Caterpillar HH75
Maintenance schedule, common problems & OEM parts breakdown
The Cat HH75 is a bare single-grip forestry harvester head, the largest and heaviest-duty member of Caterpillar's HH45/HH55/HH65/HH75 harvester head line, built for felling, delimbing, measuring, and bucking large-diameter timber rather than the thinning work the smaller heads in that range handle. It carries no engine, no independent hydraulic reservoir, and no undercarriage of its own. It mounts through a hydraulic rotator onto a host carrier, either a Cat 550, 570, or 580 Track Harvester or an excavator-based forestry carrier, and draws all hydraulic flow and pressure from that host machine. Caterpillar does not publish a standalone weight, footprint, or cutting-diameter figure for this head; buyers size it by carrier pairing and dealer configuration rather than a catalog spec sheet. No factory-documented predecessor or successor is confirmed for the HH75 specifically.
The HH75 shipped across two documented control-system generations. Early heads (serial prefix 5WZ) ran an onboard Cat-badged AR-DASA electronic control computer; later heads (serial prefix CKW) switched to a CABS/CABSWIN measuring-and-control package. Partway through the CKW run, around CKW203-and-up, Caterpillar updated the hydraulic rotator to a revised yoke-mounting design and changed the feed-roller lubrication metering hardware from needle valves to fixed-orifice washers, a running change worth knowing before sourcing a rotator or metering component against a specific serial. In the used and parts market, the HH75's value has less to do with the head holding its own resale premium and more to do with what it unlocks: with no engine or reservoir of its own to wear out, a used head extends the working life of whatever carrier hosts it, and it shares its control architecture and rotator-mount approach with the smaller HH45/HH55/HH65 heads, giving buyers a common parts and controls ecosystem across the whole range.
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 HH75 specifications
Engine
| Engine | None. The HH75 is a bare single-grip harvester head with no engine of its own. It mounts to a carrier through a hydraulic rotator and draws all hydraulic flow and pressure from that carrier's own engine and pump circuit. Approved carriers include the Cat 550, 570, and 580 Track Harvesters, and excavator-based forestry carriers fitted with a harvester-head circuit. Gross/net power, displacement, cylinder count, and emissions tier are properties of the carrier, not the head, and are not part of this attachment's spec sheet. |
Weights
| Head weight | Not published as a standalone catalog figure. Factory documentation for the 550/570/580 Track Harvester carriers does not break out a separate HH75 attachment weight, and no independent HH75 spec sheet with an overall weight figure was found. Total machine-plus-head weight is quoted only as a combined carrier package. |
| Shipping weight | Not published separately from the carrier package. |
| Ground pressure | Not applicable. The head has no undercarriage of its own; ground pressure is a function of the host carrier. |
Dimensions
| Overall length/width/height | Not published as standalone figures for the head. Carrier literature for the 550/570/580 Track Harvesters lists boom reach and overall machine dimensions, but not separate length, width, or height figures for the HH75 head itself. |
| Cutting/delimbing diameter capacity | Not documented in available factory or dealer literature for this head. |
| Ground clearance / track gauge / wheelbase | Not applicable. The head has no undercarriage; these dimensions belong to the host carrier. |
Performance
| Feed speed | Not documented in available factory literature for this head. |
| Feed force / tree-holding force | Not documented in available factory literature for this head. |
| Cutting (saw) performance | Not documented in available factory literature for this head. Cutting performance depends on the hydraulic flow and pressure supplied by the host carrier, since the head has no engine of its own. |
| Travel speed / gradeability | Not applicable to a mounted attachment; these figures apply to the host carrier, not the head. |
Service capacities (summary)
| Fuel tank | Not applicable. The head has no fuel tank; it has no engine. |
| Hydraulic system | No independent hydraulic reservoir. The head operates entirely on hydraulic oil supplied by the host carrier's own tank and cooling circuit; there is no separate hydraulic fluid capacity to service on the head itself. |
| Engine oil | Not applicable. No engine is fitted to the head. |
| Cooling system | Not applicable. Cooling is handled by the host carrier's system; the head has no independent cooling circuit. |
| Other lubrication points | The head has grease-lubricated pivot and arm points and gear-case/chain-oil lubrication for the saw and feed-roller drive, serviced per the standard forestry-head maintenance schedule. Specific fill quantities for these points are not published in available literature. |
Values vary by configuration, region, and serial range — confirm against your machine before planning transport or lifts.
HH75 fluids & capacities
| System | Capacity | Recommended fluid |
|---|---|---|
| Hydraulic system (head actuation — delimb knives, feed rollers, saw feed, rotator) | No onboard hydraulic reservoir on the head itself. It draws all hydraulic power through hoses from the carrier machine (Cat 550/570/580 Track Harvester or an excavator-based forestry carrier). Tank size follows whichever carrier it is mounted on. | Follow the carrier's own OMM fluid spec, not a head-specific one. Typical carrier fills are Cat HYDO Advanced (mineral) for standard duty, or Cat BIO HYDO Advanced (HEES, biodegradable) where the site calls for environmentally acceptable fluid. Viscosity grade is set by the carrier's own climate chart, not by the harvester head. |
| Feed roller drive (hydraulic motor and planetary reduction at each feed roller) | Sealed unit — no drain/fill point or refill volume is listed for scheduled service. | None specified. The feed roller drives are hydraulic-motor-driven and described as requiring no routine gear-oil service; they run on carrier hydraulic oil internally, not a separate gear lubricant. |
| Saw chain and feed-roller-arm lubrication reservoir (onboard oiler tank) | Onboard tank feeds both the saw bar/chain and the feed-roller-arm pivots. An exact liter/gallon fill volume is not published in the sources checked — confirm against the capacities chart in the OMM for the specific serial range, or with a dealer. | Bar-and-chain type lubricant (a tacky, high-viscosity "honey-like" oil), not hydraulic fluid and not engine oil — both are called out as unsuitable substitutes because they lack the film strength and throw off the moving chain. Flow to the feed-roller-arm pivots and saw chain is metered by two lubrication pumps: earlier-build heads use adjustable needle valves to set the flow rate, later-build heads use fixed metering washers in the pumps instead. In cold weather or when cutting frozen wood, switch to a lighter-viscosity chain oil and increase the flow rate (roughly double) to maintain adequate film; use a heavier oil in warm conditions. Oil should be visibly present at the feed-roller pivots during operation — if not, flow needs adjustment. |
| Grease points (rotator bearing, linkage and knife pivots) | Grease-gun points only, no bulk reservoir volume applies. | |
| Grease points (rotator bearing, linkage and knife pivots) — fluid spec | N/A (see grease points row above) | General-purpose/high-speed multipurpose bearing grease at the rotator bearing and moving linkage pivots is the expected spec for this class of Cat forestry head; the exact grease name and interval specific to the HH75 OMM lubrication chart could not be independently confirmed from the sources checked — verify against the OMM or a dealer before servicing. |
Capacities are refill values from factory literature — always fill to the dipstick/sight gauge, not the number.
Caterpillar HH75 maintenance schedule
| Service interval | Tasks |
|---|---|
| Every 10 h |
|
| Every 250 h |
|
| Every 500 h |
|
| Every 1,000 h |
|
| Every 2,000 h |
|
Servicing the HH75 beyond the schedule
Predictive Maintenance & Fluid Analysis
The HH75 carries no engine oil or hydraulic reservoir of its own; its only fluid sample point is the onboard lubrication tank feeding saw chain and feed-roller-arm pivot bushings. Sample that tank on a set interval and watch for metal fines, a sign the metering pumps (needle valves on pre-CKW203 heads, fixed-orifice washers after) are wearing. Track measuring-wheel sensor drift on CABS/CABSWIN heads before it corrupts bucking accuracy, and log rotator rotation speed: a slow, uneven swing usually means motor or swivel-seal wear building before it leaks visibly.
Corrective & Common Repairs
Most HH75 downtime traces to the saw unit and feed system, not the control computer. Expect recurring work on saw bar/chain tensioning, delimb knife edges chipped or rolled from rock contact, and feed-roller arm pivot wear at the cam-curve pin, a documented check point across the HH45-75 range. On CKW-prefix (CABS) heads, wiring-harness connectors at the control computer are a common fault source after repeated boom-tip flexing; Gen-1 AR-DASA heads see the same complaint at their control-computer connectors. Rotator yoke-mount hardware loosening is the most common fastener callback.
Overhaul & Rebuild Points
Because the HH75 has no engine or independent reservoir, overhaul work centers on hydraulics and structure: feed-roller cylinders and equalizer bar linkage, the saw motor, feed-roller drive motors, and the rotator motor/bearing assembly all wear from constant duty-cycle flexing. Frame cracking around knife-arm pivots and the rotator mounting yoke is the structural item to check at teardown, especially on pre-CKW203 heads built before the revised yoke-mounting design. Recalibrate the CABS/CABSWIN measuring system after any rebuild touching the measuring arm or wheel, since sensor geometry shifts with new bushings.
Seasonal & Environment Servicing
Cold-weather starts stress the lubrication tank first, since flow to the saw chain and feed-roller pivots depends on breather condition and oil viscosity: switch to a lower-viscosity lube oil before winter felling and confirm the breather isn't ice-blocked. Wet, muddy seasons push contamination into rotator swivel seals and exposed cylinder rods faster, so shorten hose and fitting checks. In sandy or rocky ground, delimb knife edges and saw bar wear accelerate, and the exposed measuring wheel collects more debris, so clean it more often to protect sensor accuracy.
HH75 attachments & work tools
Carrier compatibility
HH75 is the largest head in Caterpillar's HH45/55/65/75 harvester-head family, positioned for final felling of large-diameter stems. Factory documentation lists it as a work tool for Cat's own 550/570/580 Track Harvester carriers, and Cat service literature also treats an excavator-mounted version as a separate factory configuration with its own hydraulic setup.
Rotator and mounting
Head hangs from the carrier through a bolted hydraulic rotator (a flange secured by a ring of cap screws), not a pin-grab quick coupler. Caterpillar ran a mid-production design change to the rotator on HH75 heads at a defined serial break, so rotator hardware differs between early- and later-build units - confirm serial number before ordering rotator components.
Feed roller / delimb knife arrangement
Independent, hydraulically actuated feed-roller arms and delimb-knife arms clamp and feed the stem; factory setup requires these arms and the holding arm to open and close at matched speed so the stem is not dropped or crushed. Saw-chain lubrication shares a metering circuit with the feed-roller-arm pivots and runs at a fixed, non-adjustable flow.
Measuring and bucking control
A computer-aided bucking configuration is documented for the HH75: paired diameter sensors track delimb-knife rotation and a wheel-driven length sensor tracks stem travel as the feed rollers close, feeding a control system that optimizes cut length. This is offered as a distinct configuration alongside the standard hydraulic-only head.
Excavator vs track-harvester setup
Delimb-knife clamping pressure is tested and adjusted differently depending on whether the head runs on an excavator carrier or as the integrated unit on a wheel/track harvester. The wheel-harvester holding-arm-pressure procedure is published for the HH45 size only, indicating the HH75 sees excavator and track-harvester duty rather than wheel-harvester duty.
Valve bank guarding
The head's main hydraulic valve cover is a single heavy guard panel over the valve bank, weighing roughly 29.5 kg (65 lb) and needing two people to remove for service - larger and heavier than on the smaller HH45/HH55/HH65 siblings, consistent with its place as the largest head in the range.
All HH75 assemblies by section
Every catalogued assembly group for the Caterpillar HH75. Open an assembly to preview the parts inside — full OEM part numbers are available in Heavy Parts AI.
Electrical And Starting System
196-4821 Control Ar-Harvester Head -Cabswin
| 19***79 | Control Group-Harvester Head | 1 |
| 19***21 | Control Ar-Harvester Head; -Cabswin | 1 |
| 19***23 | Wiring Group-Harvester Head | 1 |
196-4825 Control Ar-Harvester Head -Cabswin
| 19***25 | Control Ar-Harvester Head; -Cabswin | 1 |
| 19***27 | Control Group-Harvester Head | 1 |
| 19***30 | Wiring Group-Harvester Head | 1 |
196-4826 Control Ar-Harvester Head -Cabsdos
| 19***26 | Control Ar-Harvester Head; -Cabsdos | 1 |
| 19***28 | Control Group-Harvester Head | 1 |
| 19***30 | Wiring Group-Harvester Head | 1 |
196-1279 Control Gp-Harvester Head
| 19***79 | Control Group-Harvester Head | 1 |
| 19***11 | Harness As-Monitor; (Control Unit) | 1 |
| 19***12 | Harness As-Monitor; (Analog Output Box) | 1 |
196-4827 Control Gp-Harvester Head
| 18***01 | Plate As | 1 |
| 19***19 | Box-Control Unit | 1 |
| 19***27 | Keyboard As | 1 |
196-4828 Control Gp-Harvester Head
| 16***25 | Printer Group-Computer | 1 |
| 19***19 | Box-Control Unit | 1 |
| 19***33 | Harness As-Wiring; (Boom) | 1 |
198-1403 Module Gp-Monitor Keypad
| 09***78 | Screw; (Pan Head) | 2 |
| 19***69 | Cover-Front | 1 |
| 19***70 | Cover-Back | 1 |
198-1402 Module Gp-Monitor Keypad -Rh
| 09***78 | Screw; (Pan Head) | 2 |
| 19***69 | Cover-Front | 1 |
| 19***70 | Cover-Back | 1 |
161-5225 Printer Gp-Computer
| 16***25 | Printer Group-Computer | 1 |
| 17***46 | Paper-Printer | 1 |
198-3434 Printer Gp-Computer
| 19***34 | Printer Group-Computer | 1 |
| 19***35 | Printer Group-Portable | 1 |
| 19***52 | Case-Carrying | 1 |
196-4823 Wiring Gp-Harvester Head
| 10***01 | Kit; (Receptacle) (12-Pin) (Includes Receptacle As & Wedge) | 1 |
| 10***03 | Kit; (Receptacle) (3-Pin) (Includes Receptacle As & Wedge) | 2 |
| 13***75 | Wedge-Receptacle Lock | 2 |
196-4830 Wiring Gp-Harvester Head
| 16***85 | Washer | 2 |
| 16***18 | Bracket; (Keypad) | 4 |
| 16***66 | Handle | 2 |
Hydraulic System
184-6420 Bearing Gp-Self-Aligning
| 18***83 | Ring | 1 |
| 18***20 | Bearing Group-Self-Aligning | 1 |
| 18***21 | Support-Bearing | 1 |
199-6369 Cover & Mtg Gp-Control Valve
| 15***85 | Washer; (M12) | 4 |
| 15***91 | Spacer | 2 |
| 15***92 | Spacer | 2 |
195-9367 Cylinder & Lines Gp-Delimbing
| 15***85 | Fitting-Adapter | 1 |
| 15***95 | Fitting-Elbow | 1 |
| 15***98 | Junction Block | 2 |
195-9366 Cylinder & Lines Gp-Meas & Fdg
| 08***87 | Sealing Washer | 2 |
| 15***86 | Fitting | 1 |
| 15***95 | Fitting-Elbow | 2 |
195-9365 Cylinder & Lines Gp-Saw
| 15***85 | Fitting-Adapter | 2 |
| 15***95 | Fitting-Elbow | 1 |
| 15***98 | Junction Block | 1 |
228-3394 Cylinder Gp-Delimbing Knife
| 16***45 | Bearing | 2 |
| 21***83 | Kit-Seal; (Delimbing Knife Cylinder) | 1 |
| 22***21 | Piston | 1 |
156-4145 Cylinder Gp-Delimbing Knife
| 15***45 | Cylinder Group-Delimbing Knife | 1 |
| 16***45 | Bearing | 2 |
| 16***55 | Kit-Seal | 1 |
206-2001 Cylinder Gp-Delimbing Knife
| 16***45 | Bearing | 2 |
| 20***01 | Cylinder Group-Delimbing Knife | 1 |
| 21***13 | Kit-Seal; (Delimbing Knife Cylinder) | 1 |
157-2661 Cylinder Gp-Feed Roller Arm
| 15***61 | Cylinder Group-Feed Roller Arm | 1 |
| 16***41 | Bearing | 2 |
| 16***62 | Kit-Seal | 1 |
210-2027 Cylinder Gp-Feed Roller Arm
| 16***41 | Bearing | 2 |
| 21***27 | Cylinder Group-Feed Roller Arm | 1 |
| 21***30 | Kit-Seal | 1 |
211-2789 Cylinder Gp-Holding Arm
| 16***41 | Bearing | 2 |
| 21***89 | Cylinder Group-Holding Arm | 1 |
| 22***25 | Piston | 1 |
157-2773 Cylinder Gp-Holding Arm
| 15***73 | Cylinder Group-Holding Arm | 1 |
| 16***41 | Bearing | 2 |
| 16***56 | Kit-Seal | 1 |
206-4594 Cylinder Gp-Measuring Arm
| 09***52 | Ring | 2 |
| 16***42 | Bearing | 2 |
| 20***94 | Cylinder Group-Measuring Arm | 1 |
156-3852 Cylinder Gp-Measuring Arm
| 15***52 | Cylinder Group-Measuring Arm | 1 |
| 16***42 | Bearing | 2 |
| 16***50 | Kit-Seal | 1 |
108-0456 Cylinder Gp-Piston
| 10***56 | Cylinder Group-Piston; -Feed Roller | 1 |
| 10***58 | Kit-Retainer | 8 |
| 1G***20 | Piston Group-Clutch | 8 |
228-3397 Cylinder Gp-Saw
| 09***01 | Bolt-Socket Head; (M8x1.25x40-mm) | 1 |
| 21***85 | Kit-Seal; (Saw Cylinder) | 1 |
| 22***29 | Piston | 1 |
206-2003 Cylinder Gp-Saw
| 20***03 | Cylinder Group-Saw | 1 |
| 21***85 | Kit-Seal; (Saw Cylinder) | 1 |
| 6V***75 | Bearing | 2 |
156-1228 Cylinder Gp-Saw
| 15***28 | Cylinder Group-Saw | 1 |
| 16***52 | Kit-Seal | 1 |
| 6V***75 | Bearing | 2 |
157-2780 Cylinder Gp-Tilt
| 15***80 | Cylinder Group-Tilt | 1 |
| 16***41 | Bearing | 2 |
| 16***63 | Kit-Seal | 1 |
184-6414 Housing Gp-Motor
| 17***38 | Bolt; (M12x1.75x75-mm) | 16 |
| 18***14 | Housing Group-Motor | 1 |
| 18***15 | Cover-Valve | 1 |
194-7955 Hydraulic Ar
| 19***55 | Hydraulic Ar | 1 |
| 19***65 | Cylinder & Lines Group-Saw | 1 |
| 19***66 | Cylinder & Lines Group-Meas & Fdg | 1 |
199-6367 Lines Gp-Hydraulic
| 14***25 | Connector As. | 1 |
| 14***51 | Elbow Group | 1 |
| 19***26 | Fitting | 1 |
162-5712 Lubrication Ar -Saw & Feed Roller
| 15***82 | Pump Group-Lubrication | 1 |
| 15***48 | Pump Group-Lubrication | 1 |
| 15***99 | Tank & Lines Group-Lubrication | 1 |
165-4116 Motor Gp-Piston
| 10***56 | Cylinder Group-Piston; -Feed Roller | 1 |
| 15***41 | Seal-O-Ring; (Compressor) | 2 |
| 16***16 | Motor Group-Piston | 1 |
155-9923 Motor Gp-Saw
| 15***23 | Motor Group-Saw | 1 |
| 16***67 | Seal | 1 |
| 16***68 | Plug | 1 |
156-1248 Pump Gp-Lubrication
| 15***48 | Pump Group-Lubrication | 1 |
| 15***53 | Seal-Ring | 3 |
| 15***12 | Fitting | 1 |
183-3742 Pump Gp-Lubrication
| 15***95 | Strainer As | 1 |
| 15***79 | Gasket | 1 |
| 15***96 | Fitting | 1 |
156-0982 Pump Gp-Lubrication
| 15***95 | Strainer As | 1 |
| 15***79 | Gasket | 1 |
| 15***82 | Pump Group-Lubrication | 1 |
157-1399 Tank & Lines Gp-Lubrication
| 09***52 | Ring | 1 |
| 15***82 | Bolt-Socket Head; (M6x1x40-mm) | 4 |
| 15***85 | Washer; (M12) | 2 |
199-6366 Valve & Mtg Gp-Main Control
| 19***18 | Valve Group-Bank 8 | 1 |
| 19***66 | Valve & Mtg Group-Main Control | 1 |
| 7X***37 | Bolt-Plt; (M8 X 1.25 X 35) | 4 |
224-7577 Valve & Mtg Gp-Main Control
| 15***40 | Washer; (M10) | 4 |
| 22***77 | Valve & Mtg Group-Main Control | 1 |
| 22***85 | Valve Group-Bank 7 | 1 |
229-9785 Valve Gp-Bank 7
| 16***51 | Kit-Seal | 9 |
| 19***73 | Valve Group-Control; -Pump | 1 |
| 19***76 | Valve Group-Control; -Upper Delimbing Knife | 1 |
194-7118 Valve Gp-Bank 8
| 16***51 | Kit-Seal | 9 |
| 19***18 | Valve Group-Bank 8 | 1 |
| 19***73 | Valve Group-Control; -Pump | 1 |
156-0285 Valve Gp-Breather
| 15***85 | Valve Group-Breather | 1 |
| 15***56 | Fitting | 1 |
| 16***86 | Breather | 1 |
199-8076 Valve Gp-Control -Upper Delimbing Knife
| 17***73 | Valve As-Line Relief | 1 |
| 17***23 | Valve As-Line Relief | 1 |
| 17***32 | Kit-Seal | 1 |
214-3505 Valve Gp-Control
| 16***84 | Spool As | 1 |
| 17***32 | Kit-Seal | 1 |
| 19***08 | Seal-O-Ring | 2 |
199-8077 Valve Gp-Control -Roller Clamp
| 17***74 | Valve As-Line Relief | 1 |
| 17***75 | Valve As-Line Relief | 1 |
| 17***32 | Kit-Seal | 1 |
199-8080 Valve Gp-Control -End Block
| 19***80 | Valve Group-Control; -End Block | 1 |
| 19***00 | Manifold | 1 |
| 19***07 | Valve Group-Pressure Reducing | 2 |
211-8770 Valve Gp-Control
| 16***07 | Valve Group-Solenoid; (Medium Pressure) | 1 |
| 16***84 | Spool As | 1 |
| 17***73 | Valve As-Line Relief | 1 |
199-8073 Valve Gp-Control -Pump
| 03***27 | Seal-O-Ring; (19.18mm Id) | 1 |
| 15***40 | Washer; (M10) | 2 |
| 19***73 | Valve Group-Control; -Pump | 1 |
214-3506 Valve Gp-Control
| 16***84 | Spool As | 1 |
| 17***32 | Kit-Seal | 1 |
| 19***08 | Seal-O-Ring | 2 |
199-8074 Valve Gp-Control -Saw
| 16***84 | Spool As | 1 |
| 17***70 | Valve As-Line Relief | 1 |
| 17***76 | Valve Group-Pilot Relief | 1 |
199-8079 Valve Gp-Control -Tilt
| 16***41 | Spool As | 1 |
| 17***72 | Valve As-Line Relief | 1 |
| 17***74 | Valve As-Line Relief | 1 |
199-8078 Valve Gp-Control -Lower Delimbing Knife
| 17***74 | Valve As-Line Relief | 1 |
| 17***80 | Valve As-Line Relief | 1 |
| 17***32 | Kit-Seal | 1 |
224-6026 Valve Gp-Control -Oil Manifold
| 19***07 | Valve Group-Pressure Reducing | 2 |
| 22***26 | Valve Group-Control; -Oil Manifold | 1 |
| 23***53 | Manifold | 1 |
199-8107 Valve Gp-Pressure Reducing
| 03***27 | Seal-O-Ring; (19.18mm Id) | 1 |
| 03***43 | Seal-O-Ring | 1 |
| 18***27 | Ring-Backup | 2 |
214-3507 Valve Gp-Relief
| 19***06 | Valve Group-Relief | 2 |
| 21***18 | Manifold | 1 |
| 21***07 | Valve Group-Relief | 1 |
Service Equipment And Supplies
169-2761 Film Gp
| 16***61 | Film Group | 1 |
| 16***62 | Film | 2 |
166-9183 Plate & Film Gp
| 13***76 | Film; (Warning) (Universal) (Lh Side Post Inside Cab) | 1 |
| 16***91 | Film-Identification; (Chain Oil) | 1 |
| 16***83 | Plate & Film Group | 1 |
197-5088 Tool Gp-Hand
| 16***53 | Wrench-T-Handle; (6-mm Hex) | 1 |
| 16***56 | Hook As-Cleaning | 1 |
| 16***71 | Wrench-Spanner | 1 |
Work Tools
157-1644 Arm Gp-Feed Roller -Rh
| 15***44 | Arm Group-Feed Roller; -Rh | 1 |
| 15***46 | Scraper | 2 |
| 15***47 | Ring-Guard | 2 |
157-1645 Arm Gp-Feed Roller -Lh
| 15***45 | Arm Group-Feed Roller; -Lh | 1 |
| 15***46 | Scraper | 2 |
| 15***47 | Ring-Guard | 2 |
198-3014 Arm Gp-Grapple
| 15***45 | Fitting-Grease | 1 |
| 15***98 | Washer; (M8x1.25-Thd) | 2 |
| 16***37 | Bushing | 2 |
157-1391 Arm Gp-Measuring
| 08***73 | Screw-Countersink Head | 3 |
| 09***50 | Ring-Retaining | 1 |
| 13***40 | Locknut; (M8x1.25-Thd) | 1 |
198-3007 Control Ar-Color Marking
| 19***07 | Control Ar-Color Marking | 1 |
| 19***11 | Control Group-Color Marking | 1 |
| 19***14 | Arm Group-Grapple | 1 |
198-3011 Control Gp-Color Marking
| 09***49 | Bolt; (M8x1.25x40-mm) | 2 |
| 14***94 | Guard; (15-cm) | 0 |
| 15***71 | Kit-Connecting Plug; (4-Pin) | 1 |
155-8800 Damper Gp-Harvester Head
| 15***00 | Damper Group-Harvester Head | 1 |
| 15***40 | Body-Damper | 1 |
| 15***41 | Pin As | 1 |
189-5510 Damper Gp-Harvester Head
| 15***41 | Pin As | 1 |
| 15***43 | Washer | 1 |
| 15***44 | Nut | 1 |
196-4837 Frame Ar-Harvester Head
| 15***94 | Yoke Group-Harvester Head | 1 |
| 16***83 | Plate & Film Group | 1 |
| 19***37 | Frame Ar-Harvester Head | 1 |
197-4798 Frame Gp-Harvester Head
| 12***17 | Bolt-Socket Head; (M24x3x70-mm) | 2 |
| 13***40 | Locknut; (M8x1.25-Thd) | 1 |
| 15***45 | Fitting-Grease | 1 |
194-8103 Head Ar-Harvester
| 15***00 | Damper Group-Harvester Head | 1 |
| 15***89 | Roller Group-Feed; -Rh | 1 |
| 15***90 | Roller Group-Feed; -Lh | 1 |
156-5252 Holder Gp-Saw Bar
| 09***60 | Setscrew-Socket; (M6x1x6-mm) | 1 |
| 15***52 | Holder Group-Saw Bar | 1 |
| 15***53 | Kit-Pin; (Contains 10 Pieces) | 1 |
187-4714 Housing Gp-Chain Tensioner
| 08***65 | Bolt; (M3x0.5x8-mm) | 2 |
| 09***19 | Ring-Retaining | 1 |
| 09***73 | Setscrew-Socket | 2 |
219-2535 Measuring Ar-Harvester Head
| 21***34 | Measuring Ar-Harvester Head; (Field Installation) | 1 |
| 21***35 | Measuring Ar-Harvester Head | 1 |
157-1390 Roller Gp-Feed -Lh
| 09***76 | Setscrew-Socket | 1 |
| 15***47 | Nut | 1 |
| 15***69 | Spacer | 1 |
157-1389 Roller Gp-Feed -Rh
| 09***76 | Setscrew-Socket | 1 |
| 15***47 | Nut | 1 |
| 15***69 | Spacer | 1 |
210-1506 Rotator Gp-Hydraulic
| 12***76 | Bolt; (M10x1.5x130-mm) | 10 |
| 15***42 | Plug | 2 |
| 15***59 | Spring | 12 |
163-3978 Rotator Gp-Hydraulic
| 12***76 | Bolt; (M10x1.5x130-mm) | 10 |
| 15***42 | Plug | 2 |
| 15***59 | Spring | 12 |
162-5644 Saw Ar-Chain
| 15***23 | Motor Group-Saw | 1 |
| 16***44 | Saw Ar-Chain | 1 |
| 18***10 | Tensioner Group-Chain | 1 |
187-8458 Saw Gp-Chain
| 09***85 | Bolt-Socket Head; (M14x2x30-mm) | 2 |
| 09***87 | Bolt-Socket Head; (M14x2x45-mm) | 2 |
| 09***19 | Ring-Retaining | 1 |
187-4710 Tensioner Gp-Chain
| 09***88 | Setscrew | 3 |
| 15***52 | Holder Group-Saw Bar | 2 |
| 15***81 | Kit-Seal | 1 |
174-0261 Wheel Gp-Feed Roller -Rh
| 15***61 | Screw | 5 |
| 16***09 | Chain; (20m) | 0 |
| 17***61 | Wheel Group-Feed Roller; -Rh | 1 |
174-0262 Wheel Gp-Feed Roller -Lh
| 15***61 | Screw | 5 |
| 16***09 | Chain; (20m) | 0 |
| 17***62 | Wheel Group-Feed Roller; -Lh | 1 |
157-1394 Yoke Gp-Harvester Head
| 09***70 | Bolt-Socket Hd; (M12 X 1.75 X 45) | 4 |
| 09***31 | Ring-Retaining | 2 |
| 15***45 | Fitting-Grease | 2 |
HH75 serial number reference
The PIN/serial tag for the HH75 head is a small metal plate riveted to the main frame of the harvester head itself (not on the carrier), usually near the base of the frame or close to where the hydraulic hoses enter. The plate reads as an 8-character serial: the first 3 letters are the prefix identifying the model/generation build, followed by a sequential unit number. Match the letter prefix against the ranges above to identify which generation and control package the head has before ordering parts.
| Prefix | Identifies | Notes |
|---|---|---|
| 5WZ | Gen-1 (5WZ00001-UP) | Earlier production run of the HH75 single-grip harvester head. Electrical/control system uses the onboard AR-DASA electronic control unit (no CABS measuring computer). No engine on the head itself; it runs off the host carrier's hydraulics. Rotator uses the earlier mounting hardware, ahead of the later rotator update. |
| CKW | Gen-2 (CKW00001-UP), CABS-equipped | Later production run of the HH75, fitted with the CABS measuring/control package (CABSWIN electronic control unit) in place of the plain DASA setup. Same no-engine, carrier-hydraulics-powered arrangement as the earlier run. Within this run there is a further internal break at CKW203-UP, where an updated hydraulic rotator with a revised yoke-mounting design replaced the rotator used on CKW1-202 and earlier; lubrication-metering hardware for the feed roller arms also changed at this same break (needle valves on CKW1-202, washers on CKW203-UP). |
Frequently asked questions
What powers the Cat HH75 harvester head?
The HH75 has no engine of its own. It is a bare hydraulic attachment that draws all hydraulic flow and pressure from its host carrier, either a Cat 550/570/580 Track Harvester or an excavator-based forestry carrier, through a hydraulic rotator. Control runs through an onboard AR-DASA electronic computer on early (5WZ-prefix) heads, replaced by a CABS/CABSWIN measuring-and-control package on later (CKW-prefix) heads; neither is an engine ECM.
What is the HH75's weight and size class?
Caterpillar does not publish a standalone weight, dimension, or cutting-diameter figure for the HH75. Within the HH45/HH55/HH65/HH75 family it is positioned as the largest and heaviest-duty head, built for felling and processing large-diameter timber rather than the thinning work the smaller heads in that line handle. Actual weight and capacity vary by carrier pairing and dealer configuration.
What replaced the Cat HH75?
No factory-documented successor is confirmed. Caterpillar's later HH700 head is a separate, larger product line built for a different excavator platform, not a stated replacement for the HH75. Within its own run, the HH75 moved from an AR-DASA control computer to a CABS/CABSWIN package, with a further hydraulic-rotator and lubrication-metering update partway through that run, but that is a running change, not a model replacement.
What HH75 owners discuss
The HH75 has no engine of its own - what does that actually mean for day-to-day operation?
Does the HH75 change much between older and newer serial ranges?
What wear pattern shows up most in the saw chain and delimb knife circuit?
What do feed roller and pivot wear symptoms look like on this head?
What are the classic rotator complaints on this head?
What electrical/control quirks come up with the onboard computer?
What should a buyer check on a used HH75 before purchase?
Compiled from owner and technician discussions across the industry — experiences vary by serial range and machine history.
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