Page 1 WORKSHOP MANUAL TRACTOR ST -30,ST -35 KiSC issued 11, 2006 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 Tractor STα-30 and STα-35. It is divided into two parts, “Mechanism” and “Servicing” for each section. Mechanism Information on the construction and function are included.
Page 3 STα-30 · STα-35, WSM SAFETY INSTRUCTIONS SAFETY INSTRUCTIONS SAFETY FIRST This symbol, the industry’s “Safety Alert Symbol”, is used throughout this manual and decals 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 STα-30 · STα-35, WSM SAFETY INSTRUCTIONS SAFETY STARTING • Do not start the engine by shorting across starter terminals or bypassing the safety start switch. • Do not alter or remove any part of machine safety system. • Before starting the engine, make sure that all shift levers are in neutral positions or in disengaged positions.
Page 5 STα-30 · STα-35, WSM SAFETY INSTRUCTIONS VENTILATE WORK AREA • If the engine must be running to do some work, make sure the area is well ventilated. Never run the engine in a closed area. The exhaust gas contains poisonous carbon monoxide. PREVENT ACID BURNS •...
Page 6: Safety Decals
STα-30 · STα-35, WSM SAFETY INSTRUCTIONS 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 11, 2006 A...
Page 7 STα-30 · STα-35, WSM SAFETY INSTRUCTIONS KiSC issued 11, 2006 A...
Page 8 STα-30 · STα-35, WSM SAFETY INSTRUCTIONS KiSC issued 11, 2006 A...
Page 9: Specifications
SPECIFICATIONS Model STα-30 STα-35 PTO power 17.3 kW (23.5 PS) 21.0 kW (28.5 PS) Maker KUBOTA Model D1463-M-ST D1703-M-ST Type ETVCS, Indirect Injection. Vertical, water-cooled, 4-cycle diesel Number of cylinders 82 × 92.4 mm (3.23 × 3.64 in.) 87 × 92.4 mm (3.43 × 3.64 in.)
Page 10 Revolution 540 / 2673 min (rpm), 800 / 2738 min (rpm) PTO system PTO shaft USA No. 5 (KUBOTA 10-tooth) involute spline Mid. Revolution 1700 / 2710 min (rpm), 2500 / 2755 min (rpm) Note : * Manufacture’s estimate the company reserves the right to change the specifications without notice.
Page 11 STα-30 · STα-35, WSM TRAVELLING SPEED TRAVELLING SPEED Model STα-30 · STα-35 Tire size (Rear) 9.5-22 12.4-16 13.6-16 Range gear shift lever km/h (mile/h) km/h (mile/h) km/h (mile/h) 1 (Low) 0 to 6.6 (0 to 4.1) 0 to 6.3 (0 to 3.9) 0 to 6.5 (0 to 4.0) 2 (Middle) 0 to 12.7 (0 to 7.9)
Page 12 STα-30 · STα-35, WSM DIMENSIONS DIMENSIONS KiSC issued 11, 2006 A...
Page 13 GENERAL KiSC issued 11, 2006 A...
Page 14: Table Of Contents
GENERAL CONTENTS 1. FEATURES ...................... G-1 2. TRACTOR IDENTIFICATION ................. G-2 3. GENERAL PRECAUTIONS ................G-3 4. HANDLING PRECAUTIONS FOR ELECTRICAL PARTS AND WIRING .. G-4 [1] WIRING...................... G-4 [2] BATTERY....................G-6 [3] FUSE......................G-6 [4] CONNECTOR .................... G-6 [5] HANDLING OF CIRCUIT TESTER............G-7 5.
Page 15: Features
STα-30 · STα-35, WSM G GENERAL 1. FEATURES 1. Hydraulic Power Steering 2. E-TVCS (Three Vortex Combustion System) Diesel Engine 3. Engine Key Shut-Off System 4. Hydrostatic Transmission (HST) 5. 3 Range of Speed 6. Bi-speed Turn 7. Cruise Control 8.
Page 16: Tractor Identification
STα-30 · STα-35, WSM G GENERAL 2. TRACTOR IDENTIFICATION When contacting your local KUBOTA distributor, always specify engine serial number, tractor serial number and hour meter reading. (1) Tractor Identification Plate (3) Engine Serial Number (2) Tractor Serial Number (4) Hour Meter...
Page 17: General Precautions
Screws, bolts and nuts should be installed in their original position to prevent reassembly errors. • When special tools are required, use KUBOTA genuine special tools. Special tools which are not frequently used should be made according to the drawings provided.
Page 18: Handling Precautions For Electrical Parts And Wiring
STα-30 · STα-35, WSM G GENERAL 4. HANDLING PRECAUTIONS FOR ELECTRICAL PARTS AND WIRING To ensure safety and prevent damage to the machine and surrounding equipment, heed the following precautions in handling electrical parts and wiring. IMPORTANT • Check electrical wiring damage loosened...
Page 19 STα-30 · STα-35, WSM G GENERAL • Securely clamp, being careful not to damage wiring. (1) Clamp (3) Clamp • Wind Clamp Spirally (4) Welding Dent (2) Wire Harness W1011458 • Clamp wiring so that there is no twist, unnecessary sag, or excessive tension, except for movable part, where sag be required.
Page 20: Battery
STα-30 · STα-35, WSM G GENERAL [2] BATTERY • Take care not to confuse positive and negative terminal posts. • When removing battery cables, disconnect negative cable first. When installing battery cables, check for polarity and connect positive cable first. •...
Page 21: Handling Of Circuit Tester
STα-30 · STα-35, WSM G GENERAL • Use sandpaper to remove rust from terminals. • Repair deformed terminal. Make certain there is no terminal being exposed or displaced. (1) Exposed Terminal (3) Sandpaper (2) Deformed Terminal (4) Rust W1012346 • Make certain that there is no female connector being too open. (A) Correct (B) Incorrect W1012430...
Page 22: Lubricants Fuel And Coolant
Above 25 °C (77 °F): SAE30, 10W-30 or 10W-40 18.5 L Transmission case 4.89 U.S.gals. KUBOTA SUPER UDT fluid* 4.07 Imp.gals. 4.0 L KUBOTA SUPER UDT fluid* or SAE80, 90 gear Front axle case 1.06 U.S.gals. 0.88 Imp.gals. Grease Place No. of greasing point Capacity...
Page 23: Tightening Torques
STα-30 · STα-35, WSM G GENERAL 6. TIGHTENING TORQUES Screws, bolts and nuts whose tightening torques are not specified in this Workshop Manual should be tightened according to the table below. [1] GENERAL USE SCREWS, BOLTS AND NUTS Indication on top of No-grade or 4T bolt SCr435,...
Page 24: Maintenance
STα-30 · STα-35, WSM G GENERAL 7. MAINTENANCE Service Time Interval Period Reference Important Item 2 years page Engine oil Change G-12 Engine oil filter Replace G-12 Transmission fluid Change G-13 Hydraulic oil filter (for HST) Replace G-13 Hydraulic oil filter Replace G-13 Front axle case oil...
Page 25: Check And Maintenance
STα-30 · STα-35, WSM G GENERAL 8. CHECK AND MAINTENANCE CAUTION • Be sure to check and service the tractor on a flat place with engine shut off, the parking brake on and chock the wheels. [1] DAILY CHECK To prevent trouble from occurring, it is important to know the condition of the tractor. Check the following items before starting.
Page 26: Check Points Of Initial 50 Hours
Then, replenish the engine oil up to the specified level. IMPORTANT • To prevent serious damage to the engine, replacement element must be highly efficient. Use only a KUBOTA genuine filter or its equivalent. (1) Engine Oil Filter W1014892...
Page 27 Check the fluid level. IMPORTANT • To prevent serious damage to the hydraulic system. Use only a genuine KUBOTA filter or its equivalents. (1) Drain Plug (3) Hydraulic Oil Filter (for HST) (2) Hydraulic Oil Filter...
Page 28 3. After draining, screw in the two drain plugs. 4. Fill new oil from filling port with specified amount of oil. IMPORTANT • Use KUBOTA SUPER UDT fluid or SAE 80, 90 gear oil. Refer to “LUBRICANTS, FUEL AND COOLANT”. (See page G-8.) 4.0 L...
Page 29: Check Points Of Every 50 Hours
STα-30 · STα-35, WSM G GENERAL [3] CHECK POINTS OF EVERY 50 HOURS Greasing 1. Apply a grease to the following position as figures. (1) Grease Fitting (Top Link) (4) Grease Fitting (Brake Pedal Shaft) (2) Grease Fitting (Lifting Rod RH) (5) Grease Fitting (Clutch Pedal Shaft) (3) Battery Terminal W1016347...
Page 30 STα-30 · STα-35, WSM G GENERAL Checking Engine Start System CAUTION • Do not allow anyone near the tractor while testing. • If the tractor does not pass the test do not operate the tractor. Preparation before testing. 1. Sit on operator’s seat. 2.
Page 31: Check Points Of Every 100 Hours
STα-30 · STα-35, WSM G GENERAL [4] CHECK POINTS OF EVERY 100 HOURS Changing Engine Oil 1. See page G-12. W1017133 Checking Clutch Pedal Free Travel 1. See page G-14. W1017188 Cleaning Air Cleaner Element [Single Element and Double Element Type] 1.
Page 32 STα-30 · STα-35, WSM G GENERAL Cleaning Fuel Filter This job should not be done in the field, but in a clean place. 1. Close the fuel filter cock (1). 2. Unscrew the screw ring and remove the fuel filter bowl (2), and rinse the inside with kerosene.
Page 33 STα-30 · STα-35, WSM G GENERAL Checking Fan Belt Tension CAUTION • Be sure to stop engine before checking belt tension. 1. Stop the engine and remove the key. 2. Apply moderate thumb pressure to belt between pulleys. 3. If tension is incorrect, loosen the alternator mounting bolts and using a lever placed between the alternator and the engine block, pull the alternator out until the deflection of the belt falls within acceptable limits.
Page 34 STα-30 · STα-35, WSM G GENERAL Checking Parking Brake CAUTION • Be sure to stop engine before checking parking brake. 1. Slowly raise the parking brake lever (1) to the ratchet sound made by the parking brake lever. 2. If the No. of notch is not within the factory specifications, loosen the lock nut (2) and turn the brake rod LH (3) and RH (4) to adjust within acceptable limits.
Page 35 STα-30 · STα-35, WSM G GENERAL Checking Battery Condition DANGER To avoid the possibility of battery explosion: For the refillable type battery, follow the instructions below. • Do not use or charge the refillable type battery if the fluid level is below the LOWER (lower limit level) mark.
Page 36: Check Points Of Every 200 Hours
STα-30 · STα-35, WSM G GENERAL Battery Charging CAUTION • When the battery is being activated, hydrogen and oxygen gases in the battery are extremely explosive. Keep open sparks and flames away from the battery at all times, especially when charging the battery. •...
Page 37 STα-30 · STα-35, WSM G GENERAL Checking Radiator Hose and Hose Clamp Check to see if radiator hoses are properly fixed every 200 hours of operation or six months, whichever comes first. 1. If hose clamps are loose or water leaks, tighten bands securely. 2.
Page 38: Check Points Of Every 400 Hours
STα-30 · STα-35, WSM G GENERAL Adjusting Toe-in 1. Park the tractor on the flat place. 2. Inflate the tires to the specified pressure. 3. Turn steering wheel so front wheels are in the straight ahead position. 4. Lower the implement, lock the parking brake and stop the engine. 5.
Page 39: Check Points Of Every 800 Hours
STα-30 · STα-35, WSM G GENERAL [8] CHECK POINTS OF EVERY 800 HOURS Checking Valve Clearance 1. See page 1-S21. W1021033 [9] CHECK POINTS OF EVERY 1 YEAR Replacing Air Cleaner Element (Primary) and Secondary Element 1. See page G-17. W1021125 [10] CHECK POINTS OF EVERY 2 YEARS Replacing Radiator Hose (Water Pipes)
Page 40 STα-30 · STα-35, WSM G GENERAL Flushing Cooling System and Changing Coolant CAUTION • Do not remove the radiator cap when the engine is hot. Then loosen cap slightly to the stop to relieve any excess pressure before removing cap completely. 1.
Page 41 STα-30 · STα-35, WSM G GENERAL Flashing Cooling system and Changing Coolant (Continued) Anti-Freeze If coolant freezes, it can damage the cylinders and radiator. It is necessary, if the ambient temperature falls below 0 °C (32 °F), to remove coolant after operating or to add anti-freeze to it. 1.
Page 42: Others
STα-30 · STα-35, WSM G GENERAL [11] OTHERS Bleeding Fuel System Air must removed: 1. When the fuel filter or lines are removed. 2. When tank is completely empty. 3. After the tractor has not been used for a long period of time. Bleeding procedure is as follows: 1.
Page 43 Refer to troubleshooting section of this manual or your local KUBOTA distributor for specific information dealing with electrical problems. If any of them should blow, replace with a new one of the same capacity.
Page 44: Special Tools
STα-30 · STα-35, WSM G GENERAL 9. SPECIAL TOOLS [1] SPECIAL TOOLS FOR ENGINE Special Use Puller Set Code No: 07916-09032 Application: Use exclusively for pulling out bearing, gears and other parts with ease. W1024050 Piston Ring Compressor Code No: 07909-32111 Application: Use exclusively for pushing in the piston with piston rings into the cylinder.
Page 45 STα-30 · STα-35, WSM G GENERAL Oil Pressure Tester Code No: 07916-32032 Application: Use to measure lubricating oil pressure. (1) Gauge (5) Adaptor 2 (2) Cable (6) Adaptor 3 (3) Threaded Joint (7) Adaptor 4 (4) Adaptor 1 (8) Adaptor 5 W1024318 Valve Seat Cutter Code No:...
Page 46 STα-30 · STα-35, WSM G GENERAL Auxiliary Socket For Fixing Crankshaft Sleeve Code No: 07916-32091 Application: Use to fix the crankshaft sleeve of the diesel engine. W1077114 Plastigage Code No: 07909-30241 Application: Use to check the oil clearance between crankshaft and bearing, etc.
Page 47 STα-30 · STα-35, WSM G GENERAL NOTE • The following special tools are not provided, so make them referring to the figure. Valve Guide Replacing Tool Application: Use to press out and press fit the valve guide. 20 mm dia. (0.79 in. dia.) 11.7 to 11.9 mm dia.
Page 48 STα-30 · STα-35, WSM G GENERAL Bushing Replacing Tools Application: Use to press out and to press fit the bushing. (1) For small end bushing 162 mm (6.38 in.) 35 mm (1.38 in.) 27 mm (1.06 in.) 35 mm dia. (1.38 in. dia.) 27.90 to 27.95 mm dia.
Page 49 STα-30 · STα-35, WSM G GENERAL Crankshaft Bearing 1 Replacing Tool Application: Use to press out and press fit the crankshaft bearing 1. 1. Extracting tool 135 mm (5.31 in.) 72 mm (2.83 in.) R40 mm (R1.57 in.) 10 mm (0.39 in.) 20 mm (0.79 in.) 20 mm dia.
Page 50: Special Tools For Tractor
STα-30 · STα-35, WSM G GENERAL [2] SPECIAL TOOLS FOR TRACTOR Tie-rod End Lifter Code No: 07909-39051 Application: Use for removing the tie-rod end with ease. W1026472 Steering Wheel Puller Code No: 07916-51090 Application: Use for removing the steering wheel without damaging the steering shaft.
Page 51 STα-30 · STα-35, WSM G GENERAL Clutch Pack Disassembly Tool Code No: 07916-53741 Application: This allows easy installation of bi-speed clutch pack spring. W1073259 Relief Valve Pressure Tester Code No: 07916-50045 Application: This allows easy measurement of relief set pressure. (1) Gauge (07916-50322) (6) Adaptor C (PS3/8) (07916-50371) (2) Cable (07916-50331)
Page 52 STα-30 · STα-35, WSM G GENERAL NOTE • The following special tools are not provided, so make them referring to the figure. Adaptor for Flow Meter Application: Use for checking the hydraulic pump for 3P linkage. NOTE • When using, attach with following parts. O-ring : 04811-00180 2-8.5 mm dia.
Page 53: Tires
STα-30 · STα-35, WSM G GENERAL 10. TIRES [1] TIRE PRESSURE CAUTION • Do not attempt mount a tire. This should be down by a qualified person with the proper equipment. • Always maintain the correct tire pressure. Do not inflate tires above the recommended pressure as shown below. IMPORTANT •...
Page 54: Front Wheels
STα-30 · STα-35, WSM G GENERAL (1) Front Wheels Front wheel tread cannot be adjusted. IMPORTANT • Do not turn front discs to obtain wider tread. In setting up the front wheels, make sure that the inflation valve stem of the tires face outward. 6 –...
Page 55: Tire Liquid Injection
STα-30 · STα-35, WSM G GENERAL [3] TIRE LIQUID INJECTION Auxiliary weights can be used to increase traction force for plowing in fields or clayey ground. Another way is to inject water or another liquid, such as a calcium chloride solution in the tires. Water must not be used in winter since it freezes at 0 °C (32 °F).
Page 56 STα-30 · STα-35, WSM G GENERAL Injection CAUTION • When a calcium chloride solution is used, cool it before pouring it into the tire. • Do not fill tires with water or solution more than 75 % of full capacity (to the valve stem level). The following four ways can be used to inject water or a calcium chloride solution into tires.
Page 57: Implement Limitations
KUBOTA. Use with implements which exceed the maximum specifications listed below, or which are otherwise unfit for use with the KUBOTA Tractor may result in malfunctions or failures of the tractor, damage to other property and injury to the operator or others. [Any malfunctions or failures of the tractor resulting from use with improper implements are not covered by the warranty.]...
Page 58 ENGINE KiSC issued 11, 2006 A...
Page 59 MECHANISM CONTENTS 1. FUEL SYSTEM ..................... 1-M1 [1] GOVERNOR .................... 1-M1 NOTICE For not above-mentioned engine mechanism information, please refer ENGINE MECHANISM WSM (97897-01871). KiSC issued 11, 2006 A...
Page 60: Fuel System
STα-30 · STα-35, WSM ENGINE 1. FUEL SYSTEM [1] GOVERNOR The governor serves to keep engine speed constant by automatically adjusting the amount of fuel supplied to the engine according to changes in the load. This engine employs an all-speed governor which controls the centrifugal force of the steel ball (1) weight, produced by rotation of the fuel camshaft (5), and the tension of the governor spring 1 (7) and 2 (8) are balanced.
Page 61 STα-30 · STα-35, WSM ENGINE At Idling When the speed control lever is set at the idling position after the engine starts, the governor spring 1 (7) does not work at all and the governor spring 2 (8) does only act slightly. The governor sleeve (2) is pushed leftward by a centrifugal force of steel ball (1).
Page 62 SERVICING CONTENTS 1. TROUBLESHOOTING ..................1-S1 2. SERVICING SPECIFICATIONS ..............1-S4 3. TIGHTENING TORQUES ................1-S10 4. CHECKING, DISASSEMBLING AND SERVICING........1-S11 [1] SEPARATING ENGINE FROM TRACTOR .........1-S11 [2] ENGINE BODY ..................1-S20 (1) Checking and Adjusting ..............1-S20 (2) Disassembling and Assembling ............1-S22 (3) Servicing ...................1-S32 [3] LUBRICATING SYSTEM ...............1-S48 (1) Checking ...................1-S48 (2) Servicing ...................1-S48...
Page 63: Troubleshooting
STα-30 · STα-35, WSM ENGINE 1. TROUBLESHOOTING Reference Symptom Probable Cause Solution Page Engine Does Not • No fuel Replenish fuel Start • Air in the fuel system Bleed G-28 • Water in the fuel system Change fuel and – repair or replace fuel system •...
Page 64 STα-30 · STα-35, WSM ENGINE Reference Symptom Probable Cause Solution Page Either Black or Dark • Overload Reduce the load – Gray Exhaust Gas is • Low grade fuel used Use the specified fuel Observe • Fuel filter clogged Change G-18 •...
Page 65 STα-30 · STα-35, WSM ENGINE Reference Symptom Probable Cause Solution Page Engine Overheated • Engine oil insufficient Replenish • Fan belt broken or elongated Change or adjust 1-S49 • Coolant insufficient Replenish G-26 • Radiator net and radiator fin clogged with Clean –...
Page 66: Servicing Specifications
STα-30 · STα-35, WSM ENGINE 2. SERVICING SPECIFICATIONS ENGINE BODY Item Factory Specification Allowable Limit Cylinder Head Surface Flatness – 0.05 mm / 500 mm 0.0020 in. / 19.69 in. Compression Pressure 3.53 to 4.02 MPa / 2.55 MPa / (When Cranking with Starting Motor) 290 rpm 290 rpm...
Page 67 STα-30 · STα-35, WSM ENGINE ENGINE BODY (Continued) Item Factory Specification Allowable Limit Valve Timing (Intake Valve) D1463-M Open 0.14 rad. (8 °) – before T.D.C. Close 0.35 rad. (20 °) – after B.D.C. D1703-M Open 0.21 rad. (12 °) –...
Page 68 STα-30 · STα-35, WSM ENGINE ENGINE BODY (Continued) Item Factory Specification Allowable Limit Timing Gear Crank Gear to Idle Gear Backlash 0.0415 to 0.1122 mm 0.15 mm 0.00163 to 0.00442 in. 0.0059 in. Idle Gear to Cam Gear Backlash 0.0415 to 0.1154 mm 0.15 mm 0.00163 to 0.00454 in.
Page 69 STα-30 · STα-35, WSM ENGINE ENGINE BODY (Continued) Item Factory Specification Allowable Limit Piston Pin Bore I.D. 25.000 to 25.013 mm 25.05 mm 0.98425 to 0.98476 in. 0.9862 in. Second Ring to Ring Groove D1463-M Clearance 0.093 to 0.120 mm 0.2 mm 0.00366 to 0.00472 in.
Page 70 STα-30 · STα-35, WSM ENGINE ENGINE BODY (Continued) Item Factory Specification Allowable Limit Crankpin to Crankpin Bearing Oil Clearance 0.025 to 0.087 mm 0.2 mm 0.00098 to 0.00343 in. 0.0079 in. Crankpin O.D. 46.959 to 46.975 mm – 1.84878 to 1.84941 in. Crankpin Bearing I.D.
Page 71 STα-30 · STα-35, WSM ENGINE COOLING SYSTEM Item Factory Specification Allowable Limit Fan Belt Tension 7.0 to 9.0 mm (0.28 to – 0.35 in.) deflection at 98 N (10 kgf, 22 lbs) of force Thermostat Valve Opening 69.5 to 72.5 °C –...
Page 72: Tightening Torques
STα-30 · STα-35, WSM ENGINE 3. TIGHTENING TORQUES Tightening torques of screws, bolts and nuts on the table below are especially specified. (For general use screws, bolts and nuts : See page G-9.) Item N·m kgf·m ft-lbs Steering wheel mounting nut 48.0 to 56.0 4.9 to 5.7 35.4 to 41.22...
Page 73: Checking, Disassembling And Servicing
STα-30 · STα-35, WSM ENGINE 4. CHECKING, DISASSEMBLING AND SERVICING [1] SEPARATING ENGINE FROM TRACTOR Draining Coolant CAUTION • Do not remove the radiator cap when the engine is hot. Then loosen cap slightly to the stop to relieve any excess pressure before removing cap completely.
Page 74 • After running the engine for few minutes, stop it and check the oil level again, if low, add oil prescribed level. IMPORTANT • Use only KUBOTA SUPER UDT fluid-Use of other oils may damage the transmission or hydraulic system. Refer to “LUBRICANTS, FUEL AND COOLANT”. (See page G-8.) •...
Page 75 STα-30 · STα-35, WSM ENGINE Meter Panel and Panel Under Cover 1. Open the meter panel (1) and disconnect the meter panel connector (2) and hour-meter cable (3). Then remove the meter panel. 2. Remove the sponge. 3. Disconnect the combination switch connector (4), main switch connector (5), hazard switch connector (6) and position lamp switch connector (8).
Page 76 STα-30 · STα-35, WSM ENGINE Power Steering Controller 1. Disconnect the draining hose (7), power stering delivery hose (3), steering hose RH (4) and steering hose LH (5). 2. Remove the power steering controller (1) with steering pillar (2). (When reassembling) •...
Page 77 STα-30 · STα-35, WSM ENGINE Wire Connectors 1. Remove or disconnect the connectors, terminals as listed below and figures. 2. Remove the harness from each harness clamp. 3. Remove the fuse box mounting screws, and remove the fuse box assembly (10). (1) Horn (7) Front Wheel Turning Angle Sensor (2) Battery Positive Code...
Page 78 STα-30 · STα-35, WSM ENGINE Panel Under Frame 1. Remove the foot cover (2), step stay and plug (1). 2. Remove the panel under frame mounting screw (3) and nut, pull up the panel under frame (4) to remove it. (When reassembling) •...
Page 79 STα-30 · STα-35, WSM ENGINE Fuel Tank 1. Disconnect the fuel hose (1) at the fuel filter side, then drain fuel completely. 2. Remove the air cleaner assembly. 3. Disconnect the overflow hoses (2) of fuel line. 4. Remove the bonnet rear support (4), shutter plate (3) with fuel tank (5).
Page 80 STα-30 · STα-35, WSM ENGINE Hydraulic Pipe 1. Remove the hydraulic delivery pipe (1) from the 3P hydraulic pump. 2. Loosen the hose band of the joint hose (3) and slide the joint hose (3) to separating the HST drain pipe (2) and inlet pipe (4). 3.
Page 81 STα-30 · STα-35, WSM ENGINE Separating the Engine from Clutch Housing 1. Place the jack under the center frame and engine oil pan. 2. Remove the engine mounting screws, bolts and nuts, and separate the engine from the clutch housing. (When reassembling) •...
Page 82: Engine Body
STα-30 · STα-35, WSM ENGINE [2] ENGINE BODY (1) Checking and Adjusting Compression Pressure 1. Run the engine until it is warmed up. 2. Stop the engine and disconnect the 2P connector from the fuel pump. 3. Remove the air cleaner, the muffler and all injection nozzles. 4.
Page 83 STα-30 · STα-35, WSM ENGINE Valve Clearance IMPORTANT • Valve clearance must be checked and adjusted when engine is cold. 1. Remove the head cover, the glow plugs and the timing window cover on the clutch housing. 2. Align the “1TC” mark line on the flywheel and center of timing window so that the No.
Page 84 STα-30 · STα-35, WSM ENGINE Top Clearance 1. Remove the cylinder head. 2. Move the piston up and stick a strip of fuse on the piston head at three position with grease. 3. Lower the piston and install the cylinder head. (Use a new cylinder head gasket and tighten with a specified tightening torque.) 4.
Page 85 STα-30 · STα-35, WSM ENGINE Nozzle Holder Assembly and Glow Plug 1. Remove the overflow pipe assembly (5). 2. Remove the nozzle holder assemblies (2) using a 21 mm deep socket wrench. 3. Remove the copper gasket and heat seal (3). 4.
Page 86 STα-30 · STα-35, WSM ENGINE Cylinder Head 1. Loosen the pipe clamp, and remove the water return pipe (1). 2. Remove the cylinder head screw in the order of (n) to (a). 3. Lift up the cylinder head to detach. 4.
Page 87 STα-30 · STα-35, WSM ENGINE (B) Timing Gears, Camshaft and Fuel Camshaft Injection Pump 1. Remove the stop solenoid (2) and hi-idling body (1). 2. Remove the engine stop lever (3) and stop solenoid guide (5). 3. Remove the cover (6). 4.
Page 88 STα-30 · STα-35, WSM ENGINE Fan Drive Pulley 1. Lock the flywheel not to turn using the flywheel stopper. 2. Remove the fan drive pulley mounting nut. 3. Remove the fan drive pulley (2) with gear puller. (When reassembling) 137.3 to 156.9 N·m Fan drive pulley mounting Tightening torque 14.0 to 16.0 kgf·m...
Page 89 STα-30 · STα-35, WSM ENGINE Camshaft 1. Remove the camshaft set bolts and draw out the camshaft (1). (When reassembling) • When installing the idle gear, be sure to align the alignment marks on gears. 23.5 to 27.5 N·m Tightening torque Camshaft set bolt 2.4 to 2.8 kgf·m 17.4 to 20.3 ft-lbs...
Page 90 STα-30 · STα-35, WSM ENGINE (C) Piston and Connecting Rod Oil Pan and Oil Strainer 1. Remove the oil pan mounting screws. 2. Remove the oil pan (2) by lightly tapping the rim of the pan with a wooden hammer. 3.
Page 91 STα-30 · STα-35, WSM ENGINE Pistons 1. Turn the flywheel and bring the piston to top dead center. 2. Draw out the piston upward by lightly tapping it from the bottom of the crankcase with the grip of a hammer. 3.
Page 92 STα-30 · STα-35, WSM ENGINE Piston Ring and Connecting Rod 1. Remove the piston rings using a piston ring tool (Code No. 07909-32121). 2. Remove the piston pin (7), and separate the connecting rod (6) from the piston (5). (When reassembling) •...
Page 93 STα-30 · STα-35, WSM ENGINE (D) Crankshaft Flywheel 1. Lock the flywheel not to turn using the flywheel stopper. 2. Remove the flywheel screws (1) and flywheel (2). (When reassembling) • Apply engine oil to the flywheel screws. • Check to see that there are no metal particles left on the flywheel mounting surfaces.
Page 94: Servicing
STα-30 · STα-35, WSM ENGINE Main Bearing Case Assembly 1. Remove the two main bearing case screws 1, and remove the main bearing case assembly being careful with thrust bearing and crankshaft bearing 2. 2. Remove the main bearing case 1, 2 as above. (When reassembling) •...
Page 95 STα-30 · STα-35, WSM ENGINE Cylinder Head Flaw 1. Prepare an air spray red check (Code No. 07909-31371). 2. Clean the surface of the cylinder head with detergent (2). 3. Spray the cylinder head surface with the read permeative liquid (1).
Page 96 STα-30 · STα-35, WSM ENGINE Replacing Valve Guide (When removing) 1. Press out the used valve guide using a valve guide replacing tool. (When installing) 1. Clean a new valve guide and valve guide bore, and apply engine oil to them. 2.
Page 97 STα-30 · STα-35, WSM ENGINE Correcting Valve and Valve Seat NOTE • Before correcting the valve and seat, check the valve stem and the I.D. of valve guide section, and repair them if necessary. • After correcting the valve seat, be sure to check the valve recessing.
Page 98 STα-30 · STα-35, WSM ENGINE Free Length and Tilt of Valve Spring 1. Measure the free length (A) of valve spring with vernier calipers. If the measurement is less than the allowable limit, replace it. 2. Put the valve spring on a surface plate, place a square on the side of the valve spring.
Page 99 STα-30 · STα-35, WSM ENGINE Oil Clearance between Tappet and Tappet Guide Bore 1. Measure the tappet O.D. with an outside micrometer. 2. Measure the I.D. of the tappet guide bore with a cylinder gauge, and calculate the oil clearance. 3.
Page 100 STα-30 · STα-35, WSM ENGINE Camshaft Side Clearance 1. Set a dial indicator with its tip on the camshaft. 2. Measure the side clearance by moving the cam gear to the front and rear. 3. If the measurement exceeds the allowable limit, replace the camshaft stopper.
Page 101 STα-30 · STα-35, WSM ENGINE Cam Height 1. Measure the height of the cam at its highest point with an outside micrometer. 2. If the measurement is less than the allowable limit, replace the camshaft. 33.90 mm Factory spec. 1.3346 in. Cam height of intake 33.85 mm Allowable limit...
Page 102 STα-30 · STα-35, WSM ENGINE Oil Clearance between Piston Pin and Small End Bushing 1. Measure the piston pin O.D. where it contacts the bushing with an outside micrometer. 2. Measure the small end bushing I.D. with an inside micrometer, and calculate the oil clearance.
Page 103 STα-30 · STα-35, WSM ENGINE Clearance between Piston Ring and Groove 1. Remove carbon from the ring grooves. 2. Measure the clearance between the ring and the groove with a feeler gauge or depth gauge. 3. If the clearance exceeds allowable limit, replace the ring since compression leak and oil shortage result.
Page 104 STα-30 · STα-35, WSM ENGINE (D) Crankshaft Side Clearance of Crankshaft 1. Move the crankshaft to the flywheel side. 2. Set a dial indicator to the crankshaft. 3. Measure the end play by pulling the crankshaft toward the crank gear. 4.
Page 105 STα-30 · STα-35, WSM ENGINE Oil Clearance between Crankpin and Crankpin Bearing 1. Clean the crankpin and crankpin bearing. 2. Put a strip of plastigage (Code No.: 07909-30241) on the center of the crankpin in each direction as shown in the figure. 3.
Page 106 STα-30 · STα-35, WSM ENGINE Oil Clearance between Crankshaft Journal and Crankshaft Bearing 1 1. Measure the O.D. of the crankshaft journal with an outside micrometer. 2. Measure the I.D. of the crankshaft bearing 1 with an inside micrometer, and calculate oil clearance. 3.
Page 107 STα-30 · STα-35, WSM ENGINE Oil Clearance between Crankshaft Journal and Crankshaft Bearing 2 1. Put a strip of plastigage on the center of the journal. 2. Install the bearing case and tighten the baring case screws 1 to the specified torque, and remove the bearing case again. 3.
Page 108 STα-30 · STα-35, WSM ENGINE Crankshaft Sleeve Wear 1. Check the wear on the crankshaft sleeve (1). 2. If the wear exceeds the allowable limit or when the engine oil leaks, replace the crankshaft sleeve. 0.1 mm Wear of sleeve Allowable limit 0.0004 in.
Page 109 STα-30 · STα-35, WSM ENGINE (E) Cylinder Cylinder Wear 1. Measure the I.D. of the cylinder at the six positions (see figure) with a cylinder gauge to find the maximum and minimum I.D.’s. 2. Get the difference (Maximum wear) between the maximum and the minimum I.D.’s.
Page 110: Checking
STα-30 · STα-35, WSM ENGINE [3] LUBRICATING SYSTEM (1) Checking Engine Oil Pressure 1. Remove the engine oil pressure switch, and set a oil pressure tester (Code No.: 07916-32032). 2. Start the engine. After warming up, measure the oil pressure of both idling and rated speeds.
Page 111 STα-30 · STα-35, WSM ENGINE Clearance between Rotor and Cover 1. Put a strip of plastigage (Code No.: 07909-30241) onto the rotor face with grease. 2. Install the cover and tighten the screws. 3. Remove the cover carefully, and measure the width of the press gauge with a sheet of gauge.
Page 112 STα-30 · STα-35, WSM ENGINE Thermostat Valve Opening Temperature 1. Suspend the thermostat in the water by a string with its end inserted between the valve and seat. 2. Heating the water gradually, read the temperature when the valve opens and leaves the string. 3.
Page 113 STα-30 · STα-35, WSM ENGINE [5] FUEL SYSTEM (1) Checking and Adjusting (A) Injection Pump Injection Timing 1. Remove the injection pipes and stop solenoid. 2. Set the speed control lever to maximum fuel discharge position. (Reference) • Remove the starter motor and turn the flywheel with screwdriver. 3.
Page 114 STα-30 · STα-35, WSM ENGINE Fuel Tightness of Pump Element 1. Remove the injection pipes and glow plugs. 2. Install the injection pump pressure tester (1) to the injection pump. 3. Set the speed control lever to the maximum speed position. 4.
Page 115 STα-30 · STα-35, WSM ENGINE (B) Injection Nozzle CAUTION • Check the nozzle injection pressure and condition after confirming that there is nobody standing in the direction the fume goes. If the fume from the nozzle directly contacts the human body, cells may be destroyed and blood poisoning may be caused.
Page 116 STα-30 · STα-35, WSM ENGINE (2) Disassembling and Assembling (A) Injection Nozzle Nozzle Holder 1. Secure the nozzle retaining nut (7) with a vise. 2. Remove the nozzle holder (1), and take out parts inside. (When reassembling) • Assemble the nozzle in clean fuel oil. •...
Page 117 CLUTCH KiSC issued 11, 2006 A...
Page 118 MECHANISM CONTENTS 1. FEATURES ....................2-M1 2. OPERATION ....................2-M2 KiSC issued 11, 2006 A...
Page 119 STα-30 · STα-35, WSM CLUTCH 1. FEATURES This tractor is used dry single plate type clutch. The clutch is located between the engine and transmission and is operated by stepping on the clutch pedal. When the clutch pedal is depressed, the clutch is disengaged and when it is released, the clutch is engaged and power from the engine is transmitted to the transmission.
Page 120 STα-30 · STα-35, WSM CLUTCH 2. OPERATION Clutch “Engaged” When the clutch pedal is not depressed, the clutch release bearing (9) and the fingers of diaphragm spring (5) are not connected to each other. Accordingly, the pressure plate (4) is tightly pressed against the flywheel (1) by the diaphragm spring (5).
Page 121 SERVICING CONTENTS 1. TROUBLESHOOTING ..................2-S1 2. SERVICING SPECIFICATIONS ..............2-S2 3. TIGHTENING TORQUES ................2-S3 4. CHECKING, DISASSEMBLING AND SERVICING........2-S4 [1] CHECKING AND ADJUSTING ...............2-S4 [2] DISASSEMBLING AND ASSEMBLING..........2-S4 (1) Separating Engine from Clutch Housing..........2-S4 (2) Separating Clutch Assembly.............2-S12 (3) Disassembling Clutch Release ............2-S13 [3] SERVICING ....................2-S13 KiSC issued 11, 2006 A...
Page 122: Troubleshooting
STα-30 · STα-35, WSM CLUTCH 1. TROUBLESHOOTING Reference Symptom Probable Cause Solution Page Clutch Drags • Clutch pedal free travel excessive Adjust 2-S4 • Dust on clutch disc generated from clutch Remove rust – disc facing • Release fork broken Replace 2-S13 •...
Page 123: Servicing Specifications
STα-30 · STα-35, WSM CLUTCH 2. SERVICING SPECIFICATIONS Item Factory Specification Allowable Limit Clutch Pedal Free Travel on 20 to 30 mm – Clutch Pedal 0.78 to 1.18 in. Safety Switch Setting Position Distance “B” of Approx. 6.0 mm – Safety Switch 0.236 in.
Page 124: Tightening Torques
STα-30 · STα-35, WSM CLUTCH 3. TIGHTENING TORQUES Tightening torques of screws, bolts and nuts on the table below are especially specified. (For general use screws, bolts and nuts : See page G-9.) Item N·m kgf·m ft-lbs Steering wheel mounting nut 48.04 to 56.0 4.9 to 5.7 35.4 to 41.22...
Page 125: Checking, Disassembling And Servicing
• After running the engine for few minutes, stop it and check the oil level again, if low, add oil prescribed level. IMPORTANT • Use only KUBOTA SUPER UDT fluid-Use of other oils may damage the transmission or hydraulic system. Refer to “LUBRICANTS, FUEL AND COOLANT”. (See page G-8.) •...
Page 126 STα-30 · STα-35, WSM CLUTCH Hood, Side Cover and Battery Cord 1. Open the hood (1) and remove the front grille (3). 2. Disconnect the battery grounding cord (4). 3. Disconnect the head light connectors and remove the side covers (2) and hood (1).
Page 127 STα-30 · STα-35, WSM CLUTCH Accelerator Wire 1. Remove the accelerator wire (1) from hand accelerator lever arm (2). 2. Remove the accelerator wire (1) from speed control lever (3) and holder (4). IMPORTANT • After assembling, be sure to adjust the accelerator wire to speed control lever to operate the engine maximum speed.
Page 128 STα-30 · STα-35, WSM CLUTCH Power Steering Controller 1. Disconnect the draining hose (7), power stering delivery hose (3), steering hose RH (4) and steering hose LH (5). 2. Remove the power steering controller (1) with steering pillar (2). (When reassembling) •...
Page 129 STα-30 · STα-35, WSM CLUTCH Wire Connectors 1. Remove or disconnect the connectors, terminals as listed below and figures. 2. Remove the harness from each harness clamp. 3. Remove the fuse box mounting screws, and remove the fuse box assembly (10). (1) Horn (7) Front Wheel Turning Angle Sensor (2) Battery Positive Code...
Page 130 STα-30 · STα-35, WSM CLUTCH Panel Under Frame 1. Remove the foot cover (2), step stay and plug (1). 2. Remove the panel under frame mounting screw (3) and nut, pull up the panel under frame (4) to remove it. (When reassembling) •...
Page 131 STα-30 · STα-35, WSM CLUTCH Fuel Tank 1. Disconnect the fuel hose (1) at the fuel filter side, then drain fuel completely. 2. Remove the air cleaner assembly. 3. Disconnect the overflow hoses (2) of fuel line. 4. Remove the bonnet rear support (4), shutter plate (3) with fuel tank (5).
Page 132 STα-30 · STα-35, WSM CLUTCH Hydraulic Pipe 1. Remove the hydraulic delivery pipe (1) from the 3P hydraulic pump. 2. Loosen the hose band of the joint hose (3) and slide the joint hose (3) to separating the HST drain pipe (2) and inlet pipe (4). 3.
Page 133: Separating Clutch Assembly
STα-30 · STα-35, WSM CLUTCH Separating the Engine from Clutch Housing 1. Place the jack under the center frame and engine oil pan. 2. Remove the engine mounting screws, bolts and nuts, and separate the engine from the clutch housing. (When reassembling) •...
Page 134: Disassembling Clutch Release
STα-30 · STα-35, WSM CLUTCH (3) Disassembling Clutch Release Clutch Release Fork 1. Remove the set spring (1) from clutch release fork (2) and release hub. 2. Remove the release bearing (3) with release hub (4). (When reassembling) • Set the clutch release fork (2) and release hub with set spring (4) in the correct direction.
Page 135 STα-30 · STα-35, WSM CLUTCH Pressure Plate Flatness 1. Place a straightedge on the pressure plate and measure clearance with a feeler gauge at several points. 2. If the clearance exceeds the allowable limit, replace it. 3. When the pressure plate is worn around its outside and its inside surface only is in contact with the straightedge, replace even if the clearance is within the allowable limit.
Page 136 TRANSMISSION KiSC issued 11, 2006 A...
Page 137 MECHANISM CONTENTS 1. STRUCTURE ....................3-M1 2. TRAVELLING SYSTEM ................3-M2 [1] HYDROSTATIC TRANSMISSION ............3-M2 (1) Structure .................... 3-M2 (2) Hydraulic Circuit ................. 3-M3 (3) Pump and Motor ................3-M4 (4) Operation and Valves ................ 3-M5 (5) Control Linkage................3-M10 (6) Cruise Control Linkage ..............
Page 138: Structure
STα-30 · STα-35, WSM TRANSMISSION 1. STRUCTURE (1) Hydrostatic Transmission (3) Range Gear Shift Section (5) Mid-PTO Shift Section (7) Bi-speed Turn Section Section (4) Rear PTO Shift Section (6) Front Wheel Drive Section (2) PTO Gear Shift Section KiSC issued 11, 2006 A 3-M1...
Page 139: Travelling System
STα-30 · STα-35, WSM TRANSMISSION 2. TRAVELLING SYSTEM [1] HYDROSTATIC TRANSMISSION (1) Structure Hydrostatic transmission is composed of variable displacement piston pump, fixed displacement piston motor, charge pump and valve system. (1) Neutral Valve (Reverse) (10) Check and High Pressure (2) Neutral Valve (Forward) Relief Valve (Reverse) (3) Trunnion Shaft...
Page 140: Hydraulic Circuit
STα-30 · STα-35, WSM TRANSMISSION (2) Hydraulic Circuit (1) Oil Tank (Transmission Case) (2) Case Relief Valve (3) Variable Displacement Pump (HST Pump) (4) Charge Pump (5) Oil Filter (10 μ) (6) Check and High Pressure Relief Valve (Forward) (7) Check and High Pressure Relief Valve (Reverse) (8) Charge Relief Valve (9) Neutral Valve (Forward)
Page 141: Pump And Motor
STα-30 · STα-35, WSM TRANSMISSION (3) Pump and Motor (1) Swashplate (4) Oil (6) Piston [A] Pump (2) Piston (5) Cylinder (7) Swashplate [B] Motor (3) Cylinder Pump and motor cylinder, each containing pistons, are connected by lines. Cylinders and lines are filled with oil. Pistons ride against swashplates(1) and (7) located in pump and motor.
Page 142: Operation And Valves
STα-30 · STα-35, WSM TRANSMISSION (4) Operation and Valves Neutral Position (1) Oil Cooler (2) Charge Relief Valve (3) HST Pump (Variable Discharge Pump) (4) Oil Filter (10 μ) (5) Check and High Pressure Relief Valve (Forward) (6) Check and High Pressure Relief Valve (Reverse) (7) Charge Pump (8) HST Motor (Fixed Discharge...
Page 143 STα-30 · STα-35, WSM TRANSMISSION Forward Position (1) Oil Cooler (2) Cylinder Block (Pump) (3) Oil Filter (10 μ) (4) Check and High Pressure Relief Valve (Forward) (5) Neutral Valve (Forward) (6) Output Shaft (7) Cylinder Block (Motor) (8) Piston (Motor) (9) Fixed Swashplate (10) Variable Swashplate (11) Piston (Pump)
Page 144 STα-30 · STα-35, WSM TRANSMISSION Reverse Position (1) Oil Cooler (2) Cylinder Block (Pump) (3) Oil Filter (10 μ) (4) Check and High Pressure Relief Valve (Reverse) (5) Neutral Valve (Reverse) (6) Output Shaft (7) Cylinder Block (Motor) (8) Piston (Motor) (9) Fixed Swashplate (10) Variable Swashplate (11) Piston (Pump)
Page 145 STα-30 · STα-35, WSM TRANSMISSION Charge Pump It fills up the oil in the HST closing circuit. A part of oil fed from charge pump flows to closing circuit through the check and high pressure relief valve, and the other oil flows into the case goes to the tank through the oil cooler.
Page 146 STα-30 · STα-35, WSM TRANSMISSION Neutral Valve The neutral valves in the main oil circuit lines are open and pass the oil to the case when in neutral, and the oil pressure in their lines becomes low. And when the oil pressure in the high pressure line increases to a specified pressure, the neutral valve closes.
Page 147: Control Linkage
STα-30 · STα-35, WSM TRANSMISSION (5) Control Linkage (1) Speed Control Pedal (4) HST Lever RH (7) HST Link Rod (9) Neutral Holder (2) HST Pedal Rod (5) Trunnion Wheel (8) Neutral Cam (10) Roller (3) Damper (6) HST Lever LH The speed control pedal (1) and trunnion wheel (5) of variable swashplate are linked with the HST pedal rod (2), HST lever RH (4) ·...
Page 148: Cruise Control Linkage
STα-30 · STα-35, WSM TRANSMISSION (6) Cruise Control Linkage (1) Speed Set Lever 1 (4) Removal Lever (6) Rubber (8) Cruise Rod (2) Speed Set Lever 2 (5) Plate (7) Fix Lever Link (9) HST Lever LH (3) Return Spring When speed set lever 1 (1) is moved to forward direction then speed set lever 2 (2), fix lever link (7), cruise rod (8) and HST lever LH (9) are moved to arrow direction.
Page 149: Cruise Control Release System
STα-30 · STα-35, WSM TRANSMISSION (7) Cruise Control Release System (1) Brake Cable (4) Speed Set Lever 1 (7) Plate (9) Brake Pedal (2) Screw (5) Rubber (8) Removal Lever (10) Brake Lever (3) Spring (6) Groove The cruise control return to neutral automatically when brake pedals (9) are depressed. Speed set lever 1 (4) is set with plates (7), rubbers (5) by the removal lever (8), screw (2) and spring (3).
Page 150: Range Gear Shift Section
STα-30 · STα-35, WSM TRANSMISSION 3. RANGE GEAR SHIFT SECTION (1) Hypoid Pinion Shaft (2) 29T Gear (3) 22T Gear (4) 13T Gear (5) 29T Gear (6) 22T Gear (7) 15T Gear (8) Rear Counter Shaft W1017811 Three kind of power flow are available by operating the range shift lever to shift the gear (3) on the hypoid pinion shaft (1).
Page 151: Front Wheel Drive Shift Section
STα-30 · STα-35, WSM TRANSMISSION 4. FRONT WHEEL DRIVE SHIFT SECTION (1) Hypoid Pinion Shaft (2) 22T Gear (3) 22T Gear (4) 21T Gear (5) Rear Counter Shaft (6) Front Wheel Drive Shaft (7) 24T Gear W1018104 2-wheel drive or 4-wheel drive is selected by changing the position of 24T Gear (7) with the front wheel drive lever. Engage Hypoid Pinion Shaft (1) →...
Page 152: Rear Pto Shift Section
STα-30 · STα-35, WSM TRANSMISSION 5. REAR PTO SHIFT SECTION (1) Input Shaft (5) 27T Gear (8) 33T Gear (11) 14T Gear (2) 18T Gear (6) PTO Drive Shaft (9) Shifter (12) 18T Gear (3) PTO Counter Shaft (7) 15T Gear (10) PTO Shaft (13) 21T Gear (4) 24T Gear...
Page 153: Mid-Pto Shift Section
STα-30 · STα-35, WSM TRANSMISSION 6. MID-PTO SHIFT SECTION (1) Input Shaft (6) PTO Drive Shaft (11) Mid-PTO Drive Shaft (15) 24T Gear (2) 18T Gear (7) 15T Gear (12) 14T Gear (16) 23T Gear (3) PTO Counter Shaft (8) 33T Gear (13) 18T Gear (17) 17T Gear (4) 24T Gear...
Page 154: Differential Gear
STα-30 · STα-35, WSM TRANSMISSION 7. DIFFERENTIAL GEAR [1] STRUCTURE (1) Differential Lock Shift Fork (3) Differential Pinion Shaft (5) Spiral Bevel Gear (7) Differential Side Gear (2) Differential Pinion (4) Differential Side Gear (6) Differential Pinion (8) Differential Case The differential gear assembly is a mechanism to provide smooth steering.
Page 155: Operation
STα-30 · STα-35, WSM TRANSMISSION [2] OPERATION During Straight Running Rotation of the spiral bevel pinion (3) is transmitted to the spiral bevel gear (2) bolted to the differential case. When road resistance to the right and left wheels are equal, the differential pinions (6), and differential side gears (4), (7) are carried around by the spiral bevel gear (2), and differential case rotate as a unit.
Page 156: Differential Lock
STα-30 · STα-35, WSM TRANSMISSION [3] DIFFERENTIAL LOCK When resistances to the right and left tires are different due to ground conditions or type of work, the wheel with less resistance slips and prevents the tractor from moving ahead. To compensate for this, the differential lock restricts the differential function and causes both rear axles to rotate as a unit.
Page 157 SERVICING CONTENTS 1. TROUBLESHOOTING ..................3-S1 2. SERVICING SPECIFICATIONS ..............3-S4 3. TIGHTENING TORQUES ................3-S6 4. CHECKING, DISASSEMBLING AND SERVICING........3-S7 [1] CHECKING ....................3-S7 [2] DISASSEMBLING AND ASSEMBLING..........3-S11 (1) Separating Engine from Clutch Housing...........3-S11 (2) Step, Seat Under Cover and Seat ............3-S11 (3) Fender Assembly ................3-S12 (4) Frame....................3-S14 (5) Linkage and Hydraulic Pipes ............3-S15 (6) Clutch Housing Case ................3-S16...
Page 158: Troubleshooting
STα-30 · STα-35, WSM TRANSMISSION 1. TROUBLESHOOTING KiSC issued 11, 2006 A 3-S1...
Page 159 STα-30 · STα-35, WSM TRANSMISSION KiSC issued 11, 2006 A 3-S2...
Page 160 STα-30 · STα-35, WSM TRANSMISSION CLUTCH HOUSING Reference Symptom Probable Cause Solution Page Noise from Clutch • Transmission oil insufficient Refill Housing • Bearing worn Replace – W1013580 TRANSMISSION CASE SECTION Noise from • Transmission oil insufficient Refill Transmission • Gear worn or broken Replace 3-S29 •...
Page 161: Servicing Specifications
STα-30 · STα-35, WSM TRANSMISSION 2. SERVICING SPECIFICATIONS HYDRAULIC TRANSMISSION (HST) SECTION Item Factory Specification Allowable Limit Check and High Pressure Relief Valve Setting Pressure 26.4 to 29.4 MPa – [Relief Valve] 270 to 300 kgf/cm 3840.2 to 4266.9 psi Charge Relief Valve Setting Pressure 0.4 to 0.8 MPa...
Page 162 STα-30 · STα-35, WSM TRANSMISSION TRANSMISSION GEAR CASE SECTION (CONTINUE) Item Factory Specification Allowable Limit Differential Case to Differential Side Gear Clearance 0.05 to 0.10 mm 0.4 mm 0.0020 to 0.0039 in. 0.016 in. Differential Case I.D. 32.000 to 32.025 mm –...
Page 163: Tightening Torques
STα-30 · STα-35, WSM TRANSMISSION 3. TIGHTENING TORQUES Tightening torques of screws, bolts and nuts on the table below are especially specified. (For general use screws, bolts and nuts : See page G-9.) Item N·m kgf·m ft-lbs Rear wheel mounting screw and nut 196.1 to 225.6 20.0 to 23.0 145 to 166...
Page 164: Checking, Disassembling And Servicing
STα-30 · STα-35, WSM TRANSMISSION 4. CHECKING, DISASSEMBLING AND SERVICING [1] CHECKING Adjusting Neutral 1. Disengage the front wheel drive lever. (Drive only rear wheels.) 2. Lift the rear of the tractor so that the rear wheels are off the ground and run the engine at low idling and drive only rear wheels.
Page 165 STα-30 · STα-35, WSM TRANSMISSION Checking Clutch Pedal Free Travel CAUTION • When checking, park the tractor on flat ground, apply the parking brake, stop the engine and remove the key. 1. Slightly depress the clutch pedal (1) and measure free travel “L” at top of clutch pedal.
Page 166 STα-30 · STα-35, WSM TRANSMISSION Cruise Control Linkage (1) Speed Control Pedal (2) Cruise Lever 1 (3) Cruise Spring (4) Neutral Holder Rod (5) Turn Buckle (6) Lever Guide (7) Lock Nut W1013041 Adjusting Cruise Control Linkage 1. Fully depress the speed control pedal (1) for forward and set the cruise lever 1 (2) to fully forward.
Page 167 STα-30 · STα-35, WSM TRANSMISSION Adjusting Cruise Control Release Linkage 1. Adjust the brake pedals play first. 2. Step on one of the brake pedals to make sure the cruise control is not released. Also step on both the brake pedals coupled together to make sure that the cruise control is released.
Page 168: Disassembling And Assembling
STα-30 · STα-35, WSM TRANSMISSION Checking High-pressure Relief Valve Pressure 1. Start the engine to warm up the transmission oil until to reach 50 °C (122 °F). 2. Remove the seat under cover and the step. 3. Install adaptor C (Code No.: 07916-50371) and pressure gauge (49.0 MPa, 500 kgf/cm , 7110 psi) after removing forward or reverse high-pressure checking port plugs (2).
Page 169: Fender Assembly
STα-30 · STα-35, WSM TRANSMISSION Seat 1. Unscrew the seat support mounting screw (3). 2. Remove the seat (1) with seat support (2). (1) Seat (3) Seat Support Mounting Screw (2) Seat Support W1014446 (3) Fender Assembly Rear Wheels 1. Unscrew the ROPS mounting bolt and nut, then remove the ROPS (1).
Page 170 STα-30 · STα-35, WSM TRANSMISSION Auxiliary Hydraulic Valve 1. Disconnect the three control wire cables (2) from valve spool (15). 2. Disconnect the three hydraulic hoses (7), (8) and (9). 3. Remove the hydraulic hose clamp (10). 4. Remove the auxiliary hydraulic valve assembly (1). (When reassembling) •...
Page 171: Frame
STα-30 · STα-35, WSM TRANSMISSION (4) Frame Rear Frame and Under Frame 1. Remove the rear cross bar (2). 2. Remove the rubber mount screw (9), connecting bar (5) and rear frame mounting flange screw (10) then detach the rear frame (4). 3.
Page 172: Linkage And Hydraulic Pipes
STα-30 · STα-35, WSM TRANSMISSION (5) Linkage and Hydraulic Pipes Clutch and Brake Linkage 1. Remove the brake springs (6), cruise release wire (7) and brake rod 1 (8). 2. Remove the clutch pedal spring and clutch rod. 3. Detach the external snap ring (9) and tap out the spring pin (10) from the brake shaft (11).
Page 173: Clutch Housing Case
STα-30 · STα-35, WSM TRANSMISSION HST Linkage 1. Detach the return spring (5). 2. Remove the HST link rod (4). 3. Remove the HST pedal rod (2) and speed control pedal (1). 4. Remove the HST damper (3). (1) Speed Control Pedal (4) HST Link Rod (2) HST Pedal Rod (5) Return Spring...
Page 174: Hydrostatic Transmission (Hst)
STα-30 · STα-35, WSM TRANSMISSION 18T Gear Shaft 1. Take out the bi-speed turn hydraulic clutch assembly (1) with 18T gear shaft (2) from the clutch housing case. (When reassembling) • Apply grease to the oil seal (3) of the clutch housing. (1) Bi-speed Turn Hydraulic Clutch (5) 22T Gear Assembly...
Page 175 STα-30 · STα-35, WSM TRANSMISSION Hydrostatic Transmission (HST) (1) Case (2) Trunnion Shaft (3) Variable Displacement Piston Pump (4) Input Shaft (5) Fixed Displacement Piston Motor (6) Output Shaft (7) Neutral Valve (Reverse) (8) Neutral Valve (Forward) (9) Case Relief Valve (10) Valve Plate (Pump) (11) Valve Plate (Motor) (12) Charge Relief Valve...
Page 176 STα-30 · STα-35, WSM TRANSMISSION Neutral Valve 1. Remove the neutral valve assembly (6), (7) from the port block (8). 2. Take out the spring holder (1), spring (2) and poppet N (3) after tapping out the spring pin (5). (When reassembling) •...
Page 177 STα-30 · STα-35, WSM TRANSMISSION Valve Plates for Pump and Motor 1. Remove the valve plates (1), (4). (When reassembling) • Set the groove (2) of valve plates to spring pins firmly. IMPORTANT • Valve plates (1), (4) are not interchangeable. Valve plate (1) of pump has two fish tails (3) and the valve plate (4) of motor has not it.
Page 178: Transmission Case
STα-30 · STα-35, WSM TRANSMISSION (8) Transmission Case Separating Transmission Case 1. Remove the PTO link (1). 2. Separate the transmission case (2) and differential gear case (3). (When reassembling) • Apply liquid gasket (Three Bond 1208D or equivalent) to joint face of transmission case and differential gear case.
Page 179: Rear Pto
STα-30 · STα-35, WSM TRANSMISSION (9) Rear PTO 3 Point Linkage and Drawbar 1. Remove the both lift rod (1) and (7). 2. Remove the split pin and disconnect the check chain (2) and (8). 3. Remove the lower link (3) and (9) with check chain. 4.
Page 180: Mid-Pto Gear Case
STα-30 · STα-35, WSM TRANSMISSION (10) Mid-PTO Gear Case Mid-PTO Case and Shaft 1. Remove the mid-PTO case (9) from differential gear case. 2. Remove the oil seal (1) and internal snap ring (2). 3. Pull out the mid-PTO shaft (3). 4.
Page 181 STα-30 · STα-35, WSM TRANSMISSION Separating Rear Axle 1. Remove the brake lever (1) and hydraulic block (2). 2. Unscrew the lower link pin mounting screw (5) and draw out the lower link pin (4). 3. Separate the rear axle case (3). (When reassembling) •...
Page 182 STα-30 · STα-35, WSM TRANSMISSION (12) Differential Gear Case Front Drive Shaft 1. Remove the air cover (2) and mid cover (1). 2. Draw out the front drive shaft (3) with 24T gear (5). (When reassembling) • Toward the manufacturer’s stamp make of needle bearing (6) for forward.
Page 183 STα-30 · STα-35, WSM TRANSMISSION Hypoid Pinion, Rear Counter Shaft and Auxiliary Shift Fork 1. Take out the hypoid pinion (2), rear counter shaft (5) and auxiliary shift fork (3) as an assembly. 2. Remove the stake of the lock nut (6) and take out it. 3.
Page 184 STα-30 · STα-35, WSM TRANSMISSION Differential Gear Assembly 1. Remove the differential bearing holder (1), noting the number of shims (4). 2. Take out the differential gear as an assembly and the collar (3). (When reassembling) • Install correct shims and collar. 60.8 to 70.6 N·m Ring gear mounting UBS Tightening torque...
Page 185: Servicing
STα-30 · STα-35, WSM TRANSMISSION Differential Pinion Shaft, Differential Pinion and Differential Side Gear 1. Take out the differential side gear (3) and shim (2). 2. Tap out the dowel pin (6). 3. Pull out the differential pinion shaft (7), then take out the differential pinions (5), pinion thrust collars (4), differential side gear (10) and shim (9).
Page 186: Differential Gear Case
STα-30 · STα-35, WSM TRANSMISSION Clearance between 18T Input Shaft and PTO Counter Shaft 1. Measure the 18T input shaft I.D. and PTO counter shaft O.D.. 2. Measure the O.D. of two needles installed diagonally in the needle bearing. 3. Calculate the clearance. 4.
Page 187 STα-30 · STα-35, WSM TRANSMISSION Clearance between Hypoid Pinion Shaft and 29T Gear 1. Measure the 29T gear I.D. (1) and hypoid pinion O.D. (2). 2. Calculate the clearance. 3. If the clearance exceeds the allowable limit, replace. 0.020 to 0.051 mm Factory spec.
Page 188 STα-30 · STα-35, WSM TRANSMISSION Clearance between Differential Case and Differential Side Gear 1. Measure the differential case I.D. and ring gear I.D. with an inside micrometer. 2. Measure the differential side gear boss O.D. with an outside micrometer and calculate the clearance. 3.
Page 189 STα-30 · STα-35, WSM TRANSMISSION Adjusting of Hypoid Pinion Motive Force 1. Assemble the hypoid pinion assembly and tighten the lock nut (2) lightly with new one. 2. Rotate the hypoid pinion with applying the transmission oil to the bearings after tapping the hypoid pinion to front and rear direction by the soft hammer.
Page 190 STα-30 · STα-35, WSM TRANSMISSION Correcting of Tooth Contact 1. Proper contact. • No adjustment. W1028600 2. Correcting of the heel contact and shallow contact. • Change the differential bearing holder collar (5) to thick it. • Change the bearing holder shim (1) to thick it. •...
Page 191 STα-30 · STα-35, WSM TRANSMISSION Clearance between Mid-PTO Drive Shaft to 15T Gear 1. Measure the 15T gear I.D. (1) and mid-PTO drive shaft O.D. (2). 2. Calculate the clearance. 3. If the clearance exceeds the allowable limit, replace. 0.040 to 0.074 mm Factory spec.
Page 192: Rear Axle
REAR AXLE KiSC issued 11, 2006 A...
Page 193 MECHANISM CONTENTS 1. STRUCTURE ....................4-M1 2. OPERATION ....................4-M2 KiSC issued 11, 2006 A...
Page 194 STα-30 · STα-35, WSM REAR AXLE 1. STRUCTURE (1) Rear Axle Case (5) Rear Axle Shaft (9) Brake Case (13) Hypoid Ring Gear (2) Internal Gear (6) Planetary Carrier (10) Differential Lock Clutch (14) Transmission Case (3) Differential Lock Fork (7) Planetary (11) Differential Bearing Holder (15) Steel Plate...
Page 195 STα-30 · STα-35, WSM REAR AXLE 2. OPERATION The final reduction system has a planetary gear system. It is compact, and is durable under heavy loads since torque loads are spread over three gears, decreasing the load on each tooth. And this system also spreads the load evenly around the circumference of the system, eliminating the sideways stress on the shafts.
Page 196 SERVICING CONTENTS 1. SERVICING SPECIFICATIONS ..............4-S1 2. TIGHTENING TORQUES ................4-S2 3. DISASSEMBLING AND SERVICING............4-S3 [1] DISASSEMBLING AND ASSEMBLING..........4-S3 [2] SERVICING ....................4-S4 KiSC issued 11, 2006 A...
Page 197: Servicing Specifications
STα-30 · STα-35, WSM REAR AXLE 1. SERVICING SPECIFICATIONS Item Factory Specification Allowable Limit Internal Gear to Planetary Gear Backlash 0.1 to 0.2 mm 0.5 mm 0.0039 to 0.0079 in. 0.020 in. Planetary Gear I.D. 30.009 to 30.025 mm 30.05 mm 1.18146 to 1.18209 in.
Page 198: Tightening Torques
STα-30 · STα-35, WSM REAR AXLE 2. TIGHTENING TORQUES Tightening torques of screws, bolts and nuts on the table below are especially specified. (For general use screws, bolts and nuts : See page G-9.) Item N·m kgf·m ft-lbs Stopper mounting screw 48.1 to 55.9 4.9 to 5.7 35.4 to 41.2...
Page 199: Disassembling And Servicing
STα-30 · STα-35, WSM REAR AXLE 3. DISASSEMBLING AND SERVICING [1] DISASSEMBLING AND ASSEMBLING Separating Rear Axle 1. Refer to “DISASSEMBLING AND ASSEMBLING” section of 3. TRANSMISSION (3-S24). W1010865 Planetary Gear 1. Take out the lock washer (4), then remove the stopper (1) mounting screw.
Page 200 STα-30 · STα-35, WSM REAR AXLE Rear Axle 1. Tap out the rear axle. (When reassembling) • Apply grease to the oil seal. • Do not allow any gap (A) between the inner and outer surfaces of the oil seal (1). (Refer to figure left) (1) Oil Seal (3) Rear Axle Case (2) Rear Axle...
Page 201 BRAKES KiSC issued 11, 2006 A...
Page 202 MECHANISM CONTENTS 1. FEATURES ....................5-M1 2. OPERATION ....................5-M2 KiSC issued 11, 2006 A...
Page 203 STα-30 · STα-35, WSM BRAKES 1. FEATURES (1) Rear Axle Case (2) Parkiing Brake Rod Linkage (3) Parking Brake Lever (4) Brake Rod (5) Brake Pedal (6) Brake Cam Lever W1013188 Independent mechanical wet disc brakes are used for the right and left travelling brakes. They are operated by the brake pedals through the mechanical linkages and provide stable braking and require little adjustment.
Page 204 STα-30 · STα-35, WSM BRAKES 2. OPERATION (1) Brake Lever (4) Brake Case (6) Plate (8) Transmission Case (2) Brake Cam (5) Brake Disc (7) Ball (9) Brake Shaft (3) Cam Plate During Braking When the brake pedal is pressed, the linkage causes the brake cam lever (1) and brake cam (2) to turn into the direction of arrow shown in the above diagram.
Page 205: Servicing
SERVICING CONTENTS 1. TROUBLESHOOTING ..................5-S1 2. SERVICING SPECIFICATIONS ..............5-S2 3. CHECKING, DISASSEMBLING AND SERVICING........5-S3 [1] CHECKING AND ADJUSTING ...............5-S3 [2] DISASSEMBLING AND ASSEMBLING..........5-S4 [3] SERVICING ....................5-S4 KiSC issued 11, 2006 A...
Page 206: Troubleshooting
STα-30 · STα-35, WSM BRAKES 1. TROUBLESHOOTING Reference Symptom Probable Cause Solution Page Uneven Braking • Brake pedal play unevenly adjusted Adjust 5-S3 Force • Brake disc worn Replace 5-S5 • Cam plate warped Replace 5-S4 Brake Drags • Brake pedal play too small Adjust 5-S3 •...
Page 207: Servicing Specifications
STα-30 · STα-35, WSM BRAKES 2. SERVICING SPECIFICATIONS Item Factory Specification Allowable Limit Brake Pedal Free Travel 25 to 30 mm – 0.98 to 1.18 in. Right and Left Difference Less than 5 mm – 0.19 in. Parking Brake Lever Free Travel 2 notches –...
Page 208: Checking, Disassembling And Servicing
STα-30 · STα-35, WSM BRAKES 3. CHECKING, DISASSEMBLING AND SERVICING [1] CHECKING AND ADJUSTING Brake Pedal Free Travel CAUTION • Stop the engine and chock the wheels before checking brake pedal. • The difference between the right and left pedal plays must be less than 5.0 mm (0.19 in.).
Page 209: Disassembling And Assembling
STα-30 · STα-35, WSM BRAKES [2] DISASSEMBLING AND ASSEMBLING Removing Brake Pedal 1. Refer to “DISASSEMBLING AND ASSEMBLING” section of 3. TRANSMISSION. W1011417 Separating Brake (Rear Axle) 1. Refer to “DISASSEMBLING AND ASSEMBLING” section of 3. TRANSMISSION. W1011463 Brake Discs and Friction Plate 1.
Page 210 STα-30 · STα-35, WSM BRAKES Brake Disc Wear 1. Measure the brake disc thickness with vernier calipers. 2. If the thickness is less than the allowable limit, replace it. 3.4 to 3.6 mm Factory spec. 0.134 to 0.142 in. Brake disc thickness 3.0 mm Allowable limit 0.118 in.
Page 211: Front Axle
FRONT AXLE KiSC issued 11, 2006 A...
Page 212 MECHANISM CONTENTS 1. STRUCTURE ....................6-M1 2. FRONT WHEEL ALIGNMENT ..............6-M2 KiSC issued 11, 2006 A...
Page 213 STα-30 · STα-35, WSM FRONT AXLE 1. STRUCTURE (1) Front Axle (6) 11T Bevel Gear (11) Differential Side Gear (15) 16T Bevel Gear (2) Gear Case Cover (7) Front Axle Case (12) Differential Pinion (16) Differential Gear Shaft (3) 41T Bevel Gear (8) Front Axle Bracket, Front (13) Differential Case (17) 10T Bevel Pinion Shaft...
Page 214: Front Wheel Alignment
STα-30 · STα-35, WSM FRONT AXLE 2. FRONT WHEEL ALIGNMENT Front wheel alignment is a term given to mean four angle settings in three dimensions camber, kingpin inclination, toe-in and caster angle. These angle settings are made for the following purposes. Camber The front wheels are tilted from the vertical as viewed from the front, the wheels are farther apart at the top than...
Page 215 SERVICING CONTENTS 1. TROUBLESHOOTING ..................6-S1 2. SERVICING SPECIFICATIONS ..............6-S2 3. TIGHTENING TORQUES ................6-S4 4. CHECKING, DISASSEMBLING AND SERVICING........6-S5 [1] CHECKING AND ADJUSTING ...............6-S5 [2] DISASSEMBLING AND ASSEMBLING..........6-S6 (1) Separating Front Axle Assembly............6-S6 (2) Disassembling Front Axle Assembly...........6-S8 [3] SERVICING ....................6-S12 KiSC issued 11, 2006 A...
Page 216: Troubleshooting
STα-30 · STα-35, WSM FRONT AXLE 1. TROUBLESHOOTING Reference Symptom Probable Cause Solution Page Front Wheels • Tire pressure uneven Adjust – Wander to Right or • Improper toe-in adjustment (improper Adjust 6-S5 Left alignment) • Excessive clearance between front axle Replace 6-S15 center pivot and front axle bracket’s bushing...
Page 217: Servicing Specifications
STα-30 · STα-35, WSM FRONT AXLE 2. SERVICING SPECIFICATIONS Item Factory Specification Allowable Limit Front Wheel Alignment Toe-in 2 to 8 mm – 0.078 to 0.315 in. Camber Angle 0.035 rad. – 2 ° Caster Angle 0.088 rad. – 5 ° Kingpin Angle 0.209 rad.
Page 218 STα-30 · STα-35, WSM FRONT AXLE Item Factory Specification Allowable Limit Differential Pinion to Differential Side Gear Backlash 0.1 to 0.3 mm – 0.004 to 0.012 in. Spiral Bevel Pinion Shaft (Pinion Shaft Turning Force 58.8 to 78.4 N – Only) 6.0 to 8.0 kgf 13.2 to 17.6 lbs...
Page 219 STα-30 · STα-35, WSM FRONT AXLE 3. TIGHTENING TORQUES Tightening torques of screws, bolts and nuts on the table below are especially specified. (For general use screws, bolts and nuts : See page G-9.) Item N·m kgf·m ft-lbs Front wheel mounting screws and nuts 77.5 to 90.2 7.9 to 9.2 57.1 to 66.5...
Page 220: Checking, Disassembling And Servicing
STα-30 · STα-35, WSM FRONT AXLE 4. CHECKING, DISASSEMBLING AND SERVICING [1] CHECKING AND ADJUSTING Adjusting Toe-in 1. Park the tractor on the flat place. 2. Inflate the tires to the specified pressure. 3. Turn steering wheel so front wheels are in the straight ahead position.
Page 221: Disassembling And Assembling
3. After draining, reinstall the drain plugs (1). 4. Fill new oil with specified amount of oil. IMPORTANT • Use KUBOTA SUPER UDT fluid or SAE 80, 90 gear oil. Refer to “LUBRICANTS, FUEL AND COOLANT”. (See page G-8.) 4.0 L Front axle case oil capacity 1.06 U.S.gals.
Page 222 STα-30 · STα-35, WSM FRONT AXLE Front Wheel Turning Angle Sensor 1. Remove the wire harness clamp (1). 2. Disconnect the connector (2). 3. Remove the cotter pin and disconnect the arm (4) from the sensor lever (3). IMPORTANT • Route the wire harness under the both power steering hoses.
Page 223: Disassembling Front Axle Assembly
STα-30 · STα-35, WSM FRONT AXLE (2) Disassembling Front Axle Assembly Steering Cylinder, Axle Bracket and Front Wheel Turning Angle Sensor 1. Remove the slotted nut and remove the both RH and LH tie-rod (6). 2. Remove the front axle brackets (3), (7). 3.
Page 224 STα-30 · STα-35, WSM FRONT AXLE Gear Case Cover and Front Axle 1. Remove the gear case cover (2) from gear case (1). 2. Remove the bearing (6) with special use puller set (Code No.: 07916-09032). 3. Take out the 41T bevel gear (5). 4.
Page 225 STα-30 · STα-35, WSM FRONT AXLE Spiral Bevel Pinion Shaft and Differential Gear Assembly 1. Remove the oil seal (1) and internal snap ring (2). 2. Take out the shim (3). 3. Remove the plug (10), (11). 4. Tap out the spiral bevel pinion shaft (4) to the rear side. 5.
Page 226 STα-30 · STα-35, WSM FRONT AXLE Differential Gear 1. Remove the ball bearing (1) with a puller. 2. Remove the differential case cover mounting screws (13), then take out the differential case cover (7), ball bearing (8) and spiral bevel gear (9) as a unit. 3.
Page 227: Servicing
STα-30 · STα-35, WSM FRONT AXLE [3] SERVICING Clearance between Differential Case and Differential Side Gear and between Differential Case Cover and Differential Side Gear 1. Measure the differential side gear boss O.D.. 2. Measure the differential case bore I.D. and calculate the clearance.
Page 228 STα-30 · STα-35, WSM FRONT AXLE Turning Force of Spiral Bevel Pinion Shaft (Pinion Shaft Only) 1. Clamp the spiral bevel pinion shaft assembly to the vise and tighten the staking nut. 2. Measure the turning torque of bevel pinion shaft. 3.
Page 229 STα-30 · STα-35, WSM FRONT AXLE More than 35 % red lead contact area on the gear tooth surface. The center of tooth contact at 1/3 of the entire width from the small end. (A) Proper Contact W1018747 Replace the adjusting collars (3), (4) to move the bevel pinion shaft toward inside, and repeat above until the proper backlash and tooth contact are achieved.
Page 230 STα-30 · STα-35, WSM FRONT AXLE Backlash between 7T Pinion Shaft and 41T Bevel Gear 1. Stick a strip of fuse to three spots on the 41T bevel gear (1) with grease. 2. Fix the gear case cover and gear case. 3.
Page 231 BI-SPEED TURN KiSC issued 11, 2006 A...
Page 232 MECHANISM CONTENTS 1. STRUCTURE ....................7-M1 2. POWER TRAIN ..................... 7-M2 3. HYDRAULIC CIRCUIT .................. 7-M3 4. ELECTRICAL CONTROL ................7-M5 [1] ELECTRICAL CIRCUIT ................7-M5 [2] BI-SPEED SWITCH ................7-M5 [3] ENGINE RUNNING SENSOR ............... 7-M6 [4] FRONT WHEEL TURNING SENSOR ..........7-M6 [5] TRAVELLING SPEED SENSOR ............
Page 233: Structure
STα-30, STα-35, WSM BI-SPEED TURN 1. STRUCTURE (1) Front Wheel Turning Angle Sensor (2) Instrument Panel (3) Bi-speed Solenoid Valve (4) Hydraulic Clutch Pack (5) Bi-speed Controller (6) Travelling Speed Sensor (7) Engine Sensor (L Terminal) W1014669 It is used hydraulic and electrical control type bi-speed turn. The front wheel turning angle sensor (1) is mounted on the front axle case detects the front wheel turning angle, the bi-speed controller (5) operate the bi-speed solenoid valve (3).
Page 234: Power Train
STα-30, STα-35, WSM BI-SPEED TURN 2. POWER TRAIN The bi-speed hydraulic clutch pack is installed clutch housing case. The power is transmitted as below. 4WD (Not Bi-speed Turn) (1) 22T Gear (2) 18T Gear Shaft (3) 19T Gear (4) Front Drive Shaft (5) 27T Gear (6) Piston (7) Spring...
Page 235: Hydraulic Circuit
STα-30, STα-35, WSM BI-SPEED TURN 3. HYDRAULIC CIRCUIT Bi-speed turn hydraulic circuit is constructed shown above, and oil flow is as follows. (1) Oil Tank (Transmission Case) (2) Oil Filter (3) Hydraulic Pump (4) Engine (5) Flow Priority Valve (6) Bi-speed Valve (7) Bi-speed Hydraulic Clutch Pack (8) To 3-point Linkage Circuit...
Page 236 STα-30, STα-35, WSM BI-SPEED TURN When Bi-speed Solenoid actuates (OFF → ON) The port of hydraulic clutch (3) be opened when the bi-speed solenoid valve (2) is actuated. The unload valve (4) will close the drain port by oil pressure that through the bi-speed solenoid valve (2). The pressure increase until setting pressure of the relief valve (5), and operate the hydraulic clutch (3).
Page 237: Electrical Control
STα-30, STα-35, WSM BI-SPEED TURN 4. ELECTRICAL CONTROL [1] ELECTRICAL CIRCUIT (1) Charge Lamp (2) Controller (3) Bi-speed Solenoid (4) Bi-speed Indicate Lamp (5) Main Switch (6) Battery (7) Front Wheel Turning Angle Sensor (8) Travelling Speed Sensor (9) Alternator W1015357 The bi-speed turn system is controlled by electric device as follows.
Page 238: Engine Running Sensor
STα-30, STα-35, WSM BI-SPEED TURN [3] ENGINE RUNNING SENSOR The bi-speed system will not operate at engine stopping. It is detected from L terminal voltage of alternator (1). (1) Alternator W1015587 [4] FRONT WHEEL TURNING SENSOR The front wheel turning angle is detected by the front wheel turning angle sensor (1) mounted on the front axle case.
Page 239 SERVICING CONTENTS 1. TROUBLESHOOTING ..................7-S1 2. SERVICING SPECIFICATIONS ..............7-S2 3. TIGHTENING TORQUES ................7-S4 4. CHECKING, DISASSEMBLING AND SERVICING........7-S5 [1] CHECKING AND ADJUSTING ...............7-S5 (1) Bi-speed Solenoid Valve ..............7-S5 (2) Fail Safe System .................7-S6 [2] DISASSEMBLING AND ASSEMBLING..........7-S8 (1) Bi-speed Solenoid Valve ..............7-S8 (2) Bi-speed Clutch Pack................7-S9 [3] SERVICING ....................7-S11 (1) Bi-speed Hydraulic Clutch Pack and Gears ........7-S11...
Page 240 STα-30 · STα-35, WSM BI-SPEED TURN 1. TROUBLESHOOTING Reference Symptom Probable Cause Solution Page Bi-speed Turn • Front wheel turning angle sensor defect Replace 7-S14 system Does Not • Travelling speed sensor defect Replace 7-S13 Operate or Slipping • Alternator broken Check 10-S5 •...
Page 241: Servicing Specifications
STα-30 · STα-35, WSM BI-SPEED TURN 2. SERVICING SPECIFICATIONS Item Factory Specification Allowable Limit Relief Valve (Bi-speed Solenoid Valve) Setting Pressure 1.77 to 1.86 MPa – Condition 18.0 to 19.0 kgf/cm Engine Speed ..Maximum 256.01 to 270.24 psi Oil Temperature .. 45 to 55 °C 113 to 131 °F Unload Valve (Bi-speed Solenoid Valve) Setting Pressure...
Page 242 STα-30 · STα-35, WSM BI-SPEED TURN Item Factory Specification Allowable Limit Travelling Speed Sensor Output Voltage Approx. 1.0 V (AC) – (AC) 11 to 15 Ω Bi-speed Solenoid Valve Resistance – Front Wheel Turning Angle Sensor Terminal A and Terminal C Resistance 4.32 to 6.48 kΩ...
Page 243 STα-30 · STα-35, WSM BI-SPEED TURN 3. TIGHTENING TORQUES Tightening torques of screws, bolts and nuts on the table below are especially specified. (For general use screws, bolts and nuts : See page G-9.) Item N·m kgf·m ft-lbs Bi-speed valve delivery pipe retaining nut 34 to 39 3.5 to 4.0 25.3 to 28.9...
Page 244: Checking, Disassembling And Servicing
STα-30 · STα-35, WSM BI-SPEED TURN 4. CHECKING, DISASSEMBLING AND SERVICING [1] CHECKING AND ADJUSTING (1) Bi-speed Solenoid Valve Bi-speed Solenoid Valve Relief Pressure 1. Jack up the rear wheels and shift the front wheel drive lever to OFF position. 2.
Page 245: Fail Safe System
STα-30 · STα-35, WSM BI-SPEED TURN (2) Fail Safe System The bi-speed system equipped with “FAIL SAFE SYSTEM”, “FINE ADJUSTMENT MODE” and “SELF- DIAGNOSIS MODE”. • The fail safe system mention to the operator for some trouble occurred while operating the tractor in usually. •...
Page 246 STα-30 · STα-35, WSM BI-SPEED TURN (C) Self-diagnosis Mode Procedure 1: Making the self-diagnosis reference settings 1. Get the front wheels in the straight-run state. 2. Turn off the main switch. Procedure 2: Changing to the self-diagnosis mode 1. Hold down the bi-speed switch and turn on the main switch (The engine does not start). Now make sure the bi- speed lamp lights up and goes out 0.75 second later.
Page 247: Disassembling And Assembling
STα-30 · STα-35, WSM BI-SPEED TURN Procedure 3: Checking the bi-speed control output 1. Switch off the ignition key (main switch). 2. Switch on the ignition key (main switch) again to start the engine. Enter the ordinary control mode. 3. Turn on the bi-speed mode and turn the tractor right and left to make sure the bi-speed control functions. 4.
Page 248: Bi-Speed Clutch Pack
STα-30 · STα-35, WSM BI-SPEED TURN (2) Bi-speed Clutch Pack Separate the Clutch Housing 1. Refer to “DISASSEMBLING AND ASSEMBLING” section of 3. TRANSMISSION. (When reassembling) • Apply liquid gasket (Three Bond 1208D or equivalent) to the mission case. W1020780 Bi-speed Turn Hydraulic Clutch Assembly and 18T Gear Shaft 1.
Page 249 STα-30 · STα-35, WSM BI-SPEED TURN Disassembling Bi-speed Turn Hydraulic Clutch 1. Remove the internal snap ring (2), then take out the three pressure plates (5), three clutch discs (10) and three steel plates (4). 2. Remove the external snap ring (1) with clutch pack disassembling tool (Code No.: 07916-53741), then take out the collar (7) and spring (8).
Page 250: Servicing
STα-30 · STα-35, WSM BI-SPEED TURN [3] SERVICING (1) Bi-speed Hydraulic Clutch Pack and Gears Checking Bearing 1. Hold the inner race, and push and pull the outer race in all directions to check for wear and roughness. 2. Apply transmission fluid to the bearing, and hold the inner race. Then, turn the outer race to check rotation.
Page 251 STα-30 · STα-35, WSM BI-SPEED TURN Clearance between Counter Shaft B and 27T Gear 1. Measure the counter shaft B O.D. (2) with an outside micrometer. 2. Measure the 27T gear I.D. (1) with an inside micrometer, and calculate the clearance. 3.
Page 252: Sensors, Controller Unit And Solenoid Valve
STα-30 · STα-35, WSM BI-SPEED TURN (2) Sensors, Controller Unit and Solenoid Valve Travelling Speed Sensor 1. Disconnect the connector (1). 2. Jack up the rear wheels and shift the front wheel drive lever to OFF position. 3. Start the engine and turn the rear wheel as follow condition. - Range shift lever : 1 - Cruise control lever : 1 - Engine speed : around 1000 rpm...
Page 253 STα-30 · STα-35, WSM BI-SPEED TURN Front Wheel Turning Angle Sensor 1. Separate the arm (6) from angle sensor lever (5). 2. Disconnect the connector (7). 3. Remove the sensor with sensor cover (8), then remove the sensor from sensor cover (8). 4.
Page 254 STα-30 · STα-35, WSM BI-SPEED TURN 2) Output Voltage 1. Remove the connector for front wheel turning angle sensor and bi-speed solenoid valve. 2. Jack up the rear wheels and shift the front wheel drive lever to OFF position. 3. Start the engine and turn the rear wheels as follow condition. - Range shift lever : 1 - Cruise control lever : 1 - Engine speed : around 1000 rpm...
Page 255 STEERING KiSC issued 11, 2006 A...
Page 256 MECHANISM CONTENTS 1. FEATURES ....................8-M1 2. HYDRAULIC CIRCUIT FOR POWER STEERING SYSTEM....8-M2 3. HYDRAULIC PUMP ..................8-M3 4. STEERING CONTROLLER ................8-M4 [1] CONTROL VALVE .................. 8-M4 [2] METERING DEVICE (GEROTOR) ............8-M4 [3] RELIEF VALVE (WITH CHECK VALVE) ..........8-M5 5.
Page 257: Features
STα-30, STα-35, WSM STEERING 1. FEATURES These tractors are provided with a full hydrostatic power steering. The steering controller is connected to the steering cylinder with the hydraulic pipes only. This steering is actuated by oil pressure. Accordingly, it does not have mechanical transmitting parts such as steering gear, drag link, etc..
Page 258 STα-30, STα-35, WSM STEERING 2. HYDRAULIC CIRCUIT POWER STEERING SYSTEM Hydraulic Oil Flow 1. Power steering hydraulic pump (3), driven by the engine, sucks oil from transmission case (1), and it to steering controller (5). 2. The oil which has entered steering controller (5) is directed to control valve (6).
Page 259: Hydraulic Pump
STα-30, STα-35, WSM STEERING 3. HYDRAULIC PUMP The steering system hydraulic pump fed the oil drawn from the transmission case through the oil filter to the control valve. The steering system hydraulic pump is driven by the engine fuel camshaft. This hydraulic pump is pressure loading type gear pump with high volumetric efficiency.
Page 260: Steering Controller
STα-30, STα-35, WSM STEERING 4. STEERING CONTROLLER The steering controller mainly consists of a control valve, a metering device and a relief valve with check valve. The metering device comprises a set of special gear called “Gerotor”. [1] CONTROL VALVE The control valve is a rotary plate type valve.
Page 261: Relief Valve (With Check Valve)
STα-30, STα-35, WSM STEERING [3] RELIEF VALVE (WITH CHECK VALVE) If the pressure in the hydraulic circuit rises above the set pressure of the relief valve, the relief valve will actuate to prevent the pressure from rising further and protect the hydraulic system. Also, if no oil is supplied from the hydraulic pump, the relief valve will act as a check valve and help draw oil from the return oil line to the drain hose, thus making it possible to steer the...
Page 262: Oil Flow
STα-30, STα-35, WSM STEERING 5. OIL FLOW Neutral Position When the steering wheel (2) is not being turned, valve plate (3) is held in the neutral position by centering springs (4). Under this condition, an oil passage is formed between P port (from pump) and T port (to transmission case) in the control valve, and all oil from the hydraulic pump flows to T port.
Page 263 STα-30, STα-35, WSM STEERING Left Turn The steering system operates in the same way at a left-turn as well, except that oil flows into and out of steering cylinder in the directions opposite to those at a right-turn. (1) Steering Controller P : Pump Port (2) Steering Wheel T : Tank Port...
Page 264: Steering Cylinder
STα-30, STα-35, WSM STEERING 6. STEERING CYLINDER (1) Rod Assembly (4) O-ring (6) Internal Snap Ring (8) Rod Gasket (2) Packing (5) Cover (7) Dust Seal (9) Bushing (3) Cylinder Tube The steering cylinder is single piston both rod double-acting type. The steering cylinder provide force in both directions.
Page 265 SERVICING CONTENTS 1. TROUBLESHOOTING ..................8-S1 2. SERVICING SPECIFICATIONS ..............8-S2 3. TIGHTENING TORQUES ................8-S3 4. CHECKING, DISASSEMBLING AND SERVICING........8-S4 [1] CHECKING AND ADJUSTING ...............8-S4 (1) Hydraulic Pump (Power Steering)............8-S4 (2) Power Steering ...................8-S5 [2] DISASSEMBLING AND ASSEMBLING..........8-S6 (1) Hydraulic Pump...................8-S6 (2) Power Steering Controller ..............8-S7 (3) Power Steering Cylinder ..............8-S8 [3] SERVICING ....................8-S9 (1) Hydraulic Pump (Power Steering)............8-S9...
Page 266 STα-30 · STα-35, WSM STEERING 1. TROUBLESHOOTING Reference Symptom Probable Cause Solution Page Tractor Can Not Be • Steering controller broken Replace 8-S7 Steered • Hose broken Replace – Front Wheels Vibrate • Centering spring weaken or broken Replace steering 8-S7 controller •...
Page 267: Servicing Specifications
STα-30 · STα-35, WSM STEERING 2. SERVICING SPECIFICATIONS POWER STEERING HYDRAULIC PUMP Item Factory Specification Allowable Limit Hydraulic Pump Delivery at No 14.0 L/min. – Condition Pressure 3.70 U.S.gal/min. • Engine Speed : 2800 rpm 3.08 Imp.gal/min. • Rated Pressure : 13.24 to 13.29 MPa 135.0 to 135.5 kgf/cm Delivery at Rated 12.1 L/min.
Page 268 STα-30 · STα-35, WSM STEERING 3. TIGHTENING TORQUES Tightening torques of screws, bolts and nuts on the table below are especially specified. (For general use screws, bolts and nuts : See page G-9.) Item N·m kgf·m ft-lbs Power steering delivery hose joint screw 49.0 to 58.8 5.0 to 6.0 36.2 to 43.4...
Page 269: Checking, Disassembling And Servicing
(1) Hydraulic Pump (Power Steering) Flowmeter Connecting and Test Preparation IMPORTANT • When using a flowmeter other than KUBOTA specified flowmeter (Code No.: 07916-52792), be sure to use the instructions with that flowmeter. • In this hook-up, there is not relief valve.
Page 270: Power Steering
STα-30 · STα-35, WSM STEERING Pump Test NOTE • Before pump testing, perform the flowmeter connecting and test preparation. 1. Open the loading valve completely. 2. Start the engine and set at approx. 2800 rpm. 3. Read and note the pump delivery at no pressure. 4.
Page 271: Disassembling And Assembling
STα-30 · STα-35, WSM STEERING Relief Valve Setting Pressure 1. Remove the power steering delivery pipe from hydraulic pump. 2. Assemble the power steering delivery pipe (1) using a adaptor E (2) instead of original joint. 3. Start the engine. After warming up, set the engine speed at maximum.
Page 272: Power Steering Controller
STα-30 · STα-35, WSM STEERING (2) Power Steering Controller Disassembling Procedure 1. See page 1-S12 and 1-S13. W1013745 Power Steering Hoses 1. Disconnect the draining hose (7), power steering delivery hose (3), steering hose RH (4) and steering hose LH (5). (When reassembling) •...
Page 273: Power Steering Cylinder
STα-30 · STα-35, WSM STEERING Relief Valve and Hydraulic Joint 1. Remove the relief valve plug (2). 2. Draw out the relief valve (1). 3. Remove the joint (3), (4), (5) and (6). (When reassembling) • Apply seal tape on to the thread of power steering controller side for joints.
Page 274: Servicing
STα-30 · STα-35, WSM STEERING Power Steering Cylinder 1. Remove the cylinder mounting reamer screw (3), then slid out the power steering cylinder assembly (1). 2. Remove the rod joint (5) from the cylinder rod (4). 3. Draw out the cylinder cover (9). 4.
Page 275: Steering Cylinder
STα-30 · STα-35, WSM STEERING Clearance between Bushing and Gear Shaft 1. Measure the gear shaft O.D. with an outside micrometer. 2. Measure the bushing I.D. with a cylinder gauge. 3. If the clearance exceeds the allowable limit, replace it. 0.030 to 0.091 mm Factory spec.
Page 276 STα-30 · STα-35, WSM STEERING Cylinder Tube Wear 1. Measure the cylinder tube I.D. with a cylinder gauge. 2. If the measurement exceeds the allowable limit, replace the cylinder tube. 40.000 to 40.039 mm Factory spec. 1.5748 to 1.5763 in. Cylinder tube I.D.
Page 277: Hydraulic System
HYDRAULIC SYSTEM KiSC issued 11, 2006 A...
Page 278 MECHANISM CONTENTS 1. HYDRAULIC CIRCUIT .................. 9-M1 2. HYDRAULIC PUMP ..................9-M2 3. HYDRAULIC BLOCK TYPE OUTLET............9-M3 4. POSITION CONTROL VALVE ..............9-M4 [1] STRUCTURE ................... 9-M4 [2] OIL FLOW ....................9-M4 5. POSITION CONTROL LINKAGE ..............9-M6 6. FLOW PRIORITY VALVE ................9-M9 [1] FUNCTION AND STRUCTURE.............
Page 279: Hydraulic Circuit
STα-30, STα-35, WSM HYDRAULIC SYSTEM 1. HYDRAULIC CIRCUIT (1) Auxiliary Control Valve (5) Hydraulic Pump (9) Hydraulic Cylinder (11) Position Control Valve (2) Oil Tank (Transmission Case) (6) Relief Valve (10) Lowering Speed Adjusting (12) Hydraulic Block Type Outlet (3) Oil Filter (7) Flow Priority Valve Valve (4) Engine...
Page 280: Hydraulic Pump
STα-30, STα-35, WSM HYDRAULIC SYSTEM 2. HYDRAULIC PUMP The hydraulic pump is composed of the casing, side plate (5), and two spur gears (drive gear (3) and driven gear (4)) that are in mesh. Hydraulic pump is driven by the fuel camshaft. Maximum displacement is as follows.
Page 281: Hydraulic Block Type Outlet
STα-30, STα-35, WSM HYDRAULIC SYSTEM 3. HYDRAULIC BLOCK TYPE OUTLET The hydraulic block type outlet is located at the right hand side of the clutch housing. This hydraulic block type outlet is provided to take power out from the tractor to operate the hydraulic cylinders on the implement, such as front end loader, front blade and so on.
Page 282: Position Control Valve
STα-30, STα-35, WSM HYDRAULIC SYSTEM 4. POSITION CONTROL VALVE [1] STRUCTURE The control valve is composed as shown figure left. The spool (3) is moved by the operating the position control lever. The positions of the spool movement makes four kinds of circuit such as “Neutral”, “Lifting”, “Lowering”...
Page 283 STα-30, STα-35, WSM HYDRAULIC SYSTEM Lifting Neutral (Acting shockless mechanism) In returning from Lifting to Neutral, the spool (3) is pushed back to the arrow-mark direction. When the Neutral position comes near, the groove part D of the spool (3) makes the pressure difference at the P port and C port.
Page 284: Position Control Linkage
STα-30, STα-35, WSM HYDRAULIC SYSTEM 5. POSITION CONTROL LINKAGE (1) Position Control Lever (2) Control Arm (3) Spool Drive Lever (4) Spool (5) Control Valve (6) Feedback Lever shaft (7) Feedback Lever (8) Feedback Rod (9) Lift Arm W1014379 Position control is a mechanism to raise or lower the implement attached to the tractor in proportion to the movement of the control lever.
Page 285 STα-30, STα-35, WSM HYDRAULIC SYSTEM Lifting 1. When the position control lever is moved to the LIFT position, the control arm (2) rotates to the arrow. Therefore, the spool drive lever (1) moves around the fulcrum P and pull the spool (3) opening the LIFT circuit.
Page 286 STα-30, STα-35, WSM HYDRAULIC SYSTEM Lowering 1. When the position control lever is moved to the Lowering position, the control arm (2) rotates to the arrow. Therefore, the spool drive lever (1) moves around the fulcrum P and push the spool (3) and poppet 2 (4) opening the Lowering circuit.
Page 287: Flow Priority Valve
STα-30, STα-35, WSM HYDRAULIC SYSTEM 6. FLOW PRIORITY VALVE [1] FUNCTION AND STRUCTURE The flow priority valve is a flow divider that divides the flow from single hydraulic source (hydraulic pump) and actuates two circuits (position control circuit and Bi- speed turn circuit) simultaneously.
Page 288 STα-30, STα-35, WSM HYDRAULIC SYSTEM When Bi-speed Turn is actuating 1. When Bi-speed turn is actuated and pressure rises, the plunger (6) moves to the left, reducing the opening area of portion B, and widening the opening area of portion A. Therefore, there is no change in the controlled flow to the PF port (2).
Page 289: Relief Valve
STα-30, STα-35, WSM HYDRAULIC SYSTEM 7. RELIEF VALVE The 3-point hydraulic circuit has a relief valve to restrict the maximum pressure in its circuit. This is a guide piston relief valve with damper, a direct acting relief valve suitable for relatively high pressure and capacity, and constructed so as to prevent chattering and other unstableness associated with direct acting relief valves.
Page 290: Lowering Speed Adjusting Valve
STα-30, STα-35, WSM HYDRAULIC SYSTEM 8. LOWERING SPEED ADJUSTING VALVE This valve acts 3-point linkage lowering speed adjusting and holding. Turning the lowering speed adjusting knob (3) clockwise decreases lowering speed, counterclockwise increases lowering speed. When the lowering speed adjusting valve (2) is completely closed, the 3-point linkage is held at its position since oil in the hydraulic cylinder is sealed between the piston and lowering speed adjusting valve (2).
Page 291: Hydraulic Cylinder
STα-30, STα-35, WSM HYDRAULIC SYSTEM 9. HYDRAULIC CYLINDER (1) Lowering Speed Adjusting (5) Hydraulic Piston (9) Hydraulic Arm (13) Control Arm Shaft (6) O-ring (10) Hydraulic Arm Shaft (14) Control Valve (2) Cylinder Head (7) Back-up Ring (11) Flow Priority Valve (15) IN Port (3) Relief Valve (8) Hydraulic Rod...
Page 292: Auxiliary Control Valve
STα-30, STα-35, WSM HYDRAULIC SYSTEM AUXILIARY CONTROL VALVE [1] HYDRAULIC CIRCUIT This auxiliary control valve is a unit for three valves as single / double acting selectable valve, double acting valve and single acting valve. The pressured oil into the three each control valve with parallel connection through the P port (7).
Page 293 STα-30, STα-35, WSM HYDRAULIC SYSTEM Neutral Forced oil into the auxiliary control valve through the P port (2) and divided two oil line. The one will reach to each check valve (1), (4) and (8). The other one return to the 3-point linkage hydraulic valve from the PB outlet (9) through each PB port (3).
Page 294 STα-30, STα-35, WSM HYDRAULIC SYSTEM (When spool is moved to RH) When the spool (5) is moved, the PB port (11) is close. The pressured oil open the check valve (2) and into the valve through the P port (8). Pressured oil flow shows as follow.
Page 295 STα-30, STα-35, WSM HYDRAULIC SYSTEM (2) Single Action Between B port (11) and T port (3) passage is opened by rotary valve (4) of selector lever. (When spool is moved to LH (When Lifting)) When the spool (7) is moved, the PB port (13) is closed.
Page 296 STα-30, STα-35, WSM HYDRAULIC SYSTEM Single Acting Valve (B Outlet) (When spool is moved RH (When Lifting)) When the spool (11) is moved, the PB port (17) is closed. The pressured oil open the check valve (1) and into the valve through P port (14).
Page 297 SERVICING CONTENTS 1. TROUBLESHOOTING ..................9-S1 2. SERVICING SPECIFICATIONS ..............9-S2 3. TIGHTENING TORQUES ................9-S4 4. CHECKING, DISASSEMBLING AND SERVICING........9-S5 [1] CHECKING AND ADJUSTING ...............9-S5 (1) Hydraulic Pump...................9-S5 (2) Position Control Valve.................9-S7 [2] DISASSEMBLING AND ASSEMBLING..........9-S9 (1) Hydraulic Pump...................9-S9 (2) Position Control Valve...............9-S10 (3) Hydraulic Cylinder Cover ..............9-S11 (4) Hydraulic Cylinder ................9-S12 (5) Auxiliary Control Valve..............9-S13...
Page 298 STα-30 · STα-35, WSM HYDRAULIC SYSTEM 1. TROUBLESHOOTING Reference Symptom Probable Cause Solution Page Implement Does Not • Control linkage improperly adjusted Adjust 9-S7 Rise (Not Noise) • Control linkage improperly assembled or Repair or replace 9-S7 damaged • Position control valve malfunctioning Repair or replace 9-S10 •...
Page 299: Servicing Specifications
STα-30 · STα-35, WSM HYDRAULIC SYSTEM 2. SERVICING SPECIFICATIONS HYDRAULIC PUMP Item Factory Specification Allowable Limit Hydraulic Pump Delivery at No 23.2 L/min. – Condition Pressure 6.13 U.S.gal/min. • Engine Speed : 2800 rpm 5.10 Imp.gal/min. • Rated Pressure : 16.67 to 16.72 MPa 170.0 to 170.5 kgf/cm Delivery at Rated 19.9 L/min.
Page 300 STα-30 · STα-35, WSM HYDRAULIC SYSTEM HYDRAULIC CYLINDER Item Factory Specification Allowable Limit Cylinder Bore I.D. 75.06 to 75.10 mm 75.20 mm 2.9551 to 2.9567 in. 2.9606 in. Hydraulic Arm Shaft to Bushing Clearance 0.020 to 0.125 mm 0.30 mm 0.00079 to 0.00492 in.
Page 301 STα-30 · STα-35, WSM HYDRAULIC SYSTEM 3. TIGHTENING TORQUES Tightening torques of screws, bolts and nuts on the table below are especially specified. (For general use screws, bolts and nuts : See page G-9.) Item N·m kgf·m ft-lbs Power steering delivery hose joint screw 49.0 to 58.8 5.0 to 6.0 36.2 to 43.4...
Page 302: Checking, Disassembling And Servicing
(1) Hydraulic Pump Flowmeter Connecting and Test Preparation IMPORTANT • When using a flowmeter other than KUBOTA specified flowmeter (Code No.: 07916-52792), be sure to use the instructions with that flowmeter. • In this hook-up, there is not relief valve.
Page 303 STα-30 · STα-35, WSM HYDRAULIC SYSTEM Pump Test NOTE • Before pump testing, perform the flowmeter connecting and test preparation. 1. Open the loading valve completely. 2. Start the engine and set at approx. 2800 rpm. 3. Read and note the pump delivery at no pressure. 4.
Page 304: Position Control Valve
STα-30 · STα-35, WSM HYDRAULIC SYSTEM (2) Position Control Valve Adjusting Position Control Rod 1. Set the position control lever to the floating position. 2. Start the engine, and after warming-up, set the engine speed at 1000 to 1500 rpm. 3.
Page 305 STα-30 · STα-35, WSM HYDRAULIC SYSTEM Relief Valve Setting Pressure Test Using Pressure Tester 1. Start the engine and move the position control lever to the maximum raising position. 2. Turn the position control rod adjusting nut and lock nut until the relief valve begins to be operated.
Page 306: Disassembling And Assembling
STα-30 · STα-35, WSM HYDRAULIC SYSTEM [2] DISASSEMBLING AND ASSEMBLING (1) Hydraulic Pump IMPORTANT • The hydraulic pump is precision machined and assembled: if disassembled once, it may be unable to maintain its original performance. Therefore, when the hydraulic pump fails, replacement should be carried out with the hydraulic pump assembled except when emergency repair is unavoidable.
Page 307: Position Control Valve
STα-30 · STα-35, WSM HYDRAULIC SYSTEM (2) Position Control Valve IMPORTANT • The position control valve has been precisely machined, assembled and adjusted. It is advisable not to disassemble it, except the unload poppet 1, unload poppet 2 and poppet 1. Separating Hydraulic Cylinder 1.
Page 308: Hydraulic Cylinder Cover
STα-30 · STα-35, WSM HYDRAULIC SYSTEM (3) Hydraulic Cylinder Cover Hydraulic Cylinder Cover and Piston 1. Remove the hydraulic cylinder cover (3). 2. Push out the piston from inside of hydraulic cylinder block (1). (When reassembling) • Install the piston (2), noting O-ring (5) and back-up ring (4). •...
Page 309: Hydraulic Cylinder
STα-30 · STα-35, WSM HYDRAULIC SYSTEM (4) Hydraulic Cylinder Lift Arm and Hydraulic Arm Shaft 1. Remove the position control rod (2). 2. Remove the external snap ring and tap out the lift arm LH (4). 3. Pull out the lift arm RH (7) and hydraulic arm shaft (6) as a unit. 4.
Page 310: Auxiliary Control Valve
STα-30 · STα-35, WSM HYDRAULIC SYSTEM (5) Auxiliary Control Valve Removing Auxiliary Control Valve 1. See page 3-S12. W1016104 Auxiliary Control Valve (1) Plug (2) Spring (3) Poppet (4) Poppet Seat (5) Pilot Valve (6) Check Valve (7) Spring (8) Plug (9) Collar (10) Collar Retainer (11) Return Spring Mounting...
Page 311: Servicing
STα-30 · STα-35, WSM HYDRAULIC SYSTEM [3] SERVICING (1) Hydraulic Pump Clearance between Tip of Gear Tooth and Casing 1. Measure the clearance between gear and casing at several point with feeler gauge. 2. If the clearance exceeds the allowable limit, replace the assembly.
Page 312 STα-30 · STα-35, WSM HYDRAULIC SYSTEM Clearance between Hydraulic Arm Shaft and Bushing 1. Measure the hydraulic arm shaft O.D. with an outside micrometer. 2. Measure the bushing I.D. with a cylinder gauge. 3. If the clearance exceeds the allowable limit, replace. NOTE •...
Page 313: Electrical System
ELECTRICAL SYSTEM KiSC issued 11, 2006 A...
Page 314 MECHANISM CONTENTS 1. WIRING DIAGRAM ..................10-M1 2. STARTING SYSTEM .................. 10-M4 [1] STARTER ....................10-M5 [2] GLOW PLUG ..................10-M6 [3] SAFETY SWITCH ................. 10-M6 [4] ENGINE STOP SOLENOID ..............10-M7 3. CHARGING SYSTEM ................. 10-M8 [1] ALTERNATOR ..................10-M8 [2] IC REGULATOR ...................
Page 315: Wiring Diagram
STα-30 · STα-35, WSM ELECTRICAL SYSTEM 1. WIRING DIAGRAM Color of Wiring B ... Black G/B ..Green / Black R/W .... Red / White Br ..Brown G/L ..Green / Blue R/Y ..... Red / Yellow G ..Green G/R ..
Page 316 STα-30 · STα-35, WSM ELECTRICAL SYSTEM KiSC issued 11, 2006 A 10-M2...
Page 317 STα-30 · STα-35, WSM ELECTRICAL SYSTEM KiSC issued 11, 2006 A 10-M3...
Page 318: Starting System
STα-30 · STα-35, WSM ELECTRICAL SYSTEM 2. STARTING SYSTEM (1) Safety Switch (PTO) (5) Key Switch (8) Slow Blow Fuse (11) Safety Switch (HST) (2) Fuse (6) Battery (9) Engine Stop Solenoid (12) Glow Plug (3) Pre-heat Indicator Lamp (7) Starter (10) Safety Switch (Clutch) (13) Glow Lamp Relay (4) Starter Relay...
Page 319: Starter
STα-30 · STα-35, WSM ELECTRICAL SYSTEM [1] STARTER (1) Armature (2) Yoke (3) Brush Holder (4) End Frame (5) Gear (6) Drive End Frame (7) Pinion (8) Roller Clutch (9) Ball (10) Spring (11) Magnet Switch W1013084 The starter motor is a reduction type. The speed of the pinion gear is reduced to approximately one third of motor one.
Page 320: Glow Plug
STα-30 · STα-35, WSM ELECTRICAL SYSTEM [2] GLOW PLUG This plug is a two-material type QGS (Quick Glow System) for quick temperature rise, and has self- controlling function as well as excellent durability. The heater (4) connected in series to the heater (3), which also functions as the resistor, is incorporated in the sheath tube (1) of the super glow plug.
Page 321: Engine Stop Solenoid
STα-30 · STα-35, WSM ELECTRICAL SYSTEM [4] ENGINE STOP SOLENOID Flowing of the battery current into the fuel cut off solenoid, the plunger (5) move to right side so that the movement of control rack (1) becomes free. When the battery current stops, the plunger (5) is returned to the original position by the spring to keep the control rack (1) in “No fuel injection”...
Page 322: Charging System
STα-30 · STα-35, WSM ELECTRICAL SYSTEM 3. CHARGING SYSTEM (1) Fuse (3) Battery (5) Alternator (6) Key Switch (2) Battery Charge Lamp (4) Slow Blow Fuse The charging system supplies electric power for various electrical devices and also charges the battery while the engine runs.
Page 323: Ic Regulator
STα-30 · STα-35, WSM ELECTRICAL SYSTEM [2] IC REGULATOR (1) Alternator (2) Rectifier (3) Stator Coil (4) Rotor Coil (5) IC Regulator (6) Charge Lamp (7) Main Switch (8) Battery (9) Load W1013747 An IC regulator uses solid state transistors, chips or other semiconductor elements instead of the relays in a conventional regulator.
Page 324: Lighting System
STα-30 · STα-35, WSM ELECTRICAL SYSTEM 4. LIGHTING SYSTEM (1) Working Light (10) Connector (Cabin) (18) Hazard Indicator Lamp (26) Head Light (2) Combination Light (Left) (11) Fuse (19) High Beam Indicator Lamp (27) Battery (3) Combination Light (Right) (12) Illumination Lamp (20) Hazard / Turn Signal Indicator (28) Slow Blow Fuse (4) Position Light...
Page 325: Head Light
STα-30 · STα-35, WSM ELECTRICAL SYSTEM [1] HEAD LIGHT The head light switch, which forms a combination switch with the turn signal light switch and horn switch, has three positions; OFF, LOW-BEAM and HIGH-BEAM. Current passes through the light circuit as shown in the figure above. [2] TURN SIGNAL LIGHT The turn signal light switch, which forms a combination switch with the head light switch and horn switch, has three position;...
Page 326: Hazard Light
STα-30 · STα-35, WSM ELECTRICAL SYSTEM Combination Switch Combination switch consist of head light switch, turn signal light switch and horn switch. • Head Light Switch High • Turn Signal Light Switch • Horn Switch (1) Head Light Switch (3) Horn Switch (2) Turn Signal Light Switch W1014069 [3] HAZARD LIGHT...
Page 327: Parking (Position) Light
STα-30 · STα-35, WSM ELECTRICAL SYSTEM Hazard Switch This is a pushing type switch to turn on the hazard lights. The lamp (2) in the switch is lighted up by the current from outside of the switch. The circuit in the switch is shown below.
Page 328: Brake Light
STα-30 · STα-35, WSM ELECTRICAL SYSTEM [5] BRAKE LIGHT The brake lights are lighted up by brake switch. Current passes the circuit as shown in the figure above. Brake Switch Brake switch is turned on by pushing a brake pedal and turned off by releasing it.
Page 329: Trailer Socket
STα-30 · STα-35, WSM ELECTRICAL SYSTEM [7] TRAILER SOCKET The trailer socket is provided to take out the electrical power from tractor to trailer or implement. The function of each terminal is shown below. Terminal Function Color of wire harness Turn signal (LH) Green / White –...
Page 330: Gauges
STα-30 · STα-35, WSM ELECTRICAL SYSTEM 5. GAUGES (1) Fuse (3) Fuel Gauge (5) Battery (7) Coolant Temperature Sensor (2) Coolant Temperature Gauge (4) Key Switch (6) Slow Blow Fuse (8) Fuel Sensor The fuel quantity and coolant temperature are indicated by the ammeters. The ammeters indicate each amperage flowing through the fuel level sensor for the fuel quantity detection and through the coolant temperature sensor for the coolant temperature detection.
Page 331: Fuel Quantity
STα-30 · STα-35, WSM ELECTRICAL SYSTEM [1] FUEL QUANTITY Fuel Level Sensor The remaining fuel quantity is detected by the fuel level sensor installed in the fuel tank and indicated on the fuel gauge. For detection, a float and a resistor are used. As the float (1) lowers, the resistance of the variable resistor (2) varies.
Page 332 SERVICING CONTENTS 1. TROUBLESHOOTING ..................10-S1 2. SERVICING SPECIFICATIONS ..............10-S3 3. TIGHTENING TORQUES ................10-S4 4. CHECKING, DISASSEMBLING AND SERVICING........10-S5 [1] BATTERY....................10-S5 (1) Checking ...................10-S5 [2] STARTING SYSTEM ................10-S7 (1) Checking ...................10-S7 (2) Disassembling and Assembling ............10-S11 (3) Servicing ..................10-S12 [3] CHARGING SYSTEM ................10-S15 (1) Checking ..................10-S15 (2) Disassembling and Assembling ............10-S16 (3) Servicing ..................10-S18...
Page 333 STα-30 · STα-35, WSM ELECTRICAL SYSTEM 1. TROUBLESHOOTING Reference Symptom Probable Cause Solution Page All Electrical • Battery discharged or defective Recharge or Replace G-22 Equipment Do Not • Battery positive cable disconnected or Repair or Replace – Operate improperly connected •...
Page 334 STα-30 · STα-35, WSM ELECTRICAL SYSTEM CHARGING SYSTEM Reference Symptom Probable Cause Solution Page Charging Lamp Does • Fuse blown (10 A) Replace G-29 Not Light when Main • Wiring harness disconnected or improperly Repair or Replace – Switch is Turned ON connected (between main switch AC terminal and panel board, between panel board and alternator)
Page 335: Servicing Specifications
STα-30 · STα-35, WSM ELECTRICAL SYSTEM 2. SERVICING SPECIFICATIONS Item Factory Specification Allowable Limit Starter Commutator O.D. 30.0 mm 29.0 mm 1.181 in. 1.142 in. Mica Under Cut 0.50 to 0.80 mm 0.20 mm 0.0197 to 0.0315 in. 0.0079 in. Brush Length 15.0 mm...
Page 336: Tightening Torques
STα-30 · STα-35, WSM ELECTRICAL SYSTEM 3. TIGHTENING TORQUES Tightening torques of screws, bolts and nuts on the table below are especially specified. (For general use screws, bolts and nuts : See page G-9.) Item N·m kgf·m ft-lbs Alternator Pulley nut 58.3 to 78.9 5.95 to 8.05 43.0 to 58.2...
Page 337: Checking, Disassembling And Servicing
STα-30 · STα-35, WSM ELECTRICAL SYSTEM 4. CHECKING, DISASSEMBLING AND SERVICING CAUTION • To avoid accidental short circuit, be sure to attach the positive cable to the positive terminal before the negative cable is attached to the negative terminal. • Never remove the battery cap while the engine is running. •...
Page 338 STα-30 · STα-35, WSM ELECTRICAL SYSTEM Battery Specific Gravity 1. Check the specific gravity of the electrolyte in each cell with a hydrometer. 2. When the electrolyte temperature differs from that at which the hydrometer was calibrated, correct the specific gravity reading following the formula mentioned in (Reference).
Page 339: Starting System
STα-30 · STα-35, WSM ELECTRICAL SYSTEM [2] STARTING SYSTEM (1) Checking (A) Main Switch Main Switch Continuity 1) Main Switch Key at OFF Position 1. Set the main switch OFF position. 2. Measure the resistance with an ohmmeter across the 30 terminal and the AC terminal, 30 terminal and 50 terminal, 30 terminal and 19 terminal.
Page 340 STα-30 · STα-35, WSM ELECTRICAL SYSTEM (B) Starter Motor Test CAUTION • Secure the starter to prevent if from jumping up and down while testing the motor. 1. Disconnect the battery negative cable from the battery. 2. Disconnect the battery positive cable and the leads from the starter.
Page 341 STα-30 · STα-35, WSM ELECTRICAL SYSTEM (C) Glow Plug Lead Terminal Voltage 1. Disconnect the wiring lead (1) from the glow plug (2) after turning the main switch off. 2. Turn the main switch key to the “PREHEAT” position, and measure the voltage between the lead terminal and the chassis.
Page 342 STα-30 · STα-35, WSM ELECTRICAL SYSTEM (D) Safety Switch Safety Switch Continuity 1. Remove the safety switch leads. 2. Connect the circuit tester to the safety switch leads. 3. Measure the resistance between leads. 4. If the safety switch is defective, replace it. When switch push is Resistance (Across 0 Ω...
Page 343: Disassembling And Assembling
STα-30 · STα-35, WSM ELECTRICAL SYSTEM Stop Solenoid Coil 1. Disconnect the 2P connector from engine stop solenoid. 2. Measure the resistance with an ohmmeter between the terminal 1, terminal 2 and body. 3. If resistance differs from the factory specification, the coil is faulty.
Page 344: Servicing
STα-30 · STα-35, WSM ELECTRICAL SYSTEM Disassembling Magnet Switch 1. Remove the drive end frame (1) mounting screws. 2. Take out the overrunning clutch (2), ball (3), spring (4), gear (5), rollers (6) and retainer (7). (When reassembling) • Apply grease to the gear teeth of the gear (5) and overrunning clutch (2), and ball (3).
Page 345 STα-30 · STα-35, WSM ELECTRICAL SYSTEM Commutator and Mica 1. Check the contact face of the commutator for wear, and grind the commutator with emery paper if it is slightly worn. 2. Measure the commutator O.D. with an outside micrometer at several points.
Page 346 STα-30 · STα-35, WSM ELECTRICAL SYSTEM Armature Coil 1. Check the continuity across the commutator and armature coil core with an ohmmeter. 2. If it conducts, replace the armature. 3. Check the continuity across the segments of the commutator with an ohmmeter.
Page 347: Charging System
STα-30 · STα-35, WSM ELECTRICAL SYSTEM [3] CHARGING SYSTEM (1) Checking Alternator 1. Disconnect the 2P connector (3) from alternator after turning the main switch OFF. 2. Perform the following checkings. (1) B Terminal (3) 2P Connector (2) Alternator W1018175 Connector Voltage 1.
Page 348: Disassembling And Assembling
STα-30 · STα-35, WSM ELECTRICAL SYSTEM (2) Disassembling and Assembling Pulley 1. Secure the hexagonal end of the pulley shaft with a double- ended ratchet wrench as shown in the figure, loosen the pulley nut with a socket wrench and remove it. (When reassembling) 58.3 to 78.9 N·m Tightening torque...
Page 349 STα-30 · STα-35, WSM ELECTRICAL SYSTEM Rear End Frame 1. Unscrew the two nuts and two screws holding the drive end frame and the rear end frame. 2. Remove the rear end frame (1). (1) Rear End Frame W1019274 Rotor 1.
Page 350: Servicing
STα-30 · STα-35, WSM ELECTRICAL SYSTEM (3) Servicing Bearing 1. Check the bearing for smooth rotation. 2. If it does not rotate smoothly, replace it. W1019790 Stator 1. Measure the resistance across each lead of the stator coil with an ohmmeter.
Page 351 STα-30 · STα-35, WSM ELECTRICAL SYSTEM Rectifier 1. Check the continuity across each diode of rectifier with an analog ohmmeter. Conduct the test in the (R × 1) setting. 2. The rectifier is normal if the diode in the rectifier conducts in one direction and does not conduct in the reverse direction.
Page 352: Lighting System
STα-30 · STα-35, WSM ELECTRICAL SYSTEM [4] LIGHTING SYSTEM (1) Checking (A) Combination Switch Remove the Combination Switch 1. Remove the meter panel, and disconnect the combination switch connector 8A after turning the main switch OFF position. 2. Perform the following checkings. (1) Combination Switch W1020799 Connector Voltage...
Page 353 STα-30 · STα-35, WSM ELECTRICAL SYSTEM Head Light Switch Continuity when Setting Switch at HI-BEAM Position 1. Measure the resistance with an ohmmeter across the B1 terminal to the T terminal and the B1 terminal to the 1 terminal. 2. If 0 ohm is not indicated, renew the head light switch. B1 terminal –...
Page 354 STα-30 · STα-35, WSM ELECTRICAL SYSTEM Turn Signal Switch L Position 1. Set the hazard switch to the L position. 2. Measure the resistance with an ohmmeter across the B2 terminal to the L terminal. 3. If 0 ohm is not indicated, renew the combination switch. Resistance (Switch at L 0 Ω...
Page 355 STα-30 · STα-35, WSM ELECTRICAL SYSTEM Flasher Unit Connector Voltage 1. Open the hood, and disconnect the connector from flasher unit. 2. Measure the voltage with a voltmeter across the RB terminal and chassis. 3. If the voltage differs from the battery voltage, the wiring harness is faulty.
Page 356 STα-30 · STα-35, WSM ELECTRICAL SYSTEM Parking (Position) Switch Continuity 1. Remove the meter panel. 2. Disconnect the connector, and remove the parking switch. 3. Measure the resistance with ohmmeter across the A terminal and C terminal, and across the D terminal and E terminal. 4.
Page 357: Gauges
STα-30 · STα-35, WSM ELECTRICAL SYSTEM [5] GAUGES (1) Checking Fuel Level Sensor 1) Sensor Continuity 1. Remove the fuel level sensor from the fuel tank. 2. Measure the resistance with an ohmmeter across the sensor terminal and its body. 3.
Page 358 STα-30 · STα-35, WSM ELECTRICAL SYSTEM 2) Tail Terminals 1. Turn the main switch ON, and measure the voltage with voltmeter across the 7 terminal (1) and 5 terminal (2), and across the 5 terminal (2) and 3 terminal (3). 2.
Page 359 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 2006. 11, S, EI, EI, e Code No.9Y011-12632 KUBOTA Corporation 2000.

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Wsm sta-35

Kubota WSM STa-30 Workshop Manual

General

1 Features

2 Tractor Identification

3 General Precautions

4 Handling Precautions for Electrical Parts and Wiring

5 Lubricants Fuel and Coolant

6 Tightening Torques

7 Maintenance

8 Check and Maintenance

9 Special Tools

10 Tires

11 Implement Limitations

Servicing

Servicing

Mechanism

1 Structure

2 Travelling System

3 Range Gear Shift Section

4 Front Wheel Drive Shift Section

5 Rear Pto Shift Section

6 MID-Pto Shift Section

7 Differential Gear

Servicing

Servicing

1 Servicing Specifications

2 Tightening Torques

3 Disassembling and Servicing

Servicing

1 Troubleshooting

2 Servicing Specifications

3 Checking, Disassembling and Servicing

Servicing

1 Troubleshooting

2 Servicing Specifications

4 Checking, Disassembling and Servicing

Mechanism

Servicing

2 Servicing Specifications

4 Checking, Disassembling and Servicing

Mechanism

1 Features

3 Hydraulic Pump

4 Steering Controller

5 Oil Flow

6 Steering Cylinder

Servicing

2 Servicing Specifications

4 Checking, Disassembling and Servicing

Mechanism

Servicing

2 Servicing Specifications

4 Checking, Disassembling and Servicing

Mechanism

1 Wiring Diagram

2 Starting System

3 Charging System

4 Lighting System

5 Gauges

Servicing

2 Servicing Specifications

3 Tightening Torques

4 Checking, Disassembling and Servicing

Quick Links

Chapters

Troubleshooting

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Summary of Contents for Kubota WSM STa-30