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Suppply Air Tank Missing Petcock?
#1
Laureen and I have been hearing an air leak forward of the rear tires (single axle) on our 1984 Newell Classic and we are losing air rapidly from the supply (house) system. We can hear it from both sides of the coach, maybe a little louder on the passenger side. When we turn the coach off and the (only) compressor quits the supply air gauge on the dash quickly falls from 120 psi to zero. It takes only 15-20 seconds to lose 10 PSI for the first 60 pounds or so on the house side according to the dash gauge. The brake system psi holds fine and the air bags stay up. The coach's air system is simple, using air for brakes, air tanks, air bags, ride height adjustments, leveling and horn. We have front and rear six packs with MAC air valves. Nothing is automated. 

Today we spent some time looking around under the coach by taping a phone camera and a couple of Harbor Freight free lights to a long, narrow strip of wood flooring and taking videos of the underside of the coach. Doing so led to us finally finding our supply (house) air tank or at least one of them (don't know if we have more than one). It is right in front of the rear axle and about the middle of the coach. (The two brake air tanks are in front of the front axle.)

Please take a look at the attached  photo of the bottom of the supply air tank. It looks to me that a petcock or some kind of valve is missing off the square device in the center/bottom of the tank. I think this may be a major source of our air loss from the supply system. I did not actually crawl under the coach to check if air is coming out of that hole/area when the pressure is high but will do that probably Monday (tomorrow). Actually, I will figure out a way to check that without me crawling under there.

Does anyone know if a valve is supposed to be in that area? I would think so for draining water out of the tank from time to time. If so, what kind of valve should I put there? I would like to be able to drain it from the side of the coach by running a line over there.  Thanks for listening and for any advice.

   
Glenn & Laureen Parker
Austin, Texas
1984 Newell 35'  (Coach #58? - not confirmed)
6v92 Detroit Diesel, Allison 6 speed trans
2005 Honda Element toad
2007 Honda S2000 fun car
#2
We just realized we should be able to put a thin piece of paper on our stick and hold it under that valve to see if air is coming out.
Glenn & Laureen Parker
Austin, Texas
1984 Newell 35'  (Coach #58? - not confirmed)
6v92 Detroit Diesel, Allison 6 speed trans
2005 Honda Element toad
2007 Honda S2000 fun car
#3
That looks like an automatic drain valve on your wet tank. It is possible that it is malfunctioning.
Michael Day
1992 Newell 43.5' #281
NewellOwner.com
#4
Yeah, there is not supposed to ne a petcock valve there, but like Michael said it may be leaking. Another place to look for a leak would be at your air pressure regulator. Had to replace mine a few years ago as it was leaking badly.

Clarke and Elaine Hockwald
1982 Newell Classic, 36', 6V92 TA
2001 VW Beetle Turbo
Cannondale Tandem
Cannondale F600
Cannondale Bad Boy
Intense 5.5 MTB
http://whatsnewell.blogspot.com
#5
Please take note to block up the chassis (on Frame members not axles) with wood or qualified Jackstands on concrete. I'm too fat to fit so I Drive mine up on a group (3 or 4 each) of longer 2x12's then place 3' long 2x12's on both side near where Im working.

Be Safe !
Dave, Karen and buddy. 
06 Newell #784 towing a 05' Featherlight enclosed  trailer for toys and tools
A bunch of stuff on wheels, including 59' Nash metropolitan conv., KTM 250 dual sport. 

Carpe Diem. 
Tomorrow is not guaranteed.

#6
Glenn,

I agree with Micheal about that being an automatic drain. You could replace it with one of the same, replace it with a manual petcook, or replace it with one of the lanyard pull drain valves.

I personally don’t care for the auto drain or the lanyard drain valves for the simple reason that the device drains rusty water. The debris in the water can and sometimes does cause the valve to stick and leak as you have observed.

A different alternative, which I have been running on our coach for about five years now, is to install a DOT compliant fitting in the drain hole, run DOT air line to a convenient place on the coach and use a quarter turn valve to cap the line. I also installed a section of line to drain the from the valve to direct the water away from my feet. It is easy to give the valve a quick turn when you want to drain the tanks, with the added bonus that you get to see what is draining from the tank.

And like Dave said, chock up the frame members before crawling under there.
Richard and Rhonda Entrekin
99 Newell, 512
Subaru Outback Toad
Inverness, FL (when we're home Cool )
#7
Thanks to Michael, Clarke, Dave and Richard for your comments. I will post an update when Laureen and I make some progress and get closer to resolving this big air leak problem. BTW, I know I have to replace the air regulator/dryer apparatus with the carbonate bowl in the rear six pack area that Richard loves to use to practice his hand grenade tossing. It definitely has a leak.
Glenn & Laureen Parker
Austin, Texas
1984 Newell 35'  (Coach #58? - not confirmed)
6v92 Detroit Diesel, Allison 6 speed trans
2005 Honda Element toad
2007 Honda S2000 fun car
#8
My air dryer went bad a couple of years ago. Found a used replacement on eBay.

Clarke and Elaine Hockwald
1982 Newell Classic, 36', 6V92 TA
2001 VW Beetle Turbo
Cannondale Tandem
Cannondale F600
Cannondale Bad Boy
Intense 5.5 MTB
http://whatsnewell.blogspot.com
#9
To follow up and maybe close this thread out, Michael and Richard were correct about this valve being an automatic drain valve. It is supposed to look like that. I have not determined yet if it is leaking. If we replace it, I will probably take Richard's advice and run a line to the side of the coach for easy draining and observation.
Glenn & Laureen Parker
Austin, Texas
1984 Newell 35'  (Coach #58? - not confirmed)
6v92 Detroit Diesel, Allison 6 speed trans
2005 Honda Element toad
2007 Honda S2000 fun car
#10
Be aware there are other devices in the area of the the supply tank that can leak so rather than just replace the auto dump valve, probably a good idea in the long run anyway, get under there, safely of course, with soapy water spray and determine what is actually leaking.
Jon Kabbe
1993 coach 337 with Civic towed


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