Airbag Leaking 2006 Nimbus 336

Topic: Airbag Leaking 2006 Nimbus 336 (Read 1749 times) previous topic - next topic

Airbag Leaking 2006 Nimbus 336

January 08, 2021, 12:52:41 pm

Like others I am having problems with airbags.

o The airbags on my look good.
o Some minor surface checking.
o The front airbags look better than the rear.

Went camping this week. The campsite had a maybe a 6" slope. The pavement had a crown. Maybe 1" side to side.

I leveled the coach. Plenty of travel for that. The rear passenger bag was inflated. The passenger front was pretty high. The driver side was a little more inflated than the passenger. About what you would expect.

The problem was every 30 minutes the coach would dump air and re-level. I returned home and left the coach in travel mode. Looked at it an hour later and the passenger front was down. Drivers rear was high Passenger rear was normal and passenger front was normal.

Ok looks like a leak in passenger front.

Got on line and found the HWH web site. They have a online technical course that can be accessed by anyone. I looked through the leveling system section. There are several leveling algorithms used. The one used depends on the age or the system and conditions at the time. What I was seeing was the air was dumped then the coach was re-leveled from scratch. Every 30 minutes to 1 Hour.

So I figure the passenger front is leaking. If it leaked down far enough at the 30 minute check it would execute the algorithm where all air is dumped then the coach is leveled. Annoying to say the least. The pump on my coach pulls from the starting batteries. This is a problem because the starting battery bank is not normally charged while plugged in. The starting bank is AGM, the house bank is gel cell batteries with different charge requirements. So using the boost switch for long periods is not acceptable.

We lived with this problem for three days. When time to leave the starting bank was low but I was able to start the engine.

We made it home yesterday afternoon. I left the coach in travel mode.

An hour later the passenger front was way down. All other corners of the Coach were still at ride height. The driver Rear was elevated some "lifted because the passenger side was down
Like I said air bags look good. No obvious problems with the air lines or fittings. I have a few questions.

1. How long should the bags remain inflated before leaking down.
2. If there is not a leak in the air bags or lines where to start on the valve block. I am thinking about the dump valve for the passenger side.

PS: The only leak I can find is at the input to the pressure regulator for the leveling system. I see bubbling at the push to connect fitting screwed into that regulator. I plan to fix that leak but that is not my problem.

Looking for guidance as to what to expect and problems others have found. I have read much of the related posts on the forum. I might have missed something. Someone may have information that was never posted.

Thank you. T.O.M.

PS: As an Engineer I have worked on Seismic vibrator trucks. We put 60,000 lb vibrators on Mac truck tractors and later custom designed chassis. Our mantra was "Keep it Simple Stupid" My observation is that was unheard of in the RV business. :-{

Re: Airbag Leaking 2006 Nimbus 336

Reply #1 – January 08, 2021, 02:07:58 pm

I checked all the air connections related to the front airbags. No leaks found. Used soap.

The only leak I know of is the connection to the pressure regulator. This line could drain the front air tank. I do not see how that would cause the front air bags to deflate by its self. Still plenty of air in the front tank after the front end drops. I plan to fix that leak just because It might get worse and cause brake problems.

Re: Airbag Leaking 2006 Nimbus 336

Reply #2 – January 08, 2021, 02:13:58 pm

Are you sure one is leaking down and it's not an opposite side/corner leaking UP? Based on your description, I might suspect the driver rear raise solenoid valve on the rear sixpack.

We had very similar behavior years ago - the solenoid valve seat on a raise solenoid was leaking through, causing one corner to raise. That caused the coach to relevel every 1/2 hour to hour.

It took measuring the distance between the airbag plates on all airbags every 15 minutes for a few hours to discover the issue. The height of the bags on the corner that had the internal leak through on the raise solenoid INCREASED without the aux compressor running.

Our leveling system problem

What we found:

HWH Leveling Valve

A replacement solenoid valve (or a rebuilt one) is a good part to carry.

Have you also checked the sixpacks for leaks? A common leak point is the o-rings that seal the solenoid valves to the six pack manifold block.

Encantotom sells rebuild kits for the six packs that include all o-rings and new valve seats.

Re: Airbag Leaking 2006 Nimbus 336

Reply #3 – January 08, 2021, 02:41:37 pm

When in level mode the front passenger goes down. Rear does not change. When HWH wakes up it dumps the air and re-levels.

In travel mode in storage the front drips in about 30 minutes. If left long enough the front bags are completely deflated. Can push the sides in with fingers. The passenger side goes down first. The coach leans and causes the driver rear to rise slightly.

I suspect the problem is one of the six pack valves. I am not sure I can work in the six pack without disconnecting all the lines. It is tucked up under the coach and the air line routing sucks.

Re: Airbag Leaking 2006 Nimbus 336

Reply #4 – January 08, 2021, 02:51:25 pm

My air bags stay up for days. In over a week they will be down some.

Re: Airbag Leaking 2006 Nimbus 336

Reply #5 – January 08, 2021, 03:07:41 pm

I raised the coach for leak checking 30 minutes to one hour ago Used the All raised button Then killed engine.. Put the 12 inch safety stands in place. Just checked the rear has about an inch distance between the stands and the frame. Does not look if it went down at all.

The passenger front is down tight on the stands. Driver front has about 1/8 inch clearance between the frame and stands. Front going down passenger side faster than driver side.

Re: Airbag Leaking 2006 Nimbus 336

Reply #6 – January 08, 2021, 03:09:16 pm

Old Guy -

That is what I expected to be the norm. I purchased this coach a couple of months ago and that has never been the case for me.

Re: Airbag Leaking 2006 Nimbus 336

Reply #7 – January 08, 2021, 03:27:01 pm

I checked all the air line connections.

Put soap around the base of the six pack solenoids. Could not see leak but hard to see with manifold installed.

Re: Airbag Leaking 2006 Nimbus 336

Reply #8 – January 08, 2021, 03:31:58 pm

Another potential problem. When I started the engine to build air and raise the coach. Engine oil pressure showed 80 PSI.

It is a little cold today. 50 degrees or so.

Re: Airbag Leaking 2006 Nimbus 336

Reply #9 – January 08, 2021, 03:45:44 pm

That's normal to have high oil pressure at startup. It will drop as the engine warms up.

Re: Airbag Leaking 2006 Nimbus 336

Reply #10 – January 08, 2021, 03:50:58 pm

Michelle-

They were available in 20012. Still available? Newell forum?

Need to get part numbers off my 2006 valve body to see if correct parts?

I do not want to tear the six pack down without at least an o-ring kit.

Re: Airbag Leaking 2006 Nimbus 336

Reply #11 – January 08, 2021, 04:08:02 pm

Quote from: tmehrkam – January 08, 2021, 03:50:58 pm

Michelle-

They were available in 20012. Still available?

As of last week Rebuild-replace 6 packs

The topic linked explains how to contact Tom.

Re: Airbag Leaking 2006 Nimbus 336

Reply #12 – January 08, 2021, 11:34:39 pm

I recently experienced a similar issue and found that the auxiliary air chuck had a leak and some how affected the leveling of my coach. Perhaps your leak is not in the level system but an accessory to it. Just a thought. I wouldn't think it would be the case, but it solved my issue.

Re: Airbag Leaking 2006 Nimbus 336

Reply #13 – January 12, 2021, 10:52:56 pm

This has nothing to do with the air bags, they are above my pay grade, finding leaks ok but these forum members are genius when it comes to HWH.
HOWEVER: you mentioned the compressor pulls from the start battery system, you should add a Trick-L-Charge which will keep the engine/start batteries charged when the house batteries are charging.
Mega TRIK-L-START Starting Battery Charger/Maintainer
PS: you should fill in by "your signature" with your coach information, it helps people when they are trying to diagnose an issue.
Good luck
David

Re: Airbag Leaking 2006 Nimbus 336

Reply #14 – January 13, 2021, 09:31:55 am

I have been working on that. I have a maintainer charger. It is a little small for my starting bank. 3x AGM batteries. The one you mentioned says appropriate for 2 batteries.

Mine will time out when charging. It assumes max battery size is 260 amp hours. My bank is 300.

I upgraded my profile to include the coach description and build number.

Re: Airbag Leaking 2006 Nimbus 336

Reply #15 – January 13, 2021, 03:18:36 pm

There appears to be a small amount of moisture in the leveling system.

Opening the drain valves on the front air tank does not show any moisture.

The dryer on the aux 12v pump is beginning to need replacing looking at the color of the desiccant.

The one valve I examined on the six pack showed a small amount of moisture. Valve seats and seals look good. I am trying to get a kit before I tear anything else down. Is this to be expected even with good driers? Remember the aux pump started once an hour / 30 minutes for three days due to the air leak in the front air bags.

Re: Airbag Leaking 2006 Nimbus 336

Reply #16 – January 13, 2021, 04:49:31 pm

That desiccant (for the aux compressor) will change color fairly quickly, especially if you are in a humid environment.

You can search the forum on how to regenerate it (bake) so you don't need to throw it out.

FOT used to sell it for a ridiculous amount of $ (it was $40 10 years ago

). You can buy cans of the desiccant and make your own pouches. I don't know if the links in my old post are still good, but you get the drift

Desiccant option for the HWH system

Re: Airbag Leaking 2006 Nimbus 336

Reply #17 – January 14, 2021, 01:30:57 am

In LINE Desiccant AIR Dryer for Compressed AIR Great for Pneumatic Tools...
Wisesorb Premium Quality Desiccant Bulk Material (Indicating Silica Gel...
Great idea. I like
Scott

Re: Airbag Leaking 2006 Nimbus 336

Reply #18 – January 15, 2021, 03:03:24 pm

I purchased some desiccant off Amazon. Due here this afternoon.

PS: I have not found the source of my leak for certain. I have checked all the airline fittings for leaks with soap and made sure all the compression fittings are tight. "I was very cautious not to over tighten."

I dissembled and inspected all the valves on the side that has the worse leak. No smoking gun. O rings need replacing but no obvious leaks. One of the rubber seals on one plunger was worn more than the others. The dump solenoid. That might me the problem but It looks like it should seal to me. Valve seats look perfect. Put it back to together raised the coach leak tested again. No obvious leaks. Leaked down the same way as before. Used a mechanics stethoscope to listen for leaks. Nothing obvious.

I have requested the rebuild kits from TOM McCloud. I will rebuild the front six-pack and see where I am at.

Cannot detect any leaks around the pressure switches.

If the six packs do not fix it I may have to take the trek to MOT. Hope not I need tires this year so I do not want to spend a whole lot of money at this time but may have no choice.

Air loss is about then same raised state or travel mode. The common thing is the dump valve.

PS: I noticed the driver travel valve had been replaced some time ago. The level valve should be isolated when the coach is raised?? I have not checked it because the leak down occurs in the raised condition.

Re: Airbag Leaking 2006 Nimbus 336

Reply #19 – January 15, 2021, 04:13:39 pm

Might take a read of this thread about pulling the 6 pack and bench testing to find leaks.
Good luck finding and getting it repaired.

Re: Airbag Leaking 2006 Nimbus 336

Reply #20 – January 17, 2021, 02:57:36 pm

Received the Desiccant I ordered. I removed the dryer bowl. The tube was stuck so I removed the nut and removed it separately.

What I found is a whole lot of corrosion. The screen at the bottom of the tube is plugged. There was an O-ring at the bottom of the tube that was way to big do be of any use. Probably deteriorated.

The screen at the top of the Drier was corroded and almost plugged.

Looks like a new drier is in the near future. I cleaned it up the best I could put new Discussant in and reinstalled the bowl. Enabled the air pump and took a while but aired up to 85lb and shut off. I will order a new drier and install it when received.

Looked like photos of dryers off older coaches in the forum. The bowel was in fine shape no cracks.

Re: Airbag Leaking 2006 Nimbus 336

Reply #21 – January 17, 2021, 08:21:13 pm

Quote from: tmehrkam – January 17, 2021, 02:57:36 pm

Received the Desiccant I ordered. I removed the dryer bowl. The tube was stuck so I removed the nut and removed it separately.......Looks like a new drier is in the near future......

I have had good luck on several rvs with purchasing remanufactured units from the manufacturer, thru Napa Auto Parts.

Re: Airbag Leaking 2006 Nimbus 336

Reply #22 – January 17, 2021, 09:22:07 pm

Quote from: Jack Lewis – January 17, 2021, 08:21:13 pm

I have had good luck on several rvs with purchasing remanufactured units from the manufacturer, thru Napa Auto Parts.

He's referring to the HWH desiccant bowl, not the main engine air dryer.... NAPA's not going to have the HWH bowls...

Re: Airbag Leaking 2006 Nimbus 336

Reply #23 – January 17, 2021, 10:51:52 pm

Ordered one from ZORO on ebay. About $50 for a new one with shipping. Will be here in a little over a week. I have to old one to use before then. It is pretty stopped up but not completely. Has new desiccant so it should be fine until I get the new one. Should be able to rework the old one as a emergency spare. Need to fabricate a new bottom screen.

Re: Airbag Leaking 2006 Nimbus 336

Reply #24 – January 18, 2021, 07:25:38 pm

Raised and dumped air two times using the aux pump. Took a while to raise of course the dryer is pretty clogged.

After two cycles looked at the desiccant. The desiccant was blue at the top. A little less than 1/2. Then orange and very bottom basically white.

Tying to get dry air in the system.

The 40 year shop hygrometer read a little over 60% weather forecast says 75%

Is this what you would expect? How often do you guys change the desiccant?

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