Komatsu fit the full service coverage for its FG and FD forklift trucks, twenty-four gasoline and diesel variants from the FG20-8 and FD25-8 through the FD30H-8, into the 240 pages of Shop Manual SM029. Wiring diagrams trace every circuit from the key switch and meters back to the fuel tank unit, while hydraulic schematics lay out the pump, control valve, and lift and tilt cylinder plumbing. Power train work takes up roughly a quarter of the book: clutch, transmission, torque converter, front axle, and differential, backed by troubleshooting trees for engine, steering, and brake complaints. Mic your clutch disc against the 8.4 mm new thickness, torque front hub nuts to 294 to 490 Nm, and change the hydraulic line filter every 1200 hours or six months. A clutch job stalls while you hunt one repair limit. Bookmarks and a real text layer put you on the right page in seconds.
What's Inside This Komatsu FG20-FD30 Series Manual
| System | Pages | Key Topics |
|---|---|---|
| Foreward | 5-10 | General Specifications, Checks and Adjustments, General Disassembly and Assembly, Disassembly and Assembly of Components, Electrical System |
| General and Specifications | 11-32 | General Locations, Specifications, Overall Dimensions, Precautions for Maintenance |
| Removal and Installation of Units | 33-64 | Flow Chart, Mast Removal and Installation, Engine Removal and Installation |
| Power Train | 65-124 | Clutch, Transmission, Torque Converter, Front Axle, Differential, Front and Rear Wheels |
| Steering System | 125-144 | Power Steering Pump, Steering Gear Box, Power Steering Cylinder, Rear Axle |
| Brake System | 145-164 | Master Cylinder, Brake Valve, Accumulator, Wheel Brake, Air Bleeding, Parking Brake |
| Hydraulic System | 165-174 | Hydraulic Pump, Control Valve, Lift Cylinder, Tilt Cylinder |
| Mast and Related Parts | 175-179 | Mast Structure, Fingerboard, Lift Chain |
| Electrical | 180-188 | Buttons, Meters, Lamps, Switches, Horn, Fuel Tank Unit, Wiring Diagrams |
| Troubleshooting | 189-202 | Engine Troubleshooting, Steering System Troubleshooting, Brake System Troubleshooting |
| Testing and Adjusting | 203-218 | Engine Testing and Adjusting, Drive System Testing and Adjusting, Brake System Testing and Adjusting |
| Appendix | 219-240 | Change in Structure of Radiator Mount, Improved Tilt Valve, Quick-On Start System |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| All Models | ||
| Clutch disc outside diameter | 275 mm (11 in) | p. 68 |
| Clutch disc thickness | 8.4 mm (0.33 in) | p. 68 |
| Front wheel hub nut tightening torque | 294 - 490 Nm | p. 213 |
| Rear wheel hub nut tightening torque | 196 - 245 Nm | p. 213 |
| Hydraulic line filter replacement interval | every 6 months or 1200 hours | p. 218 |
| H20 | ||
| Engine Oil Capacity (H20) | 4.2L | p. 208 |
| C240 | ||
| Engine Oil Capacity (C240) | 3.8L | p. 208 |
| H30 | ||
| Engine Oil Capacity (H30) | 4.7L | p. 208 |
| 4D95L | ||
| Engine Oil Capacity (4D95L) | 7L | p. 208 |
| 4D95S | ||
| Engine Oil Capacity (4D95S) | 5.8L | p. 208 |
| T1 Specification | ||
| Transmission Oil Capacity (Torqflow) | 8.5L | p. 98 |
| T2 Specification | ||
| Transmission Oil Capacity (Torqflow) | 10.5L | p. 99 |
Komatsu FG20-FD30 Series Common Problems This Manual Covers
Komatsu FG25-8 clutch slips under load, engine revs but forklift barely moves and smells hot
Check pedal free play and linkage before pulling anything apart. If adjustment is correct, remove the clutch and measure the disc: new thickness is 8.4 mm (0.33 in) per page 68, and the repair limit on both faces is 0.3 mm (0.012 in), page 70. Replace a worn disc and inspect the pressure plate for heat cracks.
Manual Section: Power Train p. 70TORQFLOW transmission delayed engagement, drive kicks in late after shifting forward or reverse
Check transmission oil level hot with the engine idling before condemning the clutch packs. Refill capacity is 8.5L for T1 specification units (page 98) or 10.5L for T2 units (page 99); low oil delays clutch fill and feels like slippage. Inspect drive plates during teardown: thickness spec is 0.9 to 1.1 mm (0.035 to 0.043 in), page 109.
Manual Section: TORQFLOW System Troubleshooting p. 98Forks lift slowly with a full load, hydraulic oil runs hot after an hour of work
Test relief pressure at the pump before swapping parts; it should hold 180 to 185 kg/cm² per the adjusting procedure on page 218. Low relief pressure points to a worn pump or stuck relief valve. Replace the hydraulic line filter if it is past the 6 month or 1200 hour interval, then recheck oil level and condition.
Manual Section: Testing and Adjusting p. 218Low oil pressure warning at idle, engine loses power once it warms up
Check oil level and grade before anything else; the 4D95L diesel holds 7L at refill, listed on page 208. If level and grade are correct, work through the engine troubleshooting chart on page 190, which covers oil pressure, water temperature, and starting complaints. Test actual pressure with a mechanical gauge before replacing the sender.
Manual Section: Engine Troubleshooting p. 190Brake pedal goes soft, weak stopping power, warning buzzer sounds after repeated stops
Bleed the brakes and inspect for fluid leaks at the master cylinder and wheel brakes. On power brake trucks, test brake valve regulating pressure against the 62 kg/cm² spec on page 147, and confirm the accumulator holds its charge; maximum oil pressure is 89 kg/cm² per page 154. Air bleeding steps are in the Brake System section, page 145.
Manual Section: Brake System p. 145Frequently Asked Questions
What is the torque specification for Komatsu forklift wheel nuts?
The tightening torque for front wheel nuts is 30–50 kgm (294–490 Nm) [217–362 ft.lb], and for rear wheel nuts, it is 20–25 kgm (196–245 Nm) [145–181 ft.lb]. p. 213
What are the replacement specifications for the air filter element on the Komatsu FG20-FD30 Series forklift?
The air cleaner element should be inspected and cleaned periodically. If it is dirty, clogged, or damaged, it must be replaced. p. 205
What is the standard valve clearance for the H20 and H30 engines in the Komatsu FG20-FD30 Series forklift?
For H20 and H30 engines, the intake and exhaust valve clearance is 0.38 mm (0.015 in) when the engine is warm. p. 205
What is the standard oil capacity for the TORQFLOW transmission in a Komatsu FG20-FD30 Series forklift?
The oil capacity for the T1 specification TORQFLOW transmission is 8.5 liters (2.3 gal US), and for the T2 specification, it is 10.5 liters (2.8 gal US). p. 99
What is the tightening torque for the C240 engine mounting bolts on the Komatsu FG20-FD30 Series forklift?
The engine mounting bolts for the C240 engine should be tightened to 6–7.5 kgm (59–74 Nm) [43–54 ft.lb]. p. 49
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