Dewald leveling jacks

The friendliest place on the web for anyone with an RV or an interest in RVing!
If you have answers, please help by responding to the unanswered posts.

whokares2

Well-known member
Joined
Sep 16, 2016
Posts
132
2002 Georgetown Dewald leveling Jack's drift down one at a time.  I have them tarp strapped up for storage but they still drift down about 2 inches.  Is there one check valve I should look for, I can't believe all four legs went bad at one time.
 

Gary RV_Wizard

Site Team
Joined
Feb 2, 2005
Posts
74,316
Location
At our Silver Springs FL home
Which Dewald system do you have? Single-acting (has springs on the jack legs) or double-acting (no springs, usually auto leveling).

The system that uses springs to return simply opens the valves (there are 3) to allow the hydraulic fluid to return to the reservoir.  The valves wouldn't be leaking because they are wide open anyway.  The jacks move downward only under pressure.  The double-acting system pumps both up & down and the 4 valves actually reverse to flow at the jack. The double-acting system is always under pressure in one direction of the other.

Info on Dewald-Power Gear systems:  https://support.lci1.com/dewald-leveling-system
 

whokares2

Well-known member
Joined
Sep 16, 2016
Posts
132
I have the double action type, that's what makes it strange that all 4 would drift down all of sudden.
 

Gene50

Well-known member
Joined
Aug 25, 2019
Posts
154
whokares2 said:
2002 Georgetown Dewald leveling Jack's drift down one at a time.  I have them tarp strapped up for storage but they still drift down about 2 inches.  Is there one check valve I should look for, I can't believe all four legs went bad at one time.



It is a 2002 model so it must have seen considerable miles and use. 

Possibly the fluid has never been changed or serviced - though that will not cure the problem at this point, it may have contributed to its development by accumulating contamination over the years. 

There is only one reason for the cylinder extending as you describe and that is because fluid is leaving the rod end of the cylinder. 

There are only two ways for the fluid to leave - barring external leakage. 

1. Out the hose on the rod end of the cylinder and back to the reservoir past the directional control valve spool. 

In order to test for this leakage you would have to access the return port from the directional control valve to the reservoir - and I?m not sure that you can do that. 

2.  Past the piston seal and into the larger volume of the piston end.  In this case, fluid will not leave the cylinder because the volume on the piston side increases faster than the volume on the rod side decreases. 



You say that they drift down ?one at a time?.

Does that mean that the first one comes down the 2 inches and stops - then the second one starts down - and so on? 

Do they do it in the same order every time? 

Is the 2? drop accurate and consistent from one cylinder to the next?


In the operation I can see that the cylinder leaking  down will move fluid from the rod side of each cylinder to the larger piston end.

Since the smaller volume on the rod side will not fill the expanding larger volume on the piston side the movement will slow or stop all together once sufficient vacuum is generated on the piston end to increase the resistance to extending

Here is a link below that will describe the testing of the cylinder piston seal.  The test is on page 13. 

It would take about 30-45 minutes or less to test all cylinders.  The first cylinder to test is the one that leaks down first or the fastest.  Then go on from there. 

https://www.gulfstreamcoach.com/media/uploads/1/11486_Dewald-Hydraulic-Leveling-System-Manual.pdf


.


 

Gary RV_Wizard

Site Team
Joined
Feb 2, 2005
Posts
74,316
Location
At our Silver Springs FL home
There is no voltage when winterized.
That can't be it.
Well, no voltage is extremely low.  ;D    With no voltage at all, the solenoids  perhaps are drifting open and the loss of pressure in the lines lets the jack rams slowly fall (gravity).

It's also possible that the solenoid valves simply have very slow internal leaks, allowing pressure to drop over time.  I've seen that in more than a few motorhome leveling systems, i.e. the jacks lose pressure after a while, anywhere from several days to several weeks.
 

pb831030

New member
Joined
Jul 29, 2021
Posts
1
Location
Louisiana
I have a similar problem on my 2004 Georgetown. Does anyone make parts for this system? I was told by LCI that the Dewald company has been out of business for many years.
 
Top Bottom