Through Wall Hydraulic Slides Moved While Unhitching

[JBill9694]

Jlawles2 My system is an on-demand system in that the pump only runs when a move is called for.

TedS Thanks for the link. Yoda I agree they are pricey.

howson I recalled this thread but was not able to find it. I did find threads that talked about blocking for Schintek slides and am a little leery about doing this with a heavier hydraulic slide. Still a bent flange or bowed wall would probably be less cost than have slides deploy going down the road. Wonder if I should think about securing the jacks? I've heard a couple of stories about them dropping during travel.

Scott'n'Wendy Country Campers We are still 7 months out from our annual service and maintenance but will add an oil change to the list. And yes, I plan to be hitched to the truck before doing any testing.

howson Thanks for the link, I have downloaded the whole service manual. It looks like a test with slides in is warranted. Will follow if this turns into DIY.

Scott'n'Wendy TedS. All good input and will follow if this turns into DIY.

My situation is that locale service centers have a two to three week wait list, and there are not any mobile techs in the area (is at our next stop). We move Wednesday with an engagement on Monday p.m., So with parts store closed today that really leaves only Tuesday to do something that I haven't tried before. Yes, it looks like it should be simple, but what if I run into trouble or can't get a part?

Our next stop is for 7 days. Tomorrow, I will try to schedule a RV Mobile Tech meet us at our RV Park on Wednesday p.m. Tuesday I'll work on some just-in-case blocking for the slides, Wednesday morning will run the slides in and out a few times to try and clear any debris, and then hopefully on Wednesday p.m. I'll be able to get this all taking care of. If not, then on Thursday it will become a DIY project.

[Country Campers]

In most hydraulic systems the oil is on both sides of the piston, pressure on one side moves the piston out pressure on the other side moves the piston in. The system is closed so that the only way movement can happen is by opening a valve and sending fluid to one side or the other. The slide out system is separate from the jacking system so one should not move while the other is in motion. The only way a jack or slide should move without pump or valve input would be if there was a leak in the system allowing fluid out of one side of the piston and drawing fluid in to the other side of the piston. This could happen with the jacks as there would be downward weight, the slides would be less likely to move as they are horizontal. I agree with the others posting that there may be debris in the valve, a small fleck could allow leaking past the valve. I have not seen or heard but I wonder why there is no filter for this system.

Brian

[TedS]

The pressure of the pump outlet is common to both leg and slide valves input ports. As long as the valve is closed, the particular cylinder will not move. Oil has to flow out of a cylinder as well as into it for the cylinder to move.

[Scott'n'Wendy]

JBill9694 In the meantime, trying to identify the slide valve would be time well spent. And...if slides get stuck out, is there a manual retraction procedure in the manual for hydraulic slides?

Country Campers A lot, if not most of small scale hydraulic systems have no filter. For example my 10k lift in my garage has no filter either. But specifies yearly oil changes.

[JBill9694]

Here is a photo of the hydraulic block.

I think that there are five valves and solenoids with the first valve/solenoid on the left being for the landing jacks. If memory serves me correctly, the middle pair are the stabilizing jacks, I had to raise them manually once due to dead battery. This leaves the pair on the right for the slides. The hex-head bolts are for manually opening the valves with the middle pair numbered 1 (upper bolt) and 2, and the right pair numbered 3 (upper bolt) and 4.

[Scott'n'Wendy]

I see three solenoids/hyd circuits there. Would I be correct that there are no wires to the blue/gold device on the top left? It looks like a desiccant/moisture indicator.
Does the owners manual have a hydraulic schematic for the manifold? Or can you tell where the lines go? I can't tell where these hex head manual overide bolts are..maybe I'm blind...


By the way, that is the cleanest hydraulic block I have ever seen. In industry, they all leak.

[TedS]

doc.pdf

This may be of marginal help. GD needs help writing manuals.

[Yoda]

Here is a photo of the hydraulic block.

I think that there are five valves and solenoids with the first valve/solenoid on the left being for the landing jacks. If memory serves me correctly, the middle pair are the stabilizing jacks, I had to raise them manually once due to dead battery. This leaves the pair on the right for the slides. The hex-head bolts are for manually opening the valves with the middle pair numbered 1 (upper bolt) and 2, and the right pair numbered 3 (upper bolt) and 4.

Scott'n'Wendy howson

I agree with Scott a very clean install. I do question the quality of the hose used though. Hose information should be stamped on the hose. Std compression fittings were used and if the layout is as you say it would be a snap to add manual isolation valves to the slide circuits. This type of fitting will leak over time (not if but when). On my tractor hydraulics I do an annual tightening (takes two wrenches). Don't gorilla the fittings - it will make things worse. Don't ask how I know. Also do not use teflon tape on the fittings - it's not compatible with hydraulic fluid. Fittings should seal dry, but over time I have used special hydraulic thread sealant that comes in a tube.

I agree with Howard that solving the reason why is important, but if you choose to isolate, theses folks have a good selection of parts (hyd pressure rated valves) and possibly the solenoid valve assuming that Lippert used industry parts. https://www.surpluscenter.com/hydraulics/ I use them for for my tractor and other hydraulic equipment. There are other supply houses online too. Somewhere on those fittings will be stamped the size or part number. Having that will help identify the type of 90 and thread size and pitch . With that it will be easy to get the proper manual valve. Only one manual valve per slide wold be needed. Is there a way they could be powered momentarily when extending you jacks?

Now whats puzzling is each slide appears to have its own solenoid valve in the picture. If that is the case something is off as both valves would need to fail (seep) if both slides are moving out. But I will leave that question to the experts.

Trying to help
Keith

[TedS]

The cartridge valves have an o-ring SAE boss seal seat. I've not had one leak that had a good o-ring and seat. JIC fittings seal on a metal-to-metal cone seat and not the thread, so they don't need to be taped. Teflon tape is compatible with hydraulic fluid and would only be used on pipe thread joints.

Each function has its own valves. And black hose is extend line, orange hose is retract line.

[Scott'n'Wendy]

Also do not use teflon tape on the fittings -

This is good advice, but it's not a compatibility issue. Hydraulic fittings don't seal on the threads. If you see teflon tape on a hydraulic fitting, someone is trying to avoid repairing a damaged seat.

[Scott'n'Wendy]

Now whats puzzling is each slide appears to have its own solenoid valve in the picture. If that is the case something is off as both valves would need to fail (seep) if both slides are moving out. But I will leave that question to the experts.

Trying to help
Keith

I think one solenoid controls the slides. One for front jacks. One for stabilizers. I only see three solenoids?

[TedS]

I see three solenoids/hyd circuits there. Would I be correct that there are no wires to the blue/gold device on the top left? It looks like a desiccant/moisture indicator.
Does the owners manual have a hydraulic schematic for the manifold? Or can you tell where the lines go? I can't tell where these hex head manual overide bolts are..maybe I'm blind...


By the way, that is the cleanest hydraulic block I have ever seen. In industry, they all leak.

The blue/gold thing is a pressure switch. I don't know what pressure it senses. Maybe common retract pressure to then sequence to open stabilizer leg cylinder valves to allow all retract.

[JBill9694]

Scott'n'Wendy My miscount on the solenoids. There is a fourth solenoid on the curbside landing jack. The blue and gold device does have electrical wires, and I think TedS is correct that this is a high-pressure switch. Yoda If you look closely at the second red hose from the left you can see that there is information stamped on the hose.

I have not talked to Lippert Customer Service, but I did talk to a Mobile RV Tech. His take on the problem was there is at best a leaky valve and at worst a leaky cylinder. The leaky valve can be addressed int he field with a little work to determine which valve it is. Due to concerns about containment and disposal of hydraulic oil, he wouldn't do the test for a leaky cylinder in the field and doesn't know of anyone else who would (The testing isn't that difficult or risky but purging the system of air afterwards apparently is).

The kicker on the conversation was that the Tech said Lippert shut down for 2 1/2 weeks over the holidays, which created a backlog of orders. If a replacement valve is not readily available, he has no idea how long it would take to get one. I'm 12 days out from a 2 month stay and we agreed it would be best if I wait until then to have someone come and look at the hydraulics. The Tech also said that I should be safe to travel but could block the slides closed if I had any concerns.

Yesterday was a travel day. I did block the slides closed, but on arrival found that the slides had not moved. When the landing jacks were lowered, the slides did not move. Hmmm.

We have two more moves before reaching our 2 month stay. I'll monitor the situation until then, but don't plan on attempting any repairs unless things go terribly wrong. After all, procrastination is my reason for getting out of bed in the morning.

[TedS]

This may not be just like this trailer, but it would be representative. It's a 6-point system.

[Scott'n'Wendy]

I will say there is no chance it is a cylinder. If it was a cylinder, one slide would have moved..not both. UNLESS, one cylinder does both slides.
I believe it was a contaminant in your fluid.
If it was my trailer I'd do a fluid change and acquire a spare valve to keep on hand. And leave it at that.