Kubota WSM Instruction manual

ZD18(F),ZD21(F),
ZD25F,ZD28(F)
WORKSHOP MANUAL
ZERO TURN MOWER
KiSC issued 04, 2009 A

TO THE READER
This Workshop Manual has been prepared to provide servicing personnel with
information on the mechanism, service and maintenance of ZD18(F), ZD21(F) and
ZD28(F) KUBOTA ZD Series ZERO-TURN MOWER. It is divided into two parts,
“Mechanism” and “Servicing” for each section.
Mechanism
Information on the Features and New Mechanisms are described. This information
should be understood before proceeding with troubleshooting, disassembling and
servicing.
Servicing
The heading “General” includes general precautions, check and maintenance and
special tools. Other section, there are troubleshooting, checking and adjusting,
disassembling and assembling, and servicing which cover procedures, precautions,
factory specifications and allowable limits.
All information illustrations and specifications contained in this manual are based on
the latest product information available at the time of publication. The right is reserved
to make changes in all information at any time without notice.
March 2002
© KUBOTA Corporation 2002
KiSC issued 04, 2009 A

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ZD18(F) · ZD21(F) · ZD28(F), WSM SAFETY INSTRUCTIONS
SAFETY INSTRUCTIONS
BEFORE SERVICING AND REPAIRING
• Read all instructions and safety instructions in this
manual and on your generator safety decals.
• Clean the work area and generator.
• 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.
SAFETY FIRST
This symbol, the industry’s “Safety Alert Symbol”, is used throughout this manual and on labels on
the machine itself to warn of the possibility of personal injury. Read these instructions carefully.
It is essential that you read the instructions and safety regulations before you attempt to repair or use
this unit.
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.
KiSC issued 04, 2009 A

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ZD18(F) · ZD21(F) · ZD28(F), WSM SAFETY INSTRUCTIONS
SAFETY STARTING
• Do not start the engine by shorting across starter
terminals or bypassing the safety start switch.
• Do not alter or remove any part of machine safety
system.
• Before starting the engine, make sure that all shift
levers are in neutral positions or in disengaged
positions.
• 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. Makeshift 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 from 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) under 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 conditions. Do not smoke or allow flames or
sparks in your working area.
• To avoid sparks from an accidental short circuit,
always disconnect the battery negative cable first and
connect it last.
• Battery gas can explode. Keep sparks and open
flame away from the top of battery, especially when
charging the battery.
• Mark sure that no fuel has been spilled on the engine.
KiSC issued 04, 2009 A

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ZD18(F) · ZD21(F) · ZD28(F), WSM SAFETY INSTRUCTIONS
VENTILATE WORK AREA
• If the engine must be running to do some work, make
sure the area is well ventilated. Never run the engine
in a closed area. The exhaust gas contains
poisonous carbon monoxide.
PREVENT ACID BURNS
• Sulfuric acid in battery electrolyte is poisonous. 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 protection regulations when disposing
of oil, fuel, coolant, electrolyte and other harmful
waste.
PREPARE FOR EMERGENCIES
• Keep a first aid kit and fire extinguisher handy at all
times.
• Keep emergency numbers for doctors, ambulance
service, hospital and fire department near your
telephone.
KiSC issued 04, 2009 A

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ZD18(F) · ZD21(F) · ZD28(F), WSM SAFETY INSTRUCTIONS
· 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.
[ZD18 · ZD21 · ZD28]
SAFETY DECALS
KiSC issued 04, 2009 A

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ZD18(F) · ZD21(F) · ZD28(F), WSM SAFETY INSTRUCTIONS
KiSC issued 04, 2009 A

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ZD18(F) · ZD21(F) · ZD28(F), WSM SAFETY INSTRUCTIONS
KiSC issued 04, 2009 A

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ZD18(F) · ZD21(F) · ZD28(F), WSM SAFETY INSTRUCTIONS
[ZD18F · ZD21F · ZD28F]
KiSC issued 04, 2009 A

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ZD18(F) · ZD21(F) · ZD28(F), WSM SAFETY INSTRUCTIONS
(4)
(2)
(1)
KiSC issued 04, 2009 A

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ZD18(F) · ZD21(F) · ZD28(F), WSM SAFETY INSTRUCTIONS
KiSC issued 04, 2009 A

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ZD18(F) · ZD21(F) · ZD28(F), WSM SPECIFICATIONS
SPECIFICATIONS
W1028929
Model ZD18 ZD21 ZD28
Maximum gross power 13.4 kW (18 HP)*115.7 kW (21 HP)*120.9 kW (28 HP)*1
Engine
Model D722-E-XFM5 D782-E-XFM5 D1105-E-ZD
Type Indirect injection, vertical, water cooled, 4-cycle diesel engine
Number of cylinders 3
Bore and stroke 67.0 × 68.0 mm
(2.64 × 2.68 in.)
67.0 × 73.6 mm
(2.64 × 2.90 in.)
78.0 × 78.4 mm
(3.07 × 3.09 in.)
Total displacement 719 cm3(43.9 cu.in.) 778 cm3(47.5 cu.in.) 1123 cm3(68.5 cu.in.)
Rated revolution 3200 rpm 3000 rpm
Combustion chamber Spherical type (E-TVCS)
Fuel injection pump Bosch MD type mini pump
Governor Centrifugal ball mechanical governor
Injection nozzle Bosch throttle type Throttle type
Injection timing 0.33 to 0.37 rad. (19°to 21°) before T.D.C.
Injection order 1-2-3
Injection pressure 13.73 MPa (140 kgf/cm2, 1990 psi)
Lubricating system Forced Iubrication by gear pump
Cooling system Pressurized radiator, forced circulation with water pump
Lubricating oil API Service classification CC or CD, Below 0 °C (32 °F) : SAE 10W or 10W-30, 0 to 25 °C
(32 °F to 77 °F) : SAE 20 or 10W-30, Above 25 °C (77 °F) : SAE 30 or 10W-30
Starting system Electric starter (12 V, 1.1 kW)
Battery 51 R (12 V, 450 CCA)
Fuel No. 2-D Diesel fuel (ASTM D975)
[No. 1-D diesel fuel, if temperature is below – 10 °C (14 °F)]
Capacities
Fuel tank 30 L (5.8 U.S.gals., 4.8 lmp.gals.)
Engine crankcase 3.2 L
(3.4 U.S.qts., 2.8 Imp.qts.)
3.5 L
(3.7 U.S.qts., 3.1 Imp.qts.)
3.4 L
(3.6 U.S.qts., 3.0 Imp.qts.)
Engine coolant 2.6 L
(2.7 U.S.qts., 2.3 Imp.qts.)
3.8 L
(4.0 U.S.qts., 3.3 Imp.qts.)
Recovery tank 0.25 L (0.26 U.S.qts., 0.22 Imp.qts.)
Transmission (Including
HST and cylinder) 4.0 L (4.2 U.S.qts., 3.5 Imp.qts.)*2
Rear axle gear case 1.8 L (1.9 U.S.qts., 1.6 Imp.qts.)*2each
Mower gear case oil 0.40 L (0.42 U.S.qts., 0.35 Imp.qts.)
Tires Front 15 × 6.0-6 (4PR) Rib
Rear 23 × 10.5-12 (4PR) Turf 24 × 12.0-12 (4PR) Turf
Travelling
speeds
Forward 0 to 14.5 km/h
(0 to 9.0 mph)*3
0 to 15.0 km/h
(0 to 9.3 mph)*3
0 to 15.0 km/h
(0 to 9.3 mph)*4
Reverse 0 to 8.0 km/h
(0 to 5.0 mph)*3
0 to 8.3 km/h
(0 to 5.2 mph)*3
0 to 8.3 km/h
(0 to 5.2 mph)*4
NOTE: *
1Manufacturer’s estimate
*2Oil amount when the oil level is at the upper level.
*3At 3200 engine rpm
*4At 3000 engine rpm
KiSC issued 04, 2009 A

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ZD18(F) · ZD21(F) · ZD28(F), WSM SPECIFICATIONS
W1033163
Model ZD18 ZD21 ZD28
Dimensions
Overall length 2040 mm (80.3 in.) 2260 mm (90.0 in.)
Overall width (Without mower) 1328 mm (52.3 in.) 1451 mm (57.1 in.)
Overall height (Without ROPS) 1175 mm (46.3 in.) 1190 mm (46.9 in.)
Wheel base 1250 mm (49.2 in.) 1365 mm (53.7 in.)
Treads Front 975 mm (38.4 in.) 1070 mm (42.1 in.)
Rear 1080 mm (42.5 in.) 1150 mm (45.3 in.)
Weight (With mower deck) 560 kg (1234.6 lbs) /
With 54" mower deck
570 kg (1256.6 lbs) /
With 60" mower deck
650 kg (1433 lbs) /
With 60" mower deck,
680 kg (1499 lbs) /
With 72" mower deck
KiSC issued 04, 2009 A

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ZD18(F) · ZD21(F) · ZD28(F), WSM SPECIFICATIONS
Model ZD18F ZD21F ZD28F
Maximum gross power 13.4 kW (18 HP)*115.7 kW (21 HP)*120.9 kW (28 HP)*1
Engine
Model D722-E-XFM5 D782-E-XFM5 D1105-E-ZD
Type Indirect injection, vertical, water cooled, 4-cycle diesel engine
Number of cylinders 3
Bore and stroke 67.0 × 68.0 mm
(2.64 × 2.68 in.)
67.0 × 73.6 mm
(2.64 × 2.90 in.)
78.0 × 78.4 mm
(3.07 × 3.09 in.)
Total displacement 719 cm3(43.9 cu.in.) 778 cm3(47.5 cu.in.) 1123 cm3(68.5 cu.in.)
Rated revolution 3200 rpm 3000 rpm
Combustion chamber Spherical type (E-TVCS)
Fuel injection pump Bosch MD type mini pump
Governor Centrifugal ball mechanical governor
Injection nozzle Bosch throttle type Throttle type
Injection timing 0.33 to 0.37 rad. (19°to 21°) before T.D.C.
Injection order 1-2-3
Injection pressure 13.73 MPa (140 kgf/cm2, 1990 psi)
Lubricating system Forced Iubrication by gear pump
Cooling system Pressurized radiator, forced circulation with water pump
Lubricating oil API Service classification CC or CD, Below 0 °C (32 °F) : SAE 10W or 10W-30, 0 to 25 °C
(32 °F to 77 °F) : SAE 20 or 10W-30, Above 25 °C (77 °F) : SAE 30 or 10W-30
Starting system Electric starter (12 V, 1.1 kW)
Battery 51 R (12 V, 450 CCA)
Fuel No. 2-D Diesel fuel (ASTM D975)
[No. 1-D diesel fuel, if temperature is below – 10 °C (14 °F)]
Capacities
Fuel tank 30 L (5.8 U.S.gals., 4.8 lmp.gals.)
Engine crankcase 3.2 L
(3.4 U.S.qts., 2.8 Imp.qts.)
3.5 L
(3.7 U.S.qts., 3.1 Imp.qts.)
3.4 L
(3.6 U.S.qts., 3.0 Imp.qts.)
Engine coolant 2.6 L
(2.7 U.S.qts., 2.3 Imp.qts.)
3.8 L
(4.0 U.S.qts., 3.3 Imp.qts.)
Recovery tank 0.25 L (0.26 U.S.qts., 0.22 Imp.qts.)
Transmission (Including
HST and cylinder) 4.0 L (4.2 U.S.qts., 3.5 Imp.qts.)*2
Rear axle gear case 1.8 L (1.9 U.S.qts., 1.6 Imp.qts.)*2each
Mower gear case oil 0.40 L (0.42 U.S.qts., 0.35 Imp.qts.)
Tires Front 15 × 6.0-6 (4PR) Rib
Rear 23 × 10.5-12 (4PR) Turf 24 × 12.0-12 (4PR) Turf
Travelling
speeds
Forward 0 to 14.5 km/h
(0 to 9.0 mph)*3
0 to 15.0 km/h
(0 to 9.3 mph)*3
0 to 15.0 km/h
(0 to 9.3 mph)*4
Reverse 0 to 8.0 km/h
(0 to 5.0 mph)*3
0 to 8.3 km/h
(0 to 5.2 mph)*3
0 to 8.3 km/h
(0 to 5.2 mph)*4
Dimensions
Overall length 2040 mm (80.3 in.) 2260 mm (90.0 in.)
Overall width (Without mower) 1328 mm (52.3 in.) 1451 mm (57.1 in.)
Overall
height
With ROPS upright 1895 mm (74.6 in.) 1910 mm (75.2 in.)
With ROPS folded 1455 mm (57.3 in.) 1470 mm (57.9 in.)
Wheel base 1250 mm (49.2 in.) 1365 mm (53.7 in.)
Treads Front 975 mm (38.4 in.) 1070 mm (42.1 in.)
Rear 1080 mm (42.5 in.) 1150 mm (45.3 in.)
NOTE: *
1Manufacturer’s estimate
*2Oil amount when the oil level is at the upper level.
*3At 3200 engine rpm
*4At 3000 engine rpm
KiSC issued 04, 2009 A

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ZD18(F) · ZD21(F) · ZD28(F), WSM SPECIFICATIONS
The company reserves the right to change the specifications without notice.
W1030228
The company reserves the right to change the specifications without notice.
W1029898
Model ZD18F ZD21F ZD28F
Weight (With mower deck) 640 kg (1411 lbs) /
With 54" mower deck
650 kg (1433 lbs) /
With 60" mower deck
780 kg (1718 lbs) /
With 72" mower deck
PTO Shaft drive KUBOTA 10 tooth in spline (2530 rpm) Shaft drive KUBOTA 10
tooth in spline (2540 rpm)
PTO clutch Wet multi discs
Revolution (PTO speed) 1 speed (2530 rpm at 3200 engine rpm) 1 speed (2540 rpm at 3000
engine rpm)
PTO brake Wet single disc
Steering 2-Hand levers
Transmission 2-Hydrostatic transmission with gear
Brake Internal expanding shoe / Hand
Model RCK54-18Z RCK60-21Z RCK60-28Z RCK72-28Z
Mower
Suitable machine ZD18(F) ZD18(F) / 21(F) ZD28(F)
Mounting method Quick joint, parallel linkage
Adjustment of cutting height Dial gauge
Cutting width mm (in.) 1372 (54.0) 1524 (60.0) 1829 (72.0)
Cutting height mm (in.) 25 to 127 (1.0 to 5.0)
Weight (Approx.) kg (lbs) 103 (227) 120 (265) 150 (331)
Blade spindle speed
r/s (rpm) 53.2 (3190)*154.0 (3240)*153.7 (3220)*147.8 (2870)*1
Blade tip velocity m/s (fpm) 79 (15700)*188.9 (17500)*188.4 (17400)*194.0 (18500)*1
Blade length mm (in.) 475 (18.7) 523 (20.6) 625 (24.6)
Number of blades 3
Dimensions
Total length
mm (in.) 985 (38.8) 1025 (40.35) 1095 (43.1)
To t a l w i d t h
mm (in.) 1690 (66.5) 1845 (72.6) 2245 (88.4)
Total height
mm (in.) 300 (11.8)
Discharge Right side
NOTE: *
1Engine Max rpm
KiSC issued 04, 2009 A

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ZD18(F) · ZD21(F) · ZD28(F), WSM DIMENSIONS
DIMENSIONS
[ZD18 · ZD21 · ZD28]
KiSC issued 04, 2009 A

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ZD18(F) · ZD21(F) · ZD28(F), WSM DIMENSIONS
[ZD18F · ZD21F · ZD28F]
KiSC issued 04, 2009 A

G GENERAL
KiSC issued 04, 2009 A

CONTENTS
GENERAL
1. IDENTIFICATION............................................................................................. G-1
2. GENERAL PRECAUTIONS ............................................................................ G-2
3. HANDLING PRECAUTIONS FOR ELECTRICAL PARTS AND WIRING .. G-3
[1] WIRING...................................................................................................... G-3
[2] BATTERY................................................................................................... G-5
[3] FUSE.......................................................................................................... G-5
[4] CONNECTOR ............................................................................................ G-5
[5] HANDLING OF CIRCUIT TESTER......................................................... G-6
4. LUBRICANTS, FUEL AND COOLANT ......................................................... G-7
5. TIGHTENING TORQUES ............................................................................... G-9
[1] GENERAL USE SCREWS, BOLTS AND NUTS................................... G-9
[2] METRIC SCREWS, BOLTS AND NUTS ............................................... G-9
[3] AMERICAN STANDARD SCREWS, BOLTS AND NUTS WITH UNC
OR UNF THREADS ............................................................................... G-10
6. MAINTENANCE CHECK LIST ..................................................................... G-11
7. CHECK AND MAINTENANCE ..................................................................... G-12
[1] DAILY CHECK ........................................................................................ G-12
[2] CHECK POINTS OF INITIAL 50 HOURS ........................................... G-16
[3] CHECK POINT OF INITIAL 100 HOURS ........................................... G-18
[4] CHECKING POINTS OF INITIAL 200 HOURS................................... G-19
[5] CHECK POINTS OF EVERY 50 HOURS ........................................... G-21
[6] CHECK POINTS OF EVERY 100 HOURS ......................................... G-25
[7] CHECK POINTS OF EVERY 150 HOURS ......................................... G-30
[8] CHECK POINTS OF EVERY 200 HOURS ......................................... G-30
[9] CHECK POINTS OF EVERY 400 HOURS ......................................... G-32
[10]CHECK POINTS OF EVERY 1 YEAR ................................................ G-32
[11]CHECK POINT OF EVERY 2 YEARS ................................................ G-35
[12]OTHERS .................................................................................................. G-36
8. SPECIAL TOOLS.......................................................................................... G-38
[1] SPECIAL TOOLS FOR ENGINE .......................................................... G-38
[2] SPECIAL TOOLS FOR MACHINE........................................................ G-44
KiSC issued 04, 2009 A

G-1
ZD18(F) · ZD21(F) · ZD28(F), WSM G GENERAL
1. IDENTIFICATION
When contacting your local KUBOTA distributor, always specify
engine serial number (3), machine serial number (2), mower serial
number (4) and hour meter reading.
W1010714
(1) Machine Identification Plate
(2) Machine Serial Number
(3) Engine Serial Number
(4) Mower Serial Number
(5) Mower Identification Plate
KiSC issued 04, 2009 A