Air bags up or down when parked/stored.

[Maudi2001]

As many of us are prior Wanderlodge owners I would like your opinion on whether you deflate your air bags when parked.

i was so used to dropping my coach and using the jack to stabilize the coach.
When I got my coach from Liberty. I asked about this issue. They recommended that I keep the coach aired up. Using the auto level prior to shutdown. If the site or steps needed to come down then use manual mode and level.

They said no harm would come of letting the coach down to the inner rubber stops in the bags.

I have yet to deflate my bags since my 6 months of ownership. My spot is very level.

William Jensen
2001 Liberty XLII non slide
1993 PT40 Wanderlodge (sold)

[davidbrady]

Hi William,

I'm a fan of keeping the system pressurized and at ride height. That's good dry air you have in there with a low dew point which helps eliminate any condensation forming inside the system as ambient temperatures swing. Also, buses of our vintage tend to use auxiliary tanks, ping tanks, at each air spring. This system lowers the suspension's resonant frequency which is a fancy way of saying we have a softer spring rate and a plusher ride, but if you make it too soft the suspension can bottom. What Prevost did was to include a conical rubber bump stop within the air spring. The bump stop adds to the spring stiffness at the end of the suspension travel. I know I don't want my conical bump stops permanently flattened by prolonged resting of the bus onto them. And thirdly, I've been told the same effect isn't good for our IFS bushings. These bushings shear as the suspension articulates. They're designed to operate over an angle of rotation. It's anecdotal, but a mechanic tells me he sees more suspension bushing failures with owners who store their suspension dumped. You can imagine brand new fresh bushings might not care, but as they age they might. That's my swing at it. What do others think?

Attached is a load diagram for my spring. See how the spring rate is a plush 650 lbs/in but it then escalates to 1800 lbs/in thanks to the conical bump stop:

[cmillsap]

My coach sits in an air conditioned garage when we are not on the road. I always leave my coach stored with the suspension left at road height level. Over a period of about 2 weeks the suspension will slowly drop to near the bump stops. Also, I leave my aux air compressor on so everything on the house air system continues to be operable.

Although I could simply turn a valve to connect the aux air system to the Prevost air system and raise the bus, I prefer to take the opportunity to start the engine and exercise it and other components of the chassis while raising the coach back to road height level.

[Maudi2001]

David and Chuck:

Thanks for the response.

Great explanation about the different internal bumpers on the air bags.

I keep my aux compressor on at all times. It is a noisy sucker though.
Someone needs to invent a "hush cabinet" like the generator has to quit the thing down.

William Jensen
Deerfield Beach, Fl
2001 Liberty XLII 45, non slide.

[davidbrady]

From the Goodyear's Basic Principles of Air Springs:

Do not exhaust all of the air from a rolling lobe or sleeve type air spring while attempting to compress it. A minimum of approximately 10 PSIG air pressure should be maintained internally. Not doing so may cause the flex member to buckle instead of rolling over the piston and may cause damage.

[cmillsap]

(03-28-2017 21:24)Maudi2001 Wrote:  David and Chuck:

Thanks for the response.

Great explanation about the different internal bumpers on the air bags.

I keep my aux compressor on at all times. It is a noisy sucker though.
Someone needs to invent a "hush cabinet" like the generator has to quit the thing down.

William Jensen
Deerfield Beach, Fl
2001 Liberty XLII 45, non slide.

I do not know where Liberty located their Aux air Comp on your vintage coach. Marathon locates the Aux air comp on my vintage XLII in the generator bay which is insulated quite well. I can hardly hear it from the inside of the coach. If your aux air is running frequently, you probably have some system air leaks. Sometimes the air will leak back through the compressor if you compressor is not fitted with a check valve on the delivery air line where it is connected to the air compressor. My aux air compressor may run once every 3 days for about 3 minutes.

[ERNIEE]

air leaks? just heard from prevost concerning our coach- still have some, so did my 4 bluebirds- hope they fixed a lot- get to drive her home on Friday

[Hisham Amaral]

(03-30-2017 19:30)ERNIEE Wrote:  air leaks? just heard from prevost concerning our coach- still have some, so did my 4 bluebirds- hope they fixed a lot- get to drive her home on Friday

Erniee
Hope all your air leak are gone. I am going to Mira Lome to do the same in June.

[Maudi2001]

I do not know where Liberty located their Aux air Comp on your vintage coach. Marathon locates the Aux air comp on my vintage XLII in the generator bay which is insulated quite well. I can hardly hear it from the inside of the coach. If your aux air is running frequently, you probably have some system air leaks. Sometimes the air will leak back through the compressor if you compressor is not fitted with a check valve on the delivery air line where it is connected to the air compressor. My aux air compressor may run once every 3 days for about 3 minutes.
[/quote]

Chuck:

My prevost has the aux compressor in 2nd passenger bay. They hide it behind some cabinets. Mine does not run all the time but sure can be heard for the 2-3 minutes it does run. I guess since it under my couch I hear it more. I need to make a mini hush box and air bags like gennie.

William Jensen
2001 Liberty XLII

[Hisham Amaral]

(03-30-2017 23:27)Maudi2001 Wrote:  I do not know where Liberty located their Aux air Comp on your vintage coach. Marathon locates the Aux air comp on my vintage XLII in the generator bay which is insulated quite well. I can hardly hear it from the inside of the coach. If your aux air is running frequently, you probably have some system air leaks. Sometimes the air will leak back through the compressor if you compressor is not fitted with a check valve on the delivery air line where it is connected to the air compressor. My aux air compressor may run once every 3 days for about 3 minutes.

Chuck:

My prevost has the aux compressor in 2nd passenger bay. They hide it behind some cabinets. Mine does not run all the time but sure can be heard for the 2-3 minutes it does run. I guess since it under my couch I hear it more. I need to make a mini hush box and air bags like gennie.

William Jensen
2001 Liberty XLII
[/quote]

William
My "H345" Axu. air compressor is in bay two Passenger side of the coach, it is between the 2 Crusair air compressors evaporators and the back panel of bay two on my coach, I have to remove back panel to gain access to it. In between the panel and the location where the compressor is installed there is an open area to the ground, covered with screen. Good luck working there I did that last year, you have to work laying down on the bay floor, I came out with cuts all over my arms from the screen. Also it is a bear to install the 4th nut the one that is behind one of the Crusair airs with limited space.