| Mlfunction | Cause analysis | Troubleshooting |
| Lifting height does not meet the requirements | Not enough working oil | Remove the screw plug on the hydraulic unit, inject a small amount of filtered working oil, and reinstall the screw plug. |
The lifting cylinder does not work, the fork does not rise, and the starting process is slow. | 1. There are impurities in the working oil, and the valve in the hydraulic system is not tightly closed. | Remove impurities or replace working oil |
| 2. The ejector spring in the hydraulic system loses its working ability and is unable to restore the ejector lever to the working position. | Replace the ejector spring |
| 3. Due to the deformation of the pull rod, the coordination of three working procedures of the handle position and the oil distribution valve are lost. | Adjust the adjusting nut under the oil valve switch plate to coordinate the handle position and the oil valve action. |
| 4. The poor sealing performance and leakage of the oil pump or the lifting cylinder are caused by the aging or wear due to the long time use of sealing parts in the lifting cylinder and the sealing parts in the oil pump. | Replace the seals |
| 5. The O-ring seal on the outer circle of the combination valve is damaged or aged, so that the high and low pressure working oil can pass. | Replace the O-ring |
| 6. After the pump core is pressed, it cannot be lifted by itself, so that the oil pump cannot continue to work. | If the return spring has no elastic force, replace the spring, and remove the pump core that pulls the cylinder to repair or replaces. |
| The car body cannot be left unloaded | Due to the eccentric load and overload, the component is deformed, causing severe friction and malfunction during the movement of the component. | Repair to make the components flexible. |