I'm dealing with an issue on one of our machines that I hope someone has some insight into. Out of the blue the mast on the machine started lowering painfully slowly. Every other hydraulic works normally except for the lower function. Doesn't matter which height the mast is at, it always comes down at a rate of about 1-2 inches per minute.
I have swapped the lift/lower & tilt switch (unit has mini levers) to rule out a bad switch. It did not change. I pulled the entire valve body out of the machine and checked all of the solenoids and ports and plugs on the lift/lower control valve. I saw somewhere in the forums mention of a broken spring behind the flow control valve. No broken springs and no plugged or blocked orifices that the manual said to check.
While the entire valve body was out, I swapped the lower solenoid assembly with the raise solenoid assembly since they're the same part and it would be easier to swap the raise solenoid assembly if that was the issue after the valve body was installed back into the machine. Problem stayed after swapping.
I've checked the safety down valves and the flow regulator valve and they seem to be working as they should with no obvious broken of collapsed springs.
Hopefully someone has experience with this issue or at least thoughts on what might be causing the issue.

Thanks,

Darek