Kubota WSM LA1403 Manual
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Kubota WSM LA1403 Manual

Kubota WSM LA1403 Manual

Workshop manual front loader
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WORKSHOP MANUAL
FRONT LOADER
LA1403
KiSC issued 08, 2008 A

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Summary of Contents for Kubota WSM LA1403

  • Page 1 WORKSHOP MANUAL FRONT LOADER LA1403 KiSC issued 08, 2008 A...
  • Page 2 TO THE READER This Workshop Manual has been prepared to provide servicing personnel with information on the mechanism, service and maintenance of KUBOTA Front Loader LA1403. It is divided into three parts, “General”, “Mechanism” and “Servicing”. General Information on the tractor identification, the general precautions, maintenance check list, check and maintenance and special tools are described.
  • Page 3 SAFETY INSTRUCTIONS LA1403, WSM SAFETY INSTRUCTIONS 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. It is essential that you read the instructions and safety regulations before you attempt to repair or use this unit.
  • Page 4 SAFETY INSTRUCTIONS LA1403, WSM SAFETY STARTING • Do not start the engine by shorting across starter terminals or bypassing the safety start switch. • Unauthorized modifications to the engine may impair the function and / or safety and affect engine life. SAFETY WORKING •...
  • Page 5 SAFETY INSTRUCTIONS LA1403, WSM AVOID FIRES • Fuel is extremely flammable and explosive under certain conditions. Do not smoke or allow flames or sparks in your working area. • To avoid sparks from an accidental short circuit, always disconnect the battery negative cable first and connect it last.
  • Page 6 SAFETY INSTRUCTIONS LA1403, WSM PREPARE FOR EMERGENCIES • Keep a first aid kit and fire extinguisher handy at all times. • Keep emergency numbers for doctors, ambulance service, hospital and fire department near your telephone. KiSC issued 08, 2008 A...
  • Page 7 SAFETY INSTRUCTIONS LA1403, WSM 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. KiSC issued 08, 2008 A...
  • Page 8 SAFETY INSTRUCTIONS LA1403, WSM KiSC issued 08, 2008 A...
  • Page 9 SAFETY INSTRUCTIONS LA1403, WSM KiSC issued 08, 2008 A...
  • Page 10 LOADER TERMINOLOGY LA1403, WSM LOADER TERMINOLOGY (1) Mounting Pin (4) Boom Cylinder (6) Boom (8) Bucket (2) Side Frame (5) Main Frame (7) Bucket Cylinder (9) Control Lever (3) Control Valve KiSC issued 08, 2008 A...
  • Page 11 SPECIFICATIONS LA1403, WSM SPECIFICATIONS Suitable Tractor LA1403 : M96S, M108S [1] LOADER SPECIFICATIONS Loader Model LA1403 Tractor Model M96S M108S Wheel Base (WB) 2435 mm (95.9 in.) Front Tires 12.4-24 13.6-24 Rear Tires 18.4-30 18.4-34 Bore 70 mm (2.76 in.) Boom Cylinder Stroke 606 mm (23.9 in.)
  • Page 12 SPECIFICATIONS LA1403, WSM [3] DIMENSIONAL AND OPERATIONAL SPECIFICATIONS Dimensional Specifications Loader Model LA1403 Tractor Model M96S, M108S Boom Cylinder Fulcrum Point HEIGHT POWER Maximum lift height to pivot pin 3700 mm 3370 mm (145.7 in.) (132.7 in.) Maximum lift height under level bucket 3470 mm 3160 mm (136.6 in.)

  • Page 13: Table Of Contents

    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 (FOR FRONT LOADER AND BACKHOE) ..............G-4 [2] STUD BOLTS.................... G-4 [3] AMERICAN STANDARD SCREWS, BOLTS AND NUTS WITH UNC OR UNF THREADS .................

  • Page 14: Loader Identification

    G GENERAL LA1403, WSM 1. LOADER IDENTIFICATION When contacting your local KUBOTA distributor, always specify front loader’s serial number (1). (1) Serial Number W1010477 KiSC issued 08, 2008 A...

  • Page 15: General Precautions

    Screws, bolts and nuts should be replaced in their original positions to prevent reassembly errors. • When special tools are required, use genuine KUBOTA tools. Special tools which are not used frequently should be made according to the drawings provided.

  • Page 16: Lubricants

    13.2 Imp.gals Grease nipples Until grease overflows. Moly Ep type grease** * KUBOTA original transmission hydraulic fluid ** “Extreme pressure” and containing Molybdenum disulfide is recommended. This grease may specify “Moly Ep” on it’s label. KiSC issued 08, 2008 A...

  • Page 17: Tightening Torques

    G GENERAL LA1403, WSM 4. TIGHTENING TORQUES [1] GENERAL USE SCREWS, BOLTS AND NUTS (FOR FRONT LOADER AND BACKHOE) Screws, bolts, and nuts whose tightening torques are not specified in this Workshop Manual should be tightened according to the table below. Indication on top of No-grade or 4T 7T or Property class 8.8...

  • Page 18: American Standard Screws, Bolts And Nuts With Unc Or Unf Threads

    G GENERAL LA1403, WSM [3] AMERICAN STANDARD SCREWS, BOLTS AND NUTS WITH UNC OR UNF THREADS SAE GR.5 SAE GR.8 Grade Unit Nominal N·m kgf·m lbf·ft N·m kgf·m lbf·ft Diameter 11.7 to 15.7 1.19 to 1.61 8.61 to 11.6 16.3 to 19.7 1.66 to 2.01 12.0 to 14.6 5/16...

  • Page 19: Hydraulic Fittings

    G GENERAL LA1403, WSM [5] HYDRAULIC FITTINGS Adaptors, Elbows and Others Tightening torque Item Shape Thread size N·m kgf·m lbf·ft 9/16 37 to 44 3.8 to 4.5 27 to 33 Adjustable elbow, Adaptor (O-ring 48 to 54 4.9 to 5.5 35 to 40 port) (UNF) [A] Nut Type...

  • Page 20: Maintenance Check List

    G GENERAL LA1403, WSM 5. MAINTENANCE CHECK LIST To keep the machine working in good condition as well as to avoid any accident and trouble, carry out periodic inspection and maintenance. Check the following points before use. Service Interval Check Points Reference page Daily (Each use) Check the transmission fluid level...

  • Page 21: Check And Maintenance

    1. Check the oil level at the gauge (1). 2. If the level is too low, add new oil to the prescribed level. IMPORTANT • Use only KUBOTA UDT or SUPER UDT fluid. Use of other oil may damage the transmission or hydraulic system. Refer to “3. LUBRICANTS”.

  • Page 22: Check Points Of Every 10 Hours

    G GENERAL LA1403, WSM [2] CHECK POINTS OF EVERY 10 HOURS Greasing 1. Inject grease in all grease fitting with a hand grease gun. W1011132 Lubricating 1. Lubricate joints of control lever linkage. W1011274 [3] CHECK POINT OF EVERY 50 HOURS Checking Main Frame Mounting Bolts CAUTION •...
  • Page 23 MECHANISM CONTENTS 1. CONTROL VALVE ASSEMBLY (STANDARD VALVE) ....... M-1 [1] HYDRAULIC CIRCUIT................M-1 [2] STRUCTURE ..................... M-2 [3] OPERATION ....................M-3 [4] RELIEF VALVE ..................M-9 2. CONTROL VALVE ASSEMBLY (SELF-LEVELING VALVE) ..... M-12 [1] HYDRAULIC CIRCUIT................M-12 [2] STRUCTURE ................... M-13 [3] OPERATION ....................

  • Page 24: Control Valve Assembly (Standard Valve

    FRONT LOADER LA1403, WSM 1. CONTROL VALVE ASSEMBLY (STANDARD VALVE) [1] HYDRAULIC CIRCUIT (1) Boom Cylinder (5) Boom Control Valve P : From Pump A1 : A1 Port (2) Bucket Cylinder (6) Bucket Control Valve T : To Tank A2 : A2 Port (3) Control Valve Assembly (7) Orifice P.B.: To 3-Point Hydraulic...

  • Page 25: Structure

    FRONT LOADER LA1403, WSM [2] STRUCTURE (1) Inlet Section P : P Port A1 : A1 Port B1 : B1 Port (2) Boom Control Valve T : T Port A2 : A2 Port B2 : B2 Port (3) Bucket Control Valve P.B.

  • Page 26: Operation

    FRONT LOADER LA1403, WSM [3] OPERATION Control Lever at “NEUTRAL” Position (1) Boom Control Valve (6) Outlet Section P : P Port B1 : B1 Port (2) Inlet Section (7) P.B. Passage 2 T : T Port B2 : B2 Port (3) P.B.
  • Page 27 FRONT LOADER LA1403, WSM Control Lever at “UP” Position 1. When the hydraulic control lever is set to the “UP” position, the spool (5) of the boom control valve (3) moves to the right, which forms oil passages between passage 1 (9) and B1 port, also between A1 port and P.B.
  • Page 28 FRONT LOADER LA1403, WSM Control Lever at “DOWN” Position 1. When the hydraulic control lever is set to the “DOWN” position, the spool (5) moves to the left, which forms oil passages between passage 1 (9) and A1 port, also between B1 port and P.B. passage 1 (7).
  • Page 29 FRONT LOADER LA1403, WSM Control Lever at “FLOAT” Position 1. When the hydraulic control lever is set to the “FLOAT” position, the spool (5) moves further to the left from the “DOWN” position and is retained by the detent mechanism (10). 2.
  • Page 30 FRONT LOADER LA1403, WSM Control Lever at “ROLL-BACK” Position 1. When the hydraulic control lever is set to the “ROLL- BACK” position, the spool (6) of the bucket control valve (2) moves to the left, which forms oil passages between passage 2 (10) and B2 port, also between A2 port and T port.
  • Page 31 FRONT LOADER LA1403, WSM Control Lever at “DUMP” Position 1. When the hydraulic control lever is set to the “DUMP” position, the spool (6) of the bucket control valve (2) moves to the right, which forms oil passages among passage 2 (7), A2 port and B2 port. 2.

  • Page 32: Relief Valve

    FRONT LOADER LA1403, WSM [4] RELIEF VALVE The relief valve is adopted in the loader control valve. This relief valve is pilot operated type, it is suitable for a high pressure and large volumetric flow with better pressure override performance than direct acting relief valves.
  • Page 33 FRONT LOADER LA1403, WSM Relief Operation [Step 1] The relief valve is in communication between the high pressure port HP and low pressure chamber LP. Oil is admitted through the hole in piston poppet (4) and because of the differential area between diameter A and B relief valve poppet (1) and check valve poppet (2) are tightly seated as shown in the figure.
  • Page 34 FRONT LOADER LA1403, WSM Anti-cavitation Operation The anti-void unit supplies oil to the high pressure port HP when cavitation has occurred. A lower pressure exists in the port HP compared to the low pressure chamber LP. The difference between the effective area of diameter A and C causes imbalance of the check valve poppet (1) unseats, thus allowing oil from the low pressure chamber LP to enter the port HP and fill the...

  • Page 35: Control Valve Assembly (Self-Leveling Valve

    FRONT LOADER LA1403, WSM 2. CONTROL VALVE ASSEMBLY (SELF-LEVELING VALVE) [1] HYDRAULIC CIRCUIT (1) Boom Cylinder (4) Relief Valve P : From Pump A1 :A1 Port (2) Bucket Cylinder (5) Boom Control Valve T : To Tank A2 :A2 Port (3) Control Valve Assembly (6) Bucket Control Valve P.B.: To 3-Point Hydraulic...

  • Page 36: Structure

    FRONT LOADER LA1403, WSM [2] STRUCTURE P : P Port (Pump Port) A1 : A1 Port (Connected Boom a-a : Section a-a e-e : Self-leveling Section T : T Port (Tank Port) Bottom Cylinder) b-b : Section b-b f-f : Divider Section P.B.: P.B.

  • Page 37: Operation

    FRONT LOADER LA1403, WSM [3] OPERATION Control Lever at “NEUTRAL” Position (Figure 1) (1) P Port (12) Passage D (22) Lowering Sequence Spool T : T Port (Tank Port) (2) Load Check Valve (13) Raising Overload Relief Valve (23) Raising Sequence Spool A1 : A1 Port (Connected Boom (3) Boom Spool (14) Lowering Overload Relief...
  • Page 38 FRONT LOADER LA1403, WSM Control Lever at “NEUTRAL” Position (Figure 2) (1) P Port (25) Bucket Spool P : P Port (Pump Port) a-a : Section a-a (3) Boom Spool (26) P.B. Port T : T Port (Tank Port) b-b : Section b-b (4) Center By-pass Passage P.B.: P.B.
  • Page 39 FRONT LOADER LA1403, WSM Control Lever at “NEUTRAL” Position (Figure 3) (25) Bucket Spool A2 : A2 Port (Connected Bucket c-c : Bucket Section (a) Low Pressure Rod Cylinder) d-d : Sequence Section 1 to 10 : Oil Flow B2 : B2 Port (Connected Bucket e-e : Self-leveling Section Bottom Cylinder) KiSC issued 08, 2008 A...
  • Page 40 FRONT LOADER LA1403, WSM Control Lever at “NEUTRAL” Position (Figure 4) (1) P Port P : P Port (Pump Port) A1 : A1 Port (Connected Boom f-f : Divider Section (3) Boom Spool Bottom Cylinder) g-g : Boom Section (4) Center By-pass Passage B1 : B1 Port (Connected Boom (a) Low Pressure Rod Cylinder)
  • Page 41 FRONT LOADER LA1403, WSM Boom Raising (Figure 1) (1) P Port (5) Passage A (28) Boom Cylinder 1 to 13 : Oil Flow (2) Load Check Valve (9) Raising Divider Spool (29) Bucket Cylinder (a) Low Pressure (3) Boom Spool (15) Self-leveling Spool (b) Middle Pressure (4) Center By-pass Passage...
  • Page 42 FRONT LOADER LA1403, WSM Boom Raising (Figure 2) (3) Boom Spool (9) Raising Divider Spool P : P Port (Pump Port) a-a : Section a-a (5) Passage A (15) Self-leveling Spool T : T Port (Tank Port) b-b : Section b-b P.B.: P.B.
  • Page 43 FRONT LOADER LA1403, WSM Boom Raising (Figure 3) (15) Self-leveling Spool A2 : A2 Port (Connected Bucket c-c : Bucket Section (a) Low Pressure Rod Cylinder) d-d : Sequence Section 1 to 13 : Oil Flow B2 : B2 Port (Connected Bucket e-e : Self-leveling Section Bottom Cylinder) KiSC issued 08, 2008 A...
  • Page 44 FRONT LOADER LA1403, WSM Boom Raising (Figure 4) (1) P Port A1 : A1 Port (Connected Boom P : P Port (Pump Port) (a) Low Pressure (2) Load Check Valve Bottom Cylinder) f-f : Divider Section (b) Middle Pressure (3) Boom Spool B1 : B1 Port (Connected Boom g-g: Boom Section 1 to 13 : Oil Flow...
  • Page 45 FRONT LOADER LA1403, WSM Self-leveling on Boom Raising (Figure 1) (1) P Port (7) Raising Adjuster (23) Raising Sequence Spool 1 to 22 : Oil Flow (2) Load Check Valve (9) Raising Divider Spool (26) P.B. Port (a) Low Pressure (3) Boom Spool (11) Passage C (28) Boom Cylinder...
  • Page 46 FRONT LOADER LA1403, WSM Self-leveling on Boom Raising (Figure 2) (1) P Port (13) Raising Overload Relief Valve P : P Port (Pump Port) a-a : Section a-a (3) Boom Spool (18) Check Valve T : T Port (Tank Port) b-b : Section b-b (7) Raising Adjuster (21) Passage H...
  • Page 47 FRONT LOADER LA1403, WSM Self-leveling on Boom Raising (Figure 3) (18) Check Valve A2 : A2 Port (Connected Bucket c-c : Bucket Section (a) Low Pressure (21) Passage H Rod Cylinder) d-d : Sequence Section (b) Middle Pressure (23) Raising Sequence Spool B2 : B2 Port (Connected Bucket e-e : Self-leveling Section 1 to 22 : Oil Flow...
  • Page 48 FRONT LOADER LA1403, WSM Self-leveling on Boom Raising (Figure 4) (1) P Port A1 : A1 Port (Connected Boom P : P Port (Pump Port) (a) Low Pressure (2) Load Check Valve Bottom Cylinder) f-f : Divider Section (b) Middle Pressure (3) Boom Spool B1 : B1 Port (Connected Boom g-g: Boom Section...

  • Page 49: Overload Relief Valve

    FRONT LOADER LA1403, WSM Boom Raising with Bucket Cylinder Extended (Figure 1) (1) P Port (7) Raising Adjuster (21) Passage H 1 to 17 : Oil Flow (2) Load Check Valve (9) Raising Divider Spool (23) Raising Sequence Spool (a) Low Pressure (3) Boom Spool (11) Passage C (26) P.B.
  • Page 50 FRONT LOADER LA1403, WSM Boom Raising with Bucket Cylinder Extended (Figure 2) (1) P Port (11) Passage C P : P Port (Pump Port) a-a : Section a-a (3) Boom Spool (18) Check Valve T : T Port (Tank Port) b-b : Section b-b (4) Center By-pass Passage (21) Passage H...
  • Page 51 FRONT LOADER LA1403, WSM Boom Raising with Bucket Cylinder Extended (Figure 3) (11) Passage C A2 : A2 Port (Connected Bucket c-c : Bucket Section (a) Low Pressure (13) Raising Overload Relief Valve Rod Cylinder) d-d : Sequence Section (c) High Pressure (18) Check Valve B2 : B2 Port (Connected Bucket e-e : Self-leveling Section...
  • Page 52 FRONT LOADER LA1403, WSM Boom Raising with Bucket Cylinder Extended (Figure 4) (2) Load Check Valve A1 : A1 Port (Connected Boom P : P Port (Pump Port) (a) Low Pressure (3) Boom Spool Bottom Cylinder) f-f : Divider Section (b) Middle Pressure (5) Passage A B1 : B1 Port (Connected Boom...
  • Page 53 FRONT LOADER LA1403, WSM Boom Lowering (Figure 1) (1) P Port (4) Center By-pass Passage (15) Self-leveling Spool 1 to 11 : Oil Flow (2) Load Check Valve (6) Passage B (28) Boom Cylinder (a) Low Pressure (3) Boom Spool (10) Lowering Divider Spool (29) Bucket Cylinder (b) Middle Pressure...
  • Page 54 FRONT LOADER LA1403, WSM Boom Lowering (Figure 2) (1) P Port P : P Port (Pump Port) a-a : Section a-a (a) Low Pressure (3) Boom Spool T : T Port (Tank Port) b-b : Section b-b (b) Middle Pressure (4) Center By-pass Passage P.B.
  • Page 55 FRONT LOADER LA1403, WSM Boom Lowering (Figure 3) (15) Self-leveling Spool A2 : A2 Port (Connected Bucket c-c : Bucket Section (a) Low Pressure Rod Cylinder) d-d : Sequence Section 1 to 11 : Oil Flow B2 : B2 Port (Connected Bucket e-e : Self-leveling Section Bottom Cylinder) KiSC issued 08, 2008 A...
  • Page 56 FRONT LOADER LA1403, WSM Boom Lowering (Figure 4) (1) P Port A1 : A1 Port (Connected Boom P : P Port (Pump Port) (a) Low Pressure (2) Load Check Valve Bottom Cylinder) f-f : Divider Section (b) Middle Pressure (3) Boom Spool B1 : B1 Port (Connected Boom g-g: Boom Section 1 to 11 : Oil Flow...
  • Page 57 FRONT LOADER LA1403, WSM Self-leveling on Boom Lowering (Figure 1) (1) P Port (8) Lowering Adjuster (22) Lowering Sequence Spool 1 to 19 : Oil Flow (2) Load Check Valve (10) Lowering Divider Spool (26) P.B. Port (a) Low Pressure (3) Boom Spool (12) Passage D (28) Boom Cylinder...
  • Page 58 FRONT LOADER LA1403, WSM Self-leveling on Boom Lowering (Figure 2) (1) P Port (10) Lowering Divider Spool P : P Port (Pump Port) a-a :Section a-a (3) Boom Spool (22) Lowering Sequence Spool T : T Port (Tank Port) b-b :Section b-b (4) Center By-pass Passage (26) P.B.
  • Page 59 FRONT LOADER LA1403, WSM Self-leveling on Boom Lowering (Figure 3) (22) Lowering Sequence Spool A2 : A2 Port (Connected Bucket c-c : Bucket Section (a) Low Pressure Rod Cylinder) d-d : Sequence Section (b) Middle Pressure B2 : B2 Port (Connected Bucket e-e : Self-leveling Section (c) High Pressure Bottom Cylinder)
  • Page 60 FRONT LOADER LA1403, WSM Self-leveling on Boom Lowering (Figure 4) (1) P Port A1 : A1 Port (Connected Boom P : P Port (Pump Port) (a) Low Pressure (2) Load Check Valve Bottom Cylinder) f-f : Divider Section (b) Middle Pressure (3) Boom Spool B1 : B1 Port (Connected Boom g-g: Boom Section...
  • Page 61 FRONT LOADER LA1403, WSM Boom Lowering with Bucket Cylinder Fully Retracted (Figure 1) (1) P Port (8) Lowering Adjuster (19) Check Valve (28) Boom Cylinder (2) Load Check Valve (10) Lowering Divider Spool (20) Passage G (29) Bucket Cylinder (3) Boom Spool (12) Passage D (22) Lowering Sequence Spool 1 to 20 : Oil Flow...
  • Page 62 FRONT LOADER LA1403, WSM Boom Lowering with Bucket Cylinder Fully Retracted (Figure 2) (3) Boom Spool (19) Check Valve P : P Port (Pump Port) a-a : Section a-a (4) Center By-pass Passage (20) Passage G T : T Port (Tank Port) b-b : Section b-b (8) Lowering Adjuster (22) Lowering Sequence Spool...
  • Page 63 FRONT LOADER LA1403, WSM Boom Lowering with Bucket Cylinder Fully Retracted (Figure 3) (14) Lowering Overload Relief A2 : A2 Port (Connected Bucket c-c : Bucket Section (a) Low Pressure Valve Rod Cylinder) d-d : Sequence Section (b) Middle Pressure (19) Check Valve B2 : B2 Port (Connected Bucket e-e : Self-leveling Section...
  • Page 64 FRONT LOADER LA1403, WSM Boom Lowering with Bucket Cylinder Fully Retracted (Figure 4) (1) P Port A1 : A1 Port (Connected Boom P : P Port (Pump Port) (a) Low Pressure (2) Load Check Valve Bottom Cylinder) f-f : Divider Section (b) Middle Pressure (3) Boom Spool B1 : B1 Port (Connected Boom...
  • Page 65 FRONT LOADER LA1403, WSM Boom Floating (Figure 1) (1) P Port (27) T Port 1 to 14 : Oil Flow (a) Low Pressure (3) Boom Spool (28) Boom Cylinder (b) Middle Pressure (4) Center By-pass Passage (29) Bucket Cylinder The following section explains illustration figure 1, 2, 3 and 4. When the boom spool (3) is pulled out and switched into the detent position, all the hydraulic oil from P port (1) is discharged through P.B.
  • Page 66 FRONT LOADER LA1403, WSM Boom Floating (Figure 2) (1) P Port (26) P.B. Port P : P Port (Pump Port) a-a : Section a-a (3) Boom Spool (27) T Port T : T Port (Tank Port) b-b : Section b-b (4) Center By-pass Passage P.B.: P.B.
  • Page 67 FRONT LOADER LA1403, WSM Boom Floating (Figure 3) A2 : A2 Port (Connected Bucket B2 : B2 Port (Connected Bucket c-c : Bucket Section (a) Low Pressure Rod Cylinder) Bottom Cylinder) d-d : Sequence Section (b) Middle Pressure e-e : Self-leveling Section 1 to 14 : Oil Flow KiSC issued 08, 2008 A M-44...
  • Page 68 FRONT LOADER LA1403, WSM Boom Floating (Figure 4) (1) P Port A1 : A1 Port (Connected Boom P : P Port (Pump Port) (a) Low Pressure (3) Boom Spool Bottom Cylinder) f-f : Divider Section (b) Middle Pressure B1 : B1 Port (Connected Boom g-g: Boom Section 1 to 14 : Oil Flow Rod Cylinder)
  • Page 69 FRONT LOADER LA1403, WSM Bucket (Roll-Back) (Figure 1) (1) P Port (24) Load Check Valve (27) T Port 1 to 10 : Oil Flow (4) Center By-pass Passage (25) Bucket Spool (29) Bucket Cylinder (a) Low Pressure (b) Middle Pressure The following section explains illustration figure 1, 2, 3 and 4.
  • Page 70 FRONT LOADER LA1403, WSM Bucket (Roll-Back) (Figure 2) (4) Center By-pass Passage P : P Port (Pump Port) T : T Port (Tank Port) a-a : Section a-a (25) Bucket Spool P.B.: P.B. Port (Power Beyond 1 to 10 : Oil Flow b-b : Section b-b (27) T Port Port)
  • Page 71 FRONT LOADER LA1403, WSM Bucket (Roll-Back) (Figure 3) (24) Load Check Valve A2 : A2 Port (Connected Bucket c-c : Bucket Section (a) Low Pressure (25) Bucket Spool Rod Cylinder) d-d : Sequence Section (b) Middle Pressure B2 : B2 Port (Connected Bucket e-e : Self-leveling Section 1 to 10 : Oil Flow Bottom Cylinder)
  • Page 72 FRONT LOADER LA1403, WSM Bucket (Roll-Back) (Figure 4) (1) P Port A1 : A1 Port (Connected Boom P : P Port (Pump Port) (a) Low Pressure Bottom Cylinder) f-f : Divider Section (b) Middle Pressure B1 : B1 Port (Connected Boom g-g: Boom Section 1 to 10 : Oil Flow Rod Cylinder)
  • Page 73 FRONT LOADER LA1403, WSM Bucket (Dump) (Figure 1) (1) P Port (25) Bucket Spool (27) T Port 1 to 10 : Oil Flow (4) Center BY-pass Passage (26) P.B. Port (29) Bucket Cylinder (a) Low Pressure (24) Load Check Valve The following section explains illustration figure 1, 2, 3 and 4.
  • Page 74 FRONT LOADER LA1403, WSM Bucket (Dump) (Figure 2) (1) P Port (25) Bucket Spool P : P Port (Pump Port) a-a : Section a-a (4) Center By-pass Passage (26) P.B. Port T : T Port (Tank Port) b-b : Section b-b (27) T Port P.B.: P.B.
  • Page 75 FRONT LOADER LA1403, WSM Bucket (Dump) (Figure 3) (24) Load Check Valve A2 : A2 Port (Connected Bucket c-c : Bucket Section (a) Low Pressure (25) Bucket Spool Rod Cylinder) d-d : Sequence Section 1 to 10 : Oil Flow B2 : B2 Port (Connected Bucket e-e : Self-leveling Section Bottom Cylinder)
  • Page 76 FRONT LOADER LA1403, WSM Bucket (Dump) (Figure 4) (1) P Port P : P Port (Pump Port) A1 : A1 Port (Connected Boom f-f : Divider Section Bottom Cylinder) g-g: Boom Section B1 : B1 Port (Connected Boom (a) Low Pressure Rod Cylinder) 1 to 10 : Oil Flow KiSC issued 08, 2008 A...
  • Page 77 FRONT LOADER LA1403, WSM [4] RELIEF VALVE (1) Main Relief Valve Relief Valve Closed The cylinder port P is applied to the seat B in the following route : first through the throttle a of the piston poppet (1) built in the relief valve poppet (5), second through the spring chamber A, and then through the circular clearance between the adjusting screw and the piston poppet (1).
  • Page 78 FRONT LOADER LA1403, WSM (2) Overload Relief Valve Overload relief valve in this control valve is a combination valve combining a relief operation and anti- cavitation operation. Relief Operation When the control valve is in the neutral position, both cylinder ports of control valve are blocked by the spool. If an external load is imposed on the cylinder, pressure builds in the circuit.
  • Page 79 FRONT LOADER LA1403, WSM [When the actuator port pressure is higher than the setting] When the cylinder port HP has reached the set pressure of the piston spring (3), the pressure oil in the spring chamber A opens the pilot poppet (2) and flows through the drain passage into the tank passage.

  • Page 80: Boom Cylinder And Bucket Cylinder

    FRONT LOADER LA1403, WSM 3. BOOM CYLINDER AND BUCKET CYLINDER (1) Nut (3) Cylinder Tube (4) Head (5) Piston Rod (2) Piston Both boom cylinder and bucket cylinder consist of head (4), cylinder tube (3), piston rod (5), piston (2), and other parts as shown in the figure above.

  • Page 81: Rd Function Valve (Option

    FRONT LOADER LA1403, WSM 4. 3RD FUNCTION VALVE (OPTION) [1] HYDRAULIC CIRCUIT (1) Hydraulic Pump (5) Boom Cylinder P : Pump Port A : A Port (2) 3rd Function Valve Assy. (6) Bucket Cylinder PB : Power Beyond Port A1 : A1 Port (3) Relief Valve (7) Relief Valve (Main) T : Tank Port...

  • Page 82: 3Rd Function Solenoid Valve Operation

    FRONT LOADER LA1403, WSM [2] 3RD FUNCTION SOLENOID VALVE OPERATION Spool at “Neutral” Position (1) Spring (3) Spring A : A Port PB : Power Beyond Port (2) Spool B : B Port T : Tank Port P : Pump Port C : To Backhoe Control Valve 1.
  • Page 83 FRONT LOADER LA1403, WSM Button A is pushed (Activation Switch A) (1) Coil A : A Port (To Implement) P : Pump Port C : To Backhoe Control Valve (2) Spool B : B Port (From Implement) PB : Power Beyond Port (3) Activation Switch A (4) Activation Switch B 1.
  • Page 84 FRONT LOADER LA1403, WSM Button B is pushed (Activation Switch B) (1) Spool A : A Port (From Implement) P : Pump Port C : To Backhoe Control Valve (2) Coil B : B Port (To Implement) PB : Power Beyond Port (3) Activation Switch A (4) Activation Switch B 1.

  • Page 85: Electrical Circuit

    FRONT LOADER LA1403, WSM [3] ELECTRICAL CIRCUIT (1) Relay 1 (3) Solenoid Valve 1 (5) ON - OFF Switch (For 3rd (7) Activation Switch B (2) Relay 2 (4) Solenoid Valve 2 Function Kit) (8) Battery (6) Activation Switch A Color of Wiring B ...

  • Page 86: Hydraulic Accumulator (Option

    FRONT LOADER LA1403, WSM 5. HYDRAULIC ACCUMULATOR (OPTION) [1] HYDRAULIC CIRCUIT (1) Hydraulic Pump (3) Orifice (Standard Valve Only) (5) Accumulator Valve (7) Orifice (Self-leveling Valve (2) Front Loader Valve (Standard (4) Boom Cylinder (6) Accumulator Only) Valve) (8) Bucket Cylinder If hydraulic accumulator is equipped, the shock when the boom is operated can be alleviated.

  • Page 87: Accumulator Valve

    FRONT LOADER LA1403, WSM [2] ACCUMULATOR VALVE (1) Accumulator Valve (5) Boom Cylinder A1: A1 Port [X] Accumulator Valve ON (2) Directional Valve (6) Accumulator B1: B1 Port Position (3) Relief Valve for Bottom Side (7) Orifice (Self-leveling Valve A3: A3 Port [Y] Accumulator Valve OFF (4) Relief Valve for Rod Side Only)

  • Page 88: Hydraulic Accumulator

    FRONT LOADER LA1403, WSM [3] HYDRAULIC ACCUMULATOR (1) Accumulator (5) Diaphragm [L] Low Pressure (a) Low Pressure Oil (2) Gas Chamber (6) Stopper 1 [M] Middle Pressure (b) Middle Pressure Oil (3) Oil Chamber (7) Stopper 2 [H] High Pressure (c) High Pressure Oil (4) Valve Poppet (d) Low Pressure Gas...

  • Page 89: Accumulator Relief Valve

    FRONT LOADER LA1403, WSM [4] ACCUMULATOR RELIEF VALVE Relief Valve Closed This relief valve is suitable for a high pressure and large volumetric flow with better pressure override performance than direct acting relief valves. This relief valve consists of a pilot valve (4) and main valve (8).
  • Page 90 SERVICING CONTENTS 1. TROUBLESHOOTING ..................S-1 2. SERVICING SPECIFICATIONS ..............S-2 3. TIGHTENING TORQUES (ESPECIALLY SPECIFIED) .........S-3 4. DISMOUNTING FRONT LOADER FROM TRACTOR........S-4 5. CHECKING, DISASSEMBLING AND SERVICING........S-6 [1] CHECKING AND ADJUSTING ..............S-6 (1) Control Valve ..................S-6 (2) Adjusting Self-leveling................S-7 (3) 3rd Function Valve (Option) ..............S-9 [2] DISASSEMBLING AND ASSEMBLING..........S-12 (1) Control Valve Assembly..............S-12 (2) Control Valve ..................S-14...

  • Page 91: Troubleshooting

    FRONT LOADER LA1403, WSM 1. TROUBLESHOOTING Reference Symptom Probable Cause Solution Page Boom Does Not Rise Control valve malfunctioning Repair or replace S-13 Boom cylinder defective Repair or replace S-22 Control lever cable defective Repair or replace S-19 Hydraulic pump malfunctioning Repair or replace –...

  • Page 92: Servicing Specifications

    FRONT LOADER LA1403, WSM 2. SERVICING SPECIFICATIONS Item Factory Specification Allowable Limit Relief Valve Setting Pressure 20.3 to 21.0 MPa – Condition 207 to 214 kgf/cm 2950 to 3045 psi • Engine Speed ..Approx. 2600 min (rpm) • Oil Temperature ..44 to 48 °C 110 to 120 °F Piston Rod Bend...

  • Page 93: Tightening Torques (Especially Specified

    FRONT LOADER LA1403, WSM 3. TIGHTENING TORQUES (ESPECIALLY SPECIFIED) Item N·m kgf·m lbf·ft Control valve mounting bolt 48 to 55 4.9 to 5.7 36 to 41 Look nut 5.4 to 7.8 0.55 to 0.79 4.0 to 5.7 Adaptor and elbow 3/4-16 UNF 48 to 54 4.9 to 5.5 35 to 40...

  • Page 94: Dismounting Front Loader From Tractor

    FRONT LOADER LA1403, WSM 4. DISMOUNTING FRONT LOADER FROM TRACTOR CAUTION • Make sure an approved bucket is attached before removing the loader from the tractor. • For removing the loader, choose flat and hard ground, preferably concrete. • If the ground surface is soft, place suitable planks on the ground for the bucket and stands. •...
  • Page 95 FRONT LOADER LA1403, WSM Hydraulic 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. 3.

  • Page 96: Checking, Disassembling And Servicing

    FRONT LOADER LA1403, WSM 5. CHECKING, DISASSEMBLING AND SERVICING [1] CHECKING AND ADJUSTING (1) Control Valve Relief Valve Setting Pressure (Standard Valve Type) 1. Remove the hose with quick coupler from A2 port (1) of the control valve and set a pressure gauge. 2.

  • Page 97: Adjusting Self-Leveling

    FRONT LOADER LA1403, WSM (2) Adjusting Self-leveling Self-leveling IMPORTANT • When checking, park the tractor on flat and hard ground, set the range shift lever in neutral, apply parking brake, stay clear of operating area while setting self leveling. • Do not adjust the relief valve (2) when adjusting self-leveling because it can break a pump.
  • Page 98 FRONT LOADER LA1403, WSM (Continued) Lower Leveling Adjustment −1 1. Start the engine and set at 2000 min (rpm). 2. Set the boom in the maximum raised position and the bucket (or pallet fork) parallel to the ground. 3. Lower the boom until the bucket (or pallet fork) slightly contact to the ground.

  • Page 99: 3Rd Function Valve (Option

    FRONT LOADER LA1403, WSM (3) 3rd Function Valve (Option) Relief Valve Setting Pressure 1. Assemble the relief valve set adaptor and pressure gauge (30 MPa). 2. Connect the assembled adaptor to delivery port (1). 3. Start the engine. 4. Push the ON - OFF switch (2). (ON position) 5.
  • Page 100 FRONT LOADER LA1403, WSM Solenoid Valve 1. Disconnect the 2P connector (2). 2. Perform the following checks. (1) Solenoid Valve (2) 2P Connector W1033058 1) Solenoid Valve 1. Measure the resistance with an ohmmeter between terminal 1 and terminal 2. (Solenoid side) 2.
  • Page 101 FRONT LOADER LA1403, WSM ON - OFF Switch (For 3rd Function Kit) 1. Disconnect the ON - OFF switch connector. 2. Perform the following checks. (1) ON - OFF Switch W1033411 1) ON - OFF Switch 1. Measure the resistance with an ohmmeter between RB terminal and YR terminal.

  • Page 102: Disassembling And Assembling

    FRONT LOADER LA1403, WSM [2] DISASSEMBLING AND ASSEMBLING (1) Control Valve Assembly Valve Cover and Cable 1. Remove the valve cover (1). 2. Remove the snap pins (5) and remove the cables (3). (When reassembling) • The cable with blue tape is for boom section and the cable with red tape is for bucket section.
  • Page 103 FRONT LOADER LA1403, WSM Hydraulic Hoses and Control Valve 1. Disconnect the hydraulic hoses (1), (2), (3), (4), (5), (6), (7) from the control valve (8). 2. Remove the control valve (8). IMPORTANT • If the hoses are connected wrong it can cause damage to a pump.
  • Page 104 FRONT LOADER LA1403, WSM (2) Control Valve Elbow (Standard Valve Type) 1. Remove the elbows from the control valve. (When reassembling) • Take care not to damage the O-ring. 48 to 54 N·m Adaptor and elbow 3/4-16 Tightening torque 4.9 to 5.5 kgf·m 35 to 40 lbf·ft •...

  • Page 105: Control Valve

    FRONT LOADER LA1403, WSM Control Valve (Standard Valve Type) 1. Unscrew the nuts (3), and separate each section. (When reassembling) • Take care not to damage the O-rings (1), (5) and (10). Mounting nut 45 N·m Tie rod : 9.5 mm DIA 4.6 kgf·m : 3/8 in.
  • Page 106 FRONT LOADER LA1403, WSM Boom Control Valve (Standard Valve Type) 1. Remove the spring (18) and load check valve (17). 2. Remove the seal plate (2), wiper ring (3) and spacer (5), (6) from the valve housing 1 (8). 3. Remove the cap (25) and spacer (12), and draw out the spool (16) from the valve housing 1 (8).
  • Page 107 FRONT LOADER LA1403, WSM Bucket Control Valve (Standard Valve Type) 1. Remove the spring (10) and load check valve (9). 2. Remove the seal plate (2) and wiper ring (3) from valve housing 2 (5). 3. Remove the cap (16), seal plate (8) and wiper ring (7), and draw out the spool (11) from the valve housing 2 (5).
  • Page 108 FRONT LOADER LA1403, WSM Elbow and Control Valve Assy. (Self-leveling Valve Type) 1. Remove the elbows from the control valve. 2. Remove the control valve assy.. (When reassembling) • Take care not to damage the O-ring. 48 to 54 N·m Adaptor and elbow 3/4-16 Tightening torque 4.9 to 5.5 kgf·m...

  • Page 109: Controller And Cables

    FRONT LOADER LA1403, WSM (3) Controller and Cables Controller and Cables 1. Remove the cover (12). 2. Remove the M6 lock nut (2) and cable end (1). 3. Remove the M6 lock nuts (5). 4. Disconnect the cables (3) from the controller. 5.

  • Page 110: Bucket, Boom And Hydraulic Cylinders

    FRONT LOADER LA1403, WSM (4) Bucket, Boom and Hydraulic Cylinders Bucket Skid-steer type 1. Lower the implement to ground level with the implement slightly in the rolled back position. Stop the engine and set the parking brake. 2. Pull the quick hitch handles to the unlatched position to release the latching pins.
  • Page 111 FRONT LOADER LA1403, WSM Quick Hitch Frame 1. Remove the pins (1) and remove the quick hitch frame (2). DANGER • If you install or sell aftermarket implements to the customer, these implements must meet the SAE standard of J2513. Failure to meet this standard could result in injury or death (Reference) 71 mm...
  • Page 112 FRONT LOADER LA1403, WSM Hydraulic Cylinders and Hydraulic Hoses 1. Remove the split pin and remove the indicator assy. (3). 2. Disconnect the hydraulic hoses (5). 3. Remove the pins and remove the bucket cylinders (2). 4. Disconnect the hydraulic hoses (4). 5.
  • Page 113 FRONT LOADER LA1403, WSM Piston Rod Assembly 1. Drain hydraulic oil from the cylinder, and secure the tube end of the cylinder in a vise. 2. Unscrew the cylinder head (1) with the adjustable gland nut wrench (4). 3. Pull out the piston rod assembly (2) from the cylinder tube (3). (When reassembling) •...
  • Page 114 FRONT LOADER LA1403, WSM Piston Seal and O-ring 1. Remove the piston seal (2) and O-ring (3) from the piston (1). IMPORTANT • When installing the O-ring (3) and piston seal (2) to the piston (1), use the slide jig and correcting jig as shown in the figure.

  • Page 115: Main Frame And Others

    FRONT LOADER LA1403, WSM (5) Main Frame and Others Front Guard 1. Remove the front guard (1) from the main frames (3). (When reassembling) • Make sure the plate springs are in the specified direction. • With the upper and lower front guards fitted together, tighten the hex nuts so that the guards swivel smoothly but the upper front guard does not move by gravity.
  • Page 116 FRONT LOADER LA1403, WSM Main Frame 1. Remove the main frame (1) from the clutch housing and the front axle frame. (When reassembling) 368 N·m Main frame mounting bolt 37.5 kgf·m (M20) 2712 lbf·ft 319 N·m Main frame mounting bolt Tightening torque 32.5 kgf·m (M18)

  • Page 117: Accumulator (Option

    FRONT LOADER LA1403, WSM (6) Accumulator (Option) Hydraulic Hoses and Pipe NOTE • Release the hydraulic pressure in the hydraulic circuit. 1. Disconnect the hydraulic hoses (1) and hydraulic pipe (2). (When reassembling) • Before disconnecting the hydraulic hoses, be sure to note their original positions.

  • Page 118: Servicing

    FRONT LOADER LA1403, WSM [3] SERVICING Piston Rod Bend 1. Place piston rod on V blocks. 2. Set a dial indicator on the center of the rod. 3. Turn the piston rod and read the dial indicator. 4. If the measurement exceeds the allowable limit, replace it. 0.25 mm Piston rod bend Allowable limit...
  • Page 119 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 : ksos-pub@kubota.co.jp Printed in Japan 2008. 07, S, EI, EI, e Code No.9Y111-00882 KUBOTA Corporation 2007.

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