Part of the Kubota Repair Manuals.
This Kubota GZD21 Workshop Manual is the factory service reference for the GZD21 zero-turn mower, built around the D782-GZD21 diesel engine. Across 268 pages it walks through the machine system by system: engine, transaxle, front axle, hydraulic system, electrical system, and the mower deck itself, plus full specifications and scheduled maintenance.
You get the repair-level detail an owner or independent mechanic needs: troubleshooting charts, servicing specifications, tightening torques, and step-by-step checking, disassembly, and reassembly procedures. Wiring diagrams and the starting and charging circuits are covered in the electrical section, and the hydraulic circuit, pump, and control valve work is laid out for the lift and mower linkage.
It is delivered as a downloadable PDF you can read on a phone, tablet, or shop computer, and you can print the pages you need at the bench.
What's Inside This Manual
| System | Pages | Key Topics |
|---|---|---|
| Safety Information | Safety First, Danger, Warning, Caution, Important, Note, Before Servicing and Repairing, Safety Starting | |
| Specifications | Dimensions, GZD21-Hd | |
| General | Identification, General Precautions, Lubricants, Fuel and Coolant, Check and Maintenance, Special Tools, Machine Identification Plate, Machine Serial Number, Engine Serial Number | |
| Engine | Separating Engine, Draining Coolant and Engine Oil, Engine Body, Lubricating System, Cooling System, Fuel System | |
| Transaxle | Travelling System, Hydrostatic Transmission, Pump and Motor, Check and High Pressure Relief Valve, Power Trains Operation, Motion Control Linkage, Final Reduction Gear Section, PTO System | |
| Front Axle | Separating Floor Cover and Front Axle, Disassembling Front Wheel and Wheel Bracket | |
| Hydraulic System | Hydraulic Circuit, Hydraulic Pump, Hydraulic Control Valve, Lift Cylinder, Mower Linkage, Grass Collector Control Mechanism, Mower Lift Cylinder, Hydraulic Control Valve and Pump | |
| Electrical System | Wiring Diagram, Starting System, Charging System, Starter, Glow Plug, Safety Switch (Limit Switch), Fuel Pump, Engine Stop Solenoid | |
| Mower | Power Transmission, Lifting Mechanism |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| Cylinder head screw tightening torque | 37 to 42 N·m | p. 90 |
| Air cleaner element replacement interval | every 1 year | p. 26 |
| Engine crankcase oil capacity | 2.8 L | p. 22 |
| Coolant capacity | 1.7 L | p. 22 |
| Transmission case and rear axle gear case (RH and LH) fluid capacity | 10.0 L | p. 22 |
| Motion control lever boss greasing points | 2 greasing points | p. 23 |
| Radiator cleaning interval | Clean every 1 year | p. 27 |
| Reamer bolt tightening torque | 48.1 to 55.9 N·m | p. 262 |
| Mower blade screw tightening torque | 98 to 118 N·m | p. 254 |
| Anti-freeze mixing ratio | anti-freeze mixing ratio must be less than 50 % | p. 52 |
| Engine Max Gross Power | 15.6 kW (21 HP) | p. 11 |
| Fuel Tank Capacity | 20 L (5.3 U.S.gals) | p. 11 |
