locking slides

[woodtic]

4 hydraulic slides on my trailer.

My bedroom slide is opening as it sits closed or traveling down the road. Tried a single slide lock on it in the lower rear corner. After 30 miles the bedroom slide had opened on the front end maybe a half an inch, but the rear was still snug. However I found that the other slides had each loosened up as well. None more than 3/4 inch.

So my question is, will closing each of the slide isolation valves lock the other 3 slides in position so they won't drift out while going down the road? For that to work, wouldn't the valves need to completely isolate both lines going to each cylinder? Would they only need to isolate the hose that leads to the extending connection of the cylinder? anyone know what hose the valves actually shut off?

Thanks