Hydrualic fluid resevoir

[DAN V]

I am having problems with my slide outs. Lately they will go out but not in unless I let it sit for a few minutes and play with the switches. If I go part way out with the slide they will not come back in, I have to go all the way out for them to not allow water in. My question is the hydraulic fluid reservoir supposed to be half full or is it supposed to be almost full? I know there are leaks around the fittings as it has been like this since I got it. I do plan to get rid of the MS in the near future as I am getting frustrated with this monstrosity. Any info would be greatful and helpful. Thanks.

 

[B.G. Smith]

I would say it should be full with the slide all the way in. Reasoning: With the slide in the shaft of the hyd. cylinder is inside the cylinder which displaces fluid. When it is all the way out the shaft is out and the cylinder holds more fluid. Thus when the slide is run out there is less fluid returning to the reservoir than there is being put into cylinder. If you filled it with the with the slide out it will overflow when slide is run in. Is that as clear as mud????? bg

 

[Jim W]

I would also caution you on the type of fluid you use to replenish the reservoir with. I know that my hydraulic fluid for my slides and leveler legs is ATF transmission fluid.

This fluid is also to be replaced periodically per Lippert if your system is the same.

Jim W.

 

[DAN V]

Thanks guys. I looked at it earlier today and it is half full. Looks like I will be making some calls to see what my options are.

 

[JR]

What is the level when the slide is all the way out?

If you've got a decent level in the reservoir with all slides all the way out then the pump should not be cavitating.

 

[Hoefler]

The fluid should be with in a half inch of the top of the reservoir when all cylinders are retracted, including the landing gear legs.

 

[NIsaacs]

Two way cylinders do not displace fluid from the tank, the level stays the same.

Nick

 

[mwilson]

Two way cylinders do not displace fluid from the tank, the level stays the same.

Nick

Exactly. There is fluid on both sides of the piston gland.

Single action cylinders like a dump body or snow plow lift use need the level checked with the cylinder retracted. Two way cylinders have the same amount of fluid in them regardless of position.
Easy way to tell....One way cylinders have one fitting and line on the barrel....Two way cylinders have a fitting and line on each end of the barrel.

I think that one of the valve/electric thingies on the pump has an issue....can't remember the technical term, been in the office too darn long....

 

[mwilson]

You may also have a bad packing in one cylinder. Does the pump squeal when it is having the symptoms???

This pdf is for a Dewald system, but it may help you to understand how this works and what is what...

http://support.powergearus.com/techdocs/Parts_Serv_Man_Dewald_Hyd_Slideout_Sys.pdf

 

[DAN V]

What is the level when the slide is all the way out?

If you've got a decent level in the reservoir with all slides all the way out then the pump should not be cavitating.

The fluid level is half full. the slides will not retract at this time. Have to figure out manually to retract slides.

 

[AEdelheit]

Two way cylinders do not displace fluid from the tank, the level stays the same.

Nick

Only if the Shaft goes all the way through, a traditional cylinder with a shaft and piston it will displace the amount of fluid of the shaft inside the cylinder.

 

[mwilson]

No, the shaft does not have to go all the way through...one fitting means single acting, a fitting on each end means double action.

Try this...you will see why the tank level does not drop as it would with a single action dumping or plow cylinder.

https://www.youtube.com/watch?v=kzqkPx8F3D8

 

[Jim W]

I was not going to comment but a double acting cylinder will displace some fluid back to the tank. Based on the size of the cylinder rod inside the cylinder. The head end side will accept more fluid than the rod end side since the rod does displace fluid.

Jim W.

 

[B.G. Smith]

The illustration does not address the level of fluid in the reservoir. If you watch the video you can see that the piston rod is inside the cylinder when retracted meaning that there is less fluid in that end of cylinder when fully retracted than there is in the other end when the rod is all the way out. The cylinder rod will produce more force with a give pressure when extending than when retracting because of the area of the piston that is exposed to the fluid which may give a hint to your problem if the fluid level is adequate, the relief valve may be releasing. bg

 

[Jim W]

The fluid level is half full. the slides will not retract at this time. Have to figure out manually to retract slides.

Dan is your hydraulic system a Lippert design and pump? If so there should be a circle with a hex nut in side the hydraulic pump under a paper cover. You should be able to retract the slides using this method by driving the hydraulic motor with a hand crank or an electric drill. Do the legs retract?

This is from my forest rivers owners manual but here is how to operate the slides.

Manual Slide Room Operation
Power Failure
In the event of a power failure or low battery, the slide out
room may be operated manually with a crank handle. (If
you do not have one, you may order one from your
Forest River dealer.) The manual crank shaft is located
on the motor transmission housing. Turn the crank
counter-clockwise to move the room IN and clockwise to
move the room OUT.

For more information, please consult the individual owner’s
manual or on-line at www.forestriverinc.com.

Jim W.

 

[mwilson]

The illustration does not address the level of fluid in the reservoir. If you watch the video you can see that the piston rod is inside the cylinder when retracted meaning that there is less fluid in that end of cylinder when fully retracted than there is in the other end when the rod is all the way out. The cylinder rod will produce more force with a give pressure when extending than when retracting because of the area of the piston that is exposed to the fluid which may give a hint to your problem if the fluid level is adequate, the relief valve may be releasing. bg

I couldn't find one quickly that showed an active reservoir...I tried....

 

[mwilson]

Now some of the two, three and four slide hydraulic systems I have seen work in sequence, right??? One slide comes out, then the next and so forth. I would assume that makes for simpler plumbing and less control valves on the pump. Are they now individually controlled on the high end stuff??? I just have a crappy one slide Lippert electric unit, no big dogs in my yard...

A bad packing on a piston would raise hell with that I would think......

 

[mwilson]

Only if the Shaft goes all the way through, a traditional cylinder with a shaft and piston it will displace the amount of fluid of the shaft inside the cylinder.

I mis-read this the first time, my apologies.

I looked at it in the e-mail instead of the forum and missed the context because it was in with my "Cure Herpes in 7 Days!!" and "Obama Conspiracy Unfolds!!" e-mail traffic.... I still think someone here at work suffers from it and the one hundred e-mails plus per day promising to cure it are meant for him.....