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Cat knuckleboom loaders are known for superior multifunction capability, excellent visibility and heavy-duty booms and structures. Now the Cat C Series knuckleboom loaders feature a new more fuel efficient power system, an upgraded hydraulic system for greater reliability and significantly more lift at full reach than previous models. Like the smaller model, the Cat 579C, now has a right-side operator’s cab with a walk-up platform and enlarged doorway for safe access to the cab.


Gross Power 174.0 hp 129.5 kW Less
Engine Model Cat® C6.6 ACERT™ Tier 4 Interim Cat® C6.6 ACERT™ Tier 4 Interim Less
Gross Power @ 1,800 rpm 174.0 hp 129.5 kW Less


Operating Weight 36480.0 lb 16582.0 kg Less
Counterweight 1440.0 lb 653.0 kg Less
Operating Weight (less grapple) 36480.0 lb 16582.0 kg Less
Operating Weight without grapple 36480.0 lb 16582.0 kg Less

Operating Specifications

Knuckleboom Length 32.0 ft 9.8 m Less
Swing Speed 9.5 RPM 9.5 RPM Less
Maximum Reach (standard boom) 32.0 ft 9.8 m Less
Standard Knuckleboom Reach to Pin 32.0 ft 9.8 m Less
Swing Bearing Diameter (ball path) 43.5 in 1105.0 mm Less
Swing Torque 73800.0 lb ft 100360.0 N·m Less
Tailswing 108.2 in 2750.0 mm Less

Service Refill Capacities

Hydraulic Tank 80.0 gal 302.0 L Less
Fuel Tank 100.0 gal 378.0 L Less
Cooling System 7.5 gal 29.0 L Less
Engine Oil 4.0 gal 15.0 L Less
Swing Drive 2.6 gal 10.0 L Less

Hydraulic System

Cylinders - Main two two Less
Cylinders - Stick one one Less
Hydraulic Pressure - Swing 3500.0 psi 24131.0 kPa Less
Hydraulic Pressure - System 3500.0 psi 24131.0 kPa Less
Cylinders - Stabilizers four four Less
Hydraulic Oil Flow @ 1,800 rpm 230/230 L (60/60 gal) 230/230 L (60/60 gal) Less


Stabilizer Pad Size 508 × 711 mm (20 × 28 in) 508 × 711 mm (20 × 28 in) Less
Stabilizer Reach Below Grade 12.8 in 324.0 mm Less
Stabilizer Spread at Maximum Down Reach 166.8 in 4237.0 mm Less
Stabilizer Spread at Grade 183.8 in 4670.0 mm Less
Height to Top of Cab 161.9 in 4112.0 mm Less


OFPS cab meets SAE J2267 cab meets SAE J2267 Less

Shipping Dimensions (mounted trailer)

Height 161.9 in 4112.0 mm Less
Width 101.3 in 2573.0 mm Less


Continuous, Reliable and Responsive Control

Power Train

Exceptional Power and Fuel Efficiency

Operator Station

Comfort and Convenience to Keep People Productive


Durable and Reliable

Structure and Subframe

Built to Work in Rugged Applications

Boom and Stick

Made for Heavy Lifting and Long Service Life


Work Tool Options to Meet Your Needs

Delimber/Slasher Package

A Complete Factory Installed System

Owning and Operating Costs

Proven Best Investment


Easy to Maintain. Easy to Service.

Customer Support

Ready to Help. Anytime. Anywhere.


Reducing Environmental Impacts

579C Standard Equipment

  • 24V system
  • Master disconnect
  • Circuit breaker protection
  • 95 Amp alternator
  • Two (2) 12V maintenance free batteries
  • Standard lighting package: - Two (2) cab mounted halogen light fixtures
  • Electronic engine/machine monitoring system
  • Two (2) 12V power points
  • 20 circuit electric swivel

  • Cab with swing out front window guard (meets SAE J2267)
  • Isolation mountings
  • Dual joystick control (pilot hydraulic actuation) with foot pedal swing
  • Electric stabilizer controls
  • Integrated trailer landing gear control
  • Pilot shut-off button
  • Push button throttle control
  • Reverse slope windshield
  • Skylight
  • Tinted safety glass
  • Sunshade - dual position for front window/skylight
  • High back suspension seat with lumbar support
  • High capacity AC/heater system with outside air intake
  • Defroster fan
  • Windshield wiper/washer
  • Dome light
  • Horn
  • Radio ready - includes speakers and AM/FM antennas
  • CB Radio ready - includes mounting bracket, power and ground wires, antenna cable and antenna mount bracket
  • Product Link ready
  • Cup holder
  • Fire extinguisher mounting bracket
  • Diagnostic port
  • Cell phone storage tray

  • Cat C6.6 ACERT engine meets U.S. EPA Tier 4 Interim/EU Stage IIIB emission standards
  • Electric fuel priming pump
  • Air precleaner
  • 2-stage air cleaner
  • Enlarged cooling package with isolated cores
  • 378 L (100 U.S. gal) fuel tank
  • Fuel water separator
  • Variable speed fan

  • Twin 140 cm3 (8.54 in3) variable displacement pumps
  • Excavator style “Negacon” system
  • Bar slasher/delimber hydraulic package
  • 302 L (80 U.S. gal) hydraulic tank
  • Electric hydraulic oil fill pump

  • 653 kg (1,440 lb) counterweight
  • Fabricated heavy-duty, extended length center mount subframe
  • Flat top subframe deck with bolt-on skid resistant fenders
  • Bolt-on subframe ladder

  • 9.8 m (32 ft) reach knuckleboom
  • 229 mm (9 in) grapple mounting knuckle

  • 50% concentration extended life coolant

579C Optional Equipment

  • Suspension trailer with hydraulic landing gear
  • CTR 320 three-knife delimber
  • CTR 426 four-knife delimber

  • Cat Product Link
  • AM/FM/CD/Satellite radio receiver
  • Long-range front lights on cab
  • Engine compartment lights
  • Additional subframe ladders
  • Auxiliary light package
  • Slasher port adapter fittings
  • Single “V” and double “VV” bolt on heels
  • Single “V” extended and double “VV” extended bolt on heels
  • 305 mm (12 in) grapple mounting knuckle
  • Grapples

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