Hydraulic sawmill parallel lift cylinders issue

[Rorancev]

Hi, not sure if I’m posting in the right place. I have ran into a problem on my sawmill that I have designed and fabricated. The issue is in the lift mechanism, what I like to call the “carriage” it is a constant uneven load it is a bandsaw/resaw sawmill that slides on a forty foot trailer. The uneven load is due to one side holding the motor and most of my hydraulic motors/ controllers while the other side is bare with minimal weight compared to the opposing side. I’d estimate the difference is 300 pounds to 150 pounds. Out of the pump I go into my directional controller and then out of the controller to lift I run into a flow divider for my cylinders. The carriage does actually lift quite evenly within 1/8 of an inch difference on each side and I am satisfied with that. The problem is after I have chose my desired height to cut at, the cylinder with the heavier load on top gradually weeps down while my cylinder with less load gradually weeps up creating a bind on my roller mechanism which is some steel tubing with rollers on it. Also my down feed is annoyingly different the heavier side goes faster. I’m curious what someone would do to remedy these issues I have considered buying another flow divider for the feed down and after the flow divider on each “T” running those into a double pilot operated check valve to lock the line essentially. It’s quite an investment for those 3 components and I’m just hesitant because I don’t want to be out that money and have the problem still persist. I’ll get some pics so you guys have a visual understanding

 

[Rorancev]

Pics of mill

 

[btrueblood]

Figure out if the seals on the cylinder are leaking (probably not, but just filling them and plugging the ports and watching to see if they weep down will answer the question).

If not, then the lift valve is leaking; you might look at putting pilot operated check valves on the lines feeding each cylinder.