Kubota WSM STa-30, WSM STa-35 Workshop Manual

WORKSHOP MANUAL

KiSC issued 11, 2006 A

TRACTOR

STα-30,STα-35

TO THE READER

KiSC issued 11, 2006 A

This Workshop Manual has been prepared to provide servicing personnel with
information on t he mechanism, service and maintenance of KUBOTA T ractor 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. This part should be
understood before proceeding with troubleshooting, disassembling and servicing.

■ Servicing

Under the heading “General” section comes general precautions, check and
maintenance and special tools. Other section, there are troubleshooting, servicing
specification lists, checking and adjusting, disassembling and assembling, and servicing
which cover procedures, pr ecauti ons , fac tor y spe cifi ca tion s and allowa bl e limits .

All information illustrations and specifications contained in this manual are based on
the latest production information available at the time of publication.

The right is reserved to make changes in all information at any time without notice

September 2000

© KUBOTA Corporation 2000

STα-30 · STα-35, WSM

SAFETY FIRST

KiSC issued 11, 2006 A

SAFETY INSTRUCTIONS

SAFETY INSTRUCTIONS

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.

DANGER : Indicates an imminently hazardous situation which, if not avoided, will result in

death or serious injury.

WARNING : Indicates a potentially hazardous situation which, if not avoided, could result in

death or serious injury.

CAUTION : Indicates a potentially hazardous situation which, if not avoided, may result in

minor or moderate injury.

■ IMPORTANT : Indicates that equipment or property damage could result if instructions are not

followed.

■ NOTE : Gives helpful information.

BEFORE SERVICING AND REPAIRING

• Read all instructions and safety instructions in this
manual and on your machine safety decals.

• Clean the work area and machine.

• Park the machine on a firm and level ground, and set
the parking brake.

• Lower the implement to the ground.

• Stop the engine, and remove the key.

• Disconnect the battery negative cable.

• Hang a “DO NOT OPERATE” tag in operator station.

1

STα-30 · STα-35, WSM

KiSC issued 11, 2006 A

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.

• Never start the engine while standing on ground.
Start the engine only from operator’s seat.

SAFETY WORKING

• Do not work on the machine while under the influence
of alcohol, medication , or other substances or while
fatigued.

• Wear close fitting clothing and safety equipment
appropriate to the job.

• Use tools appropriate to the work. Markshift tools,
parts, and procedures are not recommended.

• When servicing is performed together by two or more
persons, take care to perform all work safely.

• Do not work under the machine that is supported
solely by a jack. Always support the machine by
safety stands.

• Do not touch the rotating or hot parts while the engine
is running.

• Never remove the radiator cap while the engine is
running, or immediately after stopping. Otherwise,
hot water will spout out fr om radiator. Only remove
radiator cap when cool enough to touch with bare
hands. Slowly loosen the cap to first stop to relieve
pressure before removing completely.

• Escaping fluid (fuel or hydraulic oil) un der pressure
can penetrate the skin causing serious injury. Relieve
pressure before disconnecting hydraulic or fuel lines.
Tighten all connections before applying pressure.

AVOID FIRES

• Fuel is extremely flammable and explosive under
certain condition s. Do not smoke or allow flames o r
sparks in your working area.

• To avoid sparks from an accidental short circuit,
always disconnect the battery negative cable first and
connect it last.

• Battery gas can explode. Keep sparks and open
flame away from the top of b attery, especially when
charging the battery.

• Mark sure that no fuel has been spilled on the engine.

2

STα-30 · STα-35, WSM

KiSC issued 11, 2006 A

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

• Sulfuric acid in battery electr olyte is po isonous. It is
strong enough to burn skin, clothing and cause
blindness if splashed into eyes. Keep electrolyte
away from eyes, hands and clothing. If you spill
electrolyte on yourself, flush with water, and get
medical attention immediately.

DISPOSE OF FLUIDS PROPERLY

• Do not pour fluids into the ground, down a drain, or
into a stream, pond, or lake. Observe relevant
environmental prot ectio n regulati ons whe n disp osing
of oil, fuel, coolant, electrolyte and other harmful
waste.

PREPARE FOR EMERGENCIES

• Keep a first aid kit and fire extingui sher handy at all
times.

• Keep emergency numbers for doctors, ambulance
service, hospital and fire department near your
telephone.

3

STα-30 · STα-35, WSM

KiSC issued 11, 2006 A

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.

4

STα-30 · STα-35, WSM

KiSC issued 11, 2006 A

SAFETY INSTRUCTIONS

5

STα-30 · STα-35, WSM

KiSC issued 11, 2006 A

SAFETY INSTRUCTIONS

6

STα-30 · STα-35, WSM

KiSC issued 11, 2006 A

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 3
Bore and stroke 82 × 92.4 mm (3.23 × 3.64 in.) 87 × 92.4 mm (3.43 × 3.64 in.)
Total displacement 1463 cm
Engine net power

Engine

Capacities

Tires

Dimensions

Weight (with ROPS)

Minimum turning radius
(with bi-speed turn)

Clutch Dry single plate

(ECE-R24)
SAE gross 22.4 kW (30 HP) 26.8 kW (35.9 HP)
Rated revolution 45 r/s (2700 min
Maximum to rque 96.5 N·m (9.85 kgf·m) / 1500 min
Battery 12 V, RC : 110 min, CCA : 550 A
Starting system Electric starting with cell starter 12 V, 1.4 kW
Lubricating system Forced lubrication by trochoidal pump
Cooling system Pressurized radiator, forced circulation with water pump
Fuel Diesel fuel No. 2-D [above −10 °C (14 °F)], Diesel fuel No. 1 [below −10 °C (14 °F]
Fuel tank 29.5 L (7.79 U.S.gals., 6.49 Imp.gals.)
Engine crankcase

(with filter)
Engine coolant

(with recovery tank)
Transmission case 18.5 L (4.89 U.S.gals., 4.07 Imp.gals.)
Front axle case 4.0 L (1.06 U.S.gals., 0.88 Imp.gals.)

Front
Rear 12.4-16 9.5-22 13.6-16 12.4-16 9.5-22 13.6-16

Overall length (with 3P) 2870 mm (113 in.)
Overall width (minimum

tread)
Overall height (with

ROPS)
Wheel base 1610 mm (63.4 in.)
Minimum ground

clearance (Mid-PTO
case)

Front 1020 mm (40.2 in.)

Tread

Rear

with brake 2.2 m (7.2 feet)
without

brake

Farm

6-12

1465 mm

(57.7 in.)

2330 mm

(91.7 in.)

215 mm

(8.5 in.)

1148 mm

(45.2 in.)

975 kg

(2150 lbs)

3

(89.28 cu.in.) 1647 cm3 (100.51 cu.in.)

21.2 kW 25.5 kW

-1

(rpm))

-1

(rpm)) 111 N·m (11.3 kgf·m) / 1500 min-1 (rpm))

4.5 L (1.19 U.S.gals., 0.99 Imp.gals.)

5.8 L (1.56 U.S.gals., 1.28 Imp.gals.)

Farm

6.00-12

1220 mm

(48.1 in.)

2350 mm

(92.5 in.)

235 mm

(9.3 in.)

950, 1070 mm
(37.4, 42.1 in.)

965 kg

(2130 lbs)

Turf

24 × 8.50-14

1310 mm

(51.6 in.)

2345 mm

(92.3 in.)

230 mm

(9.1 in.)

965, 1055 mm
(38.0, 41.5 in.)

985 kg

(2170 lbs)

2.5 m (8.2 feet)

Farm

6-12

1465 mm

(57.7 in.)

2330 mm

(91.7 in.)

215 mm

(8.5 in.)

1148 mm

(45.2 in.)

975 kg

(2150 lbs)

Farm

6.00-12

1220 mm

(48.1 in.)

2350 mm

(92.5 in.)

235 mm

(9.3 in.)

950, 1070 mm
(37.4, 42.1 in.)

965 kg

(2130 lbs)

SPECIFICATIONS

Turf

24 × 8.50-14

1310 mm

(51.6 in.)

2345 mm

(92.3 in.)

230 mm

(9.1 in.)

965, 1055 mm
(38.0, 41.5 in.)

985 kg

(2170 lbs)

W1028117

7

STα-30 · STα-35, WSM

KiSC issued 11, 2006 A

Model STα-30 STα-35

Steering Hydrostatic power steering
Pump capacity (power

Travelling
system

Hydraulic
system

PTO system

Note : * Manufacture’s estimate the company reserves the right to change the specifications without notice.

steering)
Transmission Main-hydrostatic transmission, range gear shift (3 forward and 3 reverse)
Brake Wet disk type
Differential Bevel gear
Hydraulic control system Position control
Pump capacity 23 L/min. (6.1 U.S.gals./min., 5.1 Imp.gals./min.)
Three point hitch SAE Category I

At lift points 1150 kg (2535 lbs)

Max. lift
force

Rear

Mid.

24 in.
behind lift
points

PTO shaft S AE 1-3/ 8, 6 splines
Revolution 540 / 2673 min
PTO shaft USA No. 5 (KUBOTA 10-tooth) involute spline
Revolution 1700 / 2710 min

14.0 L/min. (3.7 U.S.gals./min., 3.1 Imp.gals./min.)

890 kg (1962 lbs)

-1

(rpm), 800 / 2738 min-1 (rpm)

-1

(rpm), 2500 / 2755 min-1 (rpm)

SPECIFICATIONS

W1031009

8

STα-30 · STα-35, WSM

KiSC issued 11, 2006 A

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)

Forward
(At rated engine rpm)

Reverse
(At rated engine rpm)

The company reserves the right to change the spe cifi ca tion s with out notic e.

2 (Middle) 0 to 12.7 (0 to 7.9) 0 to 12.2 (0 to 7.6) 0 to 12.6 (0 to 7.8)
3 (High) 0 to 28.4 (0 to 17.6) 0 to 27.2 (0 to 17.0) 0 to 28.2 (0 to 17.5)
Max. Speed

(at 2850 engine rpm)
1 (Low) 0 to 4.8 (0 to 3.0) 0 to 4.6 (0 to 2.9) 0 to 4.7 (0 to 2.9)
2 (Middle) 0 to 9.2 (0 to 5.7) 0 to 8.8 (0 to 5.5) 0 to 9.2 (0 to 5.7)
3 (High) 0 to 20.6 (0 to 12.8) 0 to 19.7 (0 to 12.2) 0 to 20.4 (0 to 12.7)
Max. Speed

(at 2850 engine rpm)

29.9 (18.6) 28.7 (17.8) 29.8 (18.5)

21.7 (13.5) 20.8 (12.9) 21.6 (13.4)

W1035065

9

STα-30 · STα-35, WSM

KiSC issued 11, 2006 A

DIMENSIONS

DIMENSIONS

10

G GENERAL

KiSC issued 11, 2006 A

GENERAL

KiSC issued 11, 2006 A

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. LUBRICANTS FUEL AND COOLANT .......................................................... G-8

6. TIGHTENING TORQUES ............................. ....... ...... ....... ...... ....... ...... ....... .... G- 9

[1] GENERAL USE SCREWS, BOLTS AND NUTS................................... G-9

[2] STUD BOLTS............................................................................................ G-9

7. MAINTENANCE............................................................................................. G-10

8. CHECK AND MAINTENANCE......... ...... ...... ....... ...... ....... ...... ....... ............... G-11

[1] DAILY CHECK........................................................................................ G-11

[2] CHECK POINTS OF INITIAL 50 HOURS........................................... G-12

[3] CHECK POINTS OF EVERY 50 HOURS........................................... G-15

[4] CHECK POINTS OF EVERY 100 HOURS......................................... G-17

[5] CHECK POINTS OF EVERY 200 HOURS......................................... G-22

[6] CHECK POINTS OF EVERY 400 HOURS......................................... G-24

[7] CHECK POINTS OF EVERY 600 HOURS......................................... G-24

[8] CHECK POINTS OF EVERY 800 HOURS......................................... G-25

[9] CHECK POINTS OF EVERY 1 YEAR ................................................ G-25

[10]CHECK POINTS OF EVERY 2 YEARS.............................................. G-25

[11]OTHERS .................................................................................................. G-28

9. SPECIAL TOOLS.......................................................................................... G-30

[1] SPECIAL TOOLS FOR ENGINE .......................................................... G-30

[2] SPECIAL TOOLS FOR TRACTOR....................................................... G-36

10. TIRES............................................................................................................. G-39

[1] TIRE PRESSURE................................................................................... G-39

[2] TREAD..................................................................................................... G-39

(1) Front Wheels...................................................................................... G-40

(2) Rear Wheels ...................................................................................... G-40

[3] TIRE LIQUID INJECTION...................................................................... G-41

11. IMPLEMENT LIMITATIONS.......................................................................... G-43

STα-30 · STα-35, WSM

KiSC issued 11, 2006 A

1. FEATURES

G GENERAL

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. Wet Disc Brake

9. Standard mid -PT O

10.Simultaneous Mounting of Both the Mid. Mount Mower and Front Loader

11.Combination Panel of Easy Checker

12.Large Hydraulic Pump

13.Position Control Valve

14.Hydraulic Block Type Outlet

15.Foldable ROPS

G-1

STα-30 · STα-35, WSM

KiSC issued 11, 2006 A

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
(2) Tractor Serial Number

G GENERAL

(3) Engine Serial Number
(4) Hour Meter

W1010805

G-2

STα-30 · STα-35, WSM

KiSC issued 11, 2006 A

3. GENERAL PRECAUTIONS

• During disasse mbly, care fully arrang e removed pa rts in a clean
area to prevent confusion later. Screws, bolts and nuts should be
installed in their original position to prevent reassembly errors.

• When special tools are requir ed, use KUBOTA ge nuine special
tools. Special tools which are not frequently used should be
made according to the drawings provided.

• Before disassembling or servicing electrical wires, always
disconnect the ground cable from the battery first.

• Remove oil and dirt from parts before measuring.

• Use only KUBOTA genuine parts for parts replacement to
maintain machine performance and to assure safety.

• Gaskets and O-rings must be replaced during reassembly.
Apply grease to new O-rings or oil seals before assembling.
See the figure left side.

• When reassemblin g external snap rings or internal snap rings,
they must be po sitioned so that sharp edge fa ces against the
direction from which a force is applied. See the figure left side.

• When inserting sp ring pins, their splits must face the direct ion
from which a force is applied. See the figure left side.

• To prevent dama ge to the hydrauli c system, use only s pecified
fluid or equivalent.

(1) Grease
(2) Force
(3) Sharp Edge
(4) Axial Force
(5) Rotating Movement

G GENERAL

(A) External Snap Ring
(B) Internal Snap Ring

W1010904

G-3

STα-30 · STα-35, WSM

IMPORTANT■

KiSC issued 11, 2006 A

G GENERAL

4. HANDLING PRECAUTIONS FOR ELECTRICAL PARTS
AND WIRING

To ensure safety and prevent damage to the machine and
surrounding equipm ent, heed the fo llowing prec autions in hand ling
electrical parts and wiring.

• Check electrical wiring for damage and loosened
connection every year. To this end, educate the customer to
do his or her own check an d at the same time recommend
the dealer to perform periodic check for a fee.

• Do not attempt to modify or remodel any electrical parts and
wiring.

• When removing the battery cables, disconnect the negative
cable first. When installing the battery cables, connect the
positive cable first.

(1) Negative Terminal (2) Positive Terminal

W1011114

[1] WIRING

• Securely tighten wiring terminals.

(1) Correct

(Securely Tighten)

(2) Incorrect

(Loosening Leads to Faulty Contact)

W1011216

• Do not let wiring contact dangerous part.

(1) Wiring (Correct)
(2) Wiring (Incorrect)

(3) Dangerous Part
(4) Dangerous Part

• Securely insert gro mm et.

(1) Grommet (A) Correct

(B) Incorrect

W1011313

W1011388

G-4

STα-30 · STα-35, WSM

KiSC issued 11, 2006 A

G GENERAL

• Securely clamp, being careful not to damage wiring.

(1) Clamp

• Wind Clamp Spirally

(2) Wire Harness

(3) Clamp
(4) Welding Dent

W1011458

• Clamp wiring so that there is no twist, unnecessary sag, or
excessive tension, except for movable part, where sag be
required.

(1) Wiring
(2) Clamp

(A) Correct
(B) Incorrect

W1011587

• In installing a part, take care not to get wiring caught by it.

(1) Wiring (A) Incorrect

W1011670

• After installing wiring, check protection of terminals and clamped
condition of wiring, only connect battery.

(1) Cover

• Securely Install Cover
W1011735

G-5

STα-30 · STα-35, WSM

KiSC issued 11, 2006 A

[2] BATTERY

[3] FUSE

G GENERAL

• Take care not to confuse positive and negative terminal posts.

• When removing battery cables, disconnec t negative cable first.
When installing battery cables, check for polarity and connect
positive cable first.

• Do not inst all any battery with capacity other th an is specified
(Ah).

• After connecting cables to battery terminal posts, apply high
temperature greas e to them and se curely instal l term inal co vers
on them.

• Do not allow dirt and dust to collect on battery.

CAUTION

• Take care not to let battery liquid spill on your skin and
clothes. If contaminated, wash it off with water immediately.

• Before recharging the battery, remove it from the machine.

• Before recharging, remove cell caps.

• Do recharging in a we ll-ventilated place where there is no
open flame nearby, as hydrogen gas and oxygen are formed.

W1011816

[4] CONNECTOR

• Use fuses with specified capacity.
Neither too large or small capacity fuse is acceptable.

• Never use steel or copper wire in place of fuse.

• Do not install working light, radio set, etc. on machine which is not
provided with reserve power supply.

• Do not install accessories if fuse capacity of reserve power
supply is exceeded.

(1) Fuse (2) Slow Blow Fuse

W1012092

• For connector with lock, push lock to separate.

(A) Push

W1012211

• In separating connectors, do not pull wire harnesses.

• Hold connector bodies to separate.

(A) Correct (B) Incorrect

W1012272

G-6

STα-30 · STα-35, WSM

KiSC issued 11, 2006 A

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
(2) Deformed Terminal

(3) Sandpaper
(4) Rust

W1012346

• Make certain that there is no female connector being too open.

(A) Correct (B) Incorrect

W1012430

• Make certain plastic cover is large enough to cover whole
connector.

(1) Cover (A) Correct

[5] HANDLING OF CIRCUIT TESTER

• Use tester correctly following manual provided with tester.

• Check for polarity and range.

(B) Incorrect

W1012519

W1012684

G-7

STα-30 · STα-35, WSM

KiSC issued 11, 2006 A

5. LUBRICANTS FUEL AND COOLANT

G GENERAL

Place

1 Fuel tank

Coolant (with recovery

2

tank)

Engine crankcase

3

(with filter)

4 Transmission case

5 Front axle case

Place No. of greasing point Capacity T ype of grease

Brake pedal shaft 1
Clutch pedal shaft 1

6

Top link 2
Lift rod 1
Battery terminal 2 Moderate amount

STα-30 STα-35

Capacity

29.5 L

7.79 U.S.gals.

6.49 Imp.gals.

5.8 L

1.56 U.S.gals.

1.28 Imp.gals.

4.5 L

1.19 U.S.gals.

0.99 Imp.gals.

18.5 L

4.89 U.S.gals.

4.07 Imp.gals.

4.0 L

1.06 U.S.gals.

0.88 Imp.gals.

No. 2-D diesel fuel
No. 1-D diesel fuel if temperature is below

−10 °C (14 °F)

Fresh clean water (soft water) with anti-freeze

Engine oil : API service CC or CD class
Below 0 °C (32 °F) : SAE10W, 10W-30 or
10W-40
0 to 25 °C (32 to 77 °F): SAE20, 10W-30 or
10W-40
Above 25 °C (77 °F): SAE30, 10W-30 or
10W-40

KUBOTA SUPER UDT fluid*

KUBOTA SUPER UDT fluid* or SAE80, 90 gear
oil

Grease

Until grease overflows

Lubricants, fuel and coolant

Multipurpose type
grease

* KUBOTA original transmission hydraulic fluid.

G-8

STα-30 · STα-35, WSM

KiSC issued 11, 2006 A

G GENERAL

6. TIGHTENING TORQUES

Screws, bolts and nuts whose ti ghtening to rques are not specifi ed in thi s Workshop Manual s hould be t ightened

according to the table below.

[1] GENERAL USE SCREWS, BOLTS AND NUTS

Indication on t o p of

bolt

Material of bolt SS400, S20C S43C, S48C

Material of opponent

part

Unit
Diameter

M6

(6 mm, 0.24 in.)

M8

(8 mm, 0.31 in.)

M10

(10 mm, 0.39 in.)

M12

(12 mm, 0.47 in.)

M14

(14 mm, 0.55 in.)

M16

(16 mm, 0.63 in.)

M18

(18 mm, 0.71 in.)

M20

(20 mm, 0.79 in.)

No-grade or 4T 7T 9T

Ordinariness Aluminum Ordinariness Aluminum Ordinariness

N·m kgf·m ft-lbs N·m kgf·m ft-lbs N·m kgf·m ft-lbs N·m kgf·m ft-lbs N·m kgf·m ft-lbs

7.85

0.80

5.79

7.85

0.80

5.79

9.81

1.00

to

9.31

17.7
to

20.5

39.3
to

45.1

62.8
to

72.5

108

to

125
167

to

191
246

to

284
334

to

392

to

0.95

1.8
to

2.1

4.0
to

4.6

6.4
to

7.4

11.0
to

12.8

17.0
to

19.5

25.0
to

29.0

34.0
to

40.0

to

6.87

13.1
to

15.1

29.0
to

33.2

46.3
to

53.5

79.6
to

92.5

123

to

141
181

to

209
246

to

289

to

to

to

8.82

0.90

6.50

16.7

1.7

12.3

to

to

19.6

2.0

31.4

3.2

to

34.3

3.5

–––

–––

–––

–––

–––

to

14.4

23.2

to

to

25.3

to

11.2

23.6
to

27.4

48.1
to

55.8

77.5
to

90.2

124

to

147
197

to

225
275

to

318
368

to

431

to

1.15

2.4
to

2.8

4.9
to

5.7

7.9
to

9.2

12.6
to

15.0

20.0
to

23.0

28.0
to

32.5

37.5
to

44.0

7.24
to

8.31

17.4
to

20.2

35.5
to

41.2

57.2
to

66.5

91.2
to

108
145

to

166
203

to

235
272

to

318

7.85

0.80
to

0.90

1.8
to

2.1

4.0
to

4.5

6.4
to

7.4

5.79
to

6.50

13.1
to

15.1

29.0
to

32.5

46.3
to

53.5

to

8.82

17.7
to

20.5

39.3
to

44.1

62.8
to

72.5

–––

–––

–––

–––

12.3
to

14.2

29.5
to

34.3

60.9
to

70.6

103

to

117
167

to

196
260

to

304
344

to

402
491

to

568

SCr435,

SCM435

1.25
to

1.45

3.0
to

3.5

6.2
to

7.2

10.5
to

12.0

17.0
to

20.0

26.5
to

31.0

35.0
to

41.0

50.0
to

58.0

W1034542

9.05
to

10.4

21.7
to

25.3

44.9
to

52.0

76.0
to

86.8

123

to

144
192

to

224
254

to

296
362

to

419

[2] STUD BOLTS

Material of opponent

part

Unit
Diameter

M8

(8 mm, 0.31 in.)

M10

(10 mm, 0.39 in.)

M12

(12 mm, 0.47 in.)

Ordinariness Aluminum

N·m kgf·m ft-lbs N·m kgf·m ft-lbs

11.8
to

15.6

24.6
to

31.3

29.5
to

49.0

1.2
to

1.6

2.5
to

3.2

3.0
to

5.0

8.68

8.82

to

11.5

18.1

23.1

21.7

36.1

to

11.8

19.7

to

to

25.4

to

31.4 3.2 23.1

0.90
to

1.2

2.0
to

2.6

6.51
to

8.67

14.5
to

18.8

W1048139

G-9

STα-30 · STα-35, WSM

IMPORTANT■

KiSC issued 11, 2006 A

7. MAINTENANCE

G GENERAL

Period

No.

Item
1 Engine oil Change ★✩ G-12
2 Engine oil filter Replac e ★✩ G-12
3 Transmission fluid Change ★✩ G-13
4 Hydraulic oil filter (for HST) Replace ★✩ G-13
5 Hydraulic oil filter Replace ★✩ G-13
6 Front axle case oil Change ★✩ G-14
7 Front axle pivot Adjust ✩ G-24
8 Engine start system Check ✩ G-16
9 Greasing – ✩ G-15

10 Wheel bolt torque Check ✩ G-16
11 Battery condition Check ✩ G-21

Air cleaner element

12

[Single type]
Air cleaner

13

element
[Double type]

14 Fuel filter element
15 Fan belt Adjust ✩ G-19

16 Clutch Adjust ★✩ G-14
17 Brake Adjust ✩ G-19
18 Parking brake Adjust ✩ G-20

19 Fuel line

20 Radiator hose and clamp

21 HST oil line

22 Power steering oil line
23 Toe-in Adjust ✩ G-24

24 Engine valve clearanc e Adjust ✩ 1-S21
25 Cooling system Flash ✩ G-26
26 Coolant Change ✩ G-26
27 Fuel system Bleed
28 Fuse Replace G-29
29 Light bulb Replace G-29

Primary
element

Secondary
element

Clean ✩ G-17
Replace ✩ G-17
Clean ✩ *G-17
Replace ✩ ** G-17

Replace ✩ G-17
Clean ✩ G-18

Replace ✩ G-18

Check ✩ G-18
Replace ✩ G-18
Check ✩ G-23
Replace ✩ G-23
Check ✩ G-23
Replace ✩ G-23
Check ✩ G-23
Replace ✩ G-23

50 100 200 400 600 800 2 years

Service Time Interval

Service

as

required

Important

Reference

page

G-28

• The jobs indicated by ★ must be done after the first 50 hours of operation.

• * : Air cleaner should be cleaned more often in dusty conditions than in normal conditions.

• ** : Every year or every 6 times of cleaning.

W1035769

G-10

STα-30 · STα-35, WSM

KiSC issued 11, 2006 A

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 kno w the condition of the tractor. Che ck the following items

before starting.

Checking

• Check areas where previous trouble was experienced.

• Walk around the tractor.

1. Check the tire press ure , and chec k for wear and dam age .

2. Check for oil and water leaks.

3. Check the engine oil lev el.

4. Check the transmi ss ion flui d level.

5. Check the coola nt lev el .

6. Check the condition of seat belt and ROPS attaching hardware.

7. Check and clean the radiator screen and grill.

8. Check the screws and nuts of tires ar e tight .

9. Check the number plate .

10.Care of danger, warning and caution labels.

11.Clean around the exhaust manifold and the muffler of the engine.

• While sitting in the operator’s seat.

1. Check the HST pedal, brake pedals and clutch pedal.

2. Check the parking brake.

3. Check the steering wheel.

• Turning the key switch.

1. Check the performance of the easy checker lights.

2. Check head lights, turn signal lights, hazard lights and other light equipment. Clean if necessary.

3. Check the performance of the meters and gauges.

• Starting the engine.

1. Check to see that the lights on the easy checker go off.

2. Check the color of the exhaust gas.

3. Check the brakes for proper operation.

G-11

STα-30 · STα-35, WSM

■

IMPORTANT■

KiSC issued 11, 2006 A

[2] CHECK POINTS OF INITIAL 50 HOURS

Changing Engine Oil

CAUTION

• Before changing oil, be sure to stop the engine.

• Allow engine to cool down sufficiently, oil can be hot and
can burn.

1. Start and warm up the engine for approx. 5 minutes.

2. Place an oil pan underneath the engine.

3. To drain the used oil, remove the both drain plug (1) at the bottom
of the engine and drain the oil completely.

4. Screw in the both drain plug (1).

5. Fill new oil up to upper line on the dipstick (2).

IMPORTANT

• When using an oil of different manufacture or viscosity from
the previous one, remove all of the old oil.

• Never mix two different types of oil.

• Use the proper SAE Engine Oil according to ambient
temperatures.

• Refer to “LUBRICANTS, FUEL AND COOLANT”. (See page
G-8.)

Engine oil capacity

G GENERAL

4.5 L

1.19 U.S.qts.

0.99 Imp.qts.

(1) Drain Plug
(2) Dipstick
(3) Oil Inlet

A : Oil level is acceptable within this

range.

W1014533

Replacing Engine Oil Filter Cartridge

CAUTION

• Be sure to stop the engine before changing oil filter
cartridge.

• Allow engine to cool down sufficiently, oil can be hot and
can burn.

1. Remove the oil filter cartridge with the filter wrench.

2. Apply a slight coat of oil onto the new cartridge gasket.

3. To install the new cartridge, screw it in by hand. Over tightening
may cause deformation of rubber gasket.

4. After the new cartridge has been replaced, the engine oil
normally decrease a little. Thus see that the engine oil does not
leak through the seal and be sure to read the oil level on the
dipstick. Then, replenish the engine oil up to the specified level.

• 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

G-12

STα-30 · STα-35, WSM

■

IMPORTANT■

KiSC issued 11, 2006 A

G GENERAL

Changing Transmission Fluid

CAUTION

• Be sure to stop the engine checking and changing the
transmission fluid.

• Allow engine to cool down sufficiently, oil can be hot and
can burn.

1. Place an oil pan under the tractor.

2. Remove the drain plug (1) at the bottom of the transmission case.

3. Drain the transmission fluid.

4. After draining, screw in the drain plug.

5. Fill new oil from filling port after removing the filling plug (2) up to
the upper notch on the dipstick.

6. After running the engine for a few minutes, stop it and check the
oil level again, if low, add oil prescribed level.

IMPORTANT

• Use only multi-grade transmission oil. Use of other oils may
damage the transmission or hydraulic system.
Refer to “LUBRICANTS, FUEL AND COOLANT”. (See page
G-8.)

• Never work the tractor immediately after changing the
transmission oil. Keeping the engine at medium speed for a
few minutes to prevents damage to the transmission.

• Do not mix different blands oil together.

Transmission fluid capacity

18.5 L

4.89 U.S.gals.

4.07 Imp.gals.

(1) Drain Plug
(2) Filling Plug
(3) Dipstick

A : Oil level is acceptable within this

range.

W1015055

Replacing Hydraulic Oil Filter Cartridge and Transmission Oil
Filter (HST) Cartridge

CAUTION

• Be sure to stop the engine before changing the oil filters.

• Allow engine to cool down sufficiently, oil can be hot and
can burn.

1. Drain the transmission fluid.

2. Remove the both oil filter cartridges by using a filter wrench.

3. Apply a slight coat of oil onto the new cartridge gasket.

4. To install the new cartridge, screw it in by hand. Over tightening
may cause deformation of rubber gasket.

5. After the new cartridge has been replaced, the transmission fluid
level will normally decrease slightly. Make sure that the
transmission fluid does not leak through the seal. Check the fluid
level.

• To prevent serious damage to the hydraulic system. Use
only a genuine KUBOTA filter or its equivalents.

(1) Drain Plug
(2) Hydraulic Oil Filter

(3) Hydraulic Oil Filter (for HST)

W1015586

G-13

STα-30 · STα-35, WSM

■

IMPORTANT■

KiSC issued 11, 2006 A

G GENERAL

Replacing Front Axle Case Oil

CAUTION

• Be sure to stop the engine before changing the front axle
case oil.

• Allow engine to cool down sufficiently, oil can be hot and
can burn.

1. Remove the both right and left dr ain plugs (1) at bottom of the
bevel gear case.

2. Drain the front axle case oil.

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.)

Front axle case oil capacity

(1) Drain Plug (2) Filling Plug

4.0 L

1.06 U.S.gals.

0.88 Imp.gals.

W1015816

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.

2. If the measurement is not within the factory specifications, loosen
the lock nut and adjust the clutch rod (2) length.

• After adjustment, be sure to check that engine does not start
without depressing the clutch pedal but engine start when
depressing the clutch pedal.

Clutch pedal free travel
on top of clutch pedal

“L”

(1) Clutch Pedal (2) Clutch Rod

Factory spec.

20.0 to 30.0 mm

0.78 to 1.18 in.

W1016124

G-14

STα-30 · STα-35, WSM

KiSC issued 11, 2006 A

[3] CHECK POINTS OF EVERY 50 HOURS

Greasing

1. Apply a grease to the following position as figures.

(1) Grease Fitting (Top Link)
(2) Grease Fitting (Lifting Rod RH)
(3) Battery Terminal

G GENERAL

(4) Grease Fitting (Brake Pedal Shaft)
(5) Grease Fitting (Clutch Pedal Shaft)

W1016347

G-15

STα-30 · STα-35, WSM

KiSC issued 11, 2006 A

G GENERAL

Checking Engine Start System

CAUTION

• Do not allow anyone near the tractor whil e testing.

• If the tractor does not pass the test do not operate the
tractor.

■ Preparation before testing.

1. Sit on operator’s seat.

2. Set the parking brake and stop the engine.

3. Shift the range gear shift lever in “NEUTRAL” position.

4. Shift the PTO gear shift lever in “NEUTRAL” position.

5. Fully depress the clutch pedal.

■ Test 1 : for safety switch on the clutch pedal

1. Release the clutch pedal.

2. Turn the key to “START” position.

3. The engine must not crank.

■ Test 2 : for safety switch on the speed control pedal

1. Fully depress the clutch pedal again.

2. Depress the pedal to Forward or Reverse.

3. Turn the key to “START” position.

4. The engine must not crank.

■ Test 3 : for safety switch on the PTO gear shift lever.

1. Engage the PTO gear shift lever.

2. Fully depress the clutch pedal again.

3. Turn the key to “START” position.

4. The engine must not crank.

■ After testing : If crank any test of the above, adjust or replace
the required safety switch.

(1) Range Gear Shift Lever
(2) PTO Gear Shift Lever

(3) Clutch Pedal
(4) Speed Control Pedal

W1016474

Checking Wheel Mounting Screws and Nuts Tight ening Torque

CAUTION

• Never operate tractor with a loose rim, wheel, or axle.

• Any time bolts and nuts are loosened, retighten to specified
torque.

• Check all screws and nuts frequently and keep them tight.

1. Check wheel screws and nuts r egularl y especia lly when new. If
there are loosened, tighten as follows.

Front wheel mounting
screws and nuts

Tightening torque

Rear wheel mounting
screws and nuts

(1) Front Wheel Mounting Screw and

Nut

(2) Rear Wheel Mounting Screw and

Nut

77 to 90 N·m

7.9 to 9.2 kgf·m

57.2 to 66.5 ft-lbs

196.1 to 225.6 N·m

20.0 to 23.0 kgf·m
145 to 166 ft-lbs

W1016937

G-16

STα-30 · STα-35, WSM

IMPORTANT■

KiSC issued 11, 2006 A

[4] CHECK POINTS OF EVERY 100 HOURS

Changing Engine Oil

1. See page G-12.

Checking Clutch Pedal Free Travel

1. See page G-14.

Cleaning Air Cleaner Element
[Single Element and Double Element Type]

1. Remove the air cleaner cover (3) and element (primary) (1).

2. Clean the element (primary) (1) if:

- When dry dust adheres to the element, blow compressed air
from the inside turning th e element. Pres sure of compr essed
air must be under 490 kPa (5 kgf/cm

- When ca rbon or oil adheres to the element, so ak the element
in detergent for 15 minutes then wash it several times in water,
rinse with clean water and dry it naturally. After element is fully
dried, inspect inside of the element with a light and check if it is
damaged or not.

3. When replacing the air cleaner element (primary) (1), replace the
secondary element (4) as well :
Once a year or after every six times of cleaning, whichever
comes first.

2

, 71 psi).

G GENERAL

W1017133

W1017188

• The air cleaner uses a dry element, never apply oil.

• Do not run the engine with filter element removed.

• Be sure to refit the du st cu p w ith th e ar row ↑ (on the rear of
cup) upright. If the dust cup i s improp erly fit ted, evacu ator
valve will not function and dust will adhere to the element.

• Do not touch the secondary element except in cases where
replacing is required.

■ Evacuator Valve

Open the evacuator valve (2) once a week under ordinary

conditions or daily when use d in a dusty place to get rid of large
particles of dust and dirt.

(1) Element (Primary)
(2) Evacuator Valve

(3) Cover
(4) Secondary Element (Safety)

W1017226

G-17

STα-30 · STα-35, WSM

IMPORTANT■

IMPORTANT■

KiSC issued 11, 2006 A

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 sc rew ring and remove the fue l filter bowl (2), and
rinse the inside with kerosene.

3. Take out the filter element (4) and dip it in the kerosene to rinse.

4. After cleaning, reassemble the fuel filter, keeping out dust and
dirt.

5. Bleed the fuel system. (See page G-28.)

• If dust and dirt enters the fuel system the fuel pump and
injection nozzles are subject to premature wear. To prevent
this, be sure to clean the fuel filter bowl periodically.

(1) Fuel Cock
(2) Fuel Filter Bowl
(3) O-ring

(4) Filter Element
(5) Screw Ring

A : Close

W1017467

Checking Fuel Line

CAUTION

• Stop the engine when attempting the check and change
prescribed below.

• Remember to check t he fuel line periodically. The fuel line
is subject to wear and aging, fuel may leak out onto the
running engine, causing a fire.

1. Check to see that all line and hose clamps are tight and not
damaged.

2. If hoses and clamps are found worn or damaged, replace or
repair them at once.

3. The fuel l in e is made of rubber and a ges r eg ar dles s of peri od of
service. Replace the fuel pipe together with the clamp every two
years and securely tighten.

4. However if the fuel pipe and clamp are found damaged or
deteriorated earlier than two years, then change or remedy.

5. After the fuel line and clamp have been changed, ble ed the fuel
system. (See page G-28.)

• When the fuel line is disconnected for change, close both
ends of the fuel line with a piece of clean cloth or paper to
prevent dust and dirt from entering. Entrance of dust and
dirt causes malfunction of the fuel injection pump. In
addition, particular care must be take n not to admit dust and
dirt into the fuel pump.

(1) Fuel Hose (2) Clamp

W1017739

G-18

STα-30 · STα-35, WSM

KiSC issued 11, 2006 A

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 incor rect, loosen the alternat or mounting bolts and
using a lever placed between the alternator and the engine block,
pull the alternator ou t until the deflection of the bel t falls within
acceptable limits.

4. Replace fan belt if it is damaged.

A deflection of between 7

Fan belt tension Factory spec.

to 9 mm (0.28 to 0.34 in.)
when the belt is pressed
in the middle of the span.

(1) Adjusting Screw
(2) Tension Bolt

A : Check the belt tension
B : To tighten

W1017926

Checking 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.).

1. Release the parking brake.

2. Slightly depress the brake pedals (1) and measure free travel (L)
at top of pedal stroke.

3. If the measurement is not within the factory specifications, loosen
the lock nut (2) and turn the brake rod (3).

4. Retighten the lock nut (2) securely.
Keep the free travel in the right and left brake pedals equal.

Brake pedal free travel

“L”

(1) Brake Pedal
(2) Lock Nut
(3) Brake Rod

Factory spec.

L : Free Travel

25 to 30 mm

0.98 to 1.18 in.

W1018154

G-19

STα-30 · STα-35, WSM

IMPORTANT■

KiSC issued 11, 2006 A

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 withi n the fac tory spec ificati ons, lo osen
the lock nut (2) and turn the brake rod LH (3) and RH (4) to adjust
within acceptable limits.

3. Retighten the lock nut (2) securely.

Parking brake lever free travel

2 notches
(Ratchet sound 2)

• Check the brake pedal free travel after checking the parking
brake.

(1) Brake Lever
(2) Lock Nut
(3) Brake Rod LH

(4) Brake Rod RH

A : Pull

W1018378

G-20

STα-30 · STα-35, WSM

■

KiSC issued 11, 2006 A

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.
Otherwise, the battery component parts may prematurely
deteriorate, which may shorten the battery’s service life or cause
an explosion. Che ck the fluid level regularly and ad d distilled
water as required so that the fluid level is b etween the UPPER
and LOWER levels.

CAUTION

• Never remove the vent plugs while the engine is running.

• Keep electrolyte away fr om eyes, h and s and clothe s. If you
are spattered with it, wash it away completely with water
immediately and get medical attention.

• Wear eye protection and rubber gloves when working
around battery.

1. Mishandling the battery shortens the service life and adds to
maintenance costs.

2. The original battery is maintenance free type battery, but need
some servicing.
If the battery is weak, the engine is difficult to start and the lights
become dim. It is important check the battery periodically.

NOTE

• The factory-installed battery is of non-refillable type. If the
indicator turns white, do not charge the battery but replace
it with new one.

■ How to read the indicator

Check the battery condition by reading the indicator.

State of indicator display

Green
Black Needs charging battery.

White Needs changing battery.

Specific gravity of electrolyte and quality of electrolyte
are both in good condition.

(1) Battery (2) Indicator

W1018707

G-21

STα-30 · STα-35, WSM

IMPORTANT■

KiSC issued 11, 2006 A

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.

• When charging battery, remove battery vent plugs.

• When disconnecting the cable from the battery, start with
the negative terminal first.
When connecting the cable to the battery, start with the
positive terminal first.

• Never check battery charge by placing a metal object across
the posts.
Use a voltmeter or hydrometer.

1. To slow charge the battery, connect the battery positive terminal
to the charger positive terminal and the negative to the negative,
then recharge in the standard fashion.

2. The battery is charged if the indicator display turns green from
black.

• Do not charge rapidly.

3. When exchanging an old battery into new one, use battery of
equal specification shown in table 1.

Table 1

Capacity at

Battery Type Volts (V)

75D26L-MF 12 65 550 –

20 H.R.

(A.H.)

CCA (SAE)

Normal

Charging Rate

■ Direction for Storage

1. When storing the tractor for long periods of time, remove the
battery from tractor, adjust the electrolyte to the proper level and
store in a dry place out of direct sunlight.

2. The battery self-discharges while it is stored.
Recharge it once every three months in hot se asons and once
every six months in cold seasons.

(1) Highest Level (2) Lowest Level

W1019057

[5] CHECK POINTS OF EVERY 200 HOURS

Replacing Engine Oil Filter Cartridge

1. See page G-12.

Replacing Hydraulic Oil Filter Cartridge and Transmission Oil
Filter (HST) Cartridge

1. See page G-13.

W1019450

W1019516

G-22

STα-30 · STα-35, WSM

KiSC issued 11, 2006 A

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. Replace hoses and tighten hose clamps securely, if radiator
hoses are swollen, hardened or cracked.
Replace hoses and hose clamps every 2 years or earlier if
checked and found that hoses are swollen, hardened or cracked.

■ Precaution at Overheating

Take the following a ctions in the even t the coolant temper ature

be nearly or more than the boiling point, what is called
“Overheating”.

1. Stop the machine operati on in a sa fe pla ce and keep the engine
unloaded idling.

2. Don’t stop the engine suddenly, but stop it after about 5 minutes
of unloaded idling.

3. Keep yourself well away from the machine for further 10 minutes
or while the steam blown out.

4. Checking that ther e gets no dange r such as burn, get rid o f the
causes of overheating according to the manual, see
“Troubleshooting” section, and then, start again the engine.

(1) Radiator Hose (2) Clamp

W1019561

Checking HST Oil Line and Power Steering Line

1. Check to see that all lines (1), (2) and hose clamps are tight and
not damaged.

2. If hoses and clamps are found worn or damaged, replace or
repair them at once.

(1) HST Oil Line (2) Power Steering Hose

W1019910

G-23

STα-30 · STα-35, WSM

IMPORTANT■

NOTE■

KiSC issued 11, 2006 A

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. Measure distance between tire beads at front of tire, hub height.

6. Measure distance between tire beads at rear of tire, hub height.

7. Front distance should be 2 to 8 mm (0.079 to 0.315 in.) less than
rear distance.

8. If the measurement is not within the factory specifications, adjust
by changing the tie-rod length .

Toe-in (B – A) Factory spec.

2 to 8 mm

0.079 to 0.315 in.

■ Adjusting

1. Detach the snap ring (1) from the dust cover (4).

2. Loosen the tie-rod lock nut (2) and turn the tie-rod joint (3) to
adjust the tie-rod l ength until the proper to e-in measurement is
obtained.

3. Retighten the tie-rod lock nut (2).

4. Attach the snap ring (1) to the dust cover (4).

117 to 137 N·m

Tightening torque Tie-rod lock nut

12 to 14 kgf·m

86.1 to 101.3 ft-lbs

• A right and left tie-rod joint is adjusted to the same length.

(1) Snap Ring
(2) Tie-rod Lock Nut
(3) Tie-rod Joint
(4) Dust Cover

[6] CHECK POINTS OF EVERY 400 HOURS

Changing Transmission Fluid

1. See page G-13.

Replacing Fuel Filter Element

1. See page G-18.

Changi ng Front Axle C a se Oil

1. See page G-14.

[7] CHECK POINTS OF EVERY 600 HOURS

Adjusting Front Axle Pivot

1. Loosen the lock nut (2), tighten the adjusti ng screw (1) all the
way, and then loosen the adjusting screw (1) by 1/6 turn.

2. Retighten the lock nut (2).

(A) Wheel to Wheel Distance at front
(B) Wheel to Wheel Distance at rear
(C) Front

W1020026

W1020659

W1020714

W1020752

• If the axle pivot pin adjustment is not correct, front wheel
vibration can occur causing vibration in the steering wheel.

(1) Adjusting Screw (2) Lock Nut

W1020797

G-24

STα-30 · STα-35, WSM

KiSC issued 11, 2006 A

[8] CHECK POINTS OF EVERY 800 HOURS

Checking Valve Clearance

1. See page 1-S21.

[9] CHECK POINTS OF EVERY 1 YEAR

Replacing Air Cleaner Element (Primary) and Secondary
Element

1. See page G-17.

[10] CHECK POINTS OF EVERY 2 YEARS

Replacing Radiator Hose (Water Pipes)

1. Replace the hoses and clamps.
Refer to “Checking Radiator Hose and Hose Clamp”. (See
page G-23.)

Replacing Fuel Hose

1. Replace the fuel hoses and clamps, if necessary.
Refer to “Checking Fuel Line”. (See page G-18.)

Replacing Power Steering Hose

1. Replace the hoses and clamps.
Refer to “HST Oil Line and Power Steering Line”. (See page
G-23.)

Replacing HST Oil Line

1. Replace the hoses and clamps.
Refer to “HST Oil Line and Power Steering Line”. (See page
G-23.)

G GENERAL

W1021033

W1021125

W1021176

W1021231

W1021269

W1021597

G-25

STα-30 · STα-35, WSM

■

KiSC issued 11, 2006 A

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. Stop the engine and let cool down.

2. To drain the coolant, open the radiator drain plug (3) and remove
radiator cap (1). The radiator cap (1) must be removed to
completely drain the coolant.

3. After all coolant is drained, close the drain plug (3).

4. Fill with clean water and cooling system cleaner.

5. Follow directions of the cleaner instruction.

6. After flushing, fill with clean water and anti-freeze until the coolant
level is just below the port. Install the radiator cap (1) securely.

7. Fill with coolant up to “FULL” mark on the recovery tank (2).

8. Start and operate the engine for few minutes.

9. Stop the engine and let cool. Check coolant level of recovery tank
(2) and add coolant if necessary.

IMPORTANT

• Do not start engine without coolant.

• Use clean, fresh water and anti-freeze to fill the radiator and
recovery tank.

• When the anti-freeze is mixed with water, the anti-freeze
mixing ratio must be less than 50 %.

• Securely tighten radiator cap. If the cap is loose or
improperly fitted, water may leak out and the engine could
overheat.

• Refer to “LUBRICANTS, FUEL AND COOLANT”. (See page
G-8.)

Coolant capacity (with recovery tank)

5.8 L

1.56 U.S.qts.

1.28 Imp.qts.

(1) Radiator Cap
(2) Recovery Tank

(3) Drain Plug

W1021307

G-26

STα-30 · STα-35, WSM

NOTE■

KiSC issued 11, 2006 A

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 ambi ent temperature falls below 0 °C (32 °F), to
remove coolant after operating or to add anti-freeze to it.

1. There are two types of anti- freeze availab le; use the perma nent

type (PT) for this engine.

2. Before adding anti-freeze for the first time, clean the radiator

interior by pouring fresh water and draining it a few times.

3. The procedure for mixing of water and anti-freeze differs

according to the make of the anti-freeze and the ambient

temperature, basically is should be referred to SAE J1034

standard, more specifically also to SAE J814c.

4. Mix the anti-freeze with water, and then fill in to the radiator.

Vol % Anti-freeze

40 −24 −12 106 222
50 −37 −34 108 226

Freezing Point Boiling Point*

°C °F °C °F

* At 760 mmHg pressure (atmospheric). A higher boiling point is
obtained by using a radiator pressure cap which permits the
development of pressure within the cooling system.

• The above date represent industry standards that
necessitate a minimum glyc ol content in the concentrated
anti-freeze.

• When the coolant level drops due to evaporation, add water
only. In case o f leakage, add anti-freeze and water in the
specified mixing ratio.

• Anti-freeze absorb s moist ure. Kee p un used a nti-f re ez e in a
tightly sealed container.

• Do not use radiator cleaning agents when anti-freeze has
been added to the coolant. (Anti-freeze contains an anti­corrosive agent, which will react with the radiato r cleaning
agent forming sludge which will affect the engine parts.)

W1022492

G-27

STα-30 · STα-35, WSM

IMPORTANT■

NOTE■

KiSC issued 11, 2006 A

[11] OTHERS

G GENERAL

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. Fill the fuel tank with fuel, and open the fuel cock (1).

2. Open the air vent cock (2) on the fuel injection pump.

3. Start the engine and run for about 30 seconds, and then stop the
engine.

4. Close the air vent cock.

• Always close the air vent cock except for bleeding fuel lines.
Otherwise, engine runs irregularly or stalls frequently.

(1) Fuel Cock
(2) Air Vent Cock

A : Close
B : Open

W1022935

Draining Clutch Housing Water

• The tractor is equipped with drain plug (1) under the clutch
housing.

• After operating in rain, snow or tractor has been washed,
water may get into the clutch housing.

1. Remove the drain plug (1) and drain th e water, then install the
plug again.

(1) Water Drain Plug

W1023306

G-28

STα-30 · STα-35, WSM

IMPORTANT■

KiSC issued 11, 2006 A

G GENERAL

Replacing Fuse

1. The tractor electric al syste m is prote cted from po tentia l dam age
by fuses.
A blown fuse indicates that there is an overload or short
somewhere in the electrical system.

2. If any of the fuses should blo w, replace with a new one of the
same capacity.

• Before replacing a blown fuse, determine why the fuse blew
and make any necessary repairs. Failure to follow this
procedure may result in serious damage to the tractor
electrical system. 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.

■ Protected Circuit

Fuse No. Capacity (A) Protected circuit

1 10 Work light
2 10 Bi-speed
3 10 Brake light
4 10 Flasher lights
5 10 Hazard lights
6 10 Position lights
7 5 Panel instrument
8 10 Alternator, key stop
9 15 Head light, Horn

10 Slow blow fuse 50 A

Check circuit against wrong battery
connection

(A) Fuse Box

Replacing Light Bulb

1. Head lights and rear combination lights:
Take the bulb out of the light body and replace with a new one.

2. Other lights:
Detach the lens and replace the bulb.

Light Capacity
Head light 45 W / 40 W
Tail light 10 W
Brake stop light 21 W
Turn signal / Hazard light 21 W
Front position light 10 W
Instrument panel light 1.7 W
Number plate light 10 W

W1023430

W1023802

G-29

STα-30 · STα-35, WSM

KiSC issued 11, 2006 A

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

Piston Ring Compressor

Code No: 07909-32111
Application: Use exclusively for pushing in the piston with piston

G GENERAL

parts with ease.

W1024050

rings into the cylinder.

W1024100

Piston Ring Tool

Code No: 07909-32121
Application: Use exclusively for removing or installing the piston ring

with ease.

W1024150

Diesel Engine Compression Tester

Code No: 07909-30208 (Assembly) 07909-31251 (G)

07909-30934 (A to F) 07909-31271 (I)
07909-31211 (E and F) 07909-31281 (J)
07909-31231 (H)

Application: Use to measure diesel engine compression and

diagnostics of need for major overhaul.

(1) Gauge
(2) L Joint
(3) Adaptor A
(4) Adaptor B
(5) Adaptor C
(6) Adaptor E

(7) Adaptor F
(8) Adaptor G

(9) Adaptor H
(10) Adaptor I
(11) Adaptor J

W1024200

G-30

STα-30 · STα-35, WSM

KiSC issued 11, 2006 A

G GENERAL

Oil Pressure Tester

Code No: 07916-32032
Application: Use to measure lubricating oil pressure.

(1) Gauge
(2) Cable
(3) Threaded Joint
(4) Adaptor 1

(5) Adaptor 2
(6) Adaptor 3
(7) Adaptor 4
(8) Adaptor 5

Valve Seat Cutter

Code No: 07909-33102
Application: Use to reseat valves.
Angle: 0.785 rad. (45°)

0.262 rad. (15°)

Diameter: 28.6 mm (1.126 in.) 38.0 mm (1.496 in.)

31.6 mm (1.244 in.) 41.3 mm (1.626 in.)

35.0 mm (1.378 in.) 50.8 mm (2.000 in.)

W1024318

W1024458

Radiator Tester

Code No: 07909-31551
Application: Use to check of radiator c ap pressu re, and leak s from

cooling system.

W1024532

Connecting Rod Alignment Tool

Code No: 07909-31661
Application: Use to check the connecting rod alignment.
Applicable: Connecting rod big end I.D.
range 30 to 75 mm (1.18 to 2.95 in.) dia.

Connecting rod length
65 to 300 mm (2.56 to 11.81 in.)

W1024583

Nozzle Tester

Code No: 07909-31361
Application: Use to check the fuel injection pressure and spray

pattern of nozzle.

Measuring: 0 to 50 MPa

2

range (0 to 500 kgf/cm

, 0 to 7000 psi)

W1024653

G-31

STα-30 · STα-35, WSM

KiSC issued 11, 2006 A

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.

Measuring: Green ....0.025 to 0.076 mm (0.001 to 0.003 in.)

range Red........0.051 to 0.152 mm (0.002 to 0.006 in.)

Blue.......0.102 to 0.229 mm (0.004 to 0.009 in.)

W1024719

Red Check

Code No: 07909-31371
Application: Use to check cracks on cyli nder head, cylinder bloc k,

etc.

W1024909

G-32

STα-30 · STα-35, WSM

NOTE■

KiSC issued 11, 2006 A

• 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.

A 20 mm dia. (0.79 in. dia.)
B 11.7 to 11.9 mm dia. (0.460 to 0.468 in. dia.)
C 6.5 to 6.6 mm dia. (0.256 to 0.259 in. dia.)
D 225 mm (8.86 in.)
E 70 mm (2.76 in.)
F 45 mm (1.77 in.)

G 25 mm (0.98 in.)

H 5 mm (0.197 in.)

I 6.7 to 7.0 mm dia. (0.263 to 0.275 in. dia.)
J 20 mm dia. (0.787 in. dia.)
K 12.5 to 12.8 mm dia. (0.492 to 0.504 in. dia.)
L 8.9 to 9.1 mm (0.350 to 358 in.)

C1 Chamfer 1.0 mm (0.039 in.)
C2 Chamfer 2.0 mm (0.079 in.)

C0.3 Chamfer 0.3 mm (0.012 in.)

Injection Pump Pressure Tester

Application: Use to check fuel tightness of injection pumps.

Pressure gauge full scale : More than 29.4 MPa (300 kgf/cm

A

psi)
B Copper gasket
C Flange (Material : Steel)
D Hex. nut 27 mm (1.06 in.) across the plat
E Injection pipe
FPF 1/2

G 5 mm (0.20 in.)

H 17 mm dia. (0.67 in. dia.)

I 8 mm dia. (0.31 in. dia.)
J 1.0 mm (0.039 in.)
K 17 mm dia. (0.67 in. dia.)
L 6.10 to 6.20 mm dia. (0.2402 to 0.2441 in. dia.)

M 8 mm (0.31 in.)

N 4 mm (0.16 in.)

O 11.97 to 11.99 mm dia. (0.4713 to 0.4721 in. dia.)

PPF 1/2

Q 23 mm (0.91 in.)

R 17 mm (0.67 in.)
S 4 mm (0.16 in.)
T 12.00 to 12.02 mm dia. (0.4724 to 0.4732 in. dia.)
U 100 mm (3.94 in.)
V M12 × P1.5
a Adhesive application
b Fillet welding on the enter circumference

G GENERAL

W1025017

2

, 4267

W1025240

G-33

STα-30 · STα-35, WSM

KiSC issued 11, 2006 A

G GENERAL

Bushing Replacing Tools

Application: Use to press out and to press fit the bushing.
(1) For small end bushing

A 162 mm (6.38 in.)
B 35 mm (1.38 in.)
C 27 mm (1.06 in.)
D 35 mm dia. (1.38 in. dia.)
E 27.90 to 27.95 mm dia. (1.098 to 1.100 in. dia.)
F 25.00 to 25.01 mm dia. (0.984 to 0.985 in. dia.)

(2) For idle gear bushing

A 175 mm (6.89 in.)
B 40 mm (1.57 in.)
C 38 mm (1.49 in.)
D 45 mm dia. (1.77 in. dia.)
E 41.90 to 41.95 mm dia. (1.650 to 1.652 in. dia.)
F 37.95 to 37.97 mm dia. (1.494 to 1.495 in. dia.)

W1025500

Flywheel Stopper

Application: Use to loosen and tighten the flywheel screw.

A 200 mm (7.87 in.)
B 30 mm (1.18 in.)
C 20 mm (0.79 in.)
D 15 mm (0.59 in.)
E 15 mm (0.59 in.)
F 8 mm (0 .3 1 i n .)
G 10 mm dia. (0.39 in. dia.)

W1025948

G-34

STα-30 · STα-35, WSM

KiSC issued 11, 2006 A

G GENERAL

Crankshaft Bearing 1 Replacing Tool

Application: Use to press out and press fit the crankshaft bearing 1.

1. Extracting tool

A 135 mm (5.31 in.)
B 72 mm (2.83 in.)
C R40 mm (R1.57 in.)
D 10 mm (0.39 in.)
E 20 mm (0.79 in.)
F 20 mm dia. (0.79 in. dia.)

G 56.8 to 56.9 mm dia. (2.236 to 2.240 in. dia.)

H 51.8 to 51.9 mm dia. (2.039 to 2.043 in. dia.)

2. Inserting tool

A 130 mm (5.12 in.)
B 72 mm (2.83 in.)
C R40 mm (R1.57 in.)
D 9 mm (0.35 in.)
E 4 mm (0.16 in.)
F 20 mm (0.79 in.)

G 20 mm dia. (0.79 in. dia.)

H 68 mm dia. (2.68 in. dia.)

I 51.8 to 51.9 mm dia. (2.039 to 2.043 in. dia.)
J 56.8 to 56.9 mm dia. (2.236 to 2.240 in. dia.)

W1026139

G-35

STα-30 · STα-35, WSM

KiSC issued 11, 2006 A

[2] SPECIAL TOOLS FOR TRACTOR

Tie-rod End Lifter

Code No: 07909-39051
Application: Use for removing the tie-rod end with ease.

Steering Wheel Puller

Code No: 07916-51090
Application: Use for removing the steering wheel without damaging

G GENERAL

W1026472

the steering shaft.

W1026533

Long Connector (HST Measurement Kit for B7100HST)

Code No: 07916-60831
Application: Use for checking HST charge relief pressure.

W1026585

Clutch Center Tool (For B and L Series Tractors)

Application: The clutch center tool can be used for all B and L series

tractors with a diaphragm clutch by changing tip guides.
Center piece diameter is 20 mm (0.79 in.).

W1026637

Toe-in Gauge

Code No: 07909-31681
Application: This allows easy measurement of toe-in for all machine

models.

W1026689

G-36

STα-30 · STα-35, WSM

KiSC issued 11, 2006 A

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)
(2) Cable (07916-50331)
(3) Threaded Joint (07916-50401)
(4) Threaded Joint (07916-50341)
(5) Adaptor B (M18 × P1.5)

(07916-50361)

(6) Adap tor C (PS3/8) (07916-50371)
(7) Adap tor D (PT1/8) (07916-50381)
(8) Adap tor E (PS 3 /8) (07916-50392)
(9) Adap tor F (PF1/2) (07916-62601)

(10) Adaptor 58 (PT1/4) (07916-52391)

W1026741

Adaptor 7

Code No: 07916-32951
Application: Use for testing the hydraulic relief pressure.

Flow Meter

Code No: 07916-52791 (Flow Meter)

07916-52651 (Hydraulic Test Hose)

Application: This allows easy testing of hydraulic system.

(1) Flow Meter (2) Hydraulic Test Hose

Adaptor Set for Flow Meter

Code No: 07916-54031
Application: Use for testing the hydraulic system.

(1) Adaptor 52
(2) Adaptor 53
(3) Adaptor 54
(4) Adaptor 61
(5) Adaptor 62
(6) Adaptor 63
(7) Adaptor 64

(8) Adap tor 65
(9) Adap tor 66

(10) Adaptor 67

(11) Adaptor 68
(12) Adaptor 69
(13) Hydraulic Adaptor 1

W1077047

W1031318

W1031396

G-37

STα-30 · STα-35, WSM

NOTE■

NOTE■

KiSC issued 11, 2006 A

• 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.

• When using, attach with following parts.
O-ring : 04811-00180

A 2-8.5 mm dia. (2-0.334 in.dia.)
B 40 mm (1.57 in.)
C 0.52 rad. (30 °)
D 25 mm (0.98 in.)
E 15 mm (0.59 in.)
F 3 mm (0.118 in.)
G 1.7 to 1.9 mm (0.067 to 0.075 in.)
H 3.0 to 3.25 mm (0.118 to 0.128 in.)

I 8.0 mm dia. (0.315 in. dia.)

J 23.9 to 24.1 mm dia. (0.941 to 0.945 in. dia.)

K 60 mm dia. (2.36 in. dia.)

L PS 3/8
M 1.5 mm Round (0.059 in. Round)
N 0.3 mm Round (0.012 in. Round)
O 0.2 mm Chamfer (0.0078 in. Chamfer)

G GENERAL

W1031593

Hydraulic Arm Shaft Bushing Replacing Tool

Applicatio n: Use for replacing the hy drau lic ar m sh aft bu shing in th e

hydraulic cylinder block.

Right Left

37.90 to 37.95 mm dia.

A

(1.492 to 1.494 in. dia.)
B 40 mm (1.575 in.) 35 mm (1.378 in.)
C 28 mm dia. (1.102 in. dia.) 25 mm dia. (0.984 in. dia.)
D 44.5 mm dia. (1.7 5 in. dia.)
E 30 mm dia. (1.18 in. dia.)
F 50 mm (1.97 in.)
G 10 mm (0.39 in.)

34.90 to 34.95 mm dia.
(1.374 to 1.376 in. dia.)

W1031655

Piston Gasket Correcting Tool

Application: Compress the power steering cyli nde r pist o n gask et to

the correct side when install the cylinder rod to the
cylinder tube with ease.

A 13.97 mm (0.55 in.)
B 35.052 mm (1.38 in.)
C 0.122 rad. (7 °)
D 40.000 to 40.039 mm dia. (1.57 to 1.58 in. dia.)
E 46 mm dia. (1.82 in. dia.)

W1073871

G-38

STα-30 · STα-35, WSM

IMPORTANT■

IMPORTANT■

KiSC issued 11, 2006 A

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.

• Do not use tires larger than specified.

• When you intend to mount different size of tires from equipped ones, consult your distributor about front
drive gear ratio for detail.
Excessive wear of tires may occur due to improper gear ratio.

Type Tire sizes Inflation pressure

Farm

Turf

6 – 12 4PR

Front

6.00 – 12 4PR

9.5 – 22 4PR

Rear

12.4 – 16 4PR

Front 24 × 8.50 – 14 4PR

Rear 13.6 – 16 4PR

200 kPa

2.0 kgf/cm

28.4 psi
180 kPa

1.8 kgf/cm

25.6 psi
140 kPa

1.4 kgf/cm

19.9 psi
120 kPa

1.2 kgf/cm

17.1 psi
160 kPa

1.6 kgf/cm

22.8 psi

96.5 kPa

1.0 kgf/cm
14 psi

2

2

2

2

2

2

Though the tire pressure is factory-set to the prescribed level, it naturally drops slowly in the course of time.
Thus, check it everyday and inflate as necessary.

[2] TREAD

CAUTION

• Support tractor securely on stands before removing a wheel.

• Never operate tractor with a loose rim, wheel or axle.

• Always attach tires as shown in the figure. (See page G-40.)

• If not attached as the figure, transmission parts may be damaged.

• Do not use tires larger than specified.

Wheel Tightening Screws and Nuts

1. When refittin g or adj ustin g a whe el, ti ghten t he sc rews an d nuts
with specified tightening torque.

2. Recheck after driving the tractor 200 m (200 yards) and therefore
according to service interval.

Front wheel mounting
screw and nut

Tightening torque

Rear wheel mounting
screw and nut

85 N·m

9.0 kgf·m

65.1 ft-lb s
215 N·m

22.0 kgf·m

159.1 ft-lbs

(1) Front Wheel (2) Rear Wheel

W1032716

G-39

STα-30 · STα-35, WSM

IMPORTANT■

KiSC issued 11, 2006 A

G GENERAL

(1) Front Wheels

Front wheel tread cannot be adjusted.

• 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.

Tires

6 – 12 Farm

6.00 – 12 Farm

24 × 8.50 – 14 Turf

Tread

(1) 1020 mm (40.16 in.) (2) 1 020 mm (40.16 in.)

(2) Rear Wheels

CAUTION

• When working on slopes or working with trailer, set the wheel tread as wide as practical for the job for
maximum stability.

Rear tread can be adjusted as shown with the standard equipped tires. To change the tread.

1. Change the position of the right and left tires.
Tires 9.5 – 22 Farm 12.4 – 16 Farm 13.6 – 16 Turf

Tread

(1) 950 mm (37.40 in.)
(2) 1070 mm (42.13 in.)

(3) 1148 mm (45.20 in.) (4) 965 mm (37.99 in.) (5) 1055 mm (41.5 in.)

G-40

STα-30 · STα-35, WSM

IMPORTANT■

KiSC issued 11, 2006 A

G GENERAL

[3] TIRE LIQUID INJE CTION

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 s ince it freezes a t 0 °C (32 °F). The calcium c hloride solution w ill not freeze a nd moreover, af fords
higher effect than water since its specific gravity is higher than that of water by about 20 %. Below is an explanation
of calcium chloride solution injection.

• Do not fill the front tires with liquid.
Preparation of Calcium Chloride Solution

CAUTION

• When making a calcium chloride solution, do not pour water
over calcium chloride since this results in chemical reaction
which will cause high temperature. Instead add a small
amount of calcium chloride to the water at a time until the
desired solution is achieved.

Freezing temp.

−5 °C (23 °F) 12 kg (26.4 lbs)

−10 °C (14 °F) 21 kg (46.3 lbs)

−15 °C (5 °F) 28 kg (61.7 lbs)

−20 °C (−4 °F) 34 kg (75.0 lbs)

−25 °C (−13 °F) 40 kg (88.2 lbs)

−30 °C (−22 °F) 44 kg (97.0 lbs)

−35 °C (−31 °F) 49 kg (108 lbs)

−40 °C (−40 °F) 52 kg (114.6 lbs)

−45 °C (−49 °F) 56 kg (123.5 lbs)

−50 °C (−58 °F) 61 kg (134.5 lbs)

Weight of CaCl

(26.5 U.S.gals., 22.0 Imp.gals.) of water

2 to be dissolved in 100 L

(a) Water (b) CaCl

2 (Calcium Chloride)

W1033083

Attaching Injector

1. Lift the rear tires off the ground.

2. Turn the tire so that the air valve is at the top.

3. Remove the air valve, and attach the injector. (Code No. 07916-

52511)

(1) Injector (2) Hose

W1033331

G-41

STα-30 · STα-35, WSM

■

KiSC issued 11, 2006 A

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 in jec t wate r or a calci um

chloride solution into tires.

1. Gravity injection (Fig. 1)

2. Pump injection (Fig. 2)

3. Pressure tank injection (Fig. 3)

4. Injection directly from tap (only when water is being use d).

NOTE

• Once injection is complete d, reset the air valve, and pump
air into the tire to the specified pressure.

Weight of Calcium Chloride Solution Filling 75 % of Full Capacity

of a Tire

Tire sizes 9.5-22 12.4-16

Slush free at −10 °C (14 °F)
Solid at −30 °C (−22 °F)
[Approx. 1 kg (2 lbs.) CaCl
water]

Slush free at −24 °C (−11 °F)
Solid at −47 °C (−53 °F)
[Approx. 1.5 kg (3.5 lbs.) CaCl
of water]

Slush free at −47 °C (−53 °F)
Solid at −52 °C (−62 °F)
[Approx. 2.25 kg (5 lbs.) CaCl
water]

2 per 4 L (1 gal.) of

2 per 4 L (1 gal.)

2 per 4 L (1 gal.) of

68 kg

(150 lbs)

72 kg

159 lbs

76 kg

(168 lbs)

85 kg

(187 lbs)

89 kg

(196 lbs)

94 kg

(207 lbs)

(1) Pump
(2) Pressure Tank
(3) Compressor
(4) Air
(5) Water

(A) Correct : 75 %

Air Compresses Like A Cushion

(B) Incorrect : 100 % Full

Water Can Not Be Compressed

W1033435

G-42

STα-30 · STα-35, WSM

NOTE■

KiSC issued 11, 2006 A

G GENERAL

11.IMPLEMENT LIMITATIONS

The KUBOTA Tractor has bee n thoroughly tested for proper performance with implemen ts sold or approved by
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 prope rty 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.]

Max. width of tire tread Lower link end

Front Rear

1070 mm

(421.26 in.)

1148 mm

(451.97 in.)

1055 mm

(415.35 in.)

STα-30
STα-35

6 – 12 Farm

9.5-22 Farm

6.00 – 12 Farm

1020 mm

(401.57 in.)

12.4-16 Farm
(Option)

24 × 8.50 – 14 Turf 13.6-16 Turf

Actual figures

Lift capacity 24 inches behind

lower link end W

STα-30
STα-35

0 :Lower link end max. hydraulic lifting capacity

W

1 :The implement’s weight which can be put on the lower link (Implement weight)

W

2 :Max. drawbar load

W

3 :The max. loading weight for trailer (without trailer’s weight) (Trailer loading weight)

W

890 kg (1962 lbs)

1

Max. Drawbar Load W2

Drawber

High-hitch

500 kg

(1102 lbs)

490.5 kg

(1081 lbs)

Trailer loading weight W3

Max. capacity

1500 kg (3300 lbs)

max. lifting

capacity W

1150 kg

(2535 lbs)

0

• Implement size may vary depending on soil operating conditions.

G-43

1 ENGINE

KiSC issued 11, 2006 A

MECHANISM

KiSC issued 11, 2006 A

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).

STα-30 · STα-35, WSM

KiSC issued 11, 2006 A

1. FUEL SYSTEM

[1] GOVERNOR

ENGINE

The governor serves to keep engine speed cons tant
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 camshaf t (5), and the tension of the
governor spring 1 (7) and 2 (8) are balanced.

(1) Steel Ball
(2) Governor Sleeve
(3) Steel Ball
(4) Governor Ball Case
(5) Fuel Camshaft
(6) Governor Lever

(7) Gov ernor Spring 1
(8) Gov ernor Spring 2

(9) Fork Lever 2
(10) Fork Lever 1
(11) Fork Lever Shaft
(12) Fork Lever Holder

W1017186

■ At Start

Flowing of the battery current into the engine stop
solenoid (16), the plunger (17) is actuated to arrow
direction.

Since the steel ball (1) have no cen trifugal for ce, the
control rack (14) is pushed to the right by the start spring
(13). Accordingly, the control rack (14) moves to the
maximum injection position to assure easy starting.

(13) Start Spring
(14) Control Rack
(15) Injection Pump
(16) Engine Stop Solenoid

(17) Plunger
(18) Guide
(19) Idling Apparatus

W1017215

1-M1

STα-30 · STα-35, WSM

KiSC issued 11, 2006 A

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).

Therefore, the fork lever 1 (10) and control rac k (14)
are moved to the left by the governor sleeve (2) and then
the start spring ( 13) is compres sed by the control rack.
As a result, the control rack is kept at a position where a
centrifugal force of st eel ball and forces of start spring
(13), governor spring 2 (8) are balanced, providing stable
idling.

(1) Steel Ball
(2) Governor Sleeve
(6) Governor Lever
(7) Governor Spring 1

(8) Governor Spring 2
(10) Fork Lever 1
(13) Start Spring
(14) Control Rack

W1017317

■ At High Speed Running with Overload

When an overload is applied to the engine running at
a high speed, the centrifugal force of steel ball (1)
becomes small as the engine speed is dropped, and fork
lever 2 (9) is pulled to the right by the governor springs 1
(7) and 2 (8), increasing fuel injection. Though, fork lever
2 (9) becomes ineffective in increasing fuel injection
when it is stopped by the adjusting screw (21).

After that, when the force of torque spring (20)
becomes greater than the ce ntrifugal force of the steel
ball, fork lever 1 (10) moves rightward to in crease fuel
injection, causing the engine to run continuously at a high
torque.

(1) Steel Ball
(7) Governor Spring 1
(8) Governor Spring 2
(9) Fork Lever 2

(10)Fork Lever 1
(19) Idling Apparatus
(20) Torque Spring
(21) Adjusting Screw

W1017384

■ To Stop Engine

When the battery current stops, the plu nger (17) of
engine stop solenoid (16) is returned to the original
position, the spring (22) to keep the control rack (14) in
“No fuel injection” position.

(14) C ontrol Rack
(16) Engine Stop Solenoid

(17) Plunger
(22) Spring

1-M2

W1018007

SERVICING

KiSC issued 11, 2006 A

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

[4] COOLING SYSTEM...............................................................................1-S49

(1) Checking and Adjusting ............................ ...... ....... ...........................1-S49

[5] FUEL SYSTEM ....................................... ....... ....................................... .1-S51

(1) Checking and Adjusting ............................ ...... ....... ...........................1-S51

(2) Disassembling and Assembling........................................................1-S54

STα-30 · STα-35, WSM

KiSC issued 11, 2006 A

1. TROUBLESHOOTING

ENGINE

Symptom Probable Cause Solution

Engine Does Not
Start

Starter Does Not Run • Battery discharged

Engine Revolution is
Not Smooth

Either White or Blue
Exhaust Gas is
Observe

• No fuel

• Air in the fuel system

• Water in the fuel system

• Fuel pipe clogged

• Fuel filter clogged

• Excessively high viscosity of fuel or engine oil
at low temperature

• Fuel with low cetane number

• Fuel leak due to l oos e inj ect ion pip e ret a ini ng
nut

• Incorrect injec tio n timi ng

• Fuel camshaft worn

• Injection nozzle clogged

• Injection pump malfunctioning

• Seizure of crankshaft, camshaft, piston,
cylinder or bearing

• Compression leak from cylinder

• Improper valve timing

• Piston ring and cylinder worn

• Excessive valve clearance

• Starter malfunctioning

• Main switch malfunctioning

• Clutch safety switch, HST safety switch or
PTO safety switch improperly adjusted or
defective

• Starter relay defective

• Wiring disconnected

• Fuel filter clogged or dirty

• Air cleaner clogged

• Fuel leak due to l oos e inj ect ion pip e ret a ini ng
nut

• Injection pump malfunctioning

• Incorrect nozzle injection pressure

• Injection nozzle stuck or clogged

• Governor malfunctioning

• Excessive engine oil

• Piston ring and cylinder worn or stuck

• Incorrect injec tio n timi ng

• Deficient compr es s ion

Replenish fuel
Bleed
Change fuel and
repair or replace fuel
system
Clean
Change
Use the spec ified fu el
or engine oil
Use the specified fuel
Tighten nut

Adjust
Replace
Clean
Repair or replace
Repair or replace

Replace head
gasket, tighten
cylinder head screw,
glow plug and nozzle
holder
Correct or replace
timing gear
Replace
Adjust

Charge
Repair or replace
Repair or replace
Repair or replace

Replace
Connect

Change
Clean or change
Tighten nut

Repair or replace
Adjust
Repair or replace
Repair

Reduce to the
specified level
Repair or replace
Adjust
Adjust top clearance

Reference
Page

G-8

G-28

–

–

G-18

G-8
G-8

–

1-S50

–
–
–
–

1-S20

–

1-S40, S47

1-S21

G-22
10-S8
10-S7

2-S4, 3-S7,

10-S10

10-S8

–

G-18

G-17

–

–
1-S53
1-S54
1-S24

G-12

1-S40, S47

1-S51
1-S22

W1014322

1-S1

STα-30 · STα-35, WSM

KiSC issued 11, 2006 A

ENGINE

Symptom Probable Cause Solution

Either Black or Dark
Gray Exhaust Gas is
Observe

•Overload

• Low grade fuel used

• Fuel filter clogged

• Air cleaner clogged

• Deficient nozzle injection

Reduce the load
Use the specified fuel
Change
Clean or change
Repair or replace the
nozzle

Deficient Output • Incorrect injection timing

• Engine’s moving parts seem to be seizing

• Uneven fuel injection

Adjust
Repair or replace
Repair or replace the
injection pump

• Deficient nozzle injection

Repair or replace the
nozzle

• Compression leak

Replace head
gasket, tighten
cylinder head bolt,
glow plug and nozzle
holder

Excessive Lubricant
Oil Consumption

Fuel Mixed into
Lubricant Oil

• Piston ring’s gap facing the same direction

• Oil ring worn or stuck

• Piston ring groove worn

• Valve stem and guide worn

• Oil leaking due to defective seals or packing

• Injection pump’s plunger worn

• Deficient nozzle injection

Shift ring gap
direction
Replace
Replace the piston
Replace
Replace

Replace pump
element or pump
Repair or replace the
nozzle

• Injection pump broken

Water Mixed into
Lubricant Oil

• Head gasket defective

• Cylinder block or cylinder head flawed

Low Oil Pressure • Engine oil insufficient

• Oil strainer clogged

• Relief valve stuck with dirt

• Relief valve spring weaken or broken

• Excessive oil clearance of crankshaft bearing

• Excessive oil clearance of crankpin bearing

• Excessive oil clearance of rocker arm

• Oil passage clogged

• Different type of oil

Replace
Replace

Replace
Replenish

Clean
Clean
Replace
Replace
Replace
Replace
Clean
Use the specified
type of oil

• Oil Pump defective

High Oil Pressure • Difference type oil

Repair or replace
Use the specified

type of oil

• Relief valve defective

Replace

Reference
Page

–

G-8
G-18
G-17

1-S53

1-S51

–

–
1-S53
1-S20

1-S29
1-S40

1-S41
1-S33

–

–
1-S52
1-S52

1-S24

–

G-8

1-S28

–

–
1-S44
1-S43
1-S36

–

G-8

1-S48

G-8

1-S48

W1014322

1-S2

STα-30 · STα-35, WSM

KiSC issued 11, 2006 A

ENGINE

Symptom Probable Cause Solution

Engine Overheated • Engine oil insufficient

• Fan belt broken or elongated

• Coolant insufficient

• Radiator net and radiator fin clogged with

Replenish
Change or adjust
Replenish
Clean

dust

• Inside of radiator corroded

• Coolant flow route corroded

• Radiator cap defective

• overload running

• Head gasket defectiv e

• Incorrect injec tio n timi ng

• Unsuitable fuel used

Clean or replace
Clean or replace
Replace
Reduce the load
Replace
Adjust
Use the specified fuel

Reference
Page

G-8

1-S49

G-26

–

G-26

–

1-S50

–
1-S24
1-S51

G-8

W1014322

1-S3

STα-30 · STα-35, WSM

KiSC issued 11, 2006 A

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
(When Cranking with Starting Motor)

3.53 to 4.02 MPa /
290 rpm

36 to 41 kgf/cm

2

/

290 rpm

512 to 583 psi /

290 rpm

2.55 MPa /
290 rpm

26 kgf/cm

290 rpm

370 psi /

290 rpm

2

/

Difference among Cylinders

–

Top Clearance 0.55 to 0.70 mm

0.0217 to 0.0276 in.

Valve Clearance (At Engine Cold) 0.18 to 0.22 mm

0.0071 to 0.0087 in.

Valve Seat Width (Intake)

2.12 mm

0.0835 in.

Width (Exhau st)

2.12 mm

0.0835 in.

Valve Seat Angle (Intake)

1.047 rad.
60 °

Angle (Exhaust)

0.785 rad.
45 °

Valve Face Angle (Intake)

1.047 rad.
60 °

Angle (Exhaust)

0.785 rad.
45 °

Valve Stem to Valve Guide

Clearance

0.040 to 0.070 mm

0.00157 to 0.00276 in.

10 % or less

–

–

–

–

–

–

–

–

0.1 mm

0.0039 in.

Valve Stem

Valve Guide

Valve Recessing Protrusion

O.D.

I.D.

Recessing

1-S4

7.960 to 7.975 mm

0.31339 to 0.31398 in.

8.015 to 8.030 mm

0.31555 to 0.31614 in.

0.05 mm

0.0020 in.

0.15 mm

0.0059 in.

–

–

–

0.4 mm

0.0157 in.

W1013874

STα-30 · STα-35, WSM

KiSC issued 11, 2006 A

ENGINE BODY (Continued)

Item Factory Specification Allowable Limit

Valve Timing (Intake Valve) D1463-M Open

0.14 rad. (8 °)
before T.D.C.

ENGINE

–

Close

D1703-M Open

Close

Valve Timing (Exhaust Valve) D1463- M Open

Close

D1703-M Open

Close

Valve Spring Free Length

Setting Load

0.35 rad. (20 °)
after B.D.C.

0.21 rad. (12 °)

before T.D.C.

0.63 rad. (36 °)
after B.D.C.

1.05 rad. (60 °)

before B.D.C.

0.21 rad. (12 °)
after T.D.C.

1.00 rad. (57 °)

before B.D.C.

0.21 rad. (12 °)
after T.D.C.

41.7 to 42.2 mm

1.6417 to 1.6614 in.

117.6 N

12.0 kgf

26.4 lbs

–

–

–

–

–

–

–

41.2 mm

1.6220 in.

100.0 N

10.2 kgf

22.5 lbs

Setting Length

35.0 mm

–

1.3780 in.

Tilt

–

1.0 mm

0.039 in.

Rocker Arm Shaft to Rocker Arm

Rocker Arm Shaft

Clearance

O.D.

0.016 to 0.045 mm

0.00063 to 0.00177 in.

13.973 to 13.984 mm

0.15 mm

0.0059 in.
–

0.55012 to 0.55055 in.

Rocker Arm

I.D.

14.000 to 14.018 mm

–

0.55118 to 0.55189 in.

Push Rod Alignment – 0.25 mm

0.0098 in.

Tappet to Tappet Guide

Tappet

Clearance

O.D.

0.020 to 0.062 mm

0.00079 to 0.00244 in.

23.959 to 23.980 mm

0.07 mm

0.0028 in.
–

0.94327 to 0.94410 in.

Tappet Guide

I.D.

24.000 to 24.021 mm

–

0.94488 to 0.94571 in.

W1013874

1-S5

STα-30 · STα-35, WSM

KiSC issued 11, 2006 A

ENGINE BODY (Continued)

Timing Gear
Crank Gear to Idle Gear

ENGINE

Item Factory Specification Allowable Limit

Backlash

0.0415 to 0.1122 mm

0.00163 to 0.00442 in.

0.15 mm

0.0059 in.

Idle Gear to Cam Gear

Idle Gear to Injection Pump Gear

Crank Gear to Oil Pump Gear

Backlash

Backlash

Backlash

Idle Gear Side Clearance 0.12 to 0.48 mm

Idle Gear Shaft to Idle Gear Bushing

Idle Gear Shaft

Clearance

O.D.

0.0415 to 0.1154 mm

0.00163 to 0.00454 in.

0.0415 to 0.1154 mm

0.00163 to 0.00454 in.

0.0415 to 0.1090 mm

0.00163 to 0.00429 in.

0.0047 to 0.0189 in.

0.025 to 0.066 mm

0.00098 to 0.00260 in.

37.959 to 37.975 mm

0.15 mm

0.0059 in.

0.15 mm

0.0059 in.

0.15 mm

0.0059 in.

0.9 mm

0.0354 in.

0.1 mm

0.0039 in.
–

1.49445 to 1.49508 in.

Idle Gear Bushing

I.D.

38.000 to 38.025 mm

–

1.49606 to 1.49704 in.

Camshaft Side Clearance 0.07 to 0.22 mm

0.0028 to 0.0087 in.

0.3 mm

0.0118 in.

Camshaft Alignment – 0.01 mm

0.0004 in.

Cam Height

(Intake / Exhaust)

Camshaft Journal to Cylinder Block Bore

Clearance

33.90 mm

1.3346 in.

0.050 to 0.091 mm

0.00197 to 0.0358 in.

33.85 mm

1.3327 in.

0.15 mm

0.0059 in.

Camshaft Journal

Cylinder Block Bore

O.D.

I.D.

1-S6

39.934 to 39.950 mm

1.57221 to 1.57284 in.

40.000 to 40.025 mm

1.57480 to 1.57579 in.

–

–

W1013874

STα-30 · STα-35, WSM

KiSC issued 11, 2006 A

ENGINE BODY (Continued)

Item Factory Specification Allowable Limit

Piston Pin Bore I.D. 25.000 to 25.013 mm

0.98425 to 0.98476 in.

Second Ring to Ring Groove D1463-M Clearance 0.093 to 0.120 mm

0.00366 to 0.00472 in.

D1703-M Clearance 0.093 to 0.128 mm

0.00366 to 0.00504 in.

Oil Ring to Ring Groove Clearance 0.020 to 0.060 mm

0.00079 to 0.00205 in.

Top R ing D1463-M Ring Gap 0.20 to 0.35 mm

0.00787 to 0.01378 in.

D1703-M Ring Gap 0.25 to 0.40 mm

0.0098 to 0.0157 in.

Second Ring Ring Gap 0.30 to 0.45 mm

0.0118 to 0.0177 in.

Oil Ring Ring Gap 0.25 to 0.45 mm

0.0098 to 0.0177 in.

25.05 mm

0.9862 in.

0.2 mm

0.0079 in.

0.2 mm

0.0079 in.

0.15 mm

0.0059 in.

1.25 mm

0.0492 in.

1.25 mm

0.0492 in.

1.25 mm

0.0492 in.

1.25 mm

0.0492 in.

Connecting Rod Alignment – 0.05 mm

0.0020 in.

Piston Pin to Small End Bushing

Clearance

0.014 to 0.038 mm

0.00055 to 0.00150 in.

0.15 mm

0.0059 in.

ENGINE

Piston Pin

O.D.

25.002 to 25.011 mm

–

0.98433 to 0.98468 in.

Small End Bushing

I.D.

25.025 to 25.040 mm

–

0.98523 to 0.98582 in.

Crankshaft Alignment – 0.02 mm

0.00079 in.

Crankshaft Journal to Crankshaft Bearing
1

Crankshaft Journal

Oil Clearance

O.D.

0.040 to 0.118 mm

0.00157 to 0.00465 in.

51.921 to 51.940 mm

0.2 mm

0.0079 in.
–

2.04413 to 2.04488 in.

Crankshaft Bearing 1

I.D.

51.980 to 52.039 mm

–

2.04646 to 2.04878 in.

Crankshaft Journal to Crankshaft Bearing
2

Crankshaft Journal

Oil Clearance

O.D.

0.040 to 0.104 mm

0.00157 to 0.00409 in.

51.921 to 51.940 mm

0.2 mm

0.0079 in.
–

2.04413 to 2.04488 in.

Crankshaft Bearing 2

I.D.

51.980 to 52.025 mm

–

2.04646 to 2.04823 in.

W1013874

1-S7

STα-30 · STα-35, WSM

KiSC issued 11, 2006 A

ENGINE BODY (Continued)

Crankpin to Crankpin Bearing

ENGINE

Item Factory Specification Allowable Limit

Oil Clearance

0.025 to 0.087 mm

0.00098 to 0.00343 in.

0.2 mm

0.0079 in.

Crankpin

O.D.

46.959 to 46.975 mm

1.84878 to 1.84941 in.

Crankpin Bearing

I.D.

47.000 to 47.046 mm

1.85039 to 1.85220 in.

Crankshaft Side Clearance 0.15 to 0.35 mm

0.0059 to 0.0138 in.

0.5 mm

0.0197 in.

Crankshaft Sleeve Wear – 0.1 mm

0.0039 in.

Cylinder Bore D1463-M I.D. (Standard)

I.D. (Oversize)

D1703-M I.D. (Standard)

I.D. (Oversize)

82.000 to 82.022 mm

3.22835 to 3.22921 in.

82.250 to 82.272 mm

3.23819 to 3.23906 in.

87.000 to 87.022 mm

3.42519 to 3.42606 in.

87.250 to 87.272 mm

3.43503 to 3.43590 in.

+ 0.15 mm

+ 0.0059 in.

+ 0.15 mm

+ 0.0059 in.

+ 0.15 mm

+ 0.0059 in.

+ 0.15 mm

+ 0.0059 in.

LUBRICATING SYSTEM

Engine Oil Pressure At Idle Speed

98 kPa or mor e

1.0 kgf/cm

2

14 psi or more

or more

49 kPa

0.5 kgf/cm
7 psi

–

–

W1013874

2

At Rated Speed

294 to 441 kPa

3.0 to 4.5 kgf/cm
43 to 64 psi

Engine Oil Pressure Switch Working Pressure 49 kPa

0.5 kgf/cm

2

7 psi

Inner Rotor to Outer Rotor Clearance 0.03 to 0.14 mm

0.0012 to 0.0055 in.

Outer Rotor to Pump Body Clearance 0.11 to 0.19 mm

0.0043 to 0.0075 in.

Inner Rotor to Cover End Clearance 0.105 to 0.150 mm

0.00413 to 0.00591 in.

2

2.5 kgf/cm

2

36 psi

–

0.2 mm

0.0079 in.

0.25 mm

0.0098 in.

0.2 mm

0.0079 in.

W1013973

245 kPa

1-S8

STα-30 · STα-35, WSM

KiSC issued 11, 2006 A

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

Temperature

69.5 to 72.5 °C

157.1 to 162.5 °F

(At Beginning)

ENGINE

–

–

Valve Opening
Temperature

85 °C

185 °F

–

(Opened
Completely)

Radiator Water Tightness No leaks at

–

137 kPa

1.4 kgf/cm

2

20 psi

Radiator Cap Pressure Falling

Time

10 seconds or mo re f or

pressure falling

–

from 88 to 59 kPa

from 0.9 to 0.6 kgf/cm

2

from 13 to 9 psi

FUEL SYSTEM

Injection Pump Injection Timing 0.30 to 0.33 rad. (17 to

–

19 °) before T.D.C.

Pump Element Fuel Tightness – 14.7 MPa

150 kgf/cm

2133 psi

Delivery Valve Fuel Tightness 10 seconds or more for

pressure falling

from 14.7 to 13.7 MPa

from 150 to 140 kgf/cm

from 2133 to 1990 psi

5 seconds for

pressure falling

from 14.7 to

2

from 150 to

13.7 MPa

140 kgf/cm

from 2133 to

1990 psi

Injection Nozzle Injection Pressure 13.73 to 14.71 MPa

140 to 150 kgf/cm

2

–

1991 to 2133 psi

Injection Nozzle Valve Seat Valve Seat

Tightness

When the pressure is

12.75 MPa

(130 kgf/cm

2

, 1849 psi),

–

the valve seat must be

fuel tightness.

W1013874

2

2

W1013973

1-S9

STα-30 · STα-35, WSM

NOTE■

KiSC issued 11, 2006 A

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
Power steering delivery hose retaining nut
Steering hose LH and RH retaining nut
Engine mounting M10 screw, bolt and nut
Engine mounting M12 nut
Clutch cover mounting screw

Item Size x Pitch N·m kgf·m ft-lbs

Cylinder head cover screw

* Cylinder head screw
* Main bearing case screw 1
* Main bearing case screw 2
* Flywheel screw
* Connecting rod screw
* Rocker arm bracket screw
* Idle gear shaft screw

Fan drive pulley mounting nut

* Bearing case cover screw

Glow plug
Nozzle holder assembly
Nozzle holder
Oil Switch taper screw
Injection pipe retaining nut
Overflow pipe assembly retaining nut
Camshaft set screw
Hi-idling body

M6 × 1.0

M11 × 1.25

M9 × 1.25
M10 × 1.25
M12 × 1.25

M8 × 1.0
M8 × 1.25
M8 × 1.25

–

M8 × 1.25

M10 × 1.25

M20 × 2.0

–

PT 1/8

M12 × 1.5

–

M8 × 1.25

–

48.0 to 56.0
50 to 60
25 to 30

48.1 to 55.8

77.5 to 90.2

23.5 to 27.5

6.9 to 11.3

93.1 to 98.0

46.1 to 50.9

68.6 to 73.5

98.0 to 107.8

44.1 to 49.0

23.5 to 27.5

23.5 to 27.5

137.3 to 156.9

23.5 to 27.5

19.6 to 24.5

49.0 to 68.6

34.3 to 39.2

14.7 to 19.6

24.5 to 34.3

19.6 to 24.5

23.5 to 27.5

44.1 to 49.0

4.9 to 5.7

5.0 to 6.0

2.5 to 3.0

4.9 to 5.7

7.9 to 9.2

2.4 to 2.8

0.7 to 1.15

9.5 to 10.0

4.7 to 5.2

7.0 to 7.5

10.0 to 11.0

4.5 to 5.0

2.4 to 2.8

2.4 to 2.8

14.0 to 16.0

2.4 to 2.8

2.0 to 2.5

5.0 to 7.0

3.5 to 4.0

1.5 to 2.0

2.5 to 3.5

2.0 to 2.5

2.4 to 2.8

4.5 to 5.0

ENGINE

35.4 to 41.22

36.16 to 43.39

18.08 to 21.69

35.5 to 41.2

57.2 to 66.5

17.4 to 20.3

W1012736

5.1 to 8.32

68.7 to 72.3

34.0 to 37.6

50.6 to 54.2

72.3 to 79.5

32.5 to 36.2

17.4 to 20.3

17.4 to 20.3

101.3 to 115.7

17.4 to 20.3

14.5 to 18.1

36.2 to 50.6

25.3 to 28.9

10.8 to 14.5

18.1 to 25.3

14.5 to 18.1

17.4 to 20.3

32.6 to 36.3

• In removing and applying the screws, bolts and nuts marked with “*”, a pneumatic wrench or similar
pneumatic tool, if employed, must be used with enough care not to get them seized.

• For * marked screws, bolts and nuts on the table, apply engine oil to their threads and seats before
tightening.

• The letter “M” in Size x Pitch means that the screw, bolt or nut dimension stands for metric. The size is
the nominal outside diameter in mm of the threads. The pitch is the nominal distance in mm between two
threads.

W1013236

1-S10

STα-30 · STα-35, WSM

IMPORTANT■

KiSC issued 11, 2006 A

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.

1. Stop the engine and let cool down.

2. To drain the coolant, open the radiator drain plug (3) and remove
radiator cap (1). The radiator cap (1) must be removed to
completely drain the coolant.

3. After all coolant is drained, close the drain plug (3).

5.8 L

Coolant capacity (with recovery tank)

1.56 U.S.qts.

1.28 Imp.qts.

ENGINE

(1) Radiator Cap
(2) Recovery Tank

(3) Drain Plug

W1048932

Draining Engine Oil

1. Place an oil pan underneath the engine.

2. To drain the oil, remove the both drain plug (1) at the bo ttom of
the engine and drain the oil completely.

3. Screw in the both drain plug (1).

(When refilling)

• Fill the engine oil up to the upper line on the dipstick (2).

• When using an oil of different manufacture or viscosity from
the previous one, remove all of the old oil.

• Never mix two different types of oil.

• Use the proper SAE Engine Oil according to ambient
temperatures.

• Refer to “LUBRICANTS, FUEL AND COOLANT”. (See page
G-8.)

Engine oil capacity

(1) Drain Plug
(2) Dipstick
(3) Oil Inlet

4.5 L

1.19 U.S.qts.

0.99 Imp.qts.

(A) Oil level is acceptable within this

range.

W1050040

1-S11

STα-30 · STα-35, WSM

IMPORTANT■

■

KiSC issued 11, 2006 A

ENGINE

Draining Transmission Fluid

1. Place oil pan underneath the transmission case, and remove the
drain plugs (1).

2. Drain the transmissio n fluid.

3. Reinstall the drain plug (1).

(When refilling)

• Fill new oil f rom f illi ng por t afte r rem aining the f illin g plug (2) up to
the upper notch on the dipstick (3).

• After running the engine for few minutes, stop it and check the oil
level again, if low, add oil prescribed level.

• 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.)

• Never work the tractor immediately after changing the
transmission oil. Keeping the engine at medium speed for a
few minutes to prevents damage to the transmission.

• Do not mix different blands oil together.

18.5 L

Transmission fluid capacity

4.89 U.S.gals.

4.07 Imp.gals.

(1) Drain Plug
(2) Filling Plug
(3) Dipstick

A : Oil level is acceptable within this

range.

W1012748

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).

NOTE

• When disconnecting the battery cords, disconnect the
grounding cord first. When connecting, positive cord first.

(1) Hood
(2) Side Cover

(3) Front Grille
(4) Battery Cord

W1012749

Steering Wheel

1. Remove the steering wheel cap.

2. Remove the steering wheel mounting nut (1) and remove the
steering wheel (2) with a steering wheel puller (Code No. 07916-

51090).

(When reassembling)

Tightening torque

Steering wheel mounting
nut

48.04 to 56.0 N·m

4.9 to 5.7 kgf·m

35.4 to 41.22 ft-lbs

(1) Nut (2) Steering Wheel

W1012884

1-S12

STα-30 · STα-35, WSM

IMPORTANT■

KiSC issued 11, 2006 A

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).

4. Remove the panel under cover (7).

(1) Meter Panel
(2) Meter Panel Connector
(3) Hour-meter Cable
(4) Combination Switch Connector

(5) Main Switch Connector
(6) Hazard Switch connector
(7) Panel Under Cover
(8) Position Lamp Switch Connector

W1013015

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).

• After assembling, b e sure to adjust the acce lerator wire to
speed control lever to operate the engine maximum speed.

• Be sure to check the acc elerator wire is not interfere with
power steering any hoses.

(1) Accelerator Wire
(2) Accelerator Lever Arm

(3) Speed Control Lever
(4) Holder

W1013265

Fuel Sensor Wire

1. Turn over the fuel sensor cover (1).

2. Disconnect the 1P connector (2) and ground wire (3) from the fuel
sensor.

(1) Fuel Sensor Cover
(2) 1P Connector

(3) Ground Wire

W1052606

1-S13

STα-30 · STα-35, WSM

KiSC issued 11, 2006 A

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)

• Connect the steering hose LH (5) to LT port (8).

• Connect the s teering hose RH (4) with wh ite tap e (6) to RT port
(11).

• Make arrangement the hose as figure and routing to original.

• When reassembling the controller with steering pillar to the panel
under frame and under frame, temporally screw in the four
screws then tighten first to panel under frame (upper side) side in
parallel between panel under frame an d screw plate o f steering
pillar.

• Be sure to clamp the delivery hoses (4) and (5) to position
hydraulic delivery pipe with clamp band (12).

• Be sure to check the hoses are not interfere with accelerator wire.

Power steering delivery
hose retaining nut

Tightening torque

Steering hose LH and RH
retaining nut

50 to 60 N·m

5.0 to 6.0 kgf·m

36.16 to 43.39 ft-lbs
25 to 30 N·m

2.5 to 3.0 kgf·m

18.08 to 21.69 ft-lbs

(1) P ower Steering Controller
(2) Steering Pillar
(3) Power Steering Delivery Hose
(4) Steering Hose RH
(5) Steering Hose LH
(6) White Tape
(7) Drain Hose
(8) LT Port
(9) Drain Port

(10) Delivery Port
(11) RT Port
(12) Clamp Band

(A) Viewed from Bottom Side

F : Front

R : Rear

a : 0.785 rad. (45 °)
b : 0.174 to 0.262 rad. (10 to 15 °)

W1052855

1-S14

STα-30 · STα-35, WSM

KiSC issued 11, 2006 A

ENGINE

Wire Connectors

1. Remove or disco nne ct the connectors, termin al s a s li ste d be low
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
(2) Battery Positive Code
(3) Alternator
(4) Starter
(5) Engine Oil Pressure Switch
(6) Harness G uide

(7) Front Wheel Turning Angle Sensor
(8) Ground Terminal
(9) Stop Solenoid

(10) Fuse Box Assembly

(11) Timer Relay

W1045601

1-S15

STα-30 · STα-35, WSM

KiSC issued 11, 2006 A

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)

• When reassemb ling the p anel un der fr ame, tigh ten t he two nu ts
(5) for insulation rubber first.

(1) Plug
(2) Foot Cover
(3) Screw

(4) Panel Under Cover
(5) Nut

W1055726

1-S16

STα-30 · STα-35, WSM

KiSC issued 11, 2006 A

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).

(When reassembling)

• Be sure to fix the sponges to the original position.

(1) Fuel Hose
(2) Overflow Hose
(3) Shutter Plate

(4) Bonnet Rear Support
(5) Fuel Tank

W1055997

Wire Harness

1. Remove the glow plug cable (1).

2. Disconnect the 1P connector from the coolant temperature
sensor (2).

3. Disconnect the coupler from bi-speed solenoid (3).

4. Remove the wire harness assembly.

(1) Glow Plug Code
(2) Coolant Temperature Sensor

(3) Bi-speed Solenoid

W1057013

1-S17

STα-30 · STα-35, WSM

KiSC issued 11, 2006 A

ENGINE

Hydraulic Pipe

1. Remove the hydraulic delivery pipe (1) from the 3P hydraulic
pump.

2. Loosen the ho se band of the joint hose (3) and slide the joi nt
hose (3) to s eparating t he HST drai n pipe (2) and inlet pipe ( 4).

3. Remove the pipe clamping screws.

4. Loosen the hose band (5) and separate the HST pipe (6) from the
HST drain hose (4).

5. Remove the HST pipe (6) clamping screw (7).

(1) Hydraulic Delivery Pipe
(2) HST Drain Pipe
(3) Joint Hose
(4) Inlet Pipe

(5) Hose Band
(6) HST Pipe
(7) Clamping Screw

W1057369

Propeller Shaft

1. Loosen the clamp (1) and slide the propeller shaft cover (2).

2. Tap out the spring pin (3) and then slide the coupling (4).

3. Remove the propeller shaft with cover.

(When reassembling)

• Apply grease to the splines of the propeller shaft and couplings.

• When inserting the spring pins (3), face their splits in the direction
parallel to the universal joint as shown in the figure.

(1) Clamp
(2) Propeller Shaft Cover
(3) Spring Pin
(4) Coupling

A : Approx. 1.0 mm (0.039 in.)
B : Split Portion

W1014306

1-S18

STα-30 · STα-35, WSM

■

■

KiSC issued 11, 2006 A

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)

• Apply liquid gasket (Three Bond 1208D or equivalent) to joint
face of the engine and clutch housing.

Engine mounting M10
screw, bolt and nut

Tightening torque

Engine mounting M12 nut

48.1 to 55.8N·m

4.9 to 5.7 kgf·m

35.5 to 41.2 ft-lbs

77.5 to 90.2 N·m

7.9 to 9.2 kgf·m

57.2 to 66.5 ft-lbs
W1056610

Separating Front Axle Assembly and Outer Parts

1. Disconnect the radiator hoses (1), (3) and (9).

2. Remove the muffler (6).

3. Remove the recovery tank (2).

4. Remove the stater motor (7) and alternator (10).

5. Remove the fuel filter (4) and hydraulic pump (5).

6. Remove the engine mounting screws and separate the front axle
assembly from engine.

(1) Radiator Hose
(2) Recovery Tank
(3) Radiator Hose
(4) Fuel Filter
(5) Hydraulic Pump

(6) Muffler
(7) Stater Motor
(8) Clutch Assembly
(9) Radiator Hose

(10) Alternator

W1058184

Clutch Assembly

1. Remove the clutch assembly (1).

(When reassembling)

• Direct the shorter end of the clutch disc boss toward the flywheel.

• Apply molybdenum di sulphide (Thre e Bond 1901 or equiva lent)
to the splines of clutch disc boss.

• Make sure of reamer scr ews posi tio n and after two reamer bolts
are tightened, other screws are tightened.

IMPORTANT

• Be sure to align the center of disc and flywheel by inserting
the clutch center tool (2).

NOTE

• Do not allow grease and oil on the clutch disc facing.

Tightening torque

(1) Clutch Assembly (2) Clutch Center Tool

Clutch cover mounting
screws

23.5 to 27.5 N·m

2.4 to 2.8 kgf·m

17.5 to 20.3 ft-lbs

W1017588

1-S19

STα-30 · STα-35, WSM

NOTE■

KiSC issued 11, 2006 A

[2] ENGINE BODY

(1) Checking and Adjusting

ENGINE

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. Set a compression tester (Code No. 07909-30208) with the
adaptor to the nozzle hole.

5. Keep the engine stop lever at “Stop Position”.

6. While cranking the engine with the starter, measure the
compression pressure.

7. Repeat steps 4 through 6 for each cylinder.

8. If the measureme nt is below the allowable limit, apply a small
amount of oil to the cylinder wall through the nozzle hole and
measure the compression pressure again.

9. If the compressio n pressure is still l ess than the allowab le limit,
check the top clearance, valve and cylinder head.

10.If th e compression pressure increa ses after applying oil, chec k
the cylinder wall and piston rings.

• Check the compression pressure with the specified valve
clearance.

• Always use a fully charged battery for performing this test.

• Variances in cylinder compression values should be under
10 %.

Compression pressure

Factory spec.

Allowable limit

3.53 to 4.02 MPa
36 to 41 kgf/cm
512 to 583 psi

2.55 MPa
26 kgf/cm
370 psi

2

2

W1018639

1-S20

STα-30 · STα-35, WSM

IMPORTANT■

NOTE■

KiSC issued 11, 2006 A

ENGINE

Valve Clearance

• Valve clearance must be checked and adjusted when engine
is cold.

1. Remove the head cov er, the glow plugs and the timing windo w
cover on the clutch housing.

2. Align the “1TC” mark lin e on the flywheel and cent er of timing
window so that the No. 1 piston comes to the compression or
overlap top dead center.

3. Check the following valve clearance marked with “✩” using a
feeler gauge.

4. If the clearance is not within the factory specifications, adjust with
the adjusting screw.

Valve clearance Factory spec.

0.18 to 0.22 mm

0.0071 to 0.0087 in.

• The “TC” marking line on the flywheel is just for No. 1
cylinder. There is no “TC” marking for the other cylinders.

• No. 1 piston comes to the T.D.C. position when the “TC”
marking is aligned with center of timing window on clutch­housing. Turn the flywheel 0.26 rad. (15 °) clockwise and
counterclockwise to see if the piston is at the compression
top dead center or the overlap position. Now referring to the
table below, readjust the valve cle arance. (The piston is at
the compression top dead center when both the IN. and EX.
valves do not move; it is at the overlap posit ion when both
the valves move.)

• Finally turn the flyw heel 6.28 ra d. (360 ° ) and align the “T C”
marking line and the center of timing window. Adjust all the
other valve clearance as required.

• After turning the flywheel counterclockwise twice or three
times, recheck the valve clearance , firmly tighten the lock
nut of the adjusting screw.

Condition

When No. 1 piston is
compression top dead center

When No. 1 piston is overlap
position

No. of

cylinder
1st ✩✩
2nd ✩
3rd ✩
1st
2nd ✩
3rd ✩

IN. Valve EX. Valve

(1) TC Mark Line
(2) Timing Window

1-S21

A : Valve Clearance

W1018974

STα-30 · STα-35, WSM

KiSC issued 11, 2006 A

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. Turn the flywheel until the piston passes through the T.D.C..

5. Remove the cylinder head and measure the thickness of the
fuses.

6. If the measurement is not within the factory specifications, check
the oil clearances between the crankpin and bearing and
between the piston pin and bushing.

Top clearance Factory spec.

Tightening torque Cylinder head screws

(1) Piston (2) Fuse

0.55 to 0.70 mm

0.0217 to 0.0276 in.

93.1 to 98.0 N·m

9.5 to 10.0 kgf·m

68.7 to 72.3 ft-lbs

W1020190

(2) Disassembling and Assembling
(A) Cylinder Head and Valves

Cylinder Head Cover

1. Remove the breather hose.

2. Remove the head cover screws.

3. Remove the cylinder head cover (1).

(When reassembling)

• Check to see if the cylinder head cover gasket is not defective.

6.9 to 11.3 N·m

Tightening torque Cylinder head cover screw

(1) Cylinder Head Cover

0.7 to 1.15 kgf·m

5.1 to 8.32 ft-lbs

W1020618

Injection Pipes

1. Loosen the screws on the pipe clamps.

2. Detach the injection pipes.

(When reassembling)

• Sent compressed air into the pipes to blow out dust. Then,
reassemble the pipes in the reverse order.

24.5 to 34.3 N·m

Tightening torque Injection pipe retaining nut

2.5 to 3.5 kgf·m

18.1 to 25.3 ft-lbs
W1020811

1-S22

STα-30 · STα-35, WSM

■

IMPORTANT■

KiSC issued 11, 2006 A

ENGINE

Nozzle Holder Assembly and Glow Plug

1. Remove the overflow pipe assembly (5).

2. Remove the nozzle holder assembl ies (2) using a 21 mm deep
socket wrench.

3. Remove the copper gasket and heat seal (3).

4. Remove the glow plugs (1).

(When reassembling)

• Replace the copper gasket and heat seal with new one.

49.0 to 68.6 N·m

Tightening torque

Nozzle holder assembly

Overflow pipe assembly
retaining nut

Glow plug

5.0 to 7.0 kgf·m

36.2 to 50.6 ft-lbs

19.6 to 24.5 N·m

2.0 to 2.5 kgf·m

14.5 to 18.1 ft-lbs

19.6 to 24.5 N·m

2.0 to 2.5 kgf·m

14.5 to 18.1 ft-lbs

(1) Glow Plug
(2) Nozzle Holder Assembly
(3) Heat Seal

(4) Lead
(5) Overflow Pipe Asse mbly

W1020917

Nozzle Heat Seal Service Removal Procedure

IMPORTANT

• Use a plus (phillips head) screw driver (1) that has a Dia.
which is bigger than the heat seal hole (Approx. 6 mm) 1/4 in.

1. Drove screw drive (1) lightly into the heat seal hole.

2. Turn screw driver three or four times each way.

3. While turning the s crew driver, slowly pull the he at seal (4) out
together with the c opper gasket (3).

4. If the heat seal drops, repeat the above procedure.

(When reassembling)

• Heat seal and copper gasket must be changed when the injection
nozzle is removed for cleaning or for service.

(1) Plus Screw Driver
(2) Nozzle Holder

(3) Copper Gasket
(4) Heat Seal

W1021255

Rocker Arm and Push Rod

1. Remove the rocker arm bracket mounting bolts.

2. Detach the rocker arm assembly (1).

3. Remove the push rods (2).

(When reassembling)

• When putting the push rods (2) onto the tappets (3), check to see
if their ends are properly engaged with the grooves.

• After installing the rocker arm, be sure to a djust the valve
clearance.

Tightening torque

(1) Rocker Arm Assem bly
(2) Push Rod

Rocker arm bracket
mounting bolt

(3) Tappet

23.5 to 27.5 N·m

2.4 to 2.8 kgf·m

17.4 to 20.3 ft-lbs

W1021437

1-S23

STα-30 · STα-35, WSM

IMPORTANT■

IMPORTANT■

KiSC issued 11, 2006 A

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. Remove the cylinder head gasket.

(When reassembling)

• Replace the cylinder head gasket with a new on.

• Tighten the cylinder head screws after applying sufficient oil.

• Tighten the cylinder head screws in diagonal sequence starting
from the center.

• Tighten them uniformly, or the head may deform in the long run.

93.1 to 98.0 N·m

Tightening torque Cylinder head screw

9.5 to 10.0 kgf·m

68.7 to 72.3 ft-lbs

(1) Return Pipe (n) to (a): To Loosen

(a) to (n): To Tighten
(A) Gear Case Side
(B) Flywheel Side

W1021755

Tappets

1. Remove the tappets from the crankcase.

(When reassembling)

• Visually check the contact between tappets and cams for proper
rotation. If defect is found, replace tappets.

• Before installing the tappets, apply engine oil thinly around them.

• Do not change the combination of tappet and tappet guide.

W1022001

Valves

1. Remove the valve caps (2).

2. Remove the valve spring collet (3), pushing the valve spring
retainer (4) by valve spring replacer (1).

3. Remove the val ve spri ng reta iner (4 ), valve spri ng (5) an d valv e
stem seal (6).

4. Remove the valve (7).

(When reassembling)

• Wash the va lve s tem and valve guid e hole, and apply eng ine oi l
sufficiently.

• After installing the valve spring collets, lightly tap the stem to
assure proper fit with a plastic hammer.

• Don’t cha nge the combination of valve and valve guide.

(1) Valve Spring Replacer
(2) Valve Cap
(3) Valve Spring Collet
(4) Valve Spring Retainer

(5) Valve Spring
(6) Valve Stem Seal
(7) Valve

W1022102

1-S24

STα-30 · STα-35, WSM

IMPORTANT■

KiSC issued 11, 2006 A

(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. Remove the fuel injection pump assembly (4).

• Before removing the injection pump assembly, be sure to
remove the stop solenoid, hi-idling body, engine stop lever
and stop solenoid guide (5).

(When reassembling)

• Before attachin g the stop solenoid, hi-idling body an d solenoid
guide, install the injection pump first into position.

• Replace the hi-idling body gasket with a new one.

• Before fitting the stop lever to the gear case , install th e so lenoid
guide first into position. Then attac h the stop lever an d use it to
see if it functions well.

• Before fitting the id li ng lim ite r in pl ac e, a ttac h th e so le noi d gu ide
and the engine stop lever in their respective positions.

• When installing the stop s olenoid, be careful to ke ep the O-r ing
in place.

• Be sure to insert the pus h rod of the stop soleno id into the hole
at the center of the solenoid guide.

Tightening torque Hi-idling body

ENGINE

44.1 to 49.0 N·m

4.5 to 5.0 kgf·m

32.6 to 36.3 ft-lbs

(1) Hi-idling Body
(2) Stop Solenoid
(3) Stop Lever

(4) Injection Pump Assembly
(5) Solenoid Guide
(6) Cover

W1023686

Speed Control Plate

1. Disconnect the governor spring (3), (4).

2. Remove the speed control plate (1).

(When reassembling)

• Check that the speed control lever (2) positions low idle, af ter
assembling governor spring.

• Check that the speed control lever returns to the high idle position
rather than the low idle position, after moving the lever to the
maximum speed position.

• After assembling the engi ne, check the idli ng speed referring to
Adjusting Idling Speed. (950 to 1000 rpm)

(1) Speed Control Plate
(2) Speed Control Lever

(3) Governor Spring 1
(4) Governor Spring 2

W1024090

1-S25

STα-30 · STα-35, WSM

KiSC issued 11, 2006 A

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)

Tightening torque

(1) Nut (2) Fan Drive Pulley

Fan drive pulley mounting
nut

137.3 to 156.9 N·m

14.0 to 16.0 kgf·m

101.3 to 115.7 ft-lbs

W1024348

Gear Case

1. Remove the hour meter gear case.

2. Remove the gear case (1).

3. Remove the O-rings (2 ).

(When reassembling)

• Apply liquid gasket (Three Bond 1215 or equivalent) to both side
of hour meter gear case gasket.

• Check to see if there are four O-rings (2) inside the gear case (1).

• Apply a thin film of engine oil to the oil seal (3), and insta ll it,
noting the lip come off.

• Before installing the gear case gasket, apply a non-drying
adhesive.

(1) Gear Case
(2) O-ring

(3) Oil Seal

W1024531

Crankshaft Oil Slinger

1. Remove the feather key.

2. Remove the crankshaft collar (3).

3. Remove the O-ring (2).

4. Detach the crankshaft oil slinger (1).

(When reassembling)

• Insert the crankshaft collar (3) after install the gear case to
cylinder body

(1) Crankshaft Oil Slinger
(2) O-ring

(3) Crankshaft Collar

W1024731

Idle Gear

1. Remove the external snap ring.

2. Detach the idle gear collar.

3. Detach the idle gear (2).

(When reassembling)

• Check to see each gear is aligned with its aligning mark:
(1) Idle gear and crank gear
(2) Idle gear and camshaft gear
(3) Idle gear and injection pump gear

(1) Injection Pump Gear
(2) Idle Gear
(3) Cam Gear

(4) Crank Gear
(5) Oil Pump Drive Gear

W1024941

1-S26

STα-30 · STα-35, WSM

KiSC issued 11, 2006 A

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

(1) Camshaft (2) Camshaft Set Bolt

2.4 to 2.8 kgf·m

17.4 to 20.3 ft-lbs

W1025098

Fuel Camshaft and Fork Lever Assembly

1. Remove the hydraulic pump drive gear from fuel camshaft.

2. Remove the fuel feed pump.

3. Detach the fuel camshaft stopper.

4. Remove the three fork lever holder mounting screws.

5. Draw out the fuel camshaft assembly (3), (4) and fork lever
assembly (1), (2), (5) at the same time.

(When reassembling)

• After installation, check to see that the fork lever 1 (1) and (2) are
fixed to the fork lever shaft, and that they can turn smoothly in the
holder (5).

(1) Fork Lever 1
(2) Fork Lever 2
(3) Injection Pump Gear

(4) Fuel Camshaft
(5) Fork Lever Holder

W1025309

Crank Gear

1. Draw out the crank gear (1) with gear puller.

2. Remove the feather key.

(1) Crank Gear

W1025476

Oil Pump

1. Remove the nut.

2. Draw out the oil pump drive gear (1) with gear puller.

3. Remove the four oil pump mounting screws. Detach the oil pump
(2).

(1) Oil Pump Drive Gear (2) Oil Pump

W1025581

1-S27

STα-30 · STα-35, WSM

KiSC issued 11, 2006 A

(C) Piston and Connecting Rod

ENGINE

Oil Pan and Oil Strainer

1. Remove the oil pan mounting screws.

2. Remove th e oil pan (2) by lightl y ta pping the rim of t he pan with
a wooden hammer.

3. Remove the oil strainer (1).

(When reassembling)

• After cleaning the oil strainer, check to see that the filter mesh in
clean, and install it.

• Visually check the O-ring, apply engine oil, and install it.

• Securely fit the O-ring to the oil strainer.

• Apply a liqui d gasket (Three B ond 1215 or equi valent) to the oi l
pan side of the oil pan gasket.

• To avoid uneven tighte ning, tighten oil pan mountin g screws in
diagonal order from the center.

(1) Oil Strainer (2) Oil Pan

W1025687

Connecting Rod Cap

1. Remove the conne cti ng rod caps .

(When reassembling)

• Align the marks (a) with each other. (Face the marks toward the
injection pump.)

• Apply engine oil to the connecting rod screws and lightly screw it
in by hand, then tighten it to the specified torque.
If the connecting rod scr ew wo n’t b e s crew ed i n s moo thly, c lean
the threads.
If the connecting rod screw is still hard to screw in, replace it.

Tightening torque Connecting rod screw

44.1 to 49.0 N·m

4.5 to 5.0 kgf·m

32.5 to 36.2 ft-lbs

(a) Mark

W1025878

1-S28

STα-30 · STα-35, WSM

IMPORTANT■

KiSC issued 11, 2006 A

ENGINE

Pistons

1. Turn the flywheel and bring the piston to top dead center.

2. Draw out the piston up ward by ligh tly tappin g it from the bo ttom
of the crankcase with the grip of a hammer.

3. Draw out the other piston in the same method as above.

(When reassembling)

• Before inserting piston into the cylinder, apply enough engine oil
to the piston.

• When inserting the pis ton into the cylinde r, f ace the mark on the
connecting rod to the injection pump.

• Do not change the combination of cylinder and piston. Make
sure of the position of each piston by marking. For example,
mark “1” on the No. 1 piston.

• Place the piston rings with their gaps at 0.79 rad. (45 °) from
the piston pin’s direction as shown in the figure.

• Carefully insert the pistons using a piston ring compressor.

• When inserting the piston in place, be careful not to get the
molybdenum disulfide coating torn off its skirt. This coating
is useful in minimizing the cle ar ance w ith th e cy linder lin er .
Just after the piston p in h as been pre ss- fit ted , in p ar ticu lar ,
the piston is still hot and the coating is easy to peel off. Wait
until the piston cools down.

(A) Top Ring Gap
(B) Second Ring Gap
(C) Oil Ring Gap

(D) Piston Pin Hole

(a) 0.79 rad. (45 °)

W1026141

1-S29

STα-30 · STα-35, WSM

NOTE■

KiSC issued 11, 2006 A

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 se parate the conn ecting rod (6)
from the piston (5).

(When reassembling)

• When installing the ring, assemble the rings so that the
manufacturer’s mark (12) near the gap faces the top of the piston.

• When installi ng the oil ring o nto the piston, plac e the expander
joint (10) on the opposite side of the oil ring gap (11).

• Apply engine oil to the piston pin.

• When installing the connecting rod to the piston, immerse the
piston in 80 °C (17 6 °F) oil for 10 to 15 mi nutes and insert the
piston pin to the piston.

• Assemble the piston to the connecting rod with the ↑ mark
(9) and the connecting rod mark (8) facing th e opposite side.

• Mark the same number on the connecting rod and the piston
so as not to change the combination.

(1) Top Ring
(2) Second Ring
(3) Oil Ring
(4) Piston Pin Snap Ring
(5) Piston
(6) Connecting Rod

(7) Piston Pin
(8) Mark

(9) Casting Ma rk
(10) Expander Joint
(11) Oil Ring Gap
(12) Manufact urer’s Mark

W1026376

1-S30

STα-30 · STα-35, WSM

KiSC issued 11, 2006 A

(D) Crankshaft

ENGINE

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.

98.0 to 107.8 N·m

Tightening torque Flywheel screws

(1) Flywheel Screw (2) Flywheel

10.0 to 11.0 kgf·m

72.3 to 79.5 ft-lbs

W1026863

Bearing Case Cover

1. Remove the bearing case cover mounting screws.

2. Remove the bearing case cover (1).

(When reassembling)

• Apply grease the oil seal lip, be careful not to peel the lip off.

• Install the bearing case cover (1) to position the casting mark
“UP” (2) on it upward.

• Tighten the bearing case cover mounting screws with even force
on the diagonal line.

(1) Bearing Case Cover (2) Casting Mark

W1027062

Crankshaft

1. Remove the main bearing case screws 2 (1).

2. Pull out the cran kshaft asse mbly (2), tak ing care no t to damage
the crankshaft bearing 1.

(When reassembling)

• Apply oil to the main bearing case screws 2.

• Clean the oil passage of the crankshaft with compressed air.

• Install the crankshaft assembly (2), aligning the screw hole of
main bearing case with the screw hole of crankcase.

68.6 to 73.5 N·m

7.0 to 7.5 kgf·m

50.6 to 54.2 ft-lbs

Tightening torque

Main bearing case screws
2

(1) Main Bearing Case Screw 2 (2) Crankshaft Assembly

W1027231

1-S31

STα-30 · STα-35, WSM

IMPORTANT■

KiSC issued 11, 2006 A

ENGINE

Main Bearing Case Assembly

1. Remove the two main bearing case sc rews 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)

• Clean the oil passage in the main bearing case.

• Apply clean engine oil on the bearings.

• Install the main bearing case assemblies in the original positions.
Since diameters of main bearing cases vary, install them in order
of makings (A, B) from the gear case side.

• Match the alignment numbers (1) and mark (2) on the main
bearing case.

• When installi ng the main bearing case 1 a nd 2, face the mark
“FLYWHEEL” to the flywheel.

• Install the thrust bearing with its oil groove facing outward.

• Confirm that the main bearing case moves smoothly after
tightening the main bearing case screw 1 to the specified torque.

46.1 to 50.9 N·m

Tightening torque Main bearing case screw 1

(1) Alignment Number (2) Alignment Mark

4.7 to 5.2 kgf·m

34.0 to 37.6 ft-lbs

W1027366

(3) Servicing
(A) Cylinder Head and Valves

Cylinder Head Surface Flatness

1. Clean the cylinder head surface.

2. Place a str aightedge on the cylind er head’s four sides and two
diagonal as shown in the figure.

3. Measure the clearance with a feeler gauge.

4. If the measurement ex ceeds the all owable limit, co rrect it with a
surface grinder.

• Do not place the straightedge on the combustion chamber.

• Be sure to check the valve recessing after correcting.

Cylinder head surface
flatness

Factory spec.

0.05 mm / 500 mm

0.0020 in. / 19.69 in.
W1027737

1-S32

STα-30 · STα-35, WSM

KiSC issued 11, 2006 A

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 cylinde r head surfac e with the read p ermeative liq uid
(1). Leave it five to ten minutes after spraying.

4. Wash away the read permeative liquid on the cylinder head
surface with the detergent (2).

5. Spray the cylinder head surface with white developer (3).

6. If flawed, it can be identified as red marks.

(1) Red Permeative Liquid
(2) Detergent

(3) White Developer

W1076542

Valve Recessing

1. Clean the cylinder head surface, valve face and valve seat.

2. Insert the valve into the valve guide.

3. Measure the valve recessing with a depth gauge.

4. If the measurement exceeds the allowable limit, replace the
valve.

5. If it still exceeds the allowable limit after replacing the valve,
correct the valve seat face of the cylinder head with a valve seat
cutter (Code No. 07909-33102) or valve seat grinder.

6. Then, correct the cylinder head surface with a surface grinder, or
replace the cylinder head.

0.05 (protrusion) to

Factory spec.

Valve recessing

Allowable limit

0.15 (recessing) mm

0.0020 (protrusion) to

0.0059 (recessing) in.

0.40 (recessing) mm

0.0157 (recessing) in.

(1) Cylinder Head Surface (A) Recessing

(B) Protrusion

W1076880

Clearance between Valve Stem and Valve Guide

1. Remove carbon from the valve guide section.

2. Measure the valve stem O.D. with an outside micrometer.

3. Measure the valve guide I.D. with a small hole gauge, and
calculate the clearance .

4. If the clearance e xceeds the allowa ble limit, rep lace the valv es.
If it still exceeds the allowable limit, replace the valve guide.

Clearance between
valve stem and guide

Valve stem O.D. Factory spec.

Valve guide I.D. Factory spec.

Factory spec.

Allowable limit

0.040 to 0.070 mm

0.00157 to 0.00276 in.

0.1 mm

0.0039 in.

7.960 to 7.975 mm

0.31339 to 0.314398 in.

8.015 to 8.030 mm

0.31555 to 0.31614 in.
W1077495

1-S33

STα-30 · STα-35, WSM

IMPORTANT■

KiSC issued 11, 2006 A

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. Press in a new valve guide using a valve guide replacing too.

3. Ream precisely the I.D. of the valve guide to the specified
dimension.

Valve guide I.D.
(Intake and exhaust)

Factory spec.

8.015 to 8.030 mm

0.31555 to 0.31614 in.

• Do not hit the valve guide with a hammer during
replacement.

(A) When Removing (B) When Installing

W1027889

Valve Seating

1. Coat the valve face lightly with prussian blue and put the valve on
its seat to check the contact.

2. If the valve does not seat all the way around the valve seat or the
valve contact is less than 70 %, correct the valve seating as
follows.

3. If the valve conta ct does not comply with the reference value,
replace the valve or correct the contact of valve seating.

(1) Correct
(2) Incorrect

(3) Incorrect

W1028219

1-S34

STα-30 · STα-35, WSM

NOTE■

IMPORTANT■

KiSC issued 11, 2006 A

ENGINE

Correcting Valve and Valve Seat

• Before correcting t he valve and seat , check the valve s tem
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.

1) Correcting Valve

1. Correct the valve with a valve refacer.

2) Correcting Valve Seat

1. Slightly correct the s eat surface with a 1.047 rad. (60 °) (intake
valve) or 0.785 r ad. ( 45 ° ) ( exh aus t v al ve) se at cut t er ( Cod e No .
07909-33102).

2. Resurface the se at surface with a 0.523 rad. (30 ° ) valve seat
cutter to intake valve seat and with a 0.262 rad. (15 °) valve seat
cutter to exhaust valve seat so that the width is close to specified
valve seat width (2.12 mm, 0.0835 in.)

3. After resurfacing the seat, inspect for even valve seating, apply a
thin film of compound between the valve face and valve seat, and
fit them with valve lapping tool.

4. Check the va lve seating with p russian blue. The valve seating
surface should show good contact all the way around.

(a) Identical Dimensions
(b) Valve Seat Width
(c) 0.523 rad. (30 °) or 0.262 rad. (15 °)
(d) 0.262 rad. (15 °) or 0.523 rad. (30 °)
(e) 0.785 rad. (45 °) or 1.047 rad. (60 °)

(A) Check Correct
(B) Correct Seat Width
(C) Check Contact

W1028350

Valve Lapping

1. Apply compound evenly to the valve lapping surface.

2. Insert the valve into t he valve gui de. Lap the val ve onto its sea t
with a valve flapper or screwdriver.

3. After lapping th e v al ve , wa sh th e c om pou nd away and apply oil,
then repeat valve lapping with oil.

4. Apply prussian bl ue to the contact surface to che ck the seated
rate. If it is less than 70 %, repeat valve lapping again.

• When valve lapping is performed, be sure to check the valve
recessing and adjust the valve clearance after assembling
the valve.

W1028814

1-S35

STα-30 · STα-35, WSM

KiSC issued 11, 2006 A

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 val ve spring on a surface plate, p lace a square on the
side of the valve spring.

3. Check to see if the entire side is in contact with the square.
Rotate the valve spring and measure the maximum tilt (B).
Check the entire surface of the valve spring for scratches.
If there is any defect, replace it.

Factory spec.

Free length (A)

Allowable limit

41.7 to 42.2 mm

1.6417 to 1.6614 in.

41.2 mm

1.6220 in.

Tilt (B) Allowable limit

1.0 mm

0.039 in.
W1028935

Valve Spring Setting Load

1. Place the valve spring on a tester and com press it to the same
length it is actually compressed in the engine.

2. Read the compression load on the gauge.

3. If the measurement is less than the allowable limit, replace it.

117.6 N / 35 mm

Factory spec.

Setting load /
Setting length

Allowable limit

12.0 kgf / 35 mm

26.4 lbs / 1.3780 in.

100.0 N / 35 mm

10.2 kgf / 35 mm

22.5 lbs / 1.3780 in.
W1078436

Oil Clearance between Rocker Arm and Rocker Arm Shaft

1. Measure the rocker arm shaft O.D. with an outside micrometer.

2. Measure the rocker arm I.D. with an inside micrometer, and then
calculate the oil clearance.

3. If the oil clearance exceeds the allowable limit, replace the rocker
arm and measure the oil clearance again. If it st ill exceeds the
allowable limit, replace also the rocker arm shaft.

Oil clearance between
rocker arm and rocker
arm shaft

Factory spec.

Allowable limit

0.016 to 0.045 mm

0.00063 to 0.00177 in.

0.10 mm

0.0039 in.

Rocker arm shaft O.D. Factory spec.

Rocker arm I.D. F actory spec.

13.973 to 13.984 mm

0.55012 to 0.55055 in.

14.000 to 14.018 mm

0.55118 to 0.55189 in.
W1029150

Push Rod Alignment

1. Place the push rod on V blocks.

2. Measure the push rod align men t.

3. If the measurement exceeds the allowable limit, replace the push
rod.

Push rod alignment Allowable limit

0.25 mm

0.0098 in.
W1029290

1-S36

STα-30 · STα-35, WSM

KiSC issued 11, 2006 A

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 wit h a cy l inder ga uge ,
and calculate the oil clearance.

3. If the oil clearance ex ceeds the allowable limit or the ta ppet is
damaged, replace the tappet.

Oil Clearance between
tappet and tappet guide
bore

Factory spec.

Allowable limit

0.020 to 0.062 mm

0.00079 to 0.00244 in.

0.07 mm

0.0028 in.

Tappet O.D. Factory spec.

Tappet guide bore I.D. Factory spec.

(B) Timing Gears, Camshaft and Fuel Camshaft

Timing Gear Backlash

1. Set a dial indicator (lever type) with its tip on the gear tooth.

2. Move the gear to measure the backlash, holding its mating gear.

3. If the backlash exceeds the allowable limit, check the oil
clearance of the shafts and the gear.

4. If the oil clearance is proper, replace the gear.

Backlash between idle
gear and crank gear

Backlash between idle
gear and cam gear

Backlash between idle
gear and injection pump
gear

Factory spec.

Allowable limit

Factory spec.

Allowable limit

Factory spec.

Allowable limit

23.959 to 23.980 mm

0.94327 to 0.94410 in.

24.000 to 24.021 mm

0.94488 to 0.94571 in.
W1029366

0.0415 to 0.1122 mm

0.00163 to 0.00442 in.

0.15 mm

0.0059 in.

0.0415 to 0.1154 mm

0.00163 to 0.00454 in.

0.15 mm

0.0059 in.

0.0415 to 0.1154 mm

0.00163 to 0.00454 in.

0.15 mm

0.0059 in.

0.0415 to 0.1090 mm

0.00163 to 0.00429 in.

0.15 mm

0.0059 in.
W1029564

Backlash between crank
gear and oil pump gear

Factory spec.

Allowable limit

Idle Gear Side Clearance

1. Set a dial indicator with its tip on the idle gear.

2. Measure the side c learance by m oving the idle gear to th e front
and rear.

3. If the measurement e xceeds the all owable limi t, replac e the idle
gear collar.

Factory spec.

Idle gear side clearance

Allowable limit

0.12 to 0.48 mm

0.0047 to 0.0189 in.

0.9 mm

0.0354 in.
W1029843

1-S37

STα-30 · STα-35, WSM

KiSC issued 11, 2006 A

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.

0.07 to 0.22 mm

0.0028 to 0.0087 in.

0.30 mm

0.0118 in.
W1030012

Camshaft side
clearance

Factory spec.

Allowable limit

Oil Clearance between Idle Gear Shaft and Idle Gear Bushing

1. Measure the idle gear shaft O.D. with an outside micrometer.

2. Measure the id le gear bushing I.D. with an inside micrometer,
and calculate the oil clearance.

3. If the oil clearance exceeds the allowable limit, replace the
bushing.

Clearance between idle
gear shaft and idle gear
bushing

Factory spec.

Allowable limit

0.025 to 0.066 mm

0.0010 to 0.0026 in.

0.1 mm

0.0039 in.

Idle gear shaft O.D. Factory spec.

Idle gear bushing I.D. Factory spec.

37.959 to 37.975 mm

1.49445 to 1.49508 in.

38.000 to 38.025 mm

1.49606 to 1.49704 in.
W1030933

Replacing Idle Gear Bushing
(A) (When removing)

1. Using an idle gear bushing replacing tool, press out the used
bushing.

(B) (When installing)

1. Clean a new idle gear bushing and idle gear bore, and apply
engine oil to them.

2. Using an idle gear bushing replacing tool, press in a new bushing
(service parts) to the specified dimension. (See figure.)

W1031083

Camshaft Alignment

1. Support the camsha ft with V b locks on th e surfa ce plate at both
end journals.

2. Set a dial indicator with its tip on the intermediate journal.

3. Measure the cams haft ali gn men t.

4. If the measurement exceeds the allowable limit, replace the
camshaft.

Camshaft alignment Allowable limit

0.01 mm

0.0004 in.
W1031413

1-S38