Skip to main content ↑ ↓
Topic: Airing up tanks from tire air valve? (Read 1213 times) previous topic - next topic - Topic derived from Retarder Temperature ...

Airing up tanks from tire air valve?

I need quick answer.

The air valve near the propane tank. I use it to air up my tires etc.

Can this be used to fill my tanks so the brakes can be released.

Thanks
Ed and Michele
2000 U295  36'  (Build #5600)
8.3 ISC 350HP.
2012 Jeep Grand Cherokee (Toad)
2001 Lance Truck Camper (Sold)
2001 Lazy Daze (Class C). RK Floor Plan (Sold)

Re: Filling tires - air valve on coach?

Reply #1 –
If you have a male to male adaptor it fills the tanks.
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: Airing up tanks from tire air valve?

Reply #2 –
Ed's question brings up the subject of providing a outside air source to your coach air system.  I think most owners are aware of this technique, but for the benefit of our newer members, it might be a good time to reiterate.

On many coaches, the tire air fill hose (or quick connect fitting if you don't have a hose) is supplied directly from your "wet" pressure tank.  This connection can be a convenient route to providing outside air pressure to your coach.  Why do you care about that?  If you ever need to have your coach towed, the tow truck operator will want to hook up a air hose from his truck to your air system.  Using the tow truck air pressure will allow him to release your parking brake, AND (with your ignition key "on") it will provide pressure to your suspension air bags to bring them up to ride height.  The other way to accomplish this is to leave your coach engine running (at idle) for the duration of the tow - not a desirable alternative.

The tow truck has a air dryer, so you don't need to worry about contaminating your air system with unfiltered air.  This is a good thing, because in almost any "tow" situation, you will already have enough other problems to worry about.  8)
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: Airing up tanks from tire air valve?

Reply #3 –
In reviewing the air system drawing for our coach, I don't see how air from the quick connect port can get to the brake system.  It feeds the leveling system for sure, but if -- and this is a big if -- the system check valves and protection valves are operational, it doesn't seem possible to recharge either the front or rear tank on our 03 U320.

Is the 03 air system the same as the one under discussion?  If yes then I must be missing something.
Mark Duckworth
2003 U320 4220
Build 6199, Motorcade 17971

Re: Airing up tanks from tire air valve?

Reply #4 –
Quote from: Mark Duckworth –
In reviewing the air system drawing for our coach, I don't see how air from the quick connect port can get to the brake system.
No, you are right - this procedure would not work on your coach.  Your system is a whole lot more complicated than the older models.  On my '93, the tire filler air hose connection comes directly off the wet tank, and no check valves in the line.

Just quickly scanning your air diagram, I don't really see a good spot to tap into the air system with a external supply.  The drain valve on the wet tank would work, but it's not in a very convenient location.  OR, you could make up a little "Y" manifold so you could attach the external air hose to both the front and rear air tank drain valves (in front of the left front tire).  That should do the trick...

Thanks for pointing out the difference in models.  I tend to forget how much the coach systems changed from year to year.  :facepalm:

(I edited my post, above)
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: Airing up tanks from tire air valve?

Reply #5 –
Photo below of a male/male adapter for connecting a external air supply.  IF connecting to the tire filler hose will work on your coach, then you could make one up ahead of time and carry it with you - might come in handy some day!
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: Airing up tanks from tire air valve?

Reply #6 –
Be aware that there are several different styles of end fittings. They do not appear at first glance to be much different, but they are NOT interchangeable.

So, make sure you get the correct ones.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Airing up tanks from tire air valve?

Reply #7 –
Quote from: Chuck & Jeannie –
Photo below of the male/male adapter for connecting a external air supply. IF connecting to the tire filler hose will work on your coach, then you should make one up ahead of time and carry it with you - might come in handy some day!
Mine is just like that. But has a shut off in the middle.
Chris and Tammy White  CDA Idaho
Previous owners 1997 U295 36' 3126 Cat 300 HP Build # 4998
Former Foretravel tech & RVIA certified tech
Former owner Custom Satellite home/RV satellites 
Former owner Vans LTD  van conversions
Unemployed, panhandler, drag racer NHRA #6348

Re: Airing up tanks from tire air valve?

Reply #8 –
Quote from: Chuck & Jeannie –
Just quickly scanning your air diagram, I don't really see a good spot to tap into the air system with a external supply.  The drain valve on the wet tank would work, but it's not in a very convenient location.  OR, you could make up a little "Y" manifold so you could attach the external air hose to both the front and rear air tank drain valves in front of the left front tire.  That should do the trick...
Here's a 20,000' view of how mine is now plumbed. The green rectangles and blue arrows show how I get external air in via a multi-stage filter/dryer system.  The aux air system was originally the HWH compressor alone, but it is now the HWH, a Porter-Cable 110v compressor and a new dryer system.  There's a shut off valve between the aux air dryer and the wet tank.  The OEM shut off valve was a solenoid operated from the driver's console, but mine is a manual ball valve because the solenoid died.  My 110V compressor has female quick connect fittings and I have a male-male as pictured above.
 
In a tow situation I can have the air line from the wrecker connected to the 110v compressor's tank via the male-male adapter.  Then it goes through the ATD dryer.  Then I open the shutoff valve and it feeds the wet tank.

 More description is available in this previous post.
Mark Duckworth
2003 U320 4220
Build 6199, Motorcade 17971

Re: Airing up tanks from tire air valve?

Reply #10 –
How can Ed & Michele's idea work?

Air hose is supplied from wet tank.  Wet tank supplies air to front brake air tanks.  Front air tanks feed air to brake canisters to compress parking spring and release parking brake.

Their idea sounds like perpetual motion. 

Re: Airing up tanks from tire air valve?

Reply #11 –
Quote from: Barry & Cindy –
How can Ed & Michele's idea work?

Air hose is supplied from wet tank.  Wet tank supplies air to front brake air tanks.  Front air tanks feed air to brake canisters to compress parking spring and release parking brake.

Their idea sounds like perpetual motion. 

The air source is external-- supplied by a tow truck, etc.  That is why the male/male adapter.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Airing up tanks from tire air valve?

Reply #12 –
I beleave my 99 has check valves in the air system that would prevent back feeding the air system from that connection.
Bruce, Linda, and Macy
Zoey RIP 1/20/19
1999 U295 40' build #5400
2017 silver Jeep Wrangler, 1260 watts of solar on top
Moving around the country

Re: Airing up tanks from tire air valve?

Reply #13 –
Quote from: bbeane –
I beleave my 99 has check valves in the air system that would prevent back feeding the air system from that connection.
If that is the case my check valves don't work as I can raise the coach from the fill hose coupler. And release brakes. Both air gauges go to whatever pressure I put in it.
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: Airing up tanks from tire air valve?

Reply #14 –
Quote from: Mark Duckworth –
I'm going to add a shut off to my M-M adapter.  Great idea.
Me 3!  Excellent upgrade!  ^.^d
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"