air loss (still)

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air loss (still)

August 28, 2014, 12:16:44 pm

Hey Yall.

Joe here. You all were most helpful as I traveled all over the eastern half of the country loosing air. Coach has been back at FOX for about 7 weeks and a few air leaks were addressed. However, leak down while not running is around 20 psi an hour. While on the highway the cycle time from 125 psi to 90 psi back to 125 is now about 105 seconds which is only 15 seconds longer than last time. Mark is driving the coach now has says he has no idea how long it should take. My thoughts are that is a whole bunch of air to be loosing and I'm inclined to not accept it as is.

It is 2005 u320, 42 ft. Can those of you with comparable coaches give me a feel for your experience on the same cycle?

Anybody have advice on how acceptable this is?

This is my first Foretravel but fourth coach and I've never experienced this kind of air loss before.

Thanks for your continued help.

Re: air loss (still)

Reply #1 – August 28, 2014, 12:48:10 pm

Joe,

That is too much air loss and cycling of the compressor. It seems that if they haven't found any leaks at the obvious places then it leads me to believe that you have a check valve leaking internally, air dryer bleeding air off, or governor going bad.

Several folks have had mystery air loss with various problems found and fixes made.

Pamela & Mike

Re: air loss (still)

Reply #2 – August 28, 2014, 02:08:41 pm

I too agree on those check valves. Easy to remove and look at anyway. One on each tank to stop reverse flow and the wet tank one may be at Dryer end of air feed line. You will not see or hear these leaks and I think they have been overlooked by many for too long.
JohnH

Re: air loss (still)

Reply #3 – August 28, 2014, 05:25:29 pm

Have you checked all your air springs.

Re: air loss (still)

Reply #4 – August 28, 2014, 08:11:23 pm

I believe that the Foretravel spec is 6 psi per hour. I'm going from memory, so check this. It should be in your owner's manual.
I would check the stems on the position valves at each wheel--- these are wearing items and tend to leak when they get a little wear on them. We just changed all three on our coach and it solved our leak down issue.

Re: air loss (still)

Reply #5 – August 28, 2014, 09:58:18 pm

John,
Funny how this thread details symptoms so similar to the ones on our coach, though of a different model and 6 years newer... Pretty sure that the check valves on the front tanks on our coach are good since they hold 110psi for at least 90 minutes, but the one at the wet tank, if it isn't the one in the bottom of the air dryer on the ½" output line is hard to get to without a pit. I know they put a new one in the dryer when they rebuilt it, but it could be leaking and of course it won't show up with the soapy water test or make sound since it is internal.
At least the coach is drivable and the air is clean and dry until I can get this dealt with once and for all.
Don

Quote from: John Haygarth – August 28, 2014, 02:08:41 pm

I too agree on those check valves. Easy to remove and look at anyway. One on each tank to stop reverse flow and the wet tank one may be at Dryer end of air feed line. You will not see or hear these leaks and I think they have been overlooked by many for too long.
JohnH

Re: air loss (still)

Reply #6 – August 28, 2014, 10:23:41 pm

Thanks all. Given that this is related to an issue that existed when I purchased the coach, FOT is chasing the leaks (thankfully). I met with Drew, Mark, Jeremy and saw the guys working hard to get it figured out. Such great people, it makes it hard to be upset about much.

The two issues are ambient air loss while stationary. The Foretravel spec is 6 psi an hour (60 in ten). We still failed this test after replacing a few check valves and other connections.

The next issue is air loss while at highway speed. Which is more like 35 pounds in 90 seconds. That only occurs at speed. There is some discussion as to if that is normal for a 2005 coach. Drew is going to research that with engineering and we will talk again. But, the former f-16 crew chief in me, says that is a whole bunch of air to be loosing in a what is a critical system.

I have confidence in these guys and will keep you posted.

Thanks again and looking forward to Grandvention.

Re: air loss (still)

Reply #7 – August 28, 2014, 10:28:24 pm

I had an air leak which they found and it was the glass bowl by the aux compressor and the bowl on the big awning. The 02 uses air to push up the awning. They will find it.

Re: air loss (still)

Reply #8 – August 28, 2014, 11:37:32 pm

Don, 110lbs if all is working right should last best part of the day as ours does. We do not go down to 90 for at least a week (I could be out a day) but today it is just above 30 and last time I ran engine was a month or more ago. Once here over pit I am sure we will replicate that on yours too. It could also be the throttle valve as that was leaking too on mine. It is a bear to get at even with pit. It needs the genset pulled out to max extension to check as does the step slide cylinder.
johnH

Re: air loss (still)

Reply #9 – August 28, 2014, 11:46:07 pm

I must be reading too much on Foreforums.

I got a call from Temecula Valley RV telling me to postpone coming over to pick up the coach. I had the refrigerator replaced, the slide fixed, the front TV upgraded, and a crack (manufacturing defect !!!) in the shower surround fixed. The owner of Temecula Valley RV walked by and noticed the 12v compressor was running constantly. Upon checking it out, they also found the breaker had tripped and my almost new batteries were down to 10.5 volts. They sent a tech to look into the leak.

I got a call back from a sheepish sounding service writer telling me she tried out the slide and didn't know to turn off the key lest the compressor keep running. She also didn't check to see how many AC units were trying to run on a 30A breaker. The owner checked with Lifeline and assures me running the batteries down to 10.5 volts didn't do any real harm.

And here I was expecting all sorts of fun and games in the air system. Maybe next time.

Re: air loss (still)

Reply #10 – August 29, 2014, 10:00:04 pm

John, that would be the result I am hoping for! Looking forward to it, and thanks for the offer to lend your knowledge and facility... very generous of you. Foretravelers helping other Foretravelers... one of the many perks of owning one of the finer coaches on the road.
Don

Quote from: John Haygarth – August 28, 2014, 11:37:32 pm

Don, 110lbs if all is working right should last best part of the day as ours does. We do not go down to 90 for at least a week (I could be out a day) but today it is just above 30 and last time I ran engine was a month or more ago. Once here over pit I am sure we will replicate that on yours too. It could also be the throttle valve as that was leaking too on mine. It is a bear to get at even with pit. It needs the genset pulled out to max extension to check as does the step slide cylinder.
johnH

Re: air loss (still)

Reply #11 – September 22, 2014, 11:40:44 am

Quote from: Lucky1 – August 28, 2014, 10:23:41 pm

The next issue is air loss while at highway speed. Which is more like 35 pounds in 90 seconds. That only occurs at speed. There is some discussion as to if that is normal for a 2005 coach. Drew is going to research that with engineering and we will talk again. But, the former f-16 crew chief in me, says that is a whole bunch of air to be loosing in a what is a critical system.

I have confidence in these guys and will keep you posted.

I am adding to this old thread because I am having a problem with the air pressure cycling and would appreciate knowing what was done to correct the problem. Thanks,
Larry

Re: air loss (still)

Reply #12 – September 22, 2014, 03:59:15 pm

Quote from: LTG – September 22, 2014, 11:40:44 am

I am adding to this old thread because I am having a problem with the air pressure cycling and would appreciate knowing what was done to correct the problem.

Larry,

Are you having exactly the same problem as Lucky or something different? Can you give us more details? And how long has it been since your air dryer was serviced and what parts of it were replaced during that service?

Michelle

Re: air loss (still)

Reply #13 – September 22, 2014, 05:20:48 pm

Like Joe (lucky1) I recently bought a 2005 with almost an identical air loss problem. Shortly after leaving FT I called back to find out if both front and rear tanks cycling from 125 down to 100 and then back to 125 in 90 seconds was normal. At first Joshua asked if I had the tag up, which I did not. He then spoke to someone and was told that was normal.

Have traveled over 1500 miles since taken delivery several weeks ago and it still continues to cycle every 90 seconds give or take a few. After reading a number of posts on air loss I am questioning if it is normal. Not sure the effect it is having on the compressor.

The one difference between the loss Joe is experiencing is the drop when we are parked. In a 12 hour period loss is down to 75 lbs and then gradually goes to O over the next four days. That is within FT specs of 6 lbs per hour. Joe's loss is greater.

As a result of FT PDI and third party inspection repairs to air system were made

Desiccant bowl was cracked, corrected with air dryer mod kit and 200 psi press relief valve
Replaced 1 solenoid and corrected 4 air leaks on the front
Replaced 2 solenoids and 1 air leak on the rear
Replaced air dryer filter
During the few days orienting myself at FT the 12 volt compressor was kicking in about every 15 minutes and would run from 40 seconds to 80 seconds. Found both vacuum solenoids on each bladder manifold were leaking thru plunger.

Before low crawling on my back (reminds me of my Army days) under the coach trying to find leaks it would be nice to know whether or not an air loss cycle of 25 pounds in 90 seconds is to be expected and safe. From previous posts I think I know the answer and I'm just wishful thinking it is for U320 2005 coaches.

Re: air loss (still)

Reply #14 – September 22, 2014, 05:24:45 pm

Michelle,
The other day after arriving at a campground and leveling the coach, I noticed that the 12 volt aux compressor would not shut off. I disconnected the 5 amp fuse. Later on the coach re-leveled a few times. We were parked on what appeared to be a very level spot and the level bubbles we use to check the level for the refrigerator showed the coach to be level. Later, upon trying to bring the slide in the slide would not work. I noticed then that the excess level light was on on the touch pad. I turned the level system off and the slide came in. However the slide made a squealing sound as it came in like maybe the seal bladder had not completely emptied. Then, on the way home I noticed that the air pressure gauges showed the pressure was cycling between about 100 and 125. I timed the cycle and it was approximately 120 seconds. I then researched using the ForeForums search function and found this thread. I also read other threads about air leaks and air leveling, including the threads that you and Steve posted.
The air dryer was serviced by FOT March 2014 and the Aux Compressor Desiccant was changed by FOT August 2014.
Thanks,
Larry

Re: air loss (still)

Reply #15 – September 22, 2014, 06:13:23 pm

Quote from: LTG – September 22, 2014, 05:24:45 pm

The other day after arriving at a campground and leveling the coach, I noticed that the 12 volt aux compressor would not shut off. I disconnected the 5 amp fuse. Later on the coach re-leveled a few times.

Later, upon trying to bring the slide in the slide would not work. I noticed then that the excess level light was on on the touch pad. I turned the level system off and the slide came in. However the slide made a squealing sound as it came in like maybe the seal bladder had not completely emptied.

Larry,

Lots of questions follow

Going off our experiences (to see if there's anything common in what you're seeing):

Do I read this correctly that you pulled the inline fuse on the aux compressor but did not reinstall it prior to bringing in the slide?

If so, do you recall hearing the aux compressor run when you turned the key to bring in the slide?

The reason I ask is that the fuse is normally needed so the aux compressor runs to pull vacuum so the bladder can be fully deflated). At least that's how our '03 operates.

Now, if you did reinstall the fuse, did the aux compressor start running again and not shut off until the fuse was pulled again? If so, have you checked the N/O solenoid valve on the bottom of the condensate bowl to make sure it's sealing during aux compressor operation (air coming out the bottom when the aux compressor is running is a sign the valve is bad). If no air escaping there, have you checked the desiccant and condensate bowls for cracks?

Also, you mentioned the excess slope light being on, preventing slide operation, and turning the level system off to bring in the slide. Does this mean you put the coach into Travel Mode? If not, what was the level state of the coach (what did the HWH system think it was) when you brought the slide in and heard the squeak? Was it in a state other than either level (no excess slope light) or travel? Generally, if the coach isn't level when you move the slide, you run a risk of the slide opening being slightly "torqued" and things not moving smoothly. You can sometimes see this by observing the gap around the slide from the outside and seeing that the gap is noticeably unequal.

Re: air loss (still)

Reply #16 – September 22, 2014, 09:46:12 pm

Michelle,
I connected the fuse to turn on the aux compressor to bring in the slide. Then after the slide was in, I turned the aux compressor off by removing the fuse.
When I retracted the slide, the coach was not in travel mode. I had turned on the ignition key and hit the emergency off to turn off the excess slope light. The coach did not have a noticeable slope during the time we were parked and the level bubbles we had on the counter next to the refrigerator were centered. They had remained that way the four days we were parked.
I did go out and look at the slide and the slide was closer on the right bottom and farther away from the left top. However, I do not remember how aligned the slide was before this.
The slide was making a squealing sound when it was extended a few days before. It was the first time we had heard that sound before. I had lubricated the seal and coach sides with Formula 303 before I brought the slide in. During the drive home I thought I heard the slide squeaking a little.
I had tried to determine if the slide seal was inflated or deflated but I have never really paid any attention to it before so I had no frame of reference. When operating the slide to bring it in I listened to hear the seal deflate and I could hear some movement but it did not seam to be as much as I had heard in earlier times when I was using the slide. The same thing when the seal was inflating. The amount of movement did not seem to be the same. It was if it was not deflating and inflating to the same degree as usual.
I listened and felt as the N/O solenoid for air movement while the compressor was running but could not feel or hear any air movement. When removing the fuse I did not hear a release of air pressure from the N/O solenoid. At the time I did not think anything about that. After reading threads on the forum, I now know that I should have heard a release. So, I do not think there was much pressure build up.
Earlier when the coach was trying to re-level, I did hear the compressor run to add air and raise the coach. It then shut off. I never went out to the bay to look at the compressor at that time.
I now know a lot more about the system and in a day or so I am going to where the coach is in storage and do some troubleshooting. However, I am real reluctant to try and run the slide in and out.

Re: air loss (still)

Reply #17 – September 23, 2014, 01:20:19 am

So much been written, will try to comment separate issues, sen pm if want to discuss. Will second what Michelle said about need for slide to have aux working.

On our coach I once saw it cycling the main compressor every 75 seconds. That is very not normal. Keith Risch found a couple of air leaks and when fixed we went back to over 200 seconds if on fairly smooth highway. I think at times I was seeing 300 seconds.

I do not leak down below 70 psi when parked for several weeks....this a separate issue than the compressor cycling, has to do with check valves.

To avoid pulling the aux fuse, install a switch. Big help if you find the aux runs too much. It is not a solution to whatever basic problem you have, but makes it easier to manage until get fixed. You must have it working so you can bring the slide in, do not want run too long and leave you with burned out aux compressor. I pulled the fuse before got switch, that not such a good way.

Mike

Re: air loss (still)

Reply #18 – September 23, 2014, 07:55:21 am

When you next stop and while in Travel mode (or just raise the coach) and while the engine compressor is still running use a soap/water solution to test the integrity of your air bags. Particularly the bottom ends which get folded over when deflated.

Re: air loss (still)

Reply #19 – September 23, 2014, 09:52:02 am

I don't have the same vintage machine, but air is air. Every air sys. will have some leakage and for me the key as to where to look has to do with temperature. Might sound strange, but boundary valve leakage varies with the temperature. On hot days I have less leakage than on cold days. If the leakage is consistent with temperature changes, then I look at things such as hoses, air bags, etc. If the leakage varies as the temperature does, then I look at boundary valves. I have replaced most of the flexible air hoses to the wheels. I had one defective one, so I just replaced all that I could at that time. Have a happy search ---- Fritz

Re: air loss (still)

Reply #20 – September 23, 2014, 11:42:03 am

Joe,

I recently had the same type of problem. It's probably the check valve on the wet tank, the first tank after the dryer. If it's leaking, the air goes back through the dryer and out the exhaust on the dryer. This tank doesn't have a gauge, but you can check it by pumping up the system and let it sit for awhile (this could be a few hours or maybe as much as 24), open the drain and if you only have a little air coming out it's probably leaking. This valve is installed in the supply air line at the tank. On my coach the 2 front brake tanks have the same identical check valve and the part number is Midland N-13526-H, yours may be different. The suspension (air springs) does use some air when the coach is being driven. The other option is to go under the vehicle after placing safety chocks between the frame members and spray soapy water on all the air lines starting at the rear of the coach.

Re: air loss (still)

Reply #21 – September 23, 2014, 01:31:16 pm

When Keith Risch inspected our coach (did a great job) he noticed a date on the the side of the air dryer which indicated it had been over two years since replacement of the air dryer filter. When he opened the wet tank valve air was dry and clean. Keith did a great job educating me on the coach while inspecting it and mentioned he had seen gray matter come out of the valve when filters deteriorate due to age. He recommended filter change every year. Had FT replace the filter.

Jerry, like Joe I'm losing 25 lbs every 90 seconds and from the info in your post I'm thinking maybe because of the age of the filter it has caused an issue with the valve prior to the wet tank. Since a bad valve would have air going out the exhaust I assume spraying with soapy water would not be a way to trouble shoot the valve?

One other question I would like to ask is there a second filter inside the dryer and would it be SOP to replace both when you have the air filter replaced at FT. Seem to remember reading past posts that there is a filter within the filter.

Thank you to all for recommendations on fixing this air loss. As a newbie I consider this a safety concern for our family, maybe wrong but it is a nagging worry.

Gary

Re: air loss (still)

Reply #22 – September 23, 2014, 02:21:51 pm

Gary,

Nothing wrong with putting some soapy water on the dryer exhaust port to look for a leak. If it's like mine covered with an oily gunk and hard to get to. I changed the filter and rebuilt the dryer once in the last 5 years, which may have been the first time it was ever done in 19 years. No doubt it may be time to do it again. The theory is the the filter collects water and oil each time the compressor runs then when the compressor shuts off some air flows backwards through the filter and most of that collection is blown out the exhaust. Not all of the water and oil is collected and some ends up in the tanks, which can be expelled through the drains. The reason for drying the air is prevention of brake failure in freezing temperatures. I don't know if there is a filter in the filter, but I don't think so. The filter could have 2 or more sections inside, but it's basically replace and discard the old one. There are shops that sell rebuilt dryers. There are 3 or 4 air lines connected to the dryer and an electrical cable for a small heating element.

Re: air loss (still)

Reply #23 – September 23, 2014, 05:02:18 pm

As additional info on dryers and leaks.
My brother called me today and reported that his year old Peterbilt had left him dead in the water on the George Washington Bridge. Turned out that air dryer was problem. He had the necessary fittings with him to bypass dryer from his older tractor, but found to his dismay that the newer type dryer cannot be bypassed. Seems that air is used to manage in some fashion the DEF , catalytic converter system.
1200 Bucks later he is back on road. Mechanic stated that even with dryer that moisture will build in tanks and that it then migrates to the dryer and corrosion in the dryer kills it.
Those of you with the later model engines with DEF might want to take a look to see why dryer cannot be bypassed, and what the service interval is.
Gary B

Re: air loss (still)

Reply #24 – September 23, 2014, 05:27:08 pm

Quote from: fkjohns6083 – September 23, 2014, 09:52:02 am

I don't have the same vintage machine, but air is air. Every air sys. will have some leakage and for me the key as to where to look has to do with temperature. Might sound strange, but boundary valve leakage varies with the temperature. On hot days I have less leakage than on cold days. If the leakage is consistent with temperature changes, then I look at things such as hoses, air bags, etc. If the leakage varies as the temperature does, then I look at boundary valves. I have replaced most of the flexible air hoses to the wheels. I had one defective one, so I just replaced all that I could at that time. Have a happy search ---- Fritz

Fritz
I agree with the temperature being a big factor on air and holding pressure...2 years ago when I drove "Ben" across the US in January, I stopped in Texas for the night and temps dropped to 35 or so, next morning wanting to get back on the road "Ben" would not air up, waited 10 mins with engine idling(turned-on the cruise to get the rpms up) then got the green light.

Hans

Now during the warm season he airs up quickly or no loss of pressure over several weeks no issues...

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