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Kubota U15, U15-3 Excavator Workshop Repair Manual

Kubota U15, U15-3 Excavator Workshop Repair Manual

$33.00

🚜 Equipment
Brand	Kubota
Type	Excavator
Model	U15, U15-3
📄 Documents
Type	Repair Manual
Publication	97899-61482
Language	English
Format	PDF
No of Pages	766

The Kubota U15 and U15-3 Excavators are compact, high-performance machines engineered for efficiency, versatility, and operator-friendly operation in tight spaces. Built with durable Kubota diesel engines and advanced hydraulic systems, these mini excavators deliver powerful digging performance and smooth operation while maintaining a compact footprint suitable for urban construction, landscaping, and utility applications.

The U15 is powered by a Kubota D1105 diesel engine producing 13 horsepower and has an operating weight of approximately 1,680 kg. It provides a digging depth of around 2 meters with a breakout force of about 1,060 kgf, making it an ideal choice for light excavation and trenching work. The upgraded U15-3 is powered by a Kubota D782 diesel engine, also rated at 13 horsepower, with an operating weight ranging from 1,570 to 1,640 kg depending on track type (rubber or steel). It offers a maximum digging depth of 2.31 meters, a reach of 3.9 meters, and a bucket breakout force of 1,545 kgf, giving it greater productivity and improved lifting capability compared to its predecessor. Both models feature compact transport widths under 1.25 meters, ensuring access to confined spaces without sacrificing stability.

The workshop repair manual provides complete service coverage for the U15 and U15-3, including detailed sections on the machine body, hydraulic systems, control valves, pumps, swing and travel motors, engine servicing, electrical systems, and operator controls. It includes step-by-step disassembly and reassembly procedures, torque specifications, lubrication schedules, wiring diagrams, hydraulic schematics, and troubleshooting charts. Special sections highlight comparative performance between the U15 and U15-3, major selling points, lifting capacities, and safety functions, ensuring accurate diagnostics, reliable servicing, and extended machine life.

Key Highlights

U15: ~1,680 kg operating weight, 13 hp Kubota D1105 engine, ~2.0 m digging depth, ~1,060 kgf breakout force
U15-3: ~1,570–1,640 kg operating weight, 13 hp Kubota D782 engine, 2.31 m digging depth, 3.9 m reach, 1,545 kgf breakout force
Compact transport width: 0.99–1.24 m for narrow site access
Hydraulic system with efficient pump and load-sensing circuits for smooth operation
Operator-focused design with simple controls, safety lever lock, and ROPS/TOPS canopy
Workshop manual covers hydraulic, electrical, mechanical, and engine systems in detail
Includes wiring and hydraulic schematics, torque values, lubrication charts, and troubleshooting guides
Comparative data between U15 and U15-3 for performance and efficiency evaluation
Designed for maneuverability, durability, and cost-effective maintenance

Table of Content

📙 Table of Contents

Wsm_U15-3_Mechanism

WSM_U15-3_Mechanism
- CONTENTS
- I Product engineering section
  - A. Developing concept and feature
    - a. Objective and Concept of Development
      - 1. Objective of Development
      - 2. Product Concept
    - b. Main Specifications
    - c. U15-3 vs U15
      - 1. Comparison between EU and PP-version
      - 2. Comparison of Main Specifications for U15 (KTC-version)
    - d. Major Selling Points and Improvements
      - 1. Quick chart : U15-3, EU – version
      - 2. Quick chart : U15-3, KTC – version
      - 3. Main feature points
    - e. Evaluation of Competitive Power with Competitors
      - 1. Workability
      - 2. Durability
      - 3. Operability
      - 4. Comfort
      - 5. Maintainability
      - 6. Safety
      - 7. Working Range
      - 8. Outline of Hydraulic System (Travel straight function)
    - f. Actual performance comparison
      - 1. On-site Excavation Test
      - 2. Comparison of Operating Speed
      - 3. Comparison of Stability
    - g. U15 featured points
  - B. Machine specifications
    - a. Major dimensions and working range (with rubber crawler)
    - b. Dimensional drawings : U15-3
    - c. Performance and lifting capacity
      - 1. Performance
      - 2. Lifting capacity
- II Service engineering section
  - A. Maintenance specifications
    - a. List of oil and water quantities
    - b. Tightening torque
      - 1. Machine
      - 2. General bolt/nut tightening torque
      - 3. Hydraulic pipe tightening torque
      - 4. Hydraulic hose tightening torque
      - 5. Engine
    - c. Quality specifications
    - d. Operating noise
    - e. Machine weight and parts weight
  - B. Machine body structure and function
    - a. Overall Arrangement
      - 2. Arrangement of Control Levers
      - 3. Press-fitting of Bushes
      - 4. Front Equipment
      - 5. Greasing (1)
      - 6. Greasing (2)
      - 7. Cleaning and greasing the Track Frame Slide Pipes
    - b. Front attachment
      - 1. Bucket dimensions
      - 2. Bucket fixture dimensions
      - 3. Bucket link pin
      - 4. Front pins and bush
      - 5. Swing bracket
    - c. Control levers and linkage
      - 1. Lever strokes and operating forces
      - 2. Accelerator Lever
      - 3. Dozer Lever
      - 4. Dozer Cables (Route)
      - 5. Swing Pedal
      - 6. Service port Pedal
    - d. Under carriage components
      - 1. Swivel bearing
      - 2. Truck Frame (Adjustment of Play)
      - 3. Structure of Track Roller
      - 4. Tension Device
      - 5. Idler and tension spring
      - 6. Idler and sprocket
      - 7. Rubber track
      - 8. Track shoe
      - 9. Steel track shoe
      - 10. Dozer
  - C. Engine
    - a. Main specification
    - b. Performance curves
    - c. Engine electrical data
    - d. Engine servicing data
    - e. Engine Mount
    - f. Fuel System
      - 1. Fuel System (1)
      - 2. Fuel System (2)
      - 3. Fuel tank
    - g. Cooling system
      - 1. Structure
      - 2. Radiator data
    - h. Air cleaner
  - D. Hydraulic system
    - a. Main pump
      - 1. Outer view
      - 2. Pump coupling
      - 3. Pump hose adapter
      - 4. structure
      - 5. P-Q performance curve
      - 6. Pump Specifications, Type : PVD-00B-14P-5G3-4552A, code NO. : RA221-6111
      - 7. Discharge rate
      - 8. Function
    - b. Control valve
      - 1. Relief valve specifications
      - 2. Control Valve (1)
      - 3. Control Valve (2)
      - 4. Control Valve (3)
      - 5. Control Valve (4)
      - 6. Control valve sectional view
      - 7. Inner sectional view
      - 8. Function of inlet section
    - c. Swivel motor
      - 1. Swivel system specifications
      - 2. Component of swivel motor
      - 3. Cross-sectional View of Swivel Motor
      - 4. Swivel Motor fittings
      - 5. Function
    - d. Travel motor (Wheel motor)
      - 1. Overview (RA221-61291)
      - 2. Specifications
      - 3. Piston motor installation
      - 4. Structure
      - 5. Principle of operation
    - e. Pilot valve (Remote control valve)
      - 1. Structure
      - 2. Sectional view
      - 3. Adaptors
      - 4. Function
    - f. Cylinders
      - 1. Cylinder speed
      - 2. Gravity fall
      - 3. Specifications and part codes of boom, arm, bucket and swing cylinder
      - 4. List of cylinder dimensions
      - 5. Cylinders’ section view
    - g. Swivel Joint (Rotary joint)
      - 1. Swivel Joint (1)
      - 2. Swivel Joint (2)
      - 3. Route of Hose (Travel, blade)
      - 4. Route of Hose (Track Cylinder Hose)
    - h. Unload valve
      - 1. Structure
      - 2. Adaptor installation
    - i. Selector valve
      - 1. Structure
      - 2. Function
      - 3. Specifications
    - j. Accessories of hydraulic components
      - 1. Check valve assy
      - 2. Hydraulic filter
      - 3. Oil Tank
      - 4. Oil cooler
      - 5. Accumulator (EU – version)
    - k. Hydraulic system flow
      - 1. Hydraulic Pressure Hose Circuit (High-pressure)
      - 2. Hydraulic Pressure Hose Circuit (Low-pressure)
      - 3. Pilot system circuit : EU – version
      - 4. Travel Unloading function
      - 5. Boom Confluence
      - 6. Service port Confluence
      - 7. Straight Travel Circuit
    - l. Service port system
      - 1. Component layout
      - 2. 1-way or 2-way valve (EU – version)
    - m. TPSS (Two Pattern Selection System) : PP – version
      - 1. Location and overview
      - 2. Hose connection
      - 3. TPSS port connection
      - 4. Technical data
      - 5. TPSS function circuit
    - n. Hydraulic components layout : U15-3, U15
    - o. Hydraulic circuit diagram
      - 1. U15-3, EU – version
      - 2. U15-3, EU – version : Track extension
      - 3. U15-3, EU – version, Service port flow
      - 4. U15, PP – version
      - 5. U15, PP – version : Three operation : boom up, arm extend, swivel R, A(JD)-pattern
      - 6. U15, PP – version : Travel forward, high speed and boom down, B(ISO, Kubota)-pattern
  - E. Electrical system
    - a. New Functions of Electric System
      - 1. Starter automatic release function
      - 2. Auto-glow
      - 3. Theft-proof Specification
    - b. Battery circuit
    - c. Key switch (Engine starter switch)
    - d. Safety lever lock switch
      - (2) Safety lever lock circuit malfunction
    - e. Solenoid valve
      - 1. Structure
      - 2. Solenoid test method
    - f. Travel hi-speed control circuit
      - 1. Hi – Low switch and circuit diagram
      - 2. Troubleshooting: Travel hi-speed malfunction
      - 3. Testing Hi – Low SW
      - 4. Hi – Low self hold circuit
    - g. Meter panel
      - 1. Installation view
      - 2. Warning lamps indication
      - 3. Meter structure
      - 4. Meter panel circuit diagram
      - 5. Fuel gauge coil resistance test
      - 6. Hour meter function test LED and stepping motor function check.
    - h. Fuses
      - 1. Replacing Fuses
      - 2. Fuse Capacities and Circuits
    - i. Auto glow circuit
      - 1. Function
      - 2. Auto glow control circuit diagram
      - 3. Auto glow controller
      - 4. Auto glow circuit
    - j. Auto release control system
      - 1. Outline
      - 2. Auto release control, structure and function
      - 3. Key SW to engine start position
      - 4. Key SW to AC position
      - 5. When the Key SW is stuck at the start position
      - 6. Key to the start position while engine is running
      - 7. Function of low-voltage detection
      - 8. Auto release and auto glow circuit combined
    - k. Water temp. sensor & gauge
      - 1. Water temp. sensor circuit malfunction
    - l. Fuel control circuit
      - (1) Function
    - m. Engine stop solenoid and coil commander
      - 1. Location
      - 2. Circuit diagram
      - 3. Function
      - 4. Inspection & troubleshooting
    - n. Fuel sensor
      - 1. Fuel sensor
      - 2. Fuel sensor testing
    - o. Engine oil pressure sensor circuit
      - Oil switch
    - p. Engine electrical system
      - 1. Engine oil pressure failure
    - q. Horn circuit
      - 1. Structure
      - 2. Function
      - 3. Current flow
      - 4. Horn circuit
    - r. Charging system (Alternator)
      - 1. Alternator structure (Code No. 16678-64012)
      - 2. Circuit diagram
      - 3. Charging system malfunction
    - s. Relay
      - 1. Relays location
      - 2. Purpose of relays
      - 3. Structure of relay
      - 4. Specifications
      - 5. Checking relays
    - t. Route of Electric Wiring
      - 1. Unloading, horn
      - 2. Route of Electric Wiring (Engine Rear)
      - 3. Route of Electric Wiring (Engine Upper Side)
      - 4. Route of Electric Wiring (Starter Motor, Body Grounding)
      - 5. Route of Electric Wiring (Right Side of the Operation Stand)
    - u. Electrical component layout
    - v. Electric Circuit
      - 1. Battery direct line and ground (Earth) line
      - 2. Key switch ON (AC – position)
      - 3. Key switch to the start position
      - 4. Engine running at travel high range
    - w. Electrical wiring diagram
      - 1. Initial type (Lever lock SW isn’t linked)
      - 2. Modified type (Lever lock SW is wired)
- ConversionTable

Wsm_U15-3_Service

WSM_U15-3_Service
- CONTENTS
- I General
  - A. Body and engine identification marks
  - B. Safety precautions for servicing, disassembly and reassembly
    - a. Safety measures before starting work
      - (1) Work clothes
      - (2) Inspecting equipment and tools
      - (3) Keep workshop in order
    - b. Safety measures during work
      - (1) Protectors
      - (2) Team work
      - (3) Disassembly and assembly
      - (4) Cranes
      - (5) Others
    - c. Preparation for disassembly
      - (1) Cleaning
      - (2) Acceptance inspection
      - (3) Equipment and tools
    - d. Precautions for disassembly and reassembly
      - (1) Disassembly
      - (2) Reassembly
      - e. Maintenance
      - f. Waste Disposal
  - C. Important Safety process and critical functional process
    - a. Essential Adhesives
    - b. Important Safety Process.
    - c. Important Critical Functional Process.
  - D. Important inspection items after reassembling
    - a. Operate the Machine and check for Unusual Noise and Vibrations.
    - b. Make Sure the Safety decals and Wireharness Clamps are in their Specified Positions.
    - c. With the Machine Front in a Specified Posture, Check the Amount of Hydraulic Oil
    - d. Piping
      - (1) General precautions
      - (2) Hydraulic hose
      - (3) Precautions in tightening the bolts and nuts
      - (4) Hose screw
      - Metric Size Hose
      - (5) Joint bodies
      - (6) Tightening torque table for hose clamp (Screw type)
      - (7) Nuts for piping
      - (8) Tightening torque of bolts and nuts
      - (9) Types and materials of bolts and nuts
      - (10) Washer-equipped elbow
      - (11) Adhesives
  - E. Maintenance intervals
    - a. EU version
    - b. PP (KTC, KCL)-version
    - b-1. KTA-version
    - c. Hydraulic Oil Check for Machines with Hydraulic Breakers
    - d. Maintenance items
      - (1) Drive unit Oil Change(First Oil Change of the 100 hours)
      - (2) Inspection and Cleaning of the Air Filter Element
      - (3) Cleaning the Track Frame Slide Pipes
    - e. Troubleshooting for operators
    - f. Periodic replacement of important component parts
    - g. Recommend oils
    - h. Lifting capacity : U15-3
  - F. Specifications
    - a. Machine Weight
      - (1) KE, KDG, KUK version
      - (2) PP (KTC, KCL, KTA) version
    - b. Main Specifications
    - c. Lever stroke and operating force
    - d. Dimensions of Parts
      - (1) Front pins and bush
      - (2) Bucket fixture dimensions
      - (3) Bucket link pin
      - (4) Track roller
      - (5) Idler and sprocket
      - (6) Dozer
      - (7) Bucket dimensions
      - (8) Machine weight and parts weight
      - (9) Water and Oil Quantity
    - e. Quality specifications
- II Machine Body
  - A. Front attachment
    - a. Pin, bush and shim installation
      - (1) Swing cylinder, swing bracket, boom
      - (2) Arm, bucket link
      - (3) Blade, blade cylinder and truck cylinder
      - (4) Clearance adjustment
    - b. Instruction to press in the bushing
      - (1) Bush installation steps
      - (2) Installing direction of dust seal
      - (3) Installation of thrust collar on the swing bracket
      - (4) Swing bracket pin & bush.
      - (5) Measuring the swing bracket looseness
      - (6) Service tip to ease customer complaint
    - c. Greasing points
  - B. Upper Structure
    - a. Swivel bearing
    - b. Travel lever
    - c. Accelerator lever
    - d. Dozer lever
    - e. Control link
    - f. Swing pedal
    - g. Service port pedal
    - h. Pilot control valve
    - i. Limit switch installation
    - j. Seat and Seat belt
    - k. Wrist rest
    - l. Canopy
    - m. Weight
  - C. Undercarriage
    - a. Track tension device
    - b. Track Roller
- III Engine
  - A. Engine accessories
    - a. Engine mount
    - b. Air cleaner
    - c. Radiator
      - (4) Thermostat
    - d. Muffler
    - e. Pump coupling
    - f. Fuel tank
    - g. Fuel hoses
    - h. Engine outlook
  - B. Engine WSM : D782 -B
- IV Hydraulic System
  - A. Troubleshooting
    - a. Common circuit
    - b. Hydraulics
    - c. Pump
    - d. Motor
    - e. Swivel performance
    - f. Traveling performance
  - B. Testing
    - a. Testing Instruments & special tools
    - b. Pump flow
    - c. Pressure measurement
      - (1) Pilot pressure
      - (2) Main relief valve
      - (3) Overload relief valve
      - (4) Swivel brake valve pressure
    - d. Drain measurement
      - (1) Traveling motor
      - (2) Swivel motor
    - e. Measurement of block performance
      - (1) Swivel
      - (2) Traveling
    - f. Operating speed
      - (1) Checking each operating speed.
      - (2) Boom cylinder
      - (3) Arm cylinder
      - (4) Bucket cylinder
      - (5) Swing cylinder
      - (6) Dozer cylinder
      - (7) Swivel speed
      - (8) Traveling speed
    - g. Straight travel performance
    - h. Swivel system diagnosis
      - (1) Main check points
      - (2) Checking the pilot valve spool performance
      - (3) Checking the control valve spool performance (stuck)
      - (4) Measuring the secondary pressure of pilot valve
      - (5) Checking the brake valve pressure
      - (6) Checking the anti-void valve movement and seating
      - (7) Checking the motor drain amount
    - i. Travel system diagnosis
      - (1) Diagnosis
      - (2) Main points
      - (3) Inlet dump spool check
      - (4) Checking the counterbalance valve and high/low-speed selector valve (travel motor)
      - (5) Checking the swivel joint for internal leak
    - j. Cylinder natural fall amount
    - k. Control and Traveling lever operating force
    - l. Lever stroke
  - C. Specifications
    - a. Pump specifications
    - b. Relief Valve
      - (1) Bench set data
      - (2) Machine set data (at the pump gauge port)
    - c. Swivel performance
    - d. Traveling performance
    - e. Cylinder
      - (1) Speed
      - (2) Natural fall
      - (3) Cylinder maintenance data
    - f. Service port flow amount
    - g. Motor oil drain amount test sample
      - (1) Travel motor
      - (2) Swivel motor
    - h. Hydraulic components layout : U15-3, U15
    - i. Hydraulic circuit diagram
      - 1. U15-3, EU – version
      - 2. U15, PP – version
  - D. Disassembling and reassembling
    - a. Pump
      - (1) Pump coupling
      - (2) Adaptor installation
      - (3) Component of pump
      - (4) Disassembling and reassembling
    - b. Control valve
      - (1) Control Valve assy
      - (2) Adaptor installation
      - (3) Inner parts of control valve
      - (4) Disassembling and reassembling
    - c. Pilot valve
      - (1) Installation
      - (2) Component of pilot valve
      - (3) Inner parts
      - (4) Function
      - (5) Adaptor installation
      - (6) Pilot hose connection
      - (7) Pilot hose (Size 1/4)
      - (8) Disassembling and assembling
    - d. Swivel motor
      - (1) Component of swivel motor
      - (2) Cross-sectional View of Swivel Motor
      - (3) Adaptor Installation
    - e. Rotary joint
      - (1) Installation
      - (2) Adaptors
      - (3) Components of Rotary Joint
      - (4) Hose connection
      - (5) Oil piping
      - (6) Assembling of the rotary joint
      - (7) Disassembling of the Rotary Joint from machine
    - f. Travel motor
      - (1) Component of travel motor
      - (2) Adaptor installation
      - (3) Hose connection
      - (4) Disassembly and reassembly
    - g. Cylinder
      - (1) Components and specifications
      - (2) Disassembling and reassembling
    - h. Change valve (Dozer, Track)
      - (1) Location and adaptor
      - (2) Components of change valve (Dozer, Track)
    - i. Unload valve
      - (1) Location and adaptor
      - (2) Structure and specifications
      - (3) Hose connection
    - j. Accumulator
      - (1) Installation
      - (2) Accumulator performance test
    - k. Oil tank
      - (1) Installation
      - (2) Filter element
    - l. Third line
    - m. TPSS valve
      - (1) Dismounting and remounting
      - (2) Disassembly and reassembly
      - (3) Pilot hose
- V Electrical system
  - A. General
    - a. New feature on electrical system
      - (1) Starter automatic release function
      - (2) Auto glow
      - (3) Anti-theft type
    - b. Electrical component layout
    - c. Electric circuit diagram
    - d. Electrical wiring diagram, initial version
    - e. Electrical wiring diagram, revised version
  - B. Troubleshooting
    - a. General
      - (1) How to diagnose
    - b. Engine
    - c. Panel relevant (Key switch: ON)
    - d. Panel relevant (Engine starting)
    - e. Others
  - C. Inspection
    - a. Coupler check
    - b. Components check
    - c. Fuse inspection
    - d. Harness check
    - e. Battery check
    - f. Measuring instruments and special tools
  - D. Wire Harness Installation
    - a. Precautions in clamping the electrical cabling
    - b. Harness layout, overview
    - c. Engine’s back
    - d. Engine’s top
    - e. Cabling the unload and horn switch
    - f. Routing the front electrical cables
    - g. High-speed switch, horn and anti-theft unit
  - E. Main Components Maintenance
    - a. Checking the fuses
      - (1) Check points
    - b. Checking the battery
      - (1) Check points
    - c. Checking the meter panel and key switch
      - (1) Fuel meter
      - (2) Check procedure of the key switch
    - d. Checking the working lamp
    - e. Checking the horn
    - f. Checking the glow relay
    - g. Glow plug
    - h. Unload safety switch
    - i. Hi-Low travel switch
    - j. Checking the solenoid valve
    - k. Checking the fuel pump
    - l. Checking the fuel sensor
    - m. Engine stop solenoid and coil commander
    - n. Checking the water temperature gauge
    - o. Oil switch
    - p. Relay
      - (1) Location
      - (2) Starter lock relay
      - (3) Auto release relay
      - (4) Auto release stabilizer relay
      - (5) Glow relay
      - (6) Auto glow controller
      - (7) Auto release controller
      - (8) Travel high – low circuit relay
    - q. Installation of Canopy Light for KTA

Specification

Specification	Kubota U15 Excavator	Kubota U15-3 Excavator
Operating Weight	~3,704 lb (~1,680 kg)	~1,570 kg (rubber) / ~1,640 kg (steel)
Engine Power	13 hp gross / 13 hp net (D1105)	13 hp (~9.6 kW) (D782-E2-BH7)
Max Digging Depth	~2 m (7 ft 6 in)	2.31 m (7 ft 6.9 in)
Max Reach Along Ground	~4 m (13 ft)	3.9 m (12 ft 9.5 in)
Bucket Breakout Force	~1,060 kgf (~2,337 lb)	1,545 kgf (~3,406 lb)
Transport Dimensions (L × W × H)	~12 ft × 4 ft × 8 ft (depending on config)	3.57 m × 0.99–1.24 m × 2.25 m
Hydraulic Pump Setup	~17 L/min (~4 gpm) pump flow	Twin variable displacement + gear pump (“3-pump system”)

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