Hydraulic Leveling/Stabilizer

[JackE]

As I make my hundred trips in and out of the bus each day, I have been thinking about leveling and stabilization. What is everybody doing for that? I have found some automatic systems, like Big Foot, that look really nice, but I can't stomach spending $5G on levelers! I think I can keep my build budget in the $10K range, but not if I buy specialty items like this.

It got me thinking about my big bottle jack, and my air/hydraulic cherry picker. Why can't I incorporate something like this and tie it into the air system already on the bus? I could even run the hose into the inside at each corner so I can do the leveling from inside, never even have to leave the bus!

https://www.harborfreight.com/12-ton-air-hydraulic-bottle-jack-94487.html

https://www.harborfreight.com/8-ton-long-ram-airhydraulic-jack-56215.html

 

[CHEESE_WAGON]

I'm not sure an air brake system is designed to build enough pressure to support such an arrangement that would hold the bus' entire weight off the ground without danger. What I can tell you is that hydraulic setups are quite common on RVs, and I'm pretty sure they can be salvaged and swapped a lot cheaper than installing a new system. These systems usually have their controls mounted by the driver's seat. But a word of caution, if they are not used often enough, they will likely be prone to leakage and become useless.

 

[JackE]

The donor RV I have had a hydraulic leveling system on it. It was not rated high enough to lift the bus. I think it was rated at 20K for the rear axle, I'm at 20,600 before building. Most of the RV systems I have found to salvage are the same. Only the ones rated for Diesel pusher are rated higher, and they are only about $1000 less than brand new. The jacks I'm looking at are air over hydraulic. They don't use the air system to maintain the weight, just to move a little fluid to extend the jack. Most of these require about 100 psi to operate. Pretty sure the air system on the bus should be sitting in the 110-130 range. Using these jacks is no different than having an auxiliary hose to air up the tires.

 

[ol trunt]

I'd agree that air over hydraulic would work OK. If you want to use the jacks to level the bus you will need more pressure than the 110# you mention though it would be enough to stabilize the floor so no one gets sea sick walking around inside. A hand operated 4 gang air valve would be needed to prevent creep down.

I opted for a completely manual hydraulic system. I repurposed 4 trailer leveling jacks replacing their innards with hydraulic rams. I ran 3/8" diam steel tubing from my 4 gang valves to a hydraulic flex line at each jack. My rams and pump came from a 4K# port-o-power kit plus 3 extra rams. A 10K# set would work better for a large bus (about $200 at Harbor Freight). The jack requires a reservoir which is easily made from a plastic oil can. When deploying the jacks you have to remember that hydraulic systems all feed the easiest load first so you must use the individual valves to equalize the load--pretty easy to figure out by looking at a RV spirit level as you go.

I'm sure you can improve some on my design but the price will be hard to beat. My whole setup came in at about $205.

Here are a few pics to get you started:
Jack

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[JackE]

I'm sure you can improve some on my design but the price will be hard to beat. My whole setup came in at about $205.

Here are a few pics to get you started:
Jack

Geez Jack, What haven't you already done!!!

With the type of jacks I'm referring to, there is no bleed down unless there is a seal problem in the hydraulic side of the jack. I would be able to extend each jack individually from inside, but would still have to go out to each jack and relieve the pressure for them to retract. Your method looks like it would make it easier to retract from one location. I'll have to spend more time thinking on this one and come back and pick your very experienced brain when I'm close to making this happen.

Do you have to go out and place your jacks each time, or are they mounted to the underside permanently? I'm looking at mounting them permanent to the frame rails somewhere along there.

 

[ol trunt]

They are permanent though I do have to reach under to swing the jacks down--they have a spring loaded latching mechanism to keep them from dragging on the ground. The actual pump/valve system is located under the bed. It both deploys and retracts the pistons from inside the bus. I then have to go outside to swing the jacks back up into their secured position. Sneak onto one of the high dollar RV lots and look at their jacks. They often have a pair of coil springs on either side of the jack that make the positioning and restoring process automatic--I'd guess they'd be big bucks but you might get some good ideas.
Jack