[encantotom]

ken,

the air port in the rear should not be leaking.  like all couplers they hold the air in until you put the air hose or mail fitting in. 

a picture would help us of what your setup is.  on my 99 it didnt have an air port but the line was there and capped off so i added a shop air port. 

some coaches have the air doubler plumbed in as well and that should be valved off when not using. 

i pretty much only use prevost non whipping couplers in my shop and coach nowadays.  pricey but really nice

https://www.amazon.com/Prevost-071201-In...B01AKEITRQ

tom

[Highlander4744]

    Tom, I think my setup is the same as you described for your 02.
Two couplers in the chassis battery bay. One for air in and one for air out.
The one at the rear, which I presume is the shop air, appears to take that Mstyle plug
Richard referenced. I just discovered O’Reilleys has them in stock.
I have not posted photos before, so I will figure that out and post them.
Thanks to all. 

   

[Richard]

Not to split hairs on words but the one in the first pic will allow air to flow in OR out.

The second picture should be connected to the air pressure doubler. It is air out only. The function of that system and of the air pressure doubler is to increase the air pressure above the 90 to 120 psi normally present in the coach air system. For those with 315 tires on the front, it is hard to inflate to 130 psi with only 120 psi in the air line. So Newell kindly added the air doubler system. It should have a shutoff valve because the air doubler is a known leaker.

[Highlander4744]

Thank you for the clarification, Richard.
I was unaware that one was in or out and also
unaware of the air doubler. Good to know.
I will check for a shutoff on that line as well.
As a novice Newell owner I appreciate any and all guru input.

[Highlander4744]

Update: the shop air coupler is positioned same as yours Tom.  The sleeve needed some sweet talking to retract as designed, indicating it had not been used in a long time.  Attached the M style air plug and all works as advertised, hooked to the HF Fortress compressor I just picked up.  Next I will put a new capacitor on the Thomas 110 volt that is up front and then a check valve in the air doubler line. Thanks for that hint, Richard. Then finally will begin the leak locating. So far so good. Thanks all.

[Richard]

Not a check valve, but a shut off valve between the air supply and the doubler.

[Highlander4744]

Right