Air bag suspension and maintenance

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KandT

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So I finally decided on a Winnebago Vectra 36RD with the Cat 350.  Quite a different machine than my e450 class C. 

What do I need to know about airbag suspension?  Do the bags need additional air added over time or does the engine compressor take care of that?  Do they frequently wear out at this age and if so what should I expect to pay for replacements?

It does drive like a dream and in my opinion is easier to drive than my e450.  I can't believe how tight of an area it will turn in.
 
The coach air system takes care of inflation on those bags. I'd not be too concerned about them being worn out this soon, unless there's been a bit of abuse. You might want to peruse the Freightliner Custom Chassis site's maintenance tips for a few diesel maintenance hints. In addition they have a lot of other information on that site. A lot of the information there is useful even if you have some other brand of chassis.

I can't believe how tight of an area it will turn in.
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Yup. They make them so that the steering turns much more sharply than you're used to in other vehicle, which helps a lot in turning radius.
 
thanks Larry!

Should I be able to adjust the bags at all?  They don?t seem to raise and lower the coach when it is running or turned off.  I think there may be a dump on the leveling jack board but no other adjustment.  The back of the coach ?looks? low.  It is at Freightliner now being Pennsylvania inspected so they may shed some light on it.

Thanks - I am new to this world!
 
The air bags should last 20-30 years. There is an onboard compressor that runs off the engine and automatic valves that control the inflation, called "ride height valves". If a ride height valve is out of adjustment, the inflation at one end or corner may be too much (high) or too little (low). The system stays inflated when the engine is off, but small leaks in the air plumbing will eventually (or sometimes quickly!) let them deflate.

Most coaches have a "dump valve" that will release air from the suspension. It may be a manual switch on the dash, or may be automatic when the leveling system is engaged at a campsite.
 
KandT said:
thanks Larry!

Should I be able to adjust the bags at all?  They don?t seem to raise and lower the coach when it is running or turned off.
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As Gary indicated, the ride height adjustment should take care of any needed adjustments (probably a shop adjustment, unless you really know what you are doing). As to raising and lowering, when you level the coach, it probably will dump the air, then extend the leveling jacks. After retracting the jacks, it'll sit low until you run the engine long enough to get the air up to normal, then you should notice the coach coming up to ride height. If you're outside watching when the air gets up, you'll probably see the coach gradually rising for a bit. Take note of how high it sits when leveled (it varies), after retracting the jacks, and after getting it up to ride height.

I'd caution you to be sure you're up to ride height before moving the coach -- you don't really want to drive when it sits low and is resting on bottom, talk about bumpy (and not good for the coach, either).
 
Another important consideration about air-ride systems, is to make sure your front wheels are straight (or close to it) before leveling the coach, and/or dumping the air. In many coaches, the front tires will hit the fenders if the air is dumped while the front tires are turned. It could do some real damage to our fiberglass fenders. Some coaches don't have that limitation, but ours does.

I'd also recommend reading up on the whole air system, because it also involves the service brakes. Here in California, I was required to receive training on our air brakes, from a Commercial DMV instructor, before I could get my license. It was good training.

Kev
 
Thanks for all the replies and information.  This is the part of the coach I am most intimidated by.  I do have to get a class B license here in Pennsylvania.  Unfortunately, they don?t offer training, just a book.

Is there likely a water bleed that I should make sure I am emptying everyday?  I know in every other compressor I have owned compressing air leaves the water in the air behind.  I read that some have air dryers to minimize this problem.  I am not sure where they might be located on a Freightliner Chassis.
 
The coach air tanks do have water valves you can open occasionally, but the compressor is equipped with an air dryer that largely makes that unnecessary. However, the air dryer has a desiccant cartridge that needs to be changed every 2-3 years (depending on run time). Most motorhomes are fine with a change every 3 years. Unless you know when (or if) the former owner changed it, I would do so now so that you know the system stays dry as it should (must).

The air tanks valves are under the coach, between the frame rails, but may have lanyards out to the front wheel wells that you can pull to open the air/water drains.
 
The transmission also has filter(s) that need to be changed periodically. As a new owner, you should change those too, so you know it is done and when the next time is due (about every 3 years for most motorhomes). Ditto for the primary & secondary fuel filters and the air filter. It can get fairly expensive if you don't have any maintenance records to prove any of that was done lately. Also, did the dealer do an oil change before you got it?
 
I bought it as a private sale and I can guarantee you he did not do an oil change.  I took it to freightliner and they are doing a PM2 as they called it which was all the filters and oil.  I doubt they meant the transmission filter though.  I am trying to take this one problem at a time and right now I am most interested in the fact that it seems to have no more power after a certain spot on the pedal.  Of course fuel filters are the suspect and I hope their is not algae in the diesel.  Right now it climbs hills slower than my e450.

Thanks Gary!
 
Is the transmission filter external on an Allison 3000 or is it a big project to change the filter???
 
If it is an Allison 3000, there are two filters under cover plates in the bottom of the tranny.  They aren't spin-ons, but they are cartridges that drop out when you remove the covers. You lose about a gallon of ATF changing them out.  There is also a main internal filter, but that only gets changed if the tranny has to be torn down for a major repair. It is not considered a maintenance item.

There are two YouTube videos on the procedure:
https://www.youtube.com/watch?v=lZD8ey8mUo8
https://www.youtube.com/watch?v=YBN6xrY1IAk
 
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