Kubota LA434 Workshop Manual
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Kubota LA434 Workshop Manual

Kubota LA434 Workshop Manual

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WORKSHOP MANUAL
FRONT LOADER
LA434
KiSC issued 11, 2014 A

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  • Page 1 WORKSHOP MANUAL FRONT LOADER LA434 KiSC issued 11, 2014 A...
  • Page 2 TO THE READER This Workshop Manual tells the servicing personnel about the mechanism, servicing and maintenance of KUBOTA Front Loader LA434. It contains 4 parts: "Information", "General", "Mechanism" and "Servicing".  Information This section primarily contains information below. • Safety First •...
  • Page 3 INFORMATION KiSC issued 11, 2014 A...

  • Page 4: Table Of Contents

    INFORMATION CONTENTS 1. SAFETY FIRST ..........................I-1 2. SAFETY DECALS .......................... I-4 3. LOADER TERMINOLOGY ......................I-6 4. SPECIFICATIONS.......................... I-7 [1] LOADER SPECIFICATIONS ....................I-7 [2] BUCKET SPECIFICATIONS ....................I-7 [3] DIMENSIONAL AND OPERATIONAL SPECIFICATIONS............I-8 KiSC issued 11, 2014 A...

  • Page 5: Safety First

    INFORMATION LA434, WSM 1. SAFETY FIRST SAFETY FIRST • This symbol, the industry's "Safety Alert Symbol", is used throughout this manual and on labels on the machine itself to warn of the possibility of personal injury. Read these instructions carefully.
  • Page 6 INFORMATION LA434, WSM OPERATE SAFELY • Do not use the machine after you consume alcohol or medication or when you are tired. • Put on applicable clothing and safety equipment. • Use applicable tools only. Do not use alternative tools or parts.
  • Page 7 INFORMATION LA434, WSM KEEP A GOOD AIRFLOW IN THE WORK AREA • If the engine is in operation, make sure that the area has good airflow. Do not operate the engine in a closed area. The exhaust gas contains poisonous carbon monoxide.

  • Page 8: Safety Decals

    INFORMATION LA434, WSM 2. SAFETY DECALS The following safety decals are installed on the machine. If a decal becomes damaged, illegible or is not on the machine, replace it. The decal part number is listed in the parts list. WSM000001INI0013US0...
  • Page 9 2. Clean danger, warning and caution labels with soap and water, dry with a soft cloth. 3. Replace damaged or missing danger, warning and caution labels with new labels from your local KUBOTA dealer. 4. If a component with danger, warning and caution label(s) affixed is replaced with new part, make sure new label(s) is (are) attached in the same location(s) as the replaced component.

  • Page 10: Loader Terminology

    INFORMATION LA434, WSM 3. LOADER TERMINOLOGY (1) Side Frame (6) Main Frame (2) Boom (7) Mounting Pin (3) Bucket Cylinder (8) Loader Control Lever (4) Bucket (9) Lock Lever (5) Boom Cylinder 9Y1211247INI0004US0 KiSC issued 11, 2014 A...

  • Page 11: Specifications

    INFORMATION LA434, WSM 4. SPECIFICATIONS  Suitable Tractor LA434 Loader Model B2301, B2601 Tractor Model 9Y1211247INI0005US0 [1] LOADER SPECIFICATIONS Loader Model LA434 Tractor Model B2301, B2601 Wheel Base (WB) 1563 mm (61.5 in.) Front Tires 7-12 Rear Tires 11.2-16 Bore 45 mm (1.77 in.)

  • Page 12: Dimensional And Operational Specifications

    INFORMATION LA434, WSM [3] DIMENSIONAL AND OPERATIONAL SPECIFICATIONS  Dimensional Specifications Loader Model LA434 Tractor Model B2301, B2601 Maximum lift height (To bucket pivot pin) 1995 mm (78.5 in.) Maximum lift height under level bucket 1853 mm (72.9 in.) Clearance with bucket dumped 1568 mm (61.7 in.)
  • Page 13 GENERAL KiSC issued 11, 2014 A...
  • Page 14 GENERAL CONTENTS 1. LOADER IDENTIFICATION ......................G-1 2. GENERAL PRECAUTIONS......................G-2 3. LUBRICANTS ..........................G-3 4. TIGHTENING TORQUES......................G-4 [1] GENERAL USE SCREWS, BOLTS AND NUTS ..............G-4 [2] STUD BOLTS ......................... G-4 [3] AMERICAN STANDARD SCREWS, BOLTS AND NUTS WITH UNC OR UNF THREADS ..........................

  • Page 15: Loader Identification

    GENERAL LA434, WSM 1. LOADER IDENTIFICATION When contacting your local KUBOTA distributor, always specify front loader serial number (1). (1) Serial Number 9Y1211247GEG0001US0 KiSC issued 11, 2014 A...

  • Page 16: General Precautions

    • When it is necessary to use special tools, use KUBOTA special tools. Refer to the drawings when you make special tools that you do not use frequently.

  • Page 17: Lubricants

    Grease fittings Until grease overflows. Moly Ep type grease** NOTE • * KUBOTA original transmission hydraulic fluid. • ** "Extreme pressure" and containing Molybdenum disulfide is recommended. This grease may specify "Moly Ep" on it's label. 9Y1211247GEG0002US0 KiSC issued 11, 2014 A...

  • Page 18: Tightening Torques

    GENERAL LA434, WSM 4. TIGHTENING TORQUES Tighten screws, bolts and nuts whose tightening torques are not specified in this Workshop Manual according to the table below. WSM000001GEG0118US0 [1] GENERAL USE SCREWS, BOLTS AND NUTS Indication on top of bolt No-grade or 4T 7T or Property class 8.8...

  • Page 19: American Standard Screws, Bolts And Nuts With Unc Or Unf Threads

    GENERAL LA434, WSM [3] AMERICAN STANDARD SCREWS, BOLTS AND NUTS WITH UNC OR UNF THREADS Grade SAE GR.5 SAE GR.8 Unit N·m kgf·m lbf·ft N·m kgf·m lbf·ft 11.7 to 15.7 1.20 to 1.60 8.63 to 11.5 16.3 to 19.7 1.67 to 2.00 12.0 to 14.6...

  • Page 20: Hydraulic Fittings

    GENERAL LA434, WSM [5] HYDRAULIC FITTINGS (1) Adapters, Elbows and Others Tightening torque Item Shape Thread size N·m kgf·m lbf·ft 37 to 44 3.8 to 4.4 28 to 32 9/16 Adjustable elbow, 48 to 54 4.9 to 5.5 36 to 39...

  • Page 21: Maintenance Check List

    GENERAL LA434, WSM 5. MAINTENANCE CHECK LIST To keep the machine working in good condition as well as to avoid any accident and trouble, do periodic inspection and maintenance. Check the following points before use. Service Interval Check Points Reference page...

  • Page 22: Check And Maintenance

    2. If the level is too low, add new oil to the prescribed level at the dipstick (2). IMPORTANT • Use only KUBOTA SUPER UDT fluid. • Use of other oils may damage the transmission or hydraulic system. Refer to "3. LUBRICANTS" on page G-3.
  • Page 23 GENERAL LA434, WSM Checking Hydraulic Hoses WARNING To avoid serious personal injury: • Escaping hydraulic fluid under pressure can have sufficient force to penetrate skin, causing serious personal injury. Before disconnecting lines, be sure to relieve all pressure. Before applying pressure to the system, be sure all connections are tight and that lines, tubes, and hoses are not damaged.

  • Page 24: Check Points Of Every 10 Hours

    GENERAL LA434, WSM [2] CHECK POINTS OF EVERY 10 HOURS Greasing 1. Inject grease in all grease fittings with a hand grease gun. [A] Quick Coupler Type (Option For LA504) 9Y1211247GEG0007US0 Lubricating 1. Lubricate joints of control lever linkage. 9Y1211247GEG0008US0...

  • Page 25: Check Points Of Every 50 Hours

    GENERAL LA434, WSM [3] CHECK POINTS OF EVERY 50 HOURS Checking Main Frame Mounting Bolts and Nuts Torque CAUTION • Never operate front loader with a loose main frame. • Any time bolts and nuts are loosened, retighten to specified torque.

  • Page 26: Front Loader

    FRONT LOADER KiSC issued 11, 2014 A...
  • Page 27 MECHANISM CONTENTS 1. HYDRAULIC CIRCUIT ....................... 1-M1 2. CONTROL VALVE ASSEMBLY ....................1-M2 [1] STRUCTURE ........................1-M2 [2] OPERATION ........................1-M3 3. 3RD. FUNCTION VALVE (OPTION) ..................1-M10 [1] HYDRAULIC CIRCUIT ....................... 1-M10 [2] SOLENOID VALVE OPERATION ..................1-M11 [3] ELECTRICAL DIAGRAM....................1-M14 KiSC issued 11, 2014 A...

  • Page 28: Hydraulic Circuit

    FRONT LOADER LA434, WSM 1. HYDRAULIC CIRCUIT (1) Bucket Control Valve (4) Boom Cylinder P Port From Pump (2) Control Valve Assembly (5) Boom Control Valve T Port To Three Points Hydraulic (3) Bucket Cylinder PB: PB Port System 9Y1211247FLM0001US0...

  • Page 29: Control Valve Assembly

    FRONT LOADER LA434, WSM 2. CONTROL VALVE ASSEMBLY [1] STRUCTURE (1) Inlet and Outlet Section (5) Spool P Port B1: B1 Port (2) Boom Control Valve (6) Spool T Port B2: B2 Port (3) Bucket Control Valve A1: A1 Port...

  • Page 30: Operation

    FRONT LOADER LA434, WSM [2] OPERATION Control Lever at "NEUTRAL" Position (1) Boom Control Section (5) PB Passage 1 T Port B1: B1 Port (2) Bucket Control Section (6) PB Passage 2 P Port B2: B2 Port (3) Spool (7) Load Check Valve...
  • Page 31 FRONT LOADER LA434, WSM Control Lever at "UP" Position (1) Boom Control Section (5) Neutral Passage 1 P Port B1: B1 Port (To Boom Cylinder) (2) Bucket Control Section (6) Load Check Valve T Port PB: PB Port (3) Spool...
  • Page 32 FRONT LOADER LA434, WSM Control Lever at "DOWN" Position (1) Boom Control Section (5) Neutral Passage 1 P Port B1: B1 Port (2) Bucket Control Section (6) Load Check Valve T Port (From Boom Cylinder) (3) Spool (7) Passage 1...
  • Page 33 FRONT LOADER LA434, WSM Control Lever at "FLOATING" Position (1) Boom Control Section (5) Detent Mechanism P Port B1: B1 Port (2) Bucket Control Section (6) Neutral Passage 1 T Port PB: PB Port (3) Spool (7) Boom Cylinder A1: A1 Port...
  • Page 34 FRONT LOADER LA434, WSM Control Lever at "ROLL-BACK" Position (1) Boom Control Section (6) PB Passage 2 P Port B2: B2 Port (2) Bucket Control Section (7) Load Check Valve T Port (To Bucket Cylinder) (3) PB Passage 1 (8) Passage 2...
  • Page 35 FRONT LOADER LA434, WSM Control Lever at "DUMP 1" Position (1) Boom Control Section (6) PB Passage 2 P Port A2: A2 Port (2) Bucket Control Section (7) Load Check Valve T Port (To Bucket Cylinder) (3) PB Passage 1...
  • Page 36 FRONT LOADER LA434, WSM Control Lever at "DUMP 2" Position (1) Boom Control Section (6) PB Passage 2 P Port A2: A2 Port (2) Bucket Control Section (7) Load Check Valve T Port (To Bucket Cylinder) (3) PB Passage 1...

  • Page 37: Rd. Function Valve (Option)

    FRONT LOADER LA434, WSM 3. 3RD. FUNCTION VALVE (OPTION) [1] HYDRAULIC CIRCUIT The hydraulic circuit and structure of the 3rd. function valve is shown in the picture. (1) Hydraulic Pump A Port (2) 3rd. Function Valve B Port Assembly Pump Port (3) 3rd.

  • Page 38: Solenoid Valve Operation

    FRONT LOADER LA434, WSM [2] SOLENOID VALVE OPERATION "NEUTRAL" Position (Neither Activation Button Switch A nor B is Pushed) (1) Spring (7) Front Hydraulic Valve Main A Port PB: Power Beyond Port (2) Spool Switch B Port Tank Port (3) Spring...
  • Page 39 FRONT LOADER LA434, WSM When Pressing the Activation Button Switch A (1) Coil (5) Activation Button Switch B A Port (To Implement) (a) Low Pressure Oil (2) Spool (6) Activation Button Switch A B Port (From Implement) (b) High Pressure Oil...
  • Page 40 FRONT LOADER LA434, WSM When Pressing the Activation Button Switch B (1) Spool (5) Activation Button Switch B A Port (From Implement) (a) Low Pressure Oil (2) Coil (6) Activation Button Switch A B Port (To Implement) (b) High Pressure Oil...

  • Page 41: Electrical Diagram

    RB ..Red / Black YR .... Yellow / Red Br ..Brown WB ..White / Black YB .... Yellow / Black The electrical diagram used in LA434 is shown in the above electrical diagram. 9Y1211247FLM0014US0 1-M14 KiSC issued 11, 2014 A...
  • Page 42 SERVICING CONTENTS 1. TROUBLESHOOTING.........................1-S1 2. SERVICING SPECIFICATIONS ....................1-S3 3. TIGHTENING TORQUES......................1-S4 4. DISMOUNTING FRONT LOADER FROM TRACTOR ..............1-S5 5. CHECKING, DISASSEMBLING AND SERVICING ..............1-S7 [1] CHECKING AND ADJUSTING....................1-S7 (1) 3rd. Function Solenoid Valve (Option)................1-S8 [2] DISASSEMBLING AND ASSEMBLING ................1-S10 (1) Removing Front Loader Control Valve Assembly............1-S10 (2) Disassembling Front Loader Control Valve and Relief Valve........1-S11 (3) Bucket, Boom and Hydraulic Cylinder ................1-S12 (4) Removing Side Frame, Front Guard and Main Frame ..........1-S13...

  • Page 43: Troubleshooting

    FRONT LOADER LA434, WSM 1. TROUBLESHOOTING Probable Cause and Reference Symptom Solution Checking Procedure Page 1. Relief valve malfunctioning Solution order 1-S7 Boom Does Not Rise 1. Check and adjust relief valve pressure 2. Repair or replace relief valve 1-S11 2.
  • Page 44 FRONT LOADER LA434, WSM Probable Cause and Reference Symptom Solution Checking Procedure Page 1. Relief valve malfunctioning Solution order 1-S7 Insufficient Bucket 1. Check and adjust relief valve pressure Speed 2. Repair or replace relief valve 1-S11 2. Oil leaks from tube joints...

  • Page 45: Servicing Specifications

    FRONT LOADER LA434, WSM 2. SERVICING SPECIFICATIONS Item Factory Specification Allowable Limit Relief Valve Setting Pressure 13.0 to 13.8 MPa – 133 to 140 kgf/cm Condition • Engine Rated Speed: 1890 to 2000 psi 2800 min (rpm) • Oil Temperature: 50 °C (122 °F)

  • Page 46: Tightening Torques

    FRONT LOADER LA434, WSM 3. TIGHTENING TORQUES Tightening torques of screws, bolts and nuts on the table below are especially specified. (For general use screws, bolts and nuts: Refer to "4. TIGHTENING TORQUES" on page G-4.) Item N·m kgf·m lbf·ft...

  • Page 47: Dismounting Front Loader From Tractor

    FRONT LOADER LA434, WSM 4. DISMOUNTING FRONT LOADER FROM TRACTOR IMPORTANT • When dismounting the loader, park the tractor on flat and hard ground, apply the parking brake. • When starting the engine or using the hydraulic control valve, always sit on the operator's seat.
  • Page 48 FRONT LOADER LA434, WSM Hoses 1. Slowly release all hydraulic pressure by moving the hydraulic control lever in all directions. 2. Disconnect the four hoses with quick couplers at the control valve and place them on the right side of the boom.

  • Page 49: Checking, Disassembling And Servicing

    FRONT LOADER LA434, WSM 5. CHECKING, DISASSEMBLING AND SERVICING [1] CHECKING AND ADJUSTING 3-Points Hitch Relief Valve Setting Pressure 1. Install the adaptor. Then connect the cable and the pressure gauge to the adaptor (Size 1/4). 2. Start the engine and set the engine speed at 2800 min (rpm).

  • Page 50: 3Rd. Function Solenoid Valve (Option)

    FRONT LOADER LA434, WSM (1) 3rd. Function Solenoid Valve (Option) 3rd. Function Solenoid Valve 1. Disconnect the 2P connector (2). 2. Perform the following checks. (1) 3rd. Function Solenoid Valve (2) 2P Connector 1) 3rd. Function Solenoid Valve 1. Measure the resistance with an ohmmeter between 1 terminal and 2 terminal.
  • Page 51 FRONT LOADER LA434, WSM ON – OFF Switch (Front Hydraulic Valve Main Switch) 1. Disconnect the ON – OFF switch connector. 2. Perform the following checks. (1) ON – OFF Switch (2) Front Loader Control Lever 1) ON – OFF Switch 1.

  • Page 52: Disassembling And Assembling

    FRONT LOADER LA434, WSM [2] DISASSEMBLING AND ASSEMBLING (1) Removing Front Loader Control Valve Assembly Rear Wheel, Fender and Seat Under Cover 1. Place the disassembling stand under the transmission case. 2. Remove the rear wheel mounting nuts. 3. Remove the rear wheel, R.H. (6).

  • Page 53: Disassembling Front Loader Control Valve And Relief Valve

    FRONT LOADER LA434, WSM (2) Disassembling Front Loader Control Valve and Relief Valve (1) Plug (2) O-ring (3) Washer (4) Shim (5) Spring (6) Poppet 2 (7) Poppet 1 (8) Plug (9) O-ring (10) Spring (11) Check Valve (12) Dust Seal...

  • Page 54: Bucket, Boom And Hydraulic Cylinder

    FRONT LOADER LA434, WSM (3) Bucket, Boom and Hydraulic Cylinder Bucket 1. Remove the pins (2) and remove the bucket (1). (1) Bucket (2) Pin 9Y1211247FLS0012US0 Hydraulic Cylinder and Hydraulic Hoses 1. Disconnect the hydraulic hoses (1). 2. Remove the pins and remove the bucket cylinders (4).

  • Page 55: Removing Side Frame, Front Guard And Main Frame

    FRONT LOADER LA434, WSM (4) Removing Side Frame, Front Guard and Main Frame Side Frame 1. Disconnecting the loader assembly from the main frame. (See page 1-S5.) 2. Remove the pin (1) and remove the side frame (2) from the boom.

  • Page 56: Disassembling Cylinder Rod And Cylinder Head

    FRONT LOADER LA434, WSM (5) Disassembling Cylinder Rod and Cylinder Head Piston Rod Assembly 1. Drain hydraulic oil from the cylinder, and secure the tube end of the cylinder in a vise. 2. Remove the cylinder head (1) with the adjustable gland nut wrench (4).
  • Page 57 FRONT LOADER LA434, WSM Removing Piston Seal and O-ring 1. Remove the piston seal (2) and expander (3) from the piston (1). IMPORTANT • When installing the expander (3) and piston seal (2) to the piston (1), use the slide jig and correcting jig as shown in the figure.

  • Page 58: Servicing

    FRONT LOADER LA434, WSM [3] SERVICING (1) Pin, Pin Hole and Piston Rod Clearance between Pin and Bushing or Pin Holes 1. Measure the pin O.D. with an outside micrometer. 2. Measure the pin holes I.D.with a cylinder gauge. 3. If the clearance exceeds the factory specifications, replace the pin or bushings.
  • Page 59 EDITOR : KUBOTA FARM & INDUSTRIAL MACHINERY SERVICE, LTD. 64, ISHIZU-KITAMACHI, SAKAI-KU, SAKAI-CITY, OSAKA, 590-0823, JAPAN PHONE : ( 81 ) 72-241-1129 : ( 81 ) 72-245-2484 E-mail : ks_g.ksos-pub@kubota.com Printed in Japan 2014. 11, S, EI, EI, engusa Code No.9Y111-12470...

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