Leveling system idea

[Fredward]

Instead of adding valves and hoses and gauges to the existing OEM leveling system on my MC-5 for campground leveling; why not simply replace the metal piece that attaches the leveling valve to the axle with a 12 or 24 volt DC actuator with a potentiometer to provide positioning information. The relative position of the actuator would be readable on a meter mounted next to the switch. A double pole/double throw center off switch could be used to control each actuator.

The OEM system stays intact, all I would be doing would be lengthening or shortening the connection between axle and leveling valve to "trick" the system into raising or lowering the respective air bag? The rears would provide side to side leveling and the front valve would provide front to back leveling.

Has anybody tried this? I searched the archives, but everybody seems to want to use valves and gauges rather than a mechanical linkage that is adjustable. I have a prototype actuator coming that I will try.

Fred

[Don4107]

Someone on one of the bus boards talked about putting a cable operated linkage in place of the link.  Don't remember who or if they did it. 

I like your idea.  I guess it depends on how long your bus holds air or if you use an auxiliary compressor to keep it aired up. 

One on the advantages of the separate leveling system is it isolates the air bags so even if the air bleeds down, if the bags out to the isolation valve holds air you won't sink.

Be sure to keep us up to speed on your project. 

Don 4107

[TomC]

Sean on his Neoplan has that exact system and it works well since he also can raise the bus up for rough roads, lower for normal or go down all the way for real low riding.  Good Luck, TomC

[Jeremy]

or go down all the way for real low riding. 

It'd be interesting to know if there would be any fuel economy gains in doing that; I know it's not really a comparable vehicle, but Range Rovers automatically lower themselves down to the road above a certain speed for exactly that reason. The system can be over-riden by the driver, and there is apparently a measurable difference in fuel consumption on long trips between the two settings. I think it's as much to do with reducing the turbulent airflow underneath the vehicle as it is in reducing the frontal area, although I have read that overall frontal area is actually far more important than shape in aerodynamic terms

Jeremy

[Ncbob]

That'd be a great idea Fred as long as you have a way of keeping the air up. Let us know if you work out something like what you describe, please.

Bob

[johns4104]

Fred you might be able to just add the actuator to the two rear leveling valves and use that for the height as well as the pitch.

John
keep it simple

[JackConrad]

Hmmm, if you manually raise the rear air bags and lower the front air bags, you will always be going downhill. That should help improve your mileage, right?  LOL  Jack

[jjrbus]

The actuator is a great idea. However Bob brings up a good point, how tight is your system? If you find your bus leaning after a day it will do the same thing with  an actuator.
Befor installing my leveling system, my 5C would sag after a few days. Now it can sit for months without leaning.
I tried jacks idea and found I get up to a 45% increase in fuel milage.   
                                                HTH Jim

[sommersed]

My 5A would leak down to the stops overnight and I wanted a kiss type leveling system.

First I installed a manual 1/4 inch shutoff valve at each of the three points between the bags and the leveling valves.  After two weeks of staying up I figured that I had no leaks at the bags.

Next I installed a normally closed 24 volt (ran with only 12 volts) air valve between air bags and manual shutoff valves and ran wires for them to the front part of the rig using one wire each as I grounded them at the switch location.

Now when I park, first thing I do is use a tool I made to manually  shut off the air to/from the bags, then level with the three switches while looking at bubble levels stuck on front and side windows.

Total time, overall, about two hours expended.  Total cost was under $50.00.


Ed, USN (Ret)

[PP]

Hmmm, if you manually raise the rear air bags and lower the front air bags, you will always be going downhill. That should help improve your mileage, right?  LOL  Jack

I had a car like that when I was younger (hehe) and I was constantly working on the brakes. Everytime I got out it rolled away, 

[Fredward]

Well I like the idea of going down hill all the time. Never thought of that. -Thanks Jack.

This bus holds air for a long time - days. Plus I carry a pancake compressor in the rear bay so that could be utilized for leveling for longer stays. Rarely are we parked in the same spot for more than four days.

I could possibly do it all from the rears, that is a good idea.

Sommersed, with your system, you can only let air out of the bags - correct? Tell me more about how this works. The Linear Actuators I looked are are about 6 inches long and cost around $220.00 each. It would be nice to accomplish the same thing for less money. I would even install turn buckles which would accomplish the same thing if I could reach in there past the tire to adjust them.

[sommersed]

Yes Fred, my system is an air out system only. As I tend to stop for two weeks to a month or more at a time I have found that an air out only system is fine for me. I loose air pressure overnight anyway so there would be no pressure to use even if I wanted to.  I HAVE recently developed a small air leak on the left rear and had to air up with my portable compressor, open the manual shutoff valve on the left rear and bring her bacl up a couple of inches after two weeks.

Not much more to tell about the system.  I used 3, 1/4 inch levered gate valves from the hardware store  to isolate each point (2 in the rear and one up forward), and 24 volt electric valves purchased from the surplus center web site, and installed between the bags and shutoff valve(s) utilizing a "T", to make them exhaust valves.

Like I said, I like the KISS system, and this was the easiest, and cheapest way I could think of to accomplish the task IMHO.

Ed

[Sojourner]

sommersed posts good suggestions...thanks.

For those are not sure the "Why" or "How long it hold air"...read on:

After all air leaks are fixed....the automatic air leveler still need the air supply from tank or optional electric compressor to maintain it adjusted level. Why? Because the coach is floating on air. Every time the coach is senses movement while stand still or traveling, it will either exhaust or add air to maintain that adjusted leveling valve linkage. In other words, every time while standing still and whenever the wind is blowing onto coach or getting in & out of coach or walking around inside of coach will cause the needs of air pressure to maintain it adjusted height.

So every time someone here on the posts about how long it hold air...it all depend on which of the factors of the above paragraph and how big your bus's air reserve tank if it park and no air pumping. So the "How long it holds air?" quotes mean nothing to the bus nut.

BTW....the only way to locking air pressure in air bag such as tires do is to added a 3 points leveling system to by pass automatic levelers. Remember air temperature will control air pressure variable....just the tires pressure change from cold to warm to hot.

Our bus nut Pete/RTS Daytona (retired IBM System Engineer) has a system available http://good-times.webshots.com/album/559324954HVWVXC

Or you can make your own system.

BTW...all coach manufacture's air levelers are 3 points system design to minimize uneven coach's body stresses. So avoid the 4 points version that is available.

FWIW

Sojourn for Christ, Gerald

[jjrbus]

Very good point Jerry. I completely missed that. It would seem the addition of a small auxillary compressor and check vlave would be a must with the actuator type system.  Jim

[gumpy]

And this is all well and good, except for one thing.... Using the airbags to level the bus will only give you about 4 inches of movement per bag. About 2 up and about 2 down.  So about the best you can hope for is about 4 inches maximum difference between left and right side, and about 4 inches maximum difference front to rear.

What this means is that unless your coach is nearly level to begin with, the air bag system isn't going to help you much.

I installed my airbag leveling system last fall, and used it on this summer's 3 week trip as well as a weekend trip prior to that. I found that unless I was parking in an improved location (meaning concrete or graded surface), I typically didn't have enought movement to really get my bus level to where the shower would drain properly (my idea of proper level is when the kitchen counter is level front to rear, and the shower drains to the center-front drain). I had to use some blocks in the mountains to get semi-level, and then used the airbags to fine-tune it. That worked ok.

I even found that parking lots that have drainage slope to them can be too much for the airbags. We parked along a curb in Laramie, and I had to pull about 2 feet away from the curb to be able to get level. The slope into the curb drain was too much for the airbags to compensate for.

I have my leveling system pressure regulated to about 85 psi. I could probably get a bit more if I raised it some, but I've heard you shouldn't put more than that in them. I haven't been able to confirm that, though. I'd sure hate to pop one.

While I like being able to adjust my air bags, I would suggest that before you spend a tremendous amount of time and money engineering a leveling system using them that you fully understand they may not give you as much leveling capability as you initially thought they would.

craig