Kubota WSM ZD321 Instruction manual

ZD321,ZD326,ZD331
WORKSHOP MANUAL
ZERO TURN MOWER
KiSC issued 04, 2007 A

TO THE READER
This Workshop Manual has been prepared to provide servicing personnel with
information on the mechanism, service and maintenance of ZD321, ZD326 and ZD331.
It is divided into three parts, "General", "Mechanism" and "Servicing".
■General
Information on the product identification, the general precautions, maintenance
check list, check and maintenance and special tools are described.
■Mechanism
Information on the construction and function are included. This part should be
understood before proceeding with troubleshooting, disassembling and servicing.
Refer to Workshop Manual Diesel Engine, Mechanism (Code No. 9Y021-01874) for
the one which has not been described to this workshop manual.
■Servicing
Information on the troubleshooting, servicing specification lists, tightening torque,
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.
Due to covering many models of this manual, information or picture being used have
not been specified as one model.
December 2006
© KUBOTA Corporation 2006
KiSC issued 04, 2007 A

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ZD321, ZD326, ZD331, WSM SAFETY INSTRUCTIONS
SAFETY INSTRUCTIONS
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.
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, 2007 A

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ZD321, ZD326, ZD331, 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.
• Make sure that no fuel has been spilled on the engine.
KiSC issued 04, 2007 A

3
ZD321, ZD326, ZD331, 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, 2007 A

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ZD321, ZD326, ZD331, 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.
SAFETY DECALS
KiSC issued 04, 2007 A

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ZD321, ZD326, ZD331, WSM SAFETY INSTRUCTIONS
KiSC issued 04, 2007 A

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ZD321, ZD326, ZD331, WSM SAFETY INSTRUCTIONS
KiSC issued 04, 2007 A

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ZD321, ZD326, ZD331, WSM SAFETY INSTRUCTIONS
KiSC issued 04, 2007 A

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ZD321, ZD326, ZD331, WSM SPECIFICATIONS
SPECIFICATIONS
NOTE: Specifications and design subject to change without notice.
*1 : Manufacurer’s estimate
[N] : Narrow tread
[S] : Special
[P] : Semi-pneumatic Non Flat Tire
[LP] : Long wheel base and equipped with 72 in. mower.
*2 : At 3200 min-1 (rpm) [ZD321, ZD326]
At 3000 min-1 (rpm) [ZD331]
*3 : Oil amount when the oil level is at the upper level.
Model ZD321N ZD321 ZD326S ZD326P ZD331P ZD331LP
Engine
Model D782-E2-ZD D1005-E2-ZD-2 D1305-E3-ZD
Maximum engine power
(Gross) 15.7 kW (21 HP)*1 19.4 kW (26 HP)*1 23.1 kW (31 HP)*1
Type Liquid-cooled
Number of cylinders 3
Bore and stroke 67 x 73.6 mm
(2.64 x 2.90 in.) 76 x 73.6 mm (2.99 x 2.90 in.) 78 x 88.0 mm (3.07 x 3.46 in.)
Total displacement 778 cm3(47.5 cu.in.) 1001 cm3(61.1 cu.in.) 1261 cm3(77.0 cu.in.)
Rated revolution 3200 min-1 (rpm) 3000 min-1 (rpm)
Fuel Diesel fuel No. 1 [below – 10 °C (14 °F)]
Diesel fuel No. 2 [above – 10 °C (14 °F)]
Starter Electric starter with battery, glow plug, 12 V, 1.1 kW
Lubrication Forced lubrication by gear pump
Cooling Liquid with pressurized radiator
Battery 51 R (12 V, RC : 70 min, CCA : 450 A)
Capacities
Fuel tank 49 L (13 U.S.gals, 11 lmp.gals)
Engine crankcase
(with filter) 3.5 L (3.70 U.S.qts, 3.08 Imp.qts) 3.9 L (4.1 U.S.qts, 3.4 Imp.qts) 5.7 L (6.0 U.S.qts, 5.0 Imp.qts)
Engine coolant 2.7 L
(2.85 U.S.qts, 2.38 Imp.qts) 3.5 L (3.70 U.S.qts, 3.08 Imp.qts)
Recovery tank 0.25 L (0.26 U.S.qts, 0.22 Imp.qts)
Transmission including rear
axle gear case 12.1 L (12.8 U.S.qts, 10.6 Imp.qts)*3
Dimensions
Overall length 2185 mm (56.0 in.) 2220 mm (87.4 in.) 2335 mm
(91.9 in.)
Overall width Without mower
deck
1365 mm
(53.7 in.) 1460 mm (57.5 in.)
Overall
height
With ROPS
upright
1915 mm (75.4 in.)
With ROPS
folded 1555 mm (61.2 in.)
Wheel base 1410 mm (55.5 in.) 1525 mm
(60.0 in.)
Minimum ground clearance 130 mm (5.12 in.)
with 54 in., 60 in. 130 mm (5.12 in.) with 60 in. 130 mm (5.12 in.) with 60 in., 72 in.
Tread Front 975 mm (38.4 in.) 1070 mm
(42.1 in.)
Rear 1100 mm
(43.3 in.) 1150 mm (45.3 in.)
KiSC issued 04, 2007 A

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ZD321, ZD326, ZD331, WSM SPECIFICATIONS
NOTE: Specifications and design subject to change without notice.
*1 : Manufacurer’s estimate
[N] : Narrow tread
[S] : Special
[P] : Semi-pneumatic Non Flat Tire
[LP] : Long wheel base and equipped with 72 in. mower.
*2 : At 3200 min-1 (rpm) [ZD321, ZD326]
At 3000 min-1 (rpm) [ZD331]
*3 : Oil amount when the oil level is at the upper level. W1030228
NOTE: Specifications and design subject to change without notice.
*1 : Engine max. revolution. W1036076
Model ZD321N ZD321 ZD326S ZD326P ZD331P ZD331LP
Weight (with Mower Deck) 730 kg (1609 lbs)
with 54 in.
755 kg
(1664 lbs)
with 60 in.
798 kg
(1759 lbs)
with 60 in.
813 kg
(1792 lbs)
with 60 in.
820 kg
(1808 lbs)
with 60 in.
845 kg
(1863 lbs)
with 72 in.
Travelling
system
Tires Front 15 x 6.0-6 (4PR) Rib 15 x 6.0-6 (Semi-pneumatic Non Flat Tire)
Rib
Rear 26x10.5-12
(4PR) Turf 26 x 12.0-12 (4PR) Turf
Travelling
speeds Forward 0 to 15.0 km/h (0 to 9.3 mph)*2 0 to 17.0 km/h (0 to 10.6 mph)*2
Reverse 0 to 8.3 km/h (0 to 5.2 mph)*2 0 to 8.5 km/h (0 to 5.3 mph)*2
Steering 2-Hand levers
Transmission 2-Hydrostatic transmission with gear
Parking brake Wet multi disc / foot applied, released
Min. turning radius 0 mm (0 in.)
PTO
Revolution 1 speed (2530 rpm at 3200 engine rpm) 1 speed (2538 rpm at 3000
engine rpm)
Drive system Shaft drive, KUBOTA 10 tooth in involute spline
Clutch type Wet multi discs
PTO brake Wet single disc
Model RCK54P-321Z RCK60P-331Z RCK72P-331Z
PRO
commercial
deck
(fabricated
deck)
Suitable machine ZD321N ZD321, ZD326S,
ZD326P, ZD331P ZD331LP
Mounting method Quick joint, parallel linkage
Adjustment of cutting height Dial gauge
Cutting width 1375 mm (54 in.) 1524 mm (60.0 in.) 1829 mm (72.0 in.)
Cutting height 25 to 127 mm (1.0 to 5.0 in.)
Weight (approx.) 128 kg (281 lbs) 148 kg (327 lbs) 169 kg (373 lbs)
Blade spindle speed 58.8 r/s (3530 min-1 (rpm))*1 56.0 r/s (3360 min-1 (rpm))*1 47.2 r/s (2830 min-1 (rpm))*1
Blade tip velocity 87.8 m/s (17300 fpm)*1 92.0 m/s (18100 fpm)*1 92.6 m/s (18200 fpm)*1
Blade length 475 mm (18.7 in.) 523 mm (20.6 in.) 625 mm (24.6 in.)
Number of blades 3
Dimensions
Total length 940 mm (37.0 in.) 1002 mm (39.4 in.) 1170 mm (46.1 in.)
Total width 1704 mm (67.1 in.) 1911 mm (75.2 in.) 2224 mm (87.6 in.)
Total height 353 mm (13.9 in.) 358 mm (14.1 in.)
KiSC issued 04, 2007 A

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ZD321, ZD326, ZD331, WSM DIMENSIONS
DIMENSIONS
KiSC issued 04, 2007 A

G GENERAL
KiSC issued 04, 2007 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] STUD BOLTS............................................................................................ G-9
[3] METRIC SCREWS, BOLTS AND NUTS ............................................. G-10
[4] AMERICAN STANDARD SCREWS, BOLTS AND NUTS WITH UNC
OR UNF THREADS............................................................................... G-10
[5] PLUGS..................................................................................................... G-10
6. MAINTENANCE CHECK LIST..................................................................... G-11
7. CHECK AND MAINTENANCE..................................................................... G-13
[1] DAILY CHECK ........................................................................................ G-13
[2] CHECK POINTS OF INITIAL 50 HOURS........................................... G-17
[3] CHECK POINT OF INITIAL 100 HOURS ........................................... G-19
[4] CHECK POINT OF INITIAL 400 HOURS ........................................... G-20
[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-29
[8] CHECK POINTS OF EVERY 200 HOURS......................................... G-29
[9] CHECK POINT OF EVERY 400 HOURS ........................................... G-31
[10]CHECK POINTS OF EVERY 1 YEAR ................................................ G-31
[11]CHECK POINT OF EVERY 2 YEARS................................................ G-34
[12]OTHERS.................................................................................................. G-35
8. SPECIAL TOOLS.......................................................................................... G-37
[1] SPECIAL TOOLS FOR ENGINE .......................................................... G-37
[2] SPECIAL TOOLS FOR MACHINE........................................................ G-43
9. IMPLEMENT LIMITATIONS.......................................................................... G-44
KiSC issued 04, 2007 A

G-1
ZD321, ZD326, ZD331, 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
(6) ROPS Serial Number
KiSC issued 04, 2007 A

G-2
ZD321, ZD326, ZD331, WSM G GENERAL
2. GENERAL PRECAUTIONS
• During disassembly, carefully arrange removed parts 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 required, use KUBOTA genuine 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 reassembling external snap rings or internal snap rings,
they must be positioned so that sharp edge faces against the
direction from which a force is applied. See the figure left side.
• When inserting spring pins, their splits must face the direction
from which a force is applied. See the figure left side.
• To prevent damage to the hydraulic system, use only specified
fluid or equivalent.
W1010904
(1) Grease
(2) Force
(3) Sharp Edge
(4) Axial Force
(5) Rotating Movement
(A) External Snap Ring
(B) Internal Snap Ring
KiSC issued 04, 2007 A

G-3
ZD321, ZD326, ZD331, WSM G GENERAL
3. HANDLING PRECAUTIONS FOR ELECTRICAL PARTS
AND WIRING
To ensure safety and prevent damage to the machine and
surrounding equipment, heed the following precautions in handling
electrical parts and wiring.
IMPORTANT■
• Check electrical wiring for damage and loosened
connection every year. To this end, educate the customer to
do his or her own check and 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.
W1011114
[1] WIRING
• Securely tighten wiring terminals.
W1011216
• Do not let wiring contact dangerous part.
W1011313
• Securely insert grommet.
W1011388
(1) Negative Terminal (2) Positive Terminal
(1) Correct
(Securely tighten) (2) Incorrect (Loosening leads to faulty contact)
(1) Wiring (Correct)
(2) Wiring (Incorrect) (3) Dangerous Part (4) Dangerous Part
(1) Grommet (A) Correct
(B) Incorrect
KiSC issued 04, 2007 A

G-4
ZD321, ZD326, ZD331, WSM G GENERAL
• Securely clamp, being careful not to damage wiring.
W1011458
• Clamp wiring so that there is no twist, unnecessary sag, or
excessive tension, except for movable part, where sag be
required.
W1011587
• In installing a part, take care not to get wiring caught by it.
W1011670
• After installing wiring, check protection of terminals and clamped
condition of wiring, only connect battery.
W1011735
(1) Clamp
• Wind Clamp Spirally
(2) Wire Harness
(3) Clamp
(4) Welding Dent
(1) Wiring
(2) Clamp (A) Correct (B) Incorrect
(1) Wiring (A) Incorrect
(1) Cover
• Securely Install Cover
KiSC issued 04, 2007 A

G-5
ZD321, ZD326, ZD331, WSM G GENERAL
[2] BATTERY
• Take care not to confuse positive and negative terminal posts.
• When removing battery cables, disconnect negative cable first.
When installing battery cables, check for polarity and connect
positive cable first.
• Do not install any battery with capacity other than is specified
(Ah).
• After connecting cables to battery terminal posts, apply high
temperature grease to them and securely install terminal covers
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 well-ventilated place where there is no
open flame nearby, as hydrogen gas and oxygen are formed.
W1011816
[3] FUSE
• 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.
W1012092
[4] CONNECTOR
• For connector with lock, push lock to separate.
W1012211
• In separating connectors, do not pull wire harnesses.
• Hold connector bodies to separate.
W1012272
(1) Fuse (2) Slow Blow Fuse
(A) Push
(A) Correct (B) Incorrect
KiSC issued 04, 2007 A

G-6
ZD321, ZD326, ZD331, WSM G GENERAL
• Use sandpaper to remove rust from terminals.
• Repair deformed terminal. Make certain there is no terminal
being exposed or displaced.
W1012346
• Make certain that there is no female connector being too open.
W1012430
[5] HANDLING OF CIRCUIT TESTER
• Use tester correctly following manual provided with tester.
• Check for polarity and range. W1012684
(1) Exposed Terminal
(2) Bend Terminal (3) Sandpaper (4) Rust
(A) Correct (B) Incorrect
KiSC issued 04, 2007 A