Hello all,I just picked my 2002 Itasca Horizon 39QD from Winnebago -- they did paint & body work to the coach over the last two weeks...So I drove it about an hour south to Henderson, IA and met with a church (for what I do for work - sound/video/lighting systems) Once I fired up the rig to head home, which is a 3 hour drive, I got about 3 miles from the church and the "Low Air" light and buzzer came on. I had about 65psi in both front and rear tanks.I have tried everything I know to do and i cannot build any more pressure. Started and stopped the motor, revved it, purged the air tanks, I even tried sending compressed air into the schrader valve inlet on the air dryer. (the air dryer is only about a year old or less)There is no apparent hissing or leak anywhere that I can tell, but it more seems like the compressor is unloaded and just not building any air pressure.Help! i''m stuck here and my kids are home without me! (I'm a young widower with two young kids - 5 and 7) I had a babysitter today, but she had to leave, so I was able to get someone else to stay the night with them, but I need to get this thing running and home safely!

First of all let us know what engine you have in your Winnie...my first guess would be a stuck unloader valve. Look on your air dryer for one and tap it with a screw driver or wrench. My second guess would be a bad governor. Any mobile mechanic can fix the in about 30 mins or less if he has one on his truck...good luck....Dennis

The manual for a Jet system says that you can air it up through the Schrader valve with the system in manual mode. That is supposed to hold the air in the bags.

Stuck open unloader valve on the air dryer normally makes a lot of hissing noise but a stuck governor on the compressor will be quiet.Heard of people getting out of trouble by tapping/banging the governor to free it.

It is a CAT 3126 engine on a Freightliner XC Chassis.I don't hear any loud hissing sound.I did try to push air into the system via a small air compressor into a schrader valve on the air dryer, which dumped a bit of water when I pushed the center pin on it... but I have about 40-50 psi in my tanks now, but pushing air into the bottom of the air dryer will just amont to it going nowhere (helpful) that is.So if it is the governer - is that something I can tap with a hammer to try and free up or is it a replace only deal?

Tapping on the governor will not hurt, but it's function is to put 120psi air to the unloading valve in the compressor to stop building air. The unloading valve is like a normally closed switch so the pump should put out air without a working governor.Assuming no air leaks, broken hoses, or air coming out of the air dryer I would start by taking the hose off from the inlet to the air compressor and put your hand on the inlet and see if you have suction... not pulsating air or no indication. If no indication of air movement then I'd remove the two large bolts on the top of the heads and see if something is holding one of these oneway valves open. If you have pulsating air, then remove the two bolts that hold the air intake elbow off and see if there is any movement of the unloading valve with the engine running. Hopefully there is something holding this valve open. If no suction or pulsating air, then the drive for the pump is broken. This may help in understanding this system.

Rig Down! No air pressure... Help please | Good Sam Community

20 Replies

wny_pat1
Explorer
May 05, 2013
I believe your governor should be right after the compressor. Tony posted a good pic of it in post 4. Here is a good MeritorWabco troubleshooting flow chart for reference: http://www.meritorwabco.com/MeritorWABCO_document/tp9974.pdf
tony_lee
Explorer
May 04, 2013
wny_pat wrote:
TDInewguy wrote:
So do I need to be worried of getting too much pressure now?
That is what the governor does! There are also safety pop off valves on each tank. But I'd get that air dryer taken care of some

There is also usually a control line running between the air dryer and the governor but if it is the governor that controls the airdryer rather than the other way around then it won't matter. Which controls which?
Trackrig
Explorer II
May 04, 2013
For my education:

The OP said he now has air pressure by bypassing the air dryer and asked if he needs to be worried about too much air pressure?

wny_pat said that is what the govenor goes.

My question is: Is the govenor part of the air dryer which is now disconnected or is the govenor located elswhere in the air system and should be still functional?

Bill
wny_pat1
Explorer
May 04, 2013
TDInewguy wrote:
So do I need to be worried of getting too much pressure now?
That is what the governor does! There are also safety pop off valves on each tank. But I'd get that air dryer taken care of some
Acampingwewillg
Explorer II
May 04, 2013
I just posted a couple of days ago about what my air dryer was doing.....Over the past year or so, it was taking longer and longer for air pressure to build. I sometimes had to feather/rev up the engine to finally get pressure up. Admittedly, I hadnt done maintenance on my Dryer in a few years so during this years oil/filter changes I also got the rebuild/filter kit for my dryer. Long story short, after completing the install, pressure builds immediately again and there is No waiting for it involved.

Glad you got yours up and going....I know the frustration you speak of.
wolfe10
Explorer
May 04, 2013
Your approach is exactly on track.

If you don't hear a massive air leak with the engine running, and you know this is not a gauge issue (easy to check if you have an air chuck/hose) if there is a place you can get a couple of fittings, temporarily bypass the dryer (good parts for an emergency kit anyway).
TDInewguy
Explorer
May 04, 2013
I bypassed the air dryer and I've got air pressure now!

Yay!

So do I need to be worried of getting too much pressure now?
TDInewguy
Explorer
May 04, 2013
I took the main outlet hose off the air compressor and the compressor blows plenty of air...

So now to look underneath... Maybe the air dryer?
J_Walker
Explorer
May 04, 2013
I seem like there is a leak somewhere that you have not been able to find. In a situation like yours a mobile tech might be the best bet for quicker results.
TDInewguy
Explorer
May 04, 2013
Well,

I just got a new governer installed and no air pressure is building...

-- frustrated --

Now back to the drawing board and to keep lookin for problems...