Manual air system....

[NJT5047]

The tags aren't a problem as they don't "level" or have leveling valves. They stay at about 35lbs no matter. 
I have more of a "Fred Hobe" leveling system.  I use the rear leveling valves when driving, but isolate them with ball valves when parked.  It allows a good bit of lateral leveling.  They can be overinflated or dumped. 
The front airbags are totally mechanical.  Controlled by an IR adjustable regulator.  The bags can be dumped, overinflated for height, or just set and forget.  Once set to 60 lbs, they never require any adjustment.  The ride height  (front only) isn't affected by fuel or anything else.  When I first installed this system, ride height dimensions were checked before and after fueling, and no difference was noted.  Even my 800 lb spare tire has no effect on the ride height.   
The leveling system has been on the bus since '02.  The only problem, was leaking airbags. Any leak in the leveling system will render it useless.  Had to replace both front airbags and all four drive axle bags.  Since they are isolated when parked, the tags and bus system don't have any effect on the leveling airbags.  Nor does the leveling function negatively affect the tags.  They bleed out any excess over 35 lbs no matter. 
The bus drives a lot better at normal ride height. 
I've heard that the small adjustable regulators wouldn't last in this environment.  So far, no problem. 
About the only mod I'd make to the system would be to add a fixed diaghram pressure regulator in the supply line to the adjustable regulator in order to prevent major overinflation of the airbags.  I've not done this, but overinflation is possible...up to the limits of the gov.  The airbags ain't gonna like 120 lbs of pressure.  About 80 lbs is a good limit for new airbags.   
I created this system because the bus wouldn't go into the barn with the rooftop ACs.  Necessity is the mother of all inventions!  The bus is easy to level, or totally dump.  Comes down in a hurry too.  Doesn't go up quite as fast.  But it'll rise as fast as air builds.  Both ends will come up to operational height in 15 seconds.  When the bus is aired up. 
With my DDEC, I can hit the fast idle as soon as the engine fires.  Not a lot of waiting.  The bus airs up fast with the suspension already inflated. 
FWiW, JR

[NJT5047]

If one were really concerned about reliability, a couple of manual ball valves in the front and rear bays could be used to level the system when parked and to switch it back to automatic when travelling.  I believe J.R. has a system like this.
David 

Ahhhh yess.  I have a poor mans system that has been totally flawless....once the new airbags were installed. 
It's described in boring detail below. 
David, where's T'vill gonna be held this year?  Your place?  Gimmie the date.
i'll be there! 
I'm bummed about Dallas' T'ville.  Man that was some good food!  And GREAT entertainment! 
I can do it here too....just not a campground.  But big flat 12 acres.  Got water, some power for the lucky ones....Me feeling lucky, let me know. 
I'm open for suggestions.  Have to get Dallas and Cat up here to run it.  But we have a good bit of covered area in case of inclement weather. 
We will be gone a good bit but if anyone's interested, I'll post dates. 
Gene L would have to cook.  That it.  Gotta have  him on Barby. 
Well guys, it's past my bedtime and it's probably looking like such. 
Best, JR

[prevost82]

I just install Pete's campground air level kit on my Prevost and it works great. Highly recommend it.
Ron

[gg04]

Four air seat valves,four gauges, a hand full of air brake fittings and dot airline...last 3 buses have been air suspension ,same system put on all...If you actually use your bus this system lets you be level nearly anywhere you end up...In over 20 years and a few hundred thousand miles no problems..gg04

[DavidInWilmNC]

I don't really see much need (at this point, anyway) in much more complexity than your system.  After all, one's got to get out to plug the bus in, hook up water, etc, so what's with opening a bay door to adjust a couple of valves?  I need to take a closer look at your system and do something similar.

I'm hoping we can have another 'regional' get-together like at Timmonsville with Dallas and Cat.  In fact, we need to have one.  That first one was my first experience up close and inside of a converted bus.  Here I am, working on converting mine and I'd never been in one!  As much as I benefit from all the info available here on these forums, there's no substitute for for actually being there.  Plus, the food and entertainment were outstanding.  I'm gonna miss Timmonsville next month, that's for sure.

David

If one were really concerned about reliability, a couple of manual ball valves in the front and rear bays could be used to level the system when parked and to switch it back to automatic when travelling.  I believe J.R. has a system like this.
David 

Ahhhh yess.  I have a poor mans system that has been totally flawless....once the new airbags were installed. 
It's described in boring detail below. 
David, where's T'vill gonna be held this year?  Your place?  Gimmie the date.
i'll be there! 
I'm bummed about Dallas' T'ville.  Man that was some good food!  And GREAT entertainment! 
I can do it here too....just not a campground.  But big flat 12 acres.  Got water, some power for the lucky ones....Me feeling lucky, let me know. 
I'm open for suggestions.  Have to get Dallas and Cat up here to run it.  But we have a good bit of covered area in case of inclement weather. 
We will be gone a good bit but if anyone's interested, I'll post dates. 
Gene L would have to cook.  That it.  Gotta have  him on Barby. 
Well guys, it's past my bedtime and it's probably looking like such. 
Best, JR

[RTS/Daytona]

Hi

Here's some pics of the G4 Leveling Sytem - I make

[Utahclaimjumper]

I have the four point manual system on an 4106 and I get 10 inches of vertical at each corner, onch had to use it to get off high center, just air up and drove off.>>>Dan

[JackConrad]

I also use our to get a better drain of our holding tank. Connect drain hose, then raise passenger side of bus. Jack

[jjrbus]

 Also use system for working on bus!