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ISSUE RESOLVED. The 3/4 to 1/4 reducing bushing was leaking. Tightened and no more leak.

 

 

2004 Dynasty. Front left air bag blew due to rubbing on the shock. Fortunately it blew while leveling and not driving. 

New bag installed and has a leak around the 3/4 to 1/4 brass reducing bushing. 

The leak is bad enough to totally deflate the bag in under 10 minutes after auto leveling. (The main compressor keeps it inflated properly while driving.)

While parked, the leak in this bag is also causing the other 3 front bags to totally deflate. While parked,  so the bags are not resting in a deflated status, we are temporarily inserting 4x4 between the axel and the frame at each of the 4 bags.

I suspected the HWH 6 pack was the cause of all 4 bags deflating, so we spent yesterday at HWH in Moscow IA.

They inspected and told me that the 6 pack was not the cause of the other 3 bags deflating. The also confirmed that the brass reducing bushing was causing the leak in the bag that was replaced.

When I asked them to explain why 1 bag leaking would causing the other 3 to deflate, the answer was "depends on how it was plumbed".

I am pretty sure when other bags were replaced due to age, their replacement did not cause other bags to lose their air.

While I will fix the leak either by tighten or replacing the bushing, I don't understand why the other 3 bags are losing all their air.

The auxillary compressor does not keep up with the leak when it is in sleep (automatic) mode.

Even if the main air tank is low on pressure the bags have always held their air in the past.

Any and all suggestions are appreceiated as to why the other 3 bags are deflating.

Thanks

Mike

 

Edited by bmulvenna@hotmail.com
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From a photo of a failed airbag, showing the internals of it here in this forum, I believe that there is an internal "stop" that the weight of the coach rests on when an airbag is fully deflated, so I do not think you are doing anything of value with the 4x4's.

As for the reason all the airbags on one 'axle' deflating, I'm no expert on how the system is plumbed, but I do not believe any one airbag has a check valve to trap the air into it, that the airbag is just a 'servo' or 'actuator' and the air exchange is controlled by external components.  Your other airbags that were replaced due to age... did they have holes in them or leaks? Or were they just old and cracked?

Hope you get your leak fixed and all works as designed.

 

Edited by Cubflyer
typo
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On my 2000 Windsor,  the front air bags share the same supply line per side.   Had a flat which the steel belts took out an air bag.  The entire passengers side dropped.  Fun hearing the steps grinding on the pavement before you can stop.

Screenshot_20220903_075854.jpg

Edited by toastmn
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2 minutes ago, toastmn said:

On my 2000 Windsor,  the front air bags share the same supply line per side.   Had a flat which the steel belts took out an air bag.  The entire drivers side dropped.  Fun hearing the steps grinding on the pavement before you can stop.

Wow, I'm surprised on one hand that the designers (engineers) did not allow for;   with a flat airbag and no tire, just a rim, that the body (stairs) would not scrap the ground... on the other hand it's not too big of a surprise....

 

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On 4/4/2022 at 3:46 PM, JDCrow said:

Not sure the Blue seas will let you run lithium? 

 

On 4/5/2022 at 8:39 PM, pwhittle said:

That is very fair of you, and I am happy to pass it forward the same way when the opportunity arises to help someone.

My address is 

Paul Whittle

18 The Fairway

Woodstock, GA 30188

At one point I thought mine had an issue, and even got the program for the on-board microcontroller from Intellitec to program a new one. Turns out I wasn’t operating it correctly. 😀 Mine needed you to press the switch for 3 seconds to disconnect, but connect was instantaneous. I think that was to prevent accidental disconnects.

 

On 5/6/2022 at 9:37 AM, RVKnight said:

Just recently replaced the air pressure valve sensor on my 2006 Monaco Knight after having an issue with lowering leveling jacks. Prior to replacing valve was getting an “engage parking break” warning preventing the jacks from engaging.  The replacement resolved the issue. However, more related to your question, I did notice during the repair by moving the plunger handle which engages the break caused an air leak around where the plunger is sealed entering the valve housing.   You may want to check for leaking in that spot. 
 

I was fortunate in getting help from this forum to resolve my issue. Wish the same for you. Best of luck. 

 

On 7/8/2022 at 6:33 PM, Reka52 said:

Are you sure they are original could someone previously put in a different from original 

 

On 7/17/2022 at 9:44 AM, Duffer51 said:

Raised floor and electric 

 

41 minutes ago, Cubflyer said:

From a photo of a failed airbag, showing the internals of it here in this forum, I believe that there is an internal "stop" that the weight of the coach rests on when an airbag is fully deflated, so I do not think you are doing anything of value with the 4x4's.

As for the reason all the airbags on one 'axle' deflating, I'm no expert on how the system is plumbed, but I do not believe any one airbag has a check valve to trap the air into it, that the airbag is just a 'servo' or 'actuator' and the air exchange is controlled by external components.  Your other airbags that were replaced due to age... did they have holes in them or leaks? Or were they just old and cracked?

Hope you get your leak fixed and all works as designed.

 

Thanks for the heads up on the "stop", I found a cut away and you are correct. Appreciate the input. Save us some work until I get the leak fixed 

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If individual bags had check valves there would no way to deflate them. The only way they can deflate individually is if the each bag had a control valve and I doubt that's the case. I'm pretty sure it's normal for more than one bag to go down when one leaks. It will depend on how many control valves there are. All the bags on the same control valve will go down together.

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16 hours ago, bmulvenna@hotmail.com said:

2004 Dynasty. Front left air bag blew due to rubbing on the shock. Fortunately it blew while leveling and not driving. 

New bag installed and has a leak around the 3/4 to 1/4 brass reducing bushing. 

The leak is bad enough to totally deflate the bag in under 10 minutes after auto leveling. (The main compressor keeps it inflated properly while driving.)

While parked, the leak in this bag is also causing the other 3 front bags to totally deflate. While parked,  so the bags are not resting in a deflated status, we are temporarily inserting 4x4 between the axel and the frame at each of the 4 bags.

I suspected the HWH 6 pack was the cause of all 4 bags deflating, so we spent yesterday at HWH in Moscow IA.

They inspected and told me that the 6 pack was not the cause of the other 3 bags deflating. The also confirmed that the brass reducing bushing was causing the leak in the bag that was replaced.

When I asked them to explain why 1 bag leaking would causing the other 3 to deflate, the answer was "depends on how it was plumbed".

I am pretty sure when other bags were replaced due to age, their replacement did not cause other bags to lose their air.

While I will fix the leak either by tighten or replacing the bushing, I don't understand why the other 3 bags are losing all their air.

The auxillary compressor does not keep up with the leak when it is in sleep (automatic) mode.

Even if the main air tank is low on pressure the bags have always held their air in the past.

Any and all suggestions are appreceiated as to why the other 3 bags are deflating.

Thanks

Mike

 

The partial answer to your question is correct - "depends how how its plumbed" .  But the full explanation really depends on the MODE the air leveling system is in.

When you are in the travel mode, all 4 steer axle airbags are connected together via the air suspension valving system.  This is to allow the front axle to act like a pivot so you don't twist the chassis as you're driving down the road.  So, if one steer axle airbag leaks, you also lose air in all the other 3 steer axle airbags.  If the leak is small, the steer axle leveling valve will keep the axle level as long as the engine air compressor can keep up.  Safety Note: Be sure to do your air brake leakdown test prior to driving to be sure the leak is not compromising the air brake system on your coach.

When you are in modes level, manual or the ignition is off, the DS and PS steer axle air bags are isolated.  So if you have a leak in one airbag lets say on the steer axle passenger side, the PS will lower, but the DS will not.  This is a problem because the chassis will twist unless the aux compressor kicks in the auto level to compensate for the leak. 

If you are in level mode or the system is shut off, and both the the PS and DS lower you either have a valve leak or multiple air bag leaks.  Also, keep in mind you have steer axle ping tanks and hoses to these tanks can leak. 

So, yes, depending on the air suspension mode, you can lose air in only 2 or in all 4 airbags.

But, if you are losing more than 2 PSI/minute from your air tanks with the parking brake released and air brakes not applied, the problem needs to be fixed before the coach is safe to drive.

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