Part of the Kubota Repair Manuals.
This Kubota ZD18 and ZD21 service manual is the factory documentation for these zero-turn mowers, powered by the D722-E-XFM5 and D782-E-XFM5 diesel engines. It runs 240 pages and covers the machines from safety decals, specifications, and dimensions through identification, maintenance, and full component service.
Coverage includes the engine, transaxle with its hydrostatic transmission and PTO system, front axle, hydraulic system, electrical system, and the mower deck. You get wiring diagrams, hydraulic circuit and pump details, tightening torques, servicing specifications, and troubleshooting for the engine, transaxle, front axle, and hydraulic systems.
Owners, independent mechanics, and restorers can use it to diagnose a loss of drive, stop a deck gearbox oil leak, cure hard starting or stalling, clear an overheating condition, or trace an electrical fault through the starter and safety switches. It is a downloadable PDF you can search on any device or print by the page.
What's Inside This Kubota ZD18, ZD21 Manual
| System | Pages | Key Topics |
|---|---|---|
| Safety Decals | 4-6 | Do Not Put Hands or Feet Into Mower When Engine Is Running, To Avoid Serious Injury or Death, To Avoid Possible Injury or Death From a Machine Runaway, Hot Exhaust, Danger/Poison |
| Specifications | 7-8 | Model, Maximum Gloss Power, Engine, Capacities, Tires, PTO |
| Dimensions | 9-12 | Overall Length, Overall Width (Without Mower), Overall Height (Without ROPS), Wheel Base, Treads |
| General | 13-58 | Identification, General Precautions, Handling Precautions for Electrical Parts and Wiring, Lubricants, Fuel and Coolant, Tightening Torques, Check and Maintenance |
| Engine | 59-112 | Valve Clearance (0.145-0.185mm Cold), Fan Belt Tension, Engine Oil Filter (200h Interval), Fuel System, Cylinder Head, Engine Body Disassembly |
| Transaxle | 113-150 | Structure, Hydrostatic Transmission, PTO System, Parking Brake, Troubleshooting, Tightening Torques |
| Front Axle | 151-162 | Wheel Bearing, Spindle Disassembly, Toe-In Adjustment, Caster, Wheel Bolt Torques (1.0-1.5 N·m Front) |
| Hydraulic System | 163-182 | Hydraulic Circuit, Hydraulic Pump, Hydraulic Control Valve and Valve Adaptor, Lift Cylinder, Mower Linkage, Troubleshooting |
| Electrical | 183-216 | Wiring Diagram, Starter, Glow Plug, Safety Switch, AC Dynamo, Regulator |
| Mower | 217-240 | Power Transmission, Lifting Mechanism, Mower Blades, Gear Box, Anti-Scalp Rollers, Cutting Height |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| All Models | ||
| Mower blade screw tightening torque | 98.1 to 117.7 N·m (10.0 to 12.0 kgf·m, 72.3 to 86.8 ft-lbs) | p. 225 |
| Front wheel mounting bolt and lock nut tightening torque | 1.0 to 1.5 N·m (0.1 to 0.15 kgf·m, 0.74 to 1.11 ft-lbs) | p. 159 |
| Rear wheel mounting nut tightening torque | 48.0 to 56.0 N·m (4.9 to 5.7 kgf·m, 35.4 to 41.2 ft-lbs) | p. 130 |
| Transmission oil filter cartridge replacement interval | every 300 service hours | p. 31 |
| Transmission oil filter type | highly efficient, 10 µm filter | p. 31 |
| Engine oil filter replacement interval | every 200 hours | p. 25 |
| Transmission strainer O-rings replacement condition | replace if damaged, cracked or hardened | p. 32 |
| Radiator screen cleaning interval | Daily or after every 5 hours of operation | p. 29 |
| Fan belt tension (deflection) | Approx. 10 mm (0.4 in.) when depressed with 98 N (10 kgf, 22 lbs) force | p. 69 |
| ZD18 | ||
| Maximum Gross Power, ZD18 | 13.4 kW (18 HP) | p. 7 |
| ZD21 | ||
| Maximum Gross Power, ZD21 | 15.7 kW (21 HP) | p. 7 |
