Air bag height control???

[fighterpilot]

Replacing front airbag on 1997 Monaco Dynasty. Rather than wait 4 to 6 weeks to get the rirestone 5319 that are on there the parts man crossed over to a firestone 5422 whose differences are bolts down thru rather than studs up thru and inflated 16.3 inch height capability vice 14.3. When I questioned the difference in height he noted my aircontrol valve would control the height and it wouldn't go clear up the extra two inches. Now if all 4 bags are the same is there a system that monitors front to aft height so it would sense the front were going too high and limit them to the equivalent height of the original airbags. Or is there a valve both fron and aft that work independently, according to how they are set to monitor the height? If the bags don't inflate to their full height wouldn't that put extra stress on them? I obviously don't know how the air control valve works. Thanks

[Pds47]

The problem would be solved if you replaced all bags and then set the ride height to coach specs. All of your bags are the same age and have been down the same roads .

[Pusherpilot]

I would expect underinflated bags to produce a mushy ride. As for the way the system works, there's a ride height adjustable valve on the front axle that controls both front bags height. In the rear each bag has a valve that controls their height individually so as to control not only height but lean.

Ron

[Mike Canter]

Lets think about this. The only time that the height control valve is used is when you are in travel mode driving down the highway. So what do you think would happen if parked on a slope for the night and you did an Auto level and it needed to raise up that corner that has the extra high bag. My guess it will over extend that corner of the suspension. What if you needed to raise up the entire mh to clear an object again my guess is it would over extend that corner. The other question would be if the fill rate would be the same and the deflated full down bumper inside would be the same.

[Mr_D]

The air bags all have the same pressure whether full or half full, the amount of air in them is controlled by the height control.
Some MH's have two valves in front and one in the rear and others have one in front and two in back.

[fighterpilot]

I intend to replace all 4 front bags. The condition of the front bags are much worse than the rear which makes me suspect maybe the rears have been changeed. The rubber surface is still intact on the rear and look "normal", although they may be old. On the front bag the rubber is gone over parts of the bag and the rest is stickin out like the "butch hair cuts" for us older folks. I'll see if I can figure hout how to send a picture.

The point on uneven ground is noted. Here I guess the control rod that sets the hight would be over ridden and call for max extension of that bag, Under those circumstances would the extra distance damage the shock, that is, would it exceed its length limit?

[fighterpilot]

Here is a picture of one of the front airbags.

[Mike Canter]

Anytime you are leveling you do not use the height control valves instead you use a piezio electric leveling sensor that is attached to the roof of the basement in the center area of the mh. I do not know how much over extension room on the height control valve there is. I am amazed at the picture of your bags. They look real bad. When I wash my motorhome I raise it up and wash the bags especial on the bottom where the rubber rolls up and down. About twice a year I put a rubber protectorant on them b

[fighterpilot]

Yes they are bad, and I knew it when we bought the coach, but didn't expect one would go out the day after we got it home. At least it held up for the 600 mile trip. Going to replace all 4 and get the part number for the rear so as to be ahead of the game.

The rubber protectorant sounds like a good idea. If the rear are the same age is there a logical reason why they are still intact, other than that have been replaced.