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Author Topic: Calling for help from Hydraulic experts - slide-outs sometimes stop too soon  (Read 498 times)

billmac

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  • Posts: 33
I have a 2005 Cardinal with 3 slides that I bought new.  For the past two years or so, the opposing kitchen and couch slide will sometimes stop short of full extension, or full closing.  The bedroom slide always goes in and out first.  If the bedroom slide moves slower than normal, I know the bigger slides are probably going to stop short of their mark.  When the slides stop moving, the pump motor still runs and sounds normal to me.   

I have tried many fixes, but the intermittent problem still occurs about one out of every 10 operations.  I have replaced both batteries with group 29 marine batteries.  I have tried jumping the batteries with the two in my truck.   Replaced the slide pump/motor and fluid.  Cleaned all electrical and ground contacts to bare metal.  I have added additional grounding to battery from pump motor and Trombetta relay.  Increased fuse size from 30 to 50 amp.  Increased 7 amp slide switch to 15 amp switch.  Dry lubed all mechanical friction points and gears.  The hydraulic system never leaks fluid.  I always level my rv before moving the slides in or out.  I run the slides while hooked to my truck and shore power.  My batteries show over 14 volts while charging and moving the slides.

One interesting clue is, I can wait about 10 minutes and/or momentarily reverse the slide switch.  For some reason the slides will come to life with amazing power and immediately close or open as I originally desired.     

I have talked to many folks and read many web pages.  But I am flat running out of ideas.   I would take the slide-out issue to a dealer but fear they would keep the rig 6 weeks and tell me it never messed up for them.  The parts I have changed reflect some ideas from private techs or friends.     

I would appreciate your helpful thoughts and ideas   

Ernie n Tara

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  • Posts: 3557
  • Life is Good - Together
It sounds as if the return hose may have a sticking valve.  If pressure builds in the return line, it will eventually stall the slide. Reversing momentarily would exercise that valve perhaps freeing It up. Another remote possibility is a crimp in that line or pinching somehow.

Ernie
Ernie 'n Tara

2011 Winn Journey 34y
2012 Jeep Rubicon - Dozer (orange - kinda)
2006 Jeep Wrangler

billmac

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  • Posts: 33
Thanks so much for the reply Ernie.   Where might the sticky valve be located?  Is that something that is cleaned or replaced? 

It sounds like a hydraulic fluid line inspection may be in my future.     

Lou Schneider

  • Forum Staff
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  • Posts: 8434
It may not be a valve as such, if there's deterioration inside a hose it can block flow through the hose in one direction but release in the opposite direction.  When the debris gets sucked against the outlet it blocks the flow, then releases when fluid flow the other way pushes it aside.

This is fairly common with older automobile brake hoses, if fluid can't flow out of the wheel cylinder the brake will drag or lock on.
« Last Edit: December 08, 2017, 04:25:10 PM by Lou Schneider »

billmac

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  • Posts: 33
Just as an update, I found the "Basic Purge Procedure for Hydraulic Pump Units" .pdf from Lippert Components Inc. 

To my surprise the procedure call for the pump reservoir to be 1/4 " from the top.  Lippert said the level should be "no more than 1/2" from the top".

On my rig, the reservoir with the slides in was about 2 inches from the top.  I added 22 ounces of Dexron transmission fluid to make the reservoir 1/4" from the top. 

It is also interesting to note that Lippert says to check fluid reservoir for foam upon retracting slides or jacks.  Foam indicates air in the system.  Lipperts says not to operate the component while there is foam in the reservoir.  Wait 15 to 20 minutes for the foam to dissipate before operating the pump.

I hope this will fix my problem and further hope it will help a fellow rv when they are having issues with their hydraulics.         

taoshum

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  • Posts: 2629
Just as an update, I found the "Basic Purge Procedure for Hydraulic Pump Units" .pdf from Lippert Components Inc. 

To my surprise the procedure call for the pump reservoir to be 1/4 " from the top.  Lippert said the level should be "no more than 1/2" from the top".

On my rig, the reservoir with the slides in was about 2 inches from the top.  I added 22 ounces of Dexron transmission fluid to make the reservoir 1/4" from the top. 

It is also interesting to note that Lippert says to check fluid reservoir for foam upon retracting slides or jacks.  Foam indicates air in the system.  Lipperts says not to operate the component while there is foam in the reservoir.  Wait 15 to 20 minutes for the foam to dissipate before operating the pump.

I hope this will fix my problem and further hope it will help a fellow rv when they are having issues with their hydraulics.       


Air in the line would probably behave this way.
07 Itasca Meridian 34SH.  '08 Jeep Sahara.
Taos, NM.