I have an older Clark Forklift. (Model GCS25MC) When I raise up the forks they will not stay. They leak back down about 3" per min. there is no hydraulic fluid leaking. What could be the cause for this?
The lift cylinder needs to be rebuilt. What you have going on is called "Fork drift". The seals at the base of the lift cylinder are worn out and the hydraulic fluid drifting from one side to the other, allowing the forks to drift downward. The repair is usually not that expensive because most models can be done on site in about 2 hours. The larger cylinders are too heavy to try to do while in the lift, and they are usually taken out and sent to a hydraulic shop. Good luck