Across 80 pages, the Hyster F1.8UT service manual PDF (OEM ID 4322476) settles how the UT series forklift truck is adjusted, tested and rebuilt, covering seven variants from the F1.8UT to the F80UT. Hydraulic schematics trace the main oil circuit from the main pump through the control valve, main relief valve and bypass steering overflow valve to the lift and tilt cylinders. Wiring diagrams sit with electrical troubleshooting for the OPS and park brake alarm system, and the brake chapter ends with a test of the automatic clearance regulator. Confirm main oil pressure reads 1.1 to 1.4 MPa, and torque wheel mounting nuts to 470-550 N·m. Your truck will not start? That fault has its own diagnostic entry, as do dead lift, lowering and tilt functions. Bookmarks and a live text layer take you straight to designations such as the DCCT5 control valve or YDS40-XH.905 differential, so you order against the correct unit the first time.
What's Inside This Hyster F1.8UT, F2.5UT, F3.5UT, F4.0UT Manual
| System | Pages | Key Topics |
|---|---|---|
| Forklift Truck Main Parts | 5 | Torque Converter, Speed Reducer, Speed Differential, Steering System |
| Forklift Main Technical Parameters | 6-8 | Main Technical Parameters |
| Power System | 9-14 | Engine System (Engine Overview, Inspection, Engine Adjustment) |
| Transmission | 15-25 | Overview |
| Drive Axle | 26-27 | Overview, Maintenance of Drive Axle |
| Steering System | 28-34 | Overview (Fully Hydraulic Steering Gear Assembly, Steering Cylinder, Examination After Reassembly of Steering System) |
| Brake System | 35-46 | Overview (Brake Master Cylinder, Wheel Brake, Automatic Clearance Regulator) |
| Hydraulic System | 47-65 | Main Pump (Control Valve and Bypass Valve, Operation of Spool Valve, Neutral Position) |
| Lifting System | 66-69 | Safety Procedures When Working Near Mast (Inside and Outside Masts, Bracket, Adjust) |
| Electrical System | 70-75 | Overview (Electrical Box, Battery, Electrical Schematics) |
| Drive, Operation, and Routine Maintenance of Forklift Truck | 76-80 | Transporting the Forklift Truck, Towing, Long-Term Storage of Forklift Truck, Maintenance Procedures Prior to Operation, Cooling System |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| Torque Converter Inlet Pressure | 0.5~0.7 Mpa | p. 15 |
| Main Oil Pressure | 1.1~1.4 Mpa | p. 15 |
| Half shaft mounting nut torque | 96-111 N·m (70.80-81.86 lbf ft) | p. 27 |
| Wheel mounting nut torque | 470-550 N·m (346.65-405.65 lbf ft) | p. 27 |
| Wheel hub slot nut torque | 2.9-7.8 N·m | p. 34 |
| Wheel cylinder piston to cylinder body clearance | 0.065-0.150 mm | p. 41 |
| Rubber cup diameter | 30.1-0.2 mm | p. 41 |
| Fuel Tank Capacity | 108 liter | p. 12 |
| Brake Drum Mounting Nut Torque | 206-225 N·m | p. 27 |
| Master Cylinder Diameter | 19.05 mm | p. 35 |
| Wheel Cylinder Diameter | 28.58 mm | p. 35 |
| Brake Shoe Thickness (Minimum) | 5 mm | p. 42 |
Hyster F1.8UT, F2.5UT, F3.5UT, F4.0UT Common Problems This Manual Covers
Hyster F1.8UT to F80UT steering wheel heavy and hard to turn, truck swinging side to side while traveling
Check bypass valve pressure against 12 MPa (1740.4 psi) and adjust if low, per page 31. Purge air by jacking up the rear wheels and slowly turning the wheel left and right several times. If the truck swings, set bypass valve flow to 12 liter/min (page 47). Replace a broken positioning leaf spring and inspect steering cylinder piston seals.
Manual Section: Steering System Failure Removal p. 31Torque converter transmission showing low clutch pressure and excessive swing when checked with a gauge
Check transmission oil level first and top up to the normal mark, per the chart on page 25. Measure main oil pressure against 1.1 to 1.4 MPa listed on page 15. If level is right but pressure stays low, replace worn input shaft and piston seal rings, change a worn oil pump, and reset a sticking micro valve stem.
Manual Section: Transmission Troubleshooting p. 25Hydraulic gear pump running loud with air bubbles showing in the hydraulic fluid
Inspect the suction hose for twists and clean a blocked filter, then tighten every suction side joint so the pump stops pulling air, per page 65. Confirm fluid viscosity is correct and do not operate until fluid reaches normal temperature. If bubbles persist, check the pump seal and run the pump until the bubbles clear.
Manual Section: Hydraulic System Troubleshooting p. 65Brake pedal feels spongy and braking pressure is low when stopping the truck on the wheel brakes
Inspect the brake system for fluid leaks and repair them, then bleed air from the lines, per page 46. Turn the adjuster gear to correct brake shoe clearance and readjust the brake pedal (inching valve). Check shoes and brake fluid for contamination, and replace shoes worn below the 5 mm minimum thickness listed on page 42.
Manual Section: Wheel Brake Troubleshooting p. 46Lift, lowering and tilt functions not working with the operator seated and engine running
Check the seat switch is closed and grounded, confirm 12V at the electrical box output and solenoid valve input, per page 75. Tighten loose plugs. If voltage is present but the valve is dead, check the solenoid valve spool. Turn off the key switch and battery ground wire before examining wiring (page 74). With forks stuck up, never reach under the mast or carriage unless fully lowered or a safety chain is installed (page 66).
Manual Section: Electrical System Troubleshooting p. 75Engine will not start and starting motor does not turn over when the key is turned
Check the electric box first for a blown fuse or a burned smelling time relay, using a multimeter if damage is not visible; never fit a fuse rated above the one removed. Then verify neutral gear, OPS seat, seat belt and hand brake, the negative wiring end, the key switch, and the starting motor, per page 74. Turn off the key switch and battery ground wire before examining wires.
Manual Section: Electrical System Troubleshooting p. 74Frequently Asked Questions
Why will a Hyster UT forklift not start or move?
If the truck will not start, check if the gear is in neutral, ensure the seat switch is closed and grounded, and verify the handbrake is pulled up. For trucks that start but will not move, check the gear switch's input and output voltage; it should be 12V. If there is input voltage but no output, the gear switch is likely damaged. p. 74
What is the required fuel tank capacity for the Hyster F1.8UT–F4.0UT forklift?
The fuel tank for the diesel forklift truck has a capacity of 108 liters (28.5 gallons). p. 12
What is the specified torque for the wheel mounting nut on the Hyster F1.8UT–F4.0UT?
When performing maintenance on the drive axle, the wheel mounting nut must be tightened to a torque of 470-550 N·m (346.65-405.65 lbf ft). p. 27
What is the required transmission oil pressure on the Hyster F1.8UT–F4.0UT?
The main oil pressure for the YQXD30MKS and YQXD40MKS-XH gearboxes should be maintained between 1.1 and 1.4 MPa. p. 15
What is the procedure for adjusting the brake pedal?
Adjust the limit bolts so that the distance between the front floor and the brake pedal is 113 mm (4.4 in.) and the pedal stroke is 20 mm (0.8 in.). Tighten the limit bolts after adjustment. p. 40
What exactly do I receive with this Hyster F1.8UT Service Manual?
Immediate download of the complete 80-page searchable Service Manual. Access it on any device, from a laptop at your desk to a phone in the field.
Does this Hyster F1.8UT manual allow printing?
Yes. Print individual pages or full chapters for your own shop use, on letter or A4 paper.
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