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Topic: What is normal air pressure 48 hours after stopping? (Read 978 times) previous topic - next topic

What is normal air pressure 48 hours after stopping?

Two days ago we had to go dump our black and gray tanks.  Now, 48 hours later air pressure on both gauges is 35 psi.  Is this a normal reading?
George Stoltz.  Retired from full-time living in a great Foretravel and now are back to living in a traditional sticks and bricks in Florida.

Re: What is normal air pressure 48 hours after stopping?

Reply #1 –
Hmmm.  George,
What has been your observation in the past as to air pressure loss?  If you're losing that amount of pressure in 48 hours you may be developing a slow leak in one of the lines.  In the past most (including myself) have found that the pressure regulators under the coach front develop cracks and if not replaced, will lose air and then the crack becomes a hissing sound you will not miss.
 
That's the location I would start looking for a leak.  Others will chime in with additional places to look.
Peter & Beth Martin
No Forrest? What have you done?
MC# 15890 until Dec 2016; FMCA #F329677
Cincinnati, OH

Re: What is normal air pressure 48 hours after stopping?

Reply #2 –
Quote
48 hours later air pressure on both gauges is 35 psi.  Is this a normal reading?
Foretravel, Inc. Allowable Leakdown

1. 6 P.S.I. in the front air system in a one hour time period.

2. 6 P.S.I. in the rear air system in a one hour time period.

This translates into an approximate 60 P.S.I., allowable leakdown rate, for each air system, in an overnight park mode (10 hours). This is an extremely small air leak. The Foretravel, Inc. standard is 20 times more stringent than the D.O.T. required safety standards, which allow 120 P.S.I. per hour.
http://beamalarm.com/Documents/D.O.T._standard_allowable_leakdown.htm
The selected media item is not currently available.Barry BEAM #16014
2003 U320 40' AGDS
Beamalarm, Foretravel technical help and specifications
"Whatever the mind can conceive and believe, it can achieve"

Re: What is normal air pressure 48 hours after stopping?

Reply #3 –
Well, I certainly like Barry's response more than I do Peter's response.  It would look like we are well within Foretravel standards.
George Stoltz.  Retired from full-time living in a great Foretravel and now are back to living in a traditional sticks and bricks in Florida.

Re: What is normal air pressure 48 hours after stopping?

Reply #4 –
Quote from: George Stoltz –
Well, I certainly like Barry's response more than I do Peter's response.  It would look like we are well within Foretravel standards.
George,
The regulator replacement is easy.  Replacement regulators can be purchased at any Home Depot or Lowe's where the air compressors are displayed.  You'll need some wrenches and thread tape...that's it.  To adjust to the 60 psi specified the engine should be running and the HWH air ride system in "travel" mode.
 
You may also have another regulator next to the front step underneath if your coach also has the air operated front step.
Peter & Beth Martin
No Forrest? What have you done?
MC# 15890 until Dec 2016; FMCA #F329677
Cincinnati, OH

Re: What is normal air pressure 48 hours after stopping?

Reply #5 –
Peter,
 
From Barry's response, I don't have a problem.  .  What is gained by replacing a regulator that is within Foretravel tolerances?  What am I missing here?
George Stoltz.  Retired from full-time living in a great Foretravel and now are back to living in a traditional sticks and bricks in Florida.

Re: What is normal air pressure 48 hours after stopping?

Reply #6 –
I had that reading too. Your 12 volt is keeping that pressure up for you. I have tracked down my leaks and have replaced the leaking parts. I had a big one on the transmission retarder and on the step too.  I found them and now I sat for over a week and had 65 pounds of pressure and the 12volt never came on.

I know the standards that FT uses and that is fine but I think you can do better and it is not hard.
2025 Wanderbox Outpost 32 on F600 Expedition Motorhome
2015 Born Free Royal Splendor on Ford 550 nonslide version  for sale
Former Coaches  covering. 360,000 miles
1999 34 U270
2000 36 U320
2001 42' double slide U320
2018 Jeep Rubicon

Re: What is normal air pressure 48 hours after stopping?

Reply #7 –
Now that helps.  thanks, John.
George Stoltz.  Retired from full-time living in a great Foretravel and now are back to living in a traditional sticks and bricks in Florida.

Re: What is normal air pressure 48 hours after stopping?

Reply #8 –
George,
It's always better to do PM as you don't want a situation that will strike at an inconvenient time.  What I'm saying is, perform an inspection so you are aware...soapy water will indicate if you have visible air leaks.
 
The regulators are cheap, if they are beginning to develop cracks.
http://www.homedepot.com/h_d1/N-5yc1vZ1xkc/R-100082550/h_d2/ProductDisplay?langId=-1&storeId=10051&catalogId=10053
 
Peter & Beth Martin
No Forrest? What have you done?
MC# 15890 until Dec 2016; FMCA #F329677
Cincinnati, OH

Re: What is normal air pressure 48 hours after stopping?

Reply #9 –
Thanks, Peter and John.
George Stoltz.  Retired from full-time living in a great Foretravel and now are back to living in a traditional sticks and bricks in Florida.

Re: What is normal air pressure 48 hours after stopping?

Reply #10 –
George, Check the valve for bleeding the wet tank. It is very sensitive to the off position.
I am parked @ Beale AFB for the past 4 days and my gauges still read above 90 psi
1993 U300, 6v92
build 4366
USAF retired, Flight Engineer, C124, C130
 ATP, A & E.  & ex AI

Re: What is normal air pressure 48 hours after stopping?

Reply #11 –
Normal for our 1997 U295 after parking overnight is 10 psi +-.  That appears to be pressure for the brake system and does not indicate pressure in the suspension system when we are parked. The coach stays level, the air bags remain properly inflated, and I never hear the 12V compressor run after the initial leveling.
J D Stevens
1997 U295 CAI 36' Build #5085
2002 Subaru Outback
Motorcade 16869
Bellville, TX

Re: What is normal air pressure 48 hours after stopping?

Reply #12 –
As long as we are reporting air pressure, we have been parked at our current location almost exactly 24 hours and our pressure right now is 80 pounds.  It will take close to two weeks to leak down to near zero. 
Paul
36' 2000 U320
Paul
36' 2000 U320
2014 Jeep Grand Cherokee Summit

Re: What is normal air pressure 48 hours after stopping?

Reply #13 –
Dave M
there seems to be a difference between year  & models on a lot of things.
My 93 U300
1. my gauges are direct reading.
2. My DC compressor will not increase my gauge press, but keeps my coach level with HWH
3. the only time I have evidence of the compressor running, is when I use the panel to raise a point.( front, left,right, rear)

I have had, what I thought was a severe leak a couple of times. Thanks to Barry Beam, I now understand my system.
later models use the DC compressor to keep the suspension system charged.(I think)
1st "major leak" was the drain valve for the "wet tank". It is very sensitive to center "Off" position.
2nd was the same thing, just took longer than normal to get head above shoulder again.

ps I am now @ Beale AFB, CA .Had a great visit with Pierce Stewart (93 U300 with 6V92).
he is coming by today to inspect my coach.
You two guys help keep my 6V92 running.

Bill Chaplin
1993 U300, 6v92
build 4366
USAF retired, Flight Engineer, C124, C130
 ATP, A & E.  & ex AI

Re: What is normal air pressure 48 hours after stopping?

Reply #14 –
Very interesting thread.  This is an issue that has bugged me since I bought the coach 3 years ago. 

FOT replaced a bunch of parts including the step actuator (twice) and the retarder actuator.  That reduced the 12 v compressor's running to about every 15 minutes.  They and my wallet gave up at that point.

At home my cycle time had reduced to every 3 to 4 minutes.  With help of an air system diagram from James Trianna, I found the valve going to the slide air bladder.  I closed it and wow!!! no compressor cycling.  Of course, no air bladder seal either.  So I used painters tape on the outside of the coach with the slide in for about 6 months until I could get back to HWH.  On occassions where I felt it was safe weather wise I removed the tape and opened the slide-out.  I was in this mode for about 6 months.  HWH is a long way from southern California.

At HWH they decided that they would have to remove the slide-out and replace the seal.  They removed the slide-out and then discovered that the only problem was a cracked fitting on the end of the air hose going to the bladder.  The fitting was cracked longitudinally.

Now I'm back to where George is, my air pressure drops to about 35 psi overnight.  Also my air compressor cycles about every hour.  I used the soapy water test before I left on this years trip and was unable to find any leaks.

Peter, John, and others inspire me to try again when I get home in November. 
Thanks all.



Audrey & Harvey Nelson
2000 U-320, 40' towing 2014 Jeep Grand Cherokee
nelsonah@ieee.org
 

Re: What is normal air pressure 48 hours after stopping?

Reply #15 –
Quote from: Dave M –
Just another 2 cents worth,
Both air gauges show 125 PSI after sitting 3 weeks, that does sound just wonderful.  However when you turn on the key and power up the dash gauges, after they settle down, both air gauges show 30PSI.
I am now worried about it.  :o
When driving down the road, the compressor cycles about every 45 minutes.
Please tell me where I should be looking for my big problem.
Dave

Dave,

I changed out my electronic gauges for a couple of Manual VDOs and I have accurate readings all the time.
2025 Wanderbox Outpost 32 on F600 Expedition Motorhome
2015 Born Free Royal Splendor on Ford 550 nonslide version  for sale
Former Coaches  covering. 360,000 miles
1999 34 U270
2000 36 U320
2001 42' double slide U320
2018 Jeep Rubicon