Creeping Slides

Our Fifth Wheel came with a bar adjustable on one end that fit between the rear inside ledge, at the top, of the slide, and the inside wall that, it fit up to when the slide was out. This was a safety feature to keep it from creeping out going down the road. Never used it. It had wide cushioned feet. It was electri and not hydraulic however. If was left in place when extending the slide the wall or something might have been damaged, almost certainly would with hydraulics, I'm thinking.

Old Biscuit and Joe 417
Thanks for the replies and Slides 101 lesson.
Now I won't be concerned about the blocks I put on the slides and I did tape warning notes over the control switch and on the edge of the slides.
Having the trailer in storage brings a few new thing to watch out for. Luckily
we did not get any rain before I got the slides closed and secured.
Ed

hydraulic operated slides in an rv use hydraulic pressure to open AND to close the slides.

Fluid is ported from one side of hydraulic piston to other side
This is done via solenoid valves at the hydraulic reservoir.
When opening/open pressure is held on piston by solenoid valve
When closing/closed pressure is held on piston by solenoid valve

If pressure bleeds off nothing to hold slide out in open/closed positions.

Solenoid leaking thru allowing fluid pressure to bleed off

Slide out bars are OK.........bright red ribbon from them/place post-it note over control switch----something to remind you so that damage isn't done by trying to open with bars in place

I had a similar issues with 93 Prowler. Only one slide with 2 cylinders. The rear of the slide would come out while the front didn't.

Changes in temperature increase and decrease hydraulic pressure. These small changes push a small amount of fluid past the valve. A valve is allowing fluid to pass in one direction as pressure builds but not flow back as it cools. Enough of the heating and cooling cycles and your slide moves out.

My Prowler was out of warranty so the factory sold me a bypass kit that corrected the problem. When they designed the slide, they only put a bypass on one cylinder.

Campers with hydraulics use to come with slideout locks that were installed inside between the wall and slideout flange when the slide was in.

Thermal expansion of the hydraulic fluid will not be able to push hard enough to harm the camper if you lock them in while traveling or in storage. Don't forget to take them out when you start to put the slide out.