Kubota KX040-4 Mini Excavator – Parts, Specs & Serial Number Guide

The Kubota KX040-4 is a high-performance 4-ton class mini excavator engineered for powerful digging and fuel efficiency in compact workspaces. It features a conventional tail swing design with exceptional stability and a deluxe cab, making it ideal for trenching, backfilling, grading, and utility work. The KX040-4 also comes standard with adjustable auxiliary hydraulics, an Eco Plus mode, and a hydraulic angle blade, improving both productivity and operator control.

Key Specifications:

Engine:

• Model: Kubota D1803-CR-TE4

• Type: 3-cylinder, direct injection, turbocharged diesel (Tier 4 Final)

• Displacement: 111.4 cu in (1.826 L)

• Gross Power: 42.4 hp (31.6 kW) @ 2,200 rpm

Transmission & Travel:

• Travel Speed: Low: 1.8 mph (2.9 km/h), High: 3.1 mph (5.0 km/h)

• Drive Motors: Variable piston motors with auto-shift travel

Hydraulic System:

• Pump Capacity: 42.4 + 42.4 + 11.4 l/min (triple pump system)

• Auxiliary Flow (1st Circuit): 19.8 gpm (75 L/min)

• Auxiliary Flow (2nd Circuit): 7.9 gpm (30 L/min)

• Max Operating Pressure: 3,133 psi (216 bar)

• Hydraulic Blade: Angle blade with float and power tilt

Dimensions:

• Operating Weight: 9,195 lbs (4,170 kg)

• Max Digging Depth: 11 ft 3 in (3.43 m)

• Max Reach at Ground Level: 18 ft 3 in (5.56 m)

• Tail Swing Radius: 3 ft 6.1 in (conventional tail swing)

Performance:

• Bucket Breakout Force: 9,535 lbf (42.4 kN)

• Arm Digging Force: 4,250 lbf (18.9 kN)

Maintenance & Common Parts:

Routine Maintenance Tasks:

• Engine oil and filter: every 250 hours

• Hydraulic filter and oil: every 500 hours

• Track tension and undercarriage inspection: weekly

• Radiator and oil cooler cleaning: every 50 hours

Commonly Replaced Parts:

• KX040-4 Hydraulic Cylinder Seal Kits

• Final Drive Motors

• Rubber Tracks, Idlers & Sprockets

• Fuel, Air, and Hydraulic Filters

• Hydraulic Angle Blade Parts

Common Issues & Quick Fixes:

• Hydraulic blade not angling correctly: Usually caused by worn seals or jammed linkage—replace or repair with blade cylinder kits.

• Track wear or de-tracking: Check sprockets and adjust tension—replace with rubber track sets and undercarriage components.

• Loss of auxiliary hydraulic power: Confirm flow setting via the cab monitor and inspect hoses—use aux valve kits or new joystick switches as needed.

Pro Tips:

• Enable Eco Mode to reduce fuel consumption by up to 20% during light-duty cycles.

• Use dual auxiliary circuits to run a hydraulic thumb and other tools simultaneously.

• Grease all pivot points daily to extend the life of bushings and pins, especially on the angle blade and boom swing joints.

Serial Number Location:

• Located on a metal tag on the front-right frame, just below the cab, and also stamped near the hydraulic tank access panel.

• Record your serial number when browsing Kubota KX040-4 parts to ensure compatibility.