Does HWH leveling mess with the tag axle?

[wamcneil]

Hi all,
2003 Dynasty on RR10 chassis and HWH automatic air leveling
Took the rig on our first 1k mi journey last week! About the only issue encountered was overloading of the tag axle on the way home.
Night before our last leg of the journey, the site was a little too sloped to fully level the coach. The HWH system got it real close before it gave up, with the rear of the coach all the way up. Next morning I checked the tire pressures before taking off, and pretty soon TPMS showed unusually high pressures in the tag axle. Stopped to inspect and the tires looked visibly overloaded. So I manually lifted the tag to dump the air bags, put the tag back down and everything looked normal, pressures returned to normal pretty quickly.
I suspect that lifting the rear all the way up introduced more air into the tag airbags and it didn't get let back out when the back end came back down.
So, here's my question: is it 'normal' for the tag air bags to get stuck with excess pressure after a leveling event like this?
In other words, do I have some kind of problem I should be diagnosing, or should I just remember to lift the tag axle to reset its bag pressure before moving the coach?
Thanks!
Walter

[Twomed]

In other words, do I have some kind of problem I should be diagnosing, or should I just remember to lift the tag axle to reset its bag pressure before moving the coach?

Exactly what you figured out the same thing can happen if you raise the coach to the limits with ^^^raise^^^ button for any reason.

[wamcneil]

Ok. Thanks.
So, let me see if I understand this. The rear ride height is set by the drive axle exclusively?
Then the tag axle pressure is set by the regulator in the engine compartment, but is not directly involved with the leveling system(s)?
If that's the case, then when the rear is lifted, additional air enters the tag airbags at the regulated pressure. But check valves on the bags prevent it from returning to regulated pressure once the rear end returns to ride height.
Is that how it works?

[MTK46]

Originally Posted by wamcneil

Ok. Thanks.
So, let me see if I understand this. The rear ride height is set by the drive axle exclusively?
Then the tag axle pressure is set by the regulator in the engine compartment, but is not directly involved with the leveling system(s)?
If that's the case, then when the rear is lifted, additional air enters the tag airbags at the regulated pressure. But check valves on the bags prevent it from returning to regulated pressure once the rear end returns to ride height.
Is that how it works?

I've lifted mine to max height. Once the engine was started or I manually lowered it the tag came down like all other axles.

[Windecker]

Thanks for asking this, I am new to a tag axle coach so

I just assumed the tag was playing along so to speak with the leveling system but what you said all makes sense.
Thanks
Windecker

Originally Posted by wamcneil

Ok. Thanks.
So, let me see if I understand this. The rear ride height is set by the drive axle exclusively?
Then the tag axle pressure is set by the regulator in the engine compartment, but is not directly involved with the leveling system(s)?
If that's the case, then when the rear is lifted, additional air enters the tag airbags at the regulated pressure. But check valves on the bags prevent it from returning to regulated pressure once the rear end returns to ride height.
Is that how it works?

[RobRoy]

Originally Posted by Twomed

In other words, do I have some kind of problem I should be diagnosing, or should I just remember to lift the tag axle to reset its bag pressure before moving the coach?

Exactly what you figured out the same thing can happen if you raise the coach to the limits with ^^^raise^^^ button for any reason.

Interesting?

I have never tried to lift my coach past the automatic travel mode.

Are you saying that it will go higher than the automatic travel mode when doing it manualy? ...and if so, what are the pro and cons of doing so?

[azpete]

be careful. it will lift temporarily, but doesnt hold. it returns to regular height in about 6 minutes without you touching anything.

[Mr_D]

My MH has a Ridewell RADT-246 drive/tag axle unit and HWH air leveling. If I sit and idle for a while the rear lifts all the way up. The cure was supposed to be cutting a couple wires to one of the control modules which has been done. BUT it still does it. Considering a trip to HWH to have the Active Air installed and check the HWH slides too.

[Twomed]

Originally Posted by azpete

be careful. it will lift temporarily, but doesnt hold. it returns to regular height in about 6 minutes without you touching anything.

It will hold (engine off) if you hit the stop button. Maybe...read on

This conversation is one of those that we need to read the manual for OUR PARTICULAR system. Monaco used the HWH 600 series for early 2000's then changed to HWH 2000 series. Different control buttons on each system. Manuals for both are available online as well as a very complete install/trouble manual. After the bankruptcy they used even different systems.

SOOO this is one of those that the proper answer is read the manual first...not as a last resort as we are sometimes prone to do.

[Bill767]

Our Navigator has a Valid system and allows us to raise or lower the coach from travel height for a limited amount of time. We have used it several times when entering and exiting the Alaska Ferry when the clearance on the ramps was very close, also if turning into a driveway that was inclined enough to perhaps hit the bottom. Has proven to be very handy.

[Windecker]

I am not sure but I believe his question had nothing to do with manual raising or how long it will stay up, temporary use or whatever.

I believe the question is: after raising the back of the coach with HWH levelers for purpose of leveling the coach, does the tag axle automatically return to ride height once you are ready to get back on the road or do you need to dump it (raise the tag) first.

Somewhat easy to test I guess but I am curious also. I would be surprised if this is in the manual but good idea to check that out!
Windecker

[wamcneil]

Right, that's the question.
I guess I need to read the manual to understand what-all the system is supposed to do.
I just skimmed the 600 and 2000 series manuals, and the schematics show a bunch of gear typically connected to the tag axle (Travel, Lower and Raise valves for each wheel), so I think it probably does have the capability to bleed the tag down along with the other axles when changing from Level to Travel modes.
Seems like it would be a liability issue to overload the tag axle after leveling, unless somebody remembers to manually dump the tag.

[DtBt]

Your tag axle has its own set of air valves that work with the rear axle set. When in travel mode the presure on the tag air bags are controlled by the pressure regulator in the rear on you coach. In leveling mode there are raise and lower valves that work at the same time as the drive axle side. From what you describe I think your pressure regulator failed to dump excess air when you went from level mode to travel mode when you had max air in the tags. Another possibility is both raise valves stuck open which is highly unlikely. Those pressure regulators are known to be troublesome including the gauge.