Hydraulic slide info...
We had a situation that I want to share hopefully to save someone else some headaches.
Our rear hydraulic slide would come out about a foot after a few months in storage.
We tested the system for leaks and found none. I finally had the tech put a pressure gauge on both ends of the cylinder. What was happening was since the cylinder is dual action the pressure of retraction holds the slide in after you close things up.
The cylinder was leaking past an internal seal and loosing the pressure necessary to hold the slide closed. We actually found cylinders on both rear slides were leaking past the seals. Fixed under extended warranty but it took us just about a year, on and off, to figure this out.
Lippert has a specific test for this.
Good luck... Hope this helps someone.