If all 4 jacks are dropping at a similar rate and no leaks are visible follow your hydraulic lines and find the common two solenoids
You have to have one leaking allowing fluid back to the reservoir and one allowing fluid to fill the jacks
Try a quart of marvel mystery oil or fork oil first by adding it to the reservoir. Then manually lower and raise the jacks side to side, front to back, and repeat at least 4 times. ( make sure you add the extra oil when the jacks are up)
Let it sit and see if they still drop
__________________
|