53	Bolt-Plt; (M16 X 2.0 X 40)	10
9X***57	Washer-Pipe As To Main Pump Suction Port	10

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224-7363 Drive Gp-Cold Planer

22***63	Drive Group-Cold Planer	1
22***98	Motor Group-Piston	1
7X***53	Bolt-Plt; (M16 X 2.0 X 40)	10
9X***57	Washer-Pipe As To Main Pump Suction Port	10

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219-5425 Drive Gp-Cold Planer

1T***68	Seal-O-Ring; (Fuel Injection Pump)	1
21***07	Motor Group-Piston	2
21***08	Plate-Drive	1
21***25	Drive Group-Cold Planer	1

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220-4767 Drive Gp-Cold Planer

22***67	Drive Group-Cold Planer	1
22***08	Nut; (M14x1.5-Thd)	10
22***36	Motor Group-Gerotor; -Basic	1
23***20	Hub Group-Drive	1

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231-2573 Drum Gp-Cold Planer

21***06	Bit As-Cutter; (Standard)	24
22***08	Holder-Bit	24
23***73	Drum Group-Cold Planer	1

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231-2577 Drum Gp-Cold Planer

21***06	Bit As-Cutter; (Standard)	42
22***08	Holder-Bit	42
23***77	Drum Group-Cold Planer	1

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231-2586 Drum Gp-Cold Planer

21***06	Bit As-Cutter; (Standard)	48
22***08	Holder-Bit	48
23***86	Drum Group-Cold Planer	1

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231-2584 Drum Gp-Cold Planer

21***06	Bit As-Cutter; (Standard)	42
22***08	Holder-Bit	42
23***84	Drum Group-Cold Planer	1

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231-2581 Drum Gp-Cold Planer

21***06	Bit As-Cutter; (Standard)	24
22***08	Holder-Bit	24
23***81	Drum Group-Cold Planer	1

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219-5420 Drum Gp-Cold Planer

21***06	Bit As-Cutter; (Standard)	78
21***20	Drum Group-Cold Planer	1
22***08	Holder-Bit	78
22***40	Bit As-Cutter; (Concrete Applications)	78

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231-2574 Drum Gp-Cold Planer

21***06	Bit As-Cutter; (Standard)	36
22***08	Holder-Bit	36
23***74	Drum Group-Cold Planer	1

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231-2580 Drum Gp-Cold Planer

21***06	Bit As-Cutter; (Standard)	28
22***08	Holder-Bit	28
23***80	Drum Group-Cold Planer	1

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231-2588 Drum Gp-Cold Planer

22***08	Holder-Bit	78
22***40	Bit As-Cutter; (Concrete Applications)	78
23***88	Drum Group-Cold Planer	1

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231-2585 Drum Gp-Cold Planer

21***06	Bit As-Cutter; (Standard)	48
22***08	Holder-Bit	48
23***85	Drum Group-Cold Planer	1

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231-2576 Drum Gp-Cold Planer

21***06	Bit As-Cutter; (Standard)	42
22***08	Holder-Bit	42
23***76	Drum Group-Cold Planer	1

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224-7359 Drum Gp-Cold Planer

21***06	Bit As-Cutter; (Standard)	42
22***59	Drum Group-Cold Planer	1
22***08	Holder-Bit	42
22***40	Bit As-Cutter; (Concrete Applications)	42

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231-2582 Drum Gp-Cold Planer

21***06	Bit As-Cutter; (Standard)	36
22***08	Holder-Bit	36
23***82	Drum Group-Cold Planer	1

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231-2587 Drum Gp-Cold Planer

22***08	Holder-Bit	66
22***40	Bit As-Cutter; (Concrete Applications)	66
23***87	Drum Group-Cold Planer	1

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231-2572 Drum Gp-Cold Planer

21***06	Bit As-Cutter; (Standard)	24
22***08	Holder-Bit	24
23***72	Drum Group-Cold Planer	1

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224-7360 Drum Gp-Cold Planer

21***06	Bit As-Cutter; (Standard)	48
22***60	Drum Group-Cold Planer	1
22***08	Holder-Bit	48
22***40	Bit As-Cutter; (Concrete Applications)	48

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231-2583 Drum Gp-Cold Planer

21***06	Bit As-Cutter; (Standard)	42
22***08	Holder-Bit	42
23***83	Drum Group-Cold Planer	1

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231-2579 Drum Gp-Cold Planer

22***08	Holder-Bit	66
22***40	Bit As-Cutter; (Concrete Applications)	66
23***79	Drum Group-Cold Planer	1

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231-2575 Drum Gp-Cold Planer

21***06	Bit As-Cutter; (Standard)	42
22***08	Holder-Bit	42
23***75	Drum Group-Cold Planer	1

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224-7384 Drum Gp-Cold Planer

21***06	Bit As-Cutter; (Standard)	60
22***84	Drum Group-Cold Planer	1
22***08	Holder-Bit	60
22***40	Bit As-Cutter; (Concrete Applications)	60

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231-2590 Spray Gp-Water

11***19	Bolt-Socket Head; (M4x0.7x25-mm)	2
12***56	Clamp-Hose	6
17***92	Coupling	1
23***90	Spray Group-Water	1

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231-2591 Spray Gp-Water

11***19	Bolt-Socket Head; (M4x0.7x25-mm)	2
12***56	Clamp-Hose	8
17***92	Coupling	1
23***91	Spray Group-Water	1

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231-2592 Spray Gp-Water

11***19	Bolt-Socket Head; (M4x0.7x25-mm)	4
12***56	Clamp-Hose	12
17***92	Coupling	1
23***92	Spray Group-Water	1

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PC204 serial number reference

The PIN/serial plate on the PC204 is a riveted or stamped metal tag mounted on the attachment's main frame near the coupler or drum housing, not on a carrier machine cab. Read the first 3 characters as the prefix (identifies model and plant) and the following 5 digits as the sequence number for that prefix run (00001-UP).

Prefix	Identifies	Notes
RDG	PC204 standard-flow cold planer, 450 mm (18 in) drum width, skid steer / multi-terrain loader mount	Passive hydraulically driven work tool; runs off the carrier's standard-flow hydraulic circuit, no engine or ECM of its own. RDG is the PC204-specific serial family within the shared PC203/PC204/PC205/PC206/PC210 cold planer parts catalog; siblings each carry a different prefix (PC203=PCB, PC205=RBG, PC206=DDG, PC210=GDR) so do not cross-apply serials between them.

Frequently asked questions

What is the Caterpillar PC204?

The PC204 is not a stand-alone machine. It is a standard-flow cold planer work-tool attachment with a 450 mm (18 in) drum, built to mount on Cat skid steer, multi-terrain, and compact wheel loaders for milling asphalt and light concrete. It has no engine or ECM of its own; a direct-drive gerotor motor on the drum runs off the carrier's hydraulic system.

What is the PC204's operating weight and hydraulic flow requirement?

The PC204 weighs about 690 kg (1,521 lb) and needs a standard-flow auxiliary hydraulic circuit of 55-100 L/min at 160-240 bar (14-26 gal/min at 2,320-3,480 psi) from its host carrier. Drum width is 450 mm (18 in), rated drum speed is around 202 rpm, and the drum oscillates up to ±16 degrees for angled cuts.

What replaced the PC204?

Caterpillar retired the legacy PC203-PC210 cold planer numbering and now sells cold planers under a renumbered PC1xx/PC3xx/PC4xx line. No document states a direct one-for-one replacement, but the current PC105 standard-flow model occupies roughly the same 18 in, skid-steer-class slot the PC204 once filled.

What PC204 owners discuss

Does the PC204 need a high-flow skid steer, or will a standard-flow carrier run it fine?

The PC204 is built as a standard-flow cold planer, matched to carriers putting out roughly 55-100 L/min (14-26 gpm) at 160-240 bar (2,320-3,480 psi). Running it on a carrier well below that range leaves the drum underpowered and quick to bog in harder material; running it on a high-flow circuit without the tool's own relief doing its job risks overheating the motor and cooking seals faster than normal. Match the tool's flow/pressure window to the carrier spec sheet before buying or renting, not just the quick-attach fit.

Why does the drum slow down or stall when I try to trim cutting depth mid-pass?

On a two-function hookup the depth-adjust cylinders and the drum motor draw off the same hydraulic circuit, so asking the carrier to reposition the skid shoes while the drum is still cutting can starve the motor and stall or bog the cut. Owners report this as normal behavior for this class of attachment, not a fault - the practical fix is to set depth before advancing into the cut rather than adjusting on the fly, or slow forward travel while trimming depth.

How long do the cutting bits actually last, and is there a trick to getting more life out of them?

Consensus from operators is roughly 50-150 hours per bit in asphalt versus only 10-30 hours in concrete, since concrete is far more abrasive. Bits should spin freely in their holders - check that every 4-8 hours of use, since a seized holder wears the bit unevenly and shortens life. Rotating bits between inner and outer drum positions as they wear is a common practice to even out the wear pattern and delay a full bit change.

What's the usual cause when the drum's hydraulic motor starts leaking or losing torque?

The recurring cause mechanics point to is a restricted or kinked case-drain line at the motor coupler - if that return path is pinched, back-pressure builds against the motor's shaft seal and blows it, which shows up as an external leak and a gradual loss of drum torque. Check that the case-drain hose is fully seated at the coupler and isn't crushed or kinked before assuming the motor itself is worn. Have your dealer verify case-drain pressure and motor condition if the leak persists after clearing the hose routing.

Are the water spray / dust suppression kits worth using, and what goes wrong with them?

Owners running these kits like that they knock down silica dust and cool the bits, which helps bit life in dry, dusty milling. The tradeoff is limited runtime - a built-in tank is good for roughly 30-60 minutes of continuous spray depending on drum width and pressure setting, so it needs to be planned around on longer jobs rather than assumed to last a full shift. The other common complaint is spray nozzles clogging with milled debris and needing periodic clearing to keep even coverage across the drum.

What does worn-out drum bearing or gearbox play look like, and how do I catch it early?

Operators and mechanics describe the early sign as noticeable axial or radial play in the drum shaft - the drum can be rocked or shifted slightly by hand when the attachment is off the carrier and depressurized. Left alone, that play leads to poor gear mesh, added noise, and accelerating wear on the drive components. Routine greasing of the drum bearings and side-shift wear points on a roughly 40-hour interval is the standard preventive step owners cite. Have your dealer verify bearing condition and gearbox oil if you feel play or hear new noise from the drum end.

What should I check before buying a used PC204?

Walk the drum first: bit wear and whether holders still spin freely, then rock the drum by hand for shaft or bearing play. Check the hydraulic motor and case-drain coupler area for leak staining, and look at the skid shoes for wear thickness and whether the depth-indicator markings are still legible - badly worn shoes mean inconsistent cut depth even with a good drum. Inspect the frame and mounting plate, especially around the quick-attach and skid-shoe brackets, for cracks or repair welds from hard impacts. Finally confirm the coupler still seats tight on the carrier's quick-attach with no excess play. Have your dealer verify hydraulic relief settings and motor condition on any unit you're seriously considering before you rely on it for daily production work.

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

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