Hydraulic Levelers Lose Pressure?

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thesameguy

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With ye olde '93 Southwind doing everything I need it to really well, my next project is helping it do things I want to do!

When I first purchased it I was happy it had hydraulic leveling, but upon first use I found out the system wasn't in good shape. The controls work reasonably well, but after deployment they begin losing pressure... slowly. Over the course of a night they are pulled back by the springs, making loud SPRING noises all the while. It hasn't been any sort of issue, but it's something I'd like to deal with.

I have not observed any external leaks - the jacks and the pump seem dry on the outside. I have read several posts where people go straight to "have the jack rebuilt" but I can't help wondering if there's an intermediate step.... My involvement with hydraulics is pretty much limited to convertible tops on cars, so my first inclination was to try and flush and bleed the system, but I have no idea if that's appropriate here, or what fluid to use. Being as old as it is, I worry a little about using random fluids that may have unpredictable results on the seals in the system. On the other hand, it doesn't work now so how much worse can it get?

Any sage advice?
 
Sounds like your jacks are bleeding fluid back to the storage tank since you see no external leaks. If they have return springs then they are powered in one direction only, fluid pumped to the jacks to raise the unit and when you hit the down button the weight of the unit plus the springs re-track the jacks. When the pump is off, electric solenoid valves control the fluid flow so it sound like this is your issue, one or more are leaking allowing the fluid from the jacks to flow back to the tank under pressure. If you can control each jack separately then you have one re-track and extend solenoid for each jack.
 
I think that's a fair description of the system. What I am wondering is it perhaps slight fluid loss over time has resulted in air ingestion, and I lose pressure as aerated fluid settles down and air bleeds out of the jacks. Or if solenoids are leaking. Or if old fluid has lost viscosity. I'm just not sure exactly how to troubleshoot or what the approach to resolution is. :)
 
Most likely the system was made by HWH or RVA.  If it was RVA, I know that the hydraulic fluid is ATF and I wouldn't be surprised if HWH didn't use the same stuff.  I seriously doubt that the problem is due to fluid viscosity; most likely your jacks are losing pressure. I have one like that but it takes a week or two to bleed down. So far I've just been living with it.
 
As I recall from my 96 Southwind, the system is Power Gear. In any case, it is a one-way powered system as Top38 describes, and a leak would be in the valves that feed hydraulic pressure to the jack rams. Do they all retract uniformly, or just 1-2 of them? 

Air is not a problem in these one-way systems, since they self-bleed every time the jacks are retracted.
 
Gary RV_Wizard said:
As I recall from my 96 Southwind, the system is Power Gear. In any case, it is a one-way powered system as Top38 describes, and a leak would be in the valves that feed hydraulic pressure to the jack rams. Do they all retract uniformly, or just 1-2 of them? 

Air is not a problem in these one-way systems, since they self-bleed every time the jacks are retracted.
Click to expand...

Power Gear sounds familiar, but I will look when I get home this evening. I understand your point about self-bleeding - that makes good sense to me.

The jacks really don't do anything uniformly... :) Deploying them is a bit clumsy, but I have been assuming it's because the joystick control is a bit sloppy - of course that could be related! The jacks losing pressure doesn't appear to happen in any consistent or predictable fashion, although if I was going to rate them, the rear jacks are definitely more problematic and likely to lose pressure quickly than the front.
 
If it has a joystick, it may be HWH, but the basic operation is till the same: one way, with a valve or valves controlling pressure to the lines. Whether there is 1, 2, 3 or 4 valves depends on the specific system.  I asked about "uniformly" because odds of all the valves in a multi-valve system leaking in the same amount seems slim. 

There is quite a bit of documentation available for Power Gear leveling systems - yours may be one of them:

https://www.lci1.com/power-gear%C2%AE-hydraulic-leveling-system
 
It may be grit stuck in the valve, sometimes opening and reclosing the manual bypass valve (you need a wrench or allen wrench to do this) will dislodge the grit and fix the problem.
 
Is the main reservoir losing fluid?  If no, there is no external leak.  It must be the valves not seating properly allowing bleed back.  Inconsistent leaking seems to validate Isaac's theory of dirt.  Would a partial flush and fill be appropriate???  Is there a filter anywhere in the system?
 
Wow - sorry for the delay in following up but it's been raining cats & dogs here and getting outside to the motorhome has been difficult!

The answer is the leveling system is HWH.

Based on no external leaks and the "grit obstruction" theory, I think I am going to try and flush the system. I have done this with convertible top hydraulics and system this type of system is similar... similar approaches will apply.

One question I have: The joystick control is VERY sloppy - it doesn't self-center worth a damn and it requires "extreme" movement in a direction to affect a jack. Is this normal? Is there an adjustment or cleaning or repair that will improve precision of the control?
 
    I was curious so I looked up HWH joystick and came up with this PDF of a 200/210 system. It shows operation and troubleshooting so if this is your system it may help.

https://www.hwhcorp.com/ml23934.pdf

 
I think I saw a youtube video on rebuilding those due to excess play in the linkage a while back
 
I'll look for that too!

I'm ultimately not sure how far I'm going to take this project since I've not yet ever needed the levelers, but if it's something I can DIY, I've got time right now... :)
 
thesameguy said:
I'll look for that too!

I'm ultimately not sure how far I'm going to take this project since I've not yet ever needed the levelers, but if it's something I can DIY, I've got time right now... :)
Click to expand...

  My problem is that if something is broken, it MUST be fixed, even if I dont use it. My wife says it is a disease, I have picked up a broken appliance from the trash, fixed it, then threw it away. An example is a 14 yr old inner tube from a tractor that has a leak. Just cant bring myself to throw it away so It will be cut into big rubber bands that I probably will never use .......but it was fixed.
 
Having spent the night at at least 50 locations in my current coach in the last couple of years, I can't imagine not having levelling jacks anymore
 
catblaster said:
  My problem is that if something is broken, it MUST be fixed, even if I dont use it. My wife says it is a disease, I have picked up a broken appliance from the trash, fixed it, then threw it away. An example is a 14 yr old inner tube from a tractor that has a leak. Just cant bring myself to throw it away so It will be cut into big rubber bands that I probably will never use .......but it was fixed.
Click to expand...

I broadly agree with this statement, but I have a diesel Jeep that needs a head gasket and engine-transplanted Fiero that needs a new clutch. I have plenty of stuff that needs to be done before I worry about stuff that I'd like to get done. But, it's freezing cold here (not Midwest cold, but ~35F) and I'm trying to avoid the difficult work until it gets a bit warmer. I can probably tolerate some hydraulics work in this weather, but stuck under an '80s GM car for five or six hours in the cold is how you turn a hobby into a job and ruin it for yourself. :)
 
Isaac-1 said:
Having spent the night at at least 50 locations in my current coach in the last couple of years, I can't imagine not having levelling jacks anymore
Click to expand...

We used them once when we first got it - we were killing some time in a lightning storm and just playing with the gadgets. The second time we intended to use them (actually camping, stopped for a few days) is when the leak became apparent. That was several years ago now, and I can't say not having them has made a functional difference. Admittedly, the places we've been have been pretty flat and/or incorporated concrete pads, but we're not hurting. *Probably* it's because we use the thing mostly as a big utility trailer with a bathroom and not a mobile home. We like it because it's easy to pack, saves having to tear down tents (which I really don't like!) and we can poop in privacy. Aside from a few hours a night or a random hail storm, we don't spend much time inside.... and that's likely the reason we are completely satisfied with a 25 year old coach and don't lust after something newer... it would be wasted on us! :)

This effort is largely in line with catblaster's comment - it's something broken and I am compelled to fix it. :) The last big challenge was my power steering cooler (so nice!) and my next big challenge will probably be reupholstering the couch. SO MUCH FUN! :D
 
catblaster said:
  My problem is that if something is broken, it MUST be fixed, even if I dont use it. My wife says it is a disease, I have picked up a broken appliance from the trash, fixed it, then threw it away. An example is a 14 yr old inner tube from a tractor that has a leak. Just cant bring myself to throw it away so It will be cut into big rubber bands that I probably will never use .......but it was fixed.
Click to expand...

I'm right there with you.  Amazed at the amount of crap like that I had to get rid of when we moved out of our house.  Nowadays I have to keep reminding myself I have no where to carry broken stuff just to fix it. 
As far as the 19 year old coach we live in.  Every time we park for any length of time, I tinker with the thing until all systems are in working order.  If everything is working, I put a coat of wax on it.
 
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