Caterpillarforest productsharvester head

Caterpillar HH500

Maintenance schedule, common problems & OEM parts breakdown

Search live HH500 parts

The Caterpillar HH500 is a bare, non-cab, single-grip harvester head built to fell, delimb, and buck trees from an excavator-type carrier rather than a purpose-built harvester chassis. It carries no engine, transmission, fuel tank, cooling system, or onboard ECM of its own; every grip, feed, and rotation function runs off the host carrier's hydraulic circuit through a bolted, continuous-rotation hydraulic rotator. The head sits in the middle of Caterpillar's older HH300/HH500/HH700 excavator-mount head family, identified in Caterpillar parts and service literature by its own serial number prefix, CWH1-UP.

Public spec-sheet detail on the HH500 itself is thin. Caterpillar service literature places the HH500 one size class below the HH700, which the factory pairs with roughly 20-tonne, 320C-class excavator carriers, but no source ties an exact carrier model to the HH500 line; carrier pairing for this head varied by dealer configuration at the time it was sold. Caterpillar issued a factory rotator design update across the whole HH300/HH500/HH700 family, and today parts sourcing for this head runs through discontinued-line channels rather than active production. The HH500 predates the newer, better-documented Cat HH45/HH55/HH65/HH75 heads built for purpose-built Cat harvesters, and current owners work mainly from general service literature and carrier-side hydraulic troubleshooting rather than a published HH500 spec sheet.

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 HH500 maintenance schedule

Service intervalTasks
Every 10 h
  • Inspect all hydraulic hoses, fittings, and the rotator swivel joint for leaks, chafing, or loose clamps.
  • Grease the rotator, knife pivots, and feed-arm pivot points per the grease-point chart.
  • Check the rotator for excess rotational play or binding before starting production cutting.
  • Inspect delimb knife edges and feed roller tread for visible damage or heavy wear.
  • Confirm mounting pins and retaining hardware are seated and free of visible movement.
Every 50 h
  • Inspect feed roller spikes or tread for wear, flattening, or chipped segments and rotate or index as needed.
  • Sharpen or replace delimb knives showing rounded edges or nicks that leave a rough delimb cut.
  • Check knife-to-stem clamping pressure and adjust feed cylinder settings if grip is inconsistent.
  • Clean accumulated bark, sap, and debris from the feed roller frame and knife linkages.
  • Re-torque knife bolts and feed roller mounting hardware.
Every 250 h
  • Inspect the rotator bearing for play, roughness, or unusual noise under load.
  • Check rotator seals for weeping or hydraulic seepage around the housing.
  • Inspect mounting pins, bushings, and the head-to-rotator bracket for fatigue cracking or elongation.
  • Pressure- or flow-test the head's hydraulic circuit if cycle times have slowed.
  • Inspect hydraulic hoses routed across the rotation joint for chafing from repeated head rotation.
Every 1,000 h
  • Remove and inspect or replace the rotator seal kit and bearing assembly.
  • Replace hydraulic hoses on a full-cycle schedule rather than waiting for visible failure, given the head's constant-flex rotation joint.
  • Overhaul or replace feed roller drive motors and delimb knife cylinders showing internal leakage.
  • Inspect the full mounting bracket and pin assembly for wear beyond serviceable limits and rebuild as needed.
  • Check structural weld points on the head frame for cracking from cyclic felling and delimbing loads.

Servicing the HH500 beyond the schedule

Predictive Maintenance & Fluid Analysis

The HH500 carries no engine oil or coolant to sample, so predictive care centers on the carrier's hydraulic system and the head's wear points. Track rotator bearing play and seal weep over time, log feed roller and delimb knife wear rates against cutting volume, and watch hydraulic cycle times for gradual slowdown that signals internal leakage in the rotator or feed motors. Periodic hydraulic fluid analysis on the host carrier catches contamination before it reaches the head's seals and bearings.

Corrective & Common Repairs

Most HH500 repairs trace back to the rotator, feed system, or mounting hardware rather than a power unit. Common fixes include replacing worn or chipped delimb knives, resurfacing or swapping feed roller segments, tightening or renewing mounting pins and bushings showing play, and repairing chafed hydraulic hoses at the rotation joint. Because this head is off Caterpillar's current production line, budget extra lead time for rotator and feed-system parts compared with the newer HH45-HH75 heads.

Overhaul & Rebuild Points

A full HH500 overhaul centers on the rotator: replacing its seal kit and bearing once play or leakage passes acceptable limits restores continuous-rotation function. Feed roller drive motors and delimb knife actuating cylinders are the next major rebuild items, typically addressed when internal leakage slows cycle times. Mounting brackets and pins get inspected for fatigue cracking and elongation at the same interval, since this is a bolted, load-cycled connection to the carrier rather than a fixed structural joint.

Seasonal & Environment Servicing

Cold-climate operation calls for checking the carrier's hydraulic fluid grade feeding the HH500, since a head set up for warm-weather viscosity can run sluggish or stress seals in freezing conditions. Wet, sap-heavy, or sandy cutting sites accelerate feed roller and delimb knife wear and pack debris into rotator seals and pivot points, so shorten grease and inspection intervals accordingly. Wash bark and grit off the head at the end of each shift in abrasive conditions to protect rotator seals and pin bushings.

HH500 attachments & work tools

Product line context

The HH500 belongs to Caterpillar's earlier HH300/HH500/HH700 excavator-mount harvester head line. This is a separate product line from the later HH45/HH55/HH65/HH75 heads that Caterpillar fits to its purpose-built 550/570/580 track and wheel harvesters; the two lines are documented separately and are not interchangeable.

Host carrier size class

The HH500 is an excavator-carried single-grip harvester head, not a self-propelled machine. Caterpillar service literature groups it with the smaller HH300 and larger HH700 as one head family sharing a common rotator-mount design, and Caterpillar's own installation instructions tie the largest sibling, the HH700, to 20 tonne class (320C) excavators. This places the HH500 one step down from that class on a mid-size excavator carrier; no source names a specific excavator model for the HH500 alone, so exact carrier pairing varies by dealer configuration.

Mounting/coupler system

The head attaches to the carrier's boom/stick linkage through a hydraulic, continuous-rotation rotator bolted to the head's upper yoke, the same rotator-mount arrangement shared with the HH300 and HH700. Caterpillar issued an updated rotator design as a running production change across this head family, improving the bolted connection between the rotator and the head's lower link; this superseded the earlier rotator on both new-build and retrofit units.

Saw, delimbing, and measuring-system configuration

Available Caterpillar service and parts documentation for the HH500 covers hydraulic system pressures, feed roller arm functions, and the rotator mounting, but does not disclose saw type (bar-and-chain vs. disc), delimbing knife/roller layout, or any onboard length/diameter measuring computer specific to this head. These configuration options are not published in sources accessible outside Caterpillar dealer and service channels for this older harvester-head line.

All HH500 assemblies by section

Every catalogued assembly group for the Caterpillar HH500. Open an assembly to preview the parts inside — full OEM part numbers are available in Heavy Parts AI.

Service Equipment And Supplies
213-2262 Film Gp
13***39Film-Stripe; (Red)(625cm)0
21***62Film Group1
22***05Film1
See all parts with full part numbers in Heavy Parts AI →
219-0042 Plate & Film Gp
13***76Film; (Warning) (Universal) (Lh Side Post Inside Cab)1
16***91Film-Identification; (Chain Oil)1
16***20Film-Danger1
See all parts with full part numbers in Heavy Parts AI →
Work Tools
189-5510 Damper Gp-Harvester Head
15***41Pin As1
15***43Washer1
15***44Nut1
See all parts with full part numbers in Heavy Parts AI →
218-1890 Head Ar-Harvester
21***90Head Ar-Harvester1
21***99Head Ar-Harvester0
21***00Head Ar-Harvester1
See all parts with full part numbers in Heavy Parts AI →
218-1867 Head Ar-Harvester
21***67Head Ar-Harvester1
See all parts with full part numbers in Heavy Parts AI →
219-0040 Installation Gp-Harvester Head
18***10Damper Group-Harvester Head1
21***06Rotator Group-Hydraulic1
21***34Mounting Group-Harvester Head1
See all parts with full part numbers in Heavy Parts AI →
219-0034 Mounting Gp-Harvester Head
09***70Bolt-Socket Hd; (M12 X 1.75 X 45)4
15***24Washer; (M16)6
15***88Plug2
See all parts with full part numbers in Heavy Parts AI →
210-1506 Rotator Gp-Hydraulic
12***76Bolt; (M10x1.5x130-mm)10
15***42Plug2
15***59Spring12
See all parts with full part numbers in Heavy Parts AI →

HH500 serial number reference

A harvester head carries its own PIN plate separate from the carrier excavator's serial plate. On this class of attachment the tag is typically a riveted or bolted metal plate on the head frame itself, near the rotator or top mounting bracket, rather than anywhere on the host machine. Read the three-character model/plant prefix, then the sequential unit number, to match the head against the correct parts-manual serial break.

PrefixIdentifies
CWHHH500 harvester head, all documented configurations

Frequently asked questions

Does the Caterpillar HH500 have its own engine?

No. The HH500 is a bare hydraulic attachment with no engine, transmission, fuel tank, cooling system, or onboard ECM of its own. It mounts on a host excavator-type carrier through a bolted, continuous-rotation hydraulic rotator and runs entirely off the carrier's hydraulic circuit.

What carrier does the Caterpillar HH500 mount on?

The HH500 mounts on an excavator-type forestry carrier, one size class below the HH700, which Caterpillar pairs with roughly 20-tonne, 320C-class excavators. No single carrier model is documented specifically for the HH500; carrier pairing varied by dealer configuration at the time it was sold.

What replaced the Caterpillar HH500 harvester head?

Caterpillar's later HH45, HH55, HH65, and HH75 harvester heads succeeded the older HH300/HH500/HH700 family for use on purpose-built Cat harvesters. These newer heads represent a different generation of hardware, with more current parts support and public documentation than the HH500 line.

What HH500 owners discuss

Is the Cat HH500 harvester head something people actually discuss online?
Not really, and that itself tells you something. This is an older excavator-mounted head, no engine, no ECM, running entirely off the carrier's hydraulic circuit, and it predates most of today's forum-era equipment discussion. What little turns up publicly is OEM service literature rather than owner threads. If you run one, your best information source is a dealer parts/service counter with access to the old harvester-head documentation, not a search engine.
What wears out first on the rotator?
Seals and bearing races, same as any continuously rotating hydraulic joint under a felling/processing head. Constant full-rotation duty plus bark and dirt contamination eventually shows up as slow weeping at the rotator body and rising play at the output flange. Caterpillar actually revised the rotator design partway through this head family's production run (a documented running change across the HH300/HH500/HH700 line), which tells you the original seal and wear life on early-build units was a known improvement point. If a used HH500 still carries the earlier rotator, plan on a seal kit or a full rebuild sooner rather than later. Have your dealer verify which rotator generation is fitted before you rely on it.
What's the real-world wear pattern on the feed rollers and delimb knives?
Consistent with any single-grip style excavator-mount head of this vintage: roller spikes or teeth dull and the roller body itself can wear slightly egg-shaped from years of gripping the same size range of stems, which shows up as the head slipping on wet or frozen bark instead of pulling cleanly. Delimb knife edges lose their bite and the knife pivots pick up play, giving ragged limbing instead of a clean cut. None of this is unique to the HH500, it's standard wear for the category, and it's checked and dressed or replaced on a routine inspection cycle rather than waited out.
Are hydraulic hoses and fittings a known weak point on this class of head?
Yes, and it's the rotator lines and the knife/roller cylinder lines that take the abuse, since they flex constantly and can rub against the head frame as it rotates and cycles. Chafing and fitting fatigue account for more field downtime on heads like this than an actual internal seal blowout. Standard shop practice is to inspect hose routing and clamping at every service interval and swap a hose showing surface wear or a soft spot before it lets go mid-cut, not after.
Does the mounting bracket or pin connection to the excavator boom hold up?
The head-to-boom pin joint carries the full swinging and impact load of the attachment, so pin and bushing wear plus hairline cracking near weld toes at the high-stress points is the general failure pattern across this category of felling/harvester head, not something specific to the HH500. There isn't a large public record of HH500 owners complaining about this particular head, but the mechanism is the same as any comparable excavator-mount attachment of its age. Have your dealer or a qualified fabricator inspect the bracket and pins for cracking before returning a used head to service.
How hard is it to find parts for an HH500 today?
Harder than for a current-production head. This is a discontinued line no longer in the active Cat catalog, so wear items like roller segments, knife stock, and rotator seal kits typically come through longer-lead dealer sourcing or the used/pull-parts market rather than off-the-shelf stock. Budget extra lead time into any repair plan, and confirm parts support with your dealer before committing to a purchase or a major rebuild.
What should I check before buying a used HH500?
Run the rotator through full rotation both directions and watch for slop at the flange and any weeping at the seals. Inspect the feed rollers for flat spots, worn spikes, or out-of-round wear, and check the delimb knives for dull edges and play in their pivots. Look closely at the head-to-boom mounting pins and bushings for wear and at the bracket welds for cracking. Walk every hydraulic hose and fitting on the head for chafing, soft spots, or old leaks, especially where lines cross the rotator joint. Given the parts-sourcing lead time on a discontinued head, factor any worn item you find into the price, not into a future to-do list. Have your dealer or an independent hydraulic attachment inspector verify rotator and structural condition before you buy.

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

Need a specific HH500 part?

Search live OEM part data, check fitment, and cross-reference alternatives with Heavy Parts AI.

Search parts in the app