Rear air suspension.

[8.3Oilbuner]

Hello to all; I have a 2001 Monaco Windsor that the rear air suspension drops all the way down over night. Would come home and the next day the suspension would be all the way down. The day after that I would start the engine and build air till suspension was all the way up and would stay that way for weeks. Now that procedure makes no difference. There seems to be no leaks in the ride height valves. The suspension drops equally on both sides. I have read that there is a one way valve out of the rear air tank that supplies air to the ride height valves and then to the air bags. From what I understand is if that valve goes bad and lets air bleed back into the tank the suspension will drop. Can see the valve off the rear air tank, but I have tried to locate one online with no success. Can anyone point me in the right direction to locate one? Thanks in advance.

[windsorbill]

Not too familiar with your '01, but have you considered the 6 pack? Possibly the exhaust port? Have you tried the soap trick on all fittings?

I would think if you take the one way valve out and go to a truck supply shop, you should be able to match it up.

[CountryB]

You could install two check valves (or just one if supply air is teed to the RHC valves) - at the supply port to each of the rear "ride height control (RHC)" valves. That would isolate the air bag system for the rest of coach air system (in case the factory check valve is leaking). Then if air bags still leak down you know the leak is in the bags (or HWH manifold/valves, if you have air leveling).

https://www.anythingtruck.com/product/060-800375.html

[8.3Oilbuner]

Good morning; Thanks Windsorbill and CountryB for your suggestions. I forgot to mention that I do not have Air Leveling, so no 6 pack. As others have had air leak problems, it can be frustrating trying to find the source. I have done the soap spray on all fittings and valves and the only thing I got out of that was a bath of soapy water on myself! I am just trying to see if someone has replaced the one way valve out of the supply tank. The one I have on my tank, unfortunately, does not look anything like the one CountyB sent me the link too. That would be an easy fix to find the one like I have on my supply tank. I just might have to remove it and take it to a local truck supply. Have many close to me. Will keep looking and thanks for the responses. Have a great day!

[CountryB]

Look at the photos of check valves here. https://www.anythingtruck.com/catego...ves-check.html Most coaches have several different looking check valves.

The one I linked to in my post above was only a suggestion of a check valve you might want to add to help isolate the air suspension from the rest of the coach's air system. It would "not hurt" to add this to the inlet port of height control valve - and may aid in your troubleshooting.
For example...

[twinboat]

The ride height valves do 3 things.

1; They add air when the ride height is low.
2; They hold the air in the bags when at height.
3; They release air when the ride height is high.

If the bags are deflating, its the bags, lines to the bags or ride height valves leaking.

When at height, the valve is not supplying air to the bags, they are only holding it in. It only adds air if it sinks.

If the chassis air system pressure drops, and the ride height valves are letting the air flow back thru them, the actual leak could be anywhere. Spraying soapy water near them may be fruitless.

If there are no visible leaks, at or beyond the ride height valves, I suspect they need to be rebuilt or replaced.


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[CountryB]

Yes - to what Twinboat said.
If the air supply tank is low on air (or empty) and air bags leak down too, the ride height valve will mechanically open (to let air into air bags). But since there is no air in the tanks, any air remaining in the bags will just head out toward the tank. This is where the factory check valve at the tank comes into play - to stop air bags from deflating into the empty air tank. But if that check valve (at the tank) is leaking too (not too uncommon), all the air bag air will leak into tank and and air bags deflate completely.

[twinboat]

A second propose of the check valve would be if your depleting your air supply, possibly while slow speed maneuvering, below the pressure needed to support the MH, the bags will not drop from backflowing into the system while moving.

When parking your MH, are you letting it idle long enough to build the air system up fully ? That may be why the next day running fixed it.
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[8.3Oilbuner]

Good afternoon everyone; Thanks for your added suggestions. Of course with the older coach, the systems seem to loose more air when sitting. First, I have no problems with the front axle. Both tanks loose air at the same rate while sitting. It may take 3+ weeks for the front to start dropping. That is the norm for most of what I have read over the years. I think, like Country B mentioned, that as the rear system starts to loose some air and starts to drop, the ride height valves start to open to let air into the bags. Since there is not enough pressure in the rear tank to fill the bags, the air that is in the air bags starts flowing backwards through the ride height valves, back through the one way valve and into the rear air tank. It is that one way valve on the tank that I think is bad and letting air flow back through it into the tank. I have soaped up the ride height valves and get no bubbles. When the coach is running, I have plenty of air pressure in the system with the proper recovery when the compressor kicks in when called for even at low speeds. My 4 rear air bags are supplied through one fitting on the rear air tank. By the discussions here, and I did read somewhere, I think in this forum, that another owner had the same problem and by replacing that one way valve on the air tank cured his problem. If I can I will try to post a picture of that little devil so everyone can see what it looks like. I just have not found anything on the web that looks like what is installed on my tank. Will keep looking and thanks for everyone here who had responded to help. P.S. My system is set up just like the diagram Mike posted except I have 8 bags instead of 4 like the diagram shows.

[ZackMan]

Originally Posted by twinboat

The ride height valves do 3 things.

1; They add air when the ride height is low.
2; They hold the air in the bags when at height.
3; They release air when the ride height is high.

If the bags are deflating, its the bags, lines to the bags or ride height valves leaking.

When at height, the valve is not supplying air to the bags, they are only holding it in. It only adds air if it sinks.

If the chassis air system pressure drops, and the ride height valves are letting the air flow back thru them, the actual leak could be anywhere. Spraying soapy water near them may be fruitless.

If there are no visible leaks, at or beyond the ride height valves, I suspect they need to be rebuilt or replaced.


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twinboat,

I’m having the same issue but at the front of the motorhome. After two to three days it will drop and when I first start the engine, I need to manually raise the front, sometimes, to help reach ride height. Once I press “travel” on the Valid Pad (Power Gear), air is exhausted until It reaches the 9 inch ride height.

I had a new front ride height valve installed in 2015 and two new air bags (in front of the steers both sides) installed in May 2018. The driver’s side air bag was leaking when I sprayed a soapy solution and so I just replaced both sides. This coach has 10 air bags on a Monaco “S” chassis.

Could I possibly have a similar issue that 8.30ilbuner has with his rear air suspension?

Thanks for any feedback you or anybody else can provide.

[ZackMan]

Does anyone have feedback on my post above?

[CountryB]

Originally Posted by ZackMan

t I need to manually raise the front, sometimes, to help reach ride height. Once I press “travel” on the Valid Pad (Power Gear), air is exhausted until It reaches the 9 inch ride height.

I had a new front ride height valve installed in 2015 and two new air bags (in front of the steers both sides) installed in May 2018.

You should not need to manually raise the front. Even if you have an air leak in the front and the bags drain down, once the air pressure is built up the coach should lift to normal ride height on its own.

Unless the Valid "travel solenoid" (which I assume is similar to the HWH system) is not working. It may not be open at engine startup (system air up) so the air cant get to front air bags and raise coach.

It also sounds like you are manually "over filling" the air bags (lifting too high) then once you activate the Valid travel mode, the air is exhausted to lower coach to travel height. I don't think this is the problem - but the effect of the actual problem.

So I think two things are going on, 1) the Valid system is not going to Travel mode (the normal default mode) when the coach is started, and 2) there is an air leak in the system (but probably not ride height valves or air bags since they are relatively new).

If you have a copy of Valid Air system manual you could attach, I would be happy to study it and see where potential problems could be. I'm familiar with the HWH system and base my comments above, on the assumption that the HWH and Valid are simair.

[ZackMan]

Originally Posted by CountryB

You should not need to manually raise the front. Even if you have an air leak in the front and the bags drain down, once the air pressure is built up the coach should lift to normal ride height on its own.

Unless the Valid "travel solenoid" (which I assume is similar to the HWH system) is not working. It may not be open at engine startup (system air up) so the air cant get to front air bags and raise coach.

It also sounds like you are manually "over filling" the air bags (lifting too high) then once you activate the Valid travel mode, the air is exhausted to lower coach to travel height. I don't think this is the problem - but the effect of the actual problem.

So I think two things are going on, 1) the Valid system is not going to Travel mode (the normal default mode) when the coach is started, and 2) there is an air leak in the system (but probably not ride height valves or air bags since they are relatively new).

If you have a copy of Valid Air system manual you could attach, I would be happy to study it and see where potential problems could be. I'm familiar with the HWH system and base my comments above, on the assumption that the HWH and Valid are simair.

CountryB,

Please see attached documents and thanks!

[windsorbill]

Originally Posted by ZackMan

twinboat,

I’m having the same issue but at the front of the motorhome. After two to three days it will drop and when I first start the engine, I need to manually raise the front, sometimes, to help reach ride height. Once I press “travel” on the Valid Pad (Power Gear), air is exhausted until It reaches the 9 inch ride height.

I had a new front ride height valve installed in 2015 and two new air bags (in front of the steers both sides) installed in May 2018. The driver’s side air bag was leaking when I sprayed a soapy solution and so I just replaced both sides. This coach has 10 air bags on a Monaco “S” chassis.

Could I possibly have a similar issue that 8.30ilbuner has with his rear air suspension?

Thanks for any feedback you or anybody else can provide.

Zackman,

I have the valid system as well. You say when you start you have to manually fill the front air bags. Are you waiting enough time after the engine starts for it to do it by itself? If you push the travel mode, it might take a couple minutes, depending on how empty the air tanks are. Also there's no set way anything particular fills up first.