Slide Out Hydraulic Check Valve?

[LewisB]

We have a 2008 Raptor 3712TS. It has 3 hydraulic slides with one pump and one "in/out" switch. Slides open/close based (primarily) on weight of each slide (bedroom, kitchen, then living room). Recently, I noticed that after I close the slides (IN), in a short time (e.g. a couple of hours) the two lighter weight slides (bedroom & Kitchen) have partially opened (out) at the bottom.

Does anyone know if there is a hydraulic check valve at the pump that is supposed to hold pressure on the system? It almost looks like a check valve is leaking, allowing pressure to leak back into the system and these slides are "relaxing" into a partially opened position.

Thanks for any assistance you can provide.
Brad

2017 Ford F350 DRW
2008 Raptor 3712TS
2012 Polaris RZR-S LE or
2014 Harley Tri-Glide

[travelin texans]

Could be air in the lines, operating them eventually work the air out. Check fluid level in the reservoir, with all slides in/jacks up, if equipped with level up system, the fluid should be within 1/4-1/2" from the fill opening. Also when operating once completely in or out continue to hold the button for 3 to 5 seconds or til you hear the pump strain.

[chuckster57]

If all the above advise (good advise) doesn’t work, then the likely reason is a failed solenoid at the manifold.

[Hblick48]

I had the same problem on my '02 Montana, the main slide would creep out while going down road. Hydraulic system was made be Dewald, which was purchased by Lippert. No parts are available.

I found place that said they could fix. I sent the pump to them, and their diagnosis was an internal check valve had failed. They had me install external valves which were supposed to prevent slide from creeping...didn't work.

I finally got some 3/8 inch cotterless hitch pins. Drilled hole through the square extension tube. Attached hitch pin to chassis with small chain.

Slide still creeps, but hitch pin keeps it in. When I need to move slide I first retract to take pressure off of pin, then remove it and extend slide. Just towed 9,000 miles and slide stays in. Just need to remember to remove pins before trying to extend.

[LewisB]

Thanks for responses - I appreciate your help. Additional info:
> Fluid level full
> System has been used regularly with no apparent leaks/loss of fluid so doubt it could be air in the lines.
> 3 slides are total of hydraulic system. No hydraulic levelers & front jacks are electric.
> When I close slides, I let it run until the pump begins to "labor".
> No "manifold" for this system. Pump has one inlet and one outlet, so it must branch off to the various slides under the trailer somewhere (not visible due to winterization panels). That's what leads me to believe the pump must have some type of check valve.

I hate to start thinking about replacing this pump unless I understand the cause of the issue. Thanks again for your responses!
Brad
--------------
2017 Ford F350 DRW
2008 Raptor 3712TS
2012 Polaris RZR-S LE or
2014 Harley Tri-Glide

[ChuckS]

Has to be a separate block manifold with most likely 3 solenoid valves to control and maintain pressure on each of those hyd slide cylinders. Simply follow the pressure line and it will lead you to a manifold block with valves on it