Kubota Mini Excavator & Compact Loader Torque Specs

Quick-reference torque specifications for Kubota KX-series mini excavators, U-series compact excavators, and SVL compact track loaders. Always verify against the machine-specific Workshop Manual (WSM) before service; never substitute this table for a factory torque sequence on safety-critical fasteners.

Quick-reference torque specs

Hydraulic Fitting — 9/16"-18 ORB (SAE -06 dash size, 3/8" tube) 22-26 ft-lbs (SAE O-ring boss (ORB) straight-thread fitting into port; wet torque (lubricated). Applies to all Kubota excavators and CTLs using SAE ORB ports.). Hydraulic Fitting — 3/4"-16 ORB (SAE -08 dash size, 1/2" tube) 37-37 ft-lbs (Common main-circuit fitting size on KX/U-series boom, arm, and bucket circuits. Wet torque per SAE J1926/3.). Hydraulic Fitting — 1-1/16"-12 ORB (SAE -12 dash size, 3/4" tube) 70-70 ft-lbs (Often used on hydraulic pump/motor ports and travel motor inlets. Wet torque.). Hydraulic Fitting — 1-5/16"-12 ORB (SAE -16 dash size, 1" tube) 111-111 ft-lbs (Larger suction-side or case-drain fittings. Wet torque per SAE J1926/3.). Hydraulic Hose Union Nut — 3/8" hose fitting 27-31 ft-lbs (KX057-4/U55-4 WSM Section G-16 hose union-nut torque table. Applies to 3/8" union-nut (non-ORB swivel hose connections).). Hydraulic Hose Union Nut — 1/2" hose fitting 43-47 ft-lbs (KX057-4/U55-4 WSM 1/2" union-nut range from Section G-16. Common at boom cylinder base connections.). Hydraulic Hose Union Nut — 3/4" hose fitting 87-94 ft-lbs (KX057-4/U55-4 WSM 3/4" union-nut range from Section G-16. Used on pump-side high-flow hoses.). General-Use Bolt M10 (4T grade / no-grade, steel mating surface) 29-33 ft-lbs (Default torque for unspecified M10 bolts in KX057-4/U55-4 WSM. Do NOT use for any joint that has a model-specific spec in the WSM.). General-Use Bolt M12 (4T grade / no-grade, steel mating surface) 47-53 ft-lbs (Default M12 torque from WSM general table. Applies where no specific value is given (e.g., access-cover bolts, bracket hardware).). Control Valve Bracket Bolts M12×25 (with Loctite 271) 57-67 ft-lbs (Bracket securing main control valve assembly; Loctite 271 (red thread-lock) required per WSM. Applies to KX057-4/U55-4.). Hydraulic O-ring boss (ORB) fitting torque is set by thread size and is the same across makes. Always confirm against your machine’s service manual.

Sequence-required & verify-against-manual fasteners

These structural or safety-critical fasteners require the machine-specific tightening sequence or a service-manual value rather than a single number: Swing Bearing (Slewing Ring) Bolts — inner and outer race — See sequence (Tightening sequence is mandatory; consult model-specific WSM. Bolts are typically high-grade (10.9+) and require thread preparation (anti-seize or Loctite per OEM spec) plus a star/cross tightening pattern. Verify re-torque interval (commonly 50 hrs after replacement).). Counterweight Mounting Bolts — See sequence (Counterweight is a large unsupported mass; a tightening sequence is mandatory to prevent uneven clamp load. Exact torque varies by model. Consult WSM for your serial-number range before service.). Track Shoe (Grouser) Bolts — KX/U-series mini excavator — See service manual (Track shoe bolt torque is model-specific and depends on shoe width and bolt diameter (typically M16–M20 high-grade). WSM undercarriage section (Track Frame 1-S34) contains the values. Do not estimate; incorrect torque causes shoe loss or stud failure.). Final Drive / Travel Motor Mount Bolts — See service manual (Travel motor flange bolts are safety-critical; typically M14–M16 high-grade with Loctite. Exact torque in WSM Section 3 (Travel Motor 3-S29). Do not substitute general bolt table values for this joint.). Engine Oil Drain Plug — Kubota V2607 (KX057-4 / U55-4) — See service manual (The V2607 engine WSM torque table does not publish a crankcase drain-plug torque in freely-accessible excerpts. Two independent sources confirmed the absence. Typical Kubota small-diesel drain plug range is 18–26 ft-lbs (25–35 N·m) for M14×1.5 plugs, but do not use this estimate — confirm with the engine service manual (Kubota OEM# 9Y111-01039 for V2607).). Track Tension (sag adjustment, not a torque) — See sag note (KX/U-series: set ~80-85 mm track sag via the grease cylinder - an adjustment, not a bolt torque.).

Model coverage

KX040-4 (2015–present), Mini Excavator, Kubota D1803-CR-TE4, 3-cyl, 1,826 cc, Tier 4; KX057-4 (2009–present), Mini Excavator, Kubota V2607-DI, 4-cyl, 2,615 cc, Tier 4 Interim; U35-4 (2008–present), Compact Excavator (Zero Tail Swing), Kubota D1703M-DI-E4, 3-cyl, 1,647 cc, Tier 4; U55-4 (2012–present), Compact Excavator (Zero Tail Swing), Kubota V2607-CR-E4, 4-cyl, 2,615 cc, Tier 4; SVL75-2 (2014–present), Compact Track Loader, Kubota V3307, 4-cyl, Tier 4 Final; SVL95-2s (2014–present), Compact Track Loader, Kubota V3307-CR-TE4, 4-cyl, Tier 4 Final / SCR.

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