To inflate or not inflate

[Geom]

Thanks all for the great replies! Very useful info indeed.

Well I finally lost the battle last night to try and keep the bags full. The compressor was coming on more and more frequently (to where it eventually was coming on every 45 minutes). So I decided to cut my loses and let her settle on the stops. I shutoff the compressor, and within a few hours, we dropped the 5 or so inches down. Plus with what Dave has said about how I empty my tanks, I'm concerned if I'm emptying them correctly. I've always thought that I should blow some air through the drains until the watery mist is just air. I do that two or three times (on/off/on etc), until there's no mist. From the sounds of what Dave was saying, however, I need to occasionally completely empty the tanks of air and let gravity empty them out. That will be an occasional nuisance, so I have to figure out how to deal with it, long term.

As far as the leak, I have no doubt there's some sort of leak. But it's not a constant one (i.e. I don't think anything is necessarily broken), it's a highly variable one that only manifests when it gets this cold. When it climbs back up to the 40s+, I have little doubt she'll hold air in those bags for hours. I also have no... aspirations that I'll ever be able to hold air in there for days, weeks, or months at a time. I realize every coach is different, but in looking at what I saw underneath this coach, a few months ago, I can not imagine any way that system was ever designed to be that air tight. Heck, I wouldn't be able to get a Mylar balloon to hold air for that long, I wouldn't expect a complex series of lines, valves, switches, pumps, drains, manifolds, bags, etc to do so. That being said, I'm perfectly content if I have to fire up the compressor once or twice a day for a top off. Where things go south (or is that north because it's cold ) is when it gets really cold. Something is changing and more air is somehow escaping. I cannot hear it while I'm outside and I really don't want to go crawling around under there in 20 degree weather   So I suppose it'll remain a mystery for now. I do intend on replacing whatever looks worn or old with new(er) at her next annual (within reason of course). I also strongly suspect the leak is in the suspension system, because when I had that brake line leak a few months ago, the system had completely depressurized, but the bags stayed fairly full for a couple of days (it was warmer then), but last night it took less than 5 hours to be sitting on the stops. I strongly suspect that the "leveling" valves are the problem. I presume that as we move around in the coach, they're struggling to maintain "level" and purging too much air out and not closing correctly or quickly enough, and thus draining the bags. Does that sound feasible?

On my next visit to the local friendly mechanic, I plan on asking him how they might be defeated (hopefully temporarily) so as to not bleed air.

Thank you John for the tip on the water separator. I had no idea they there this reasonably priced. I'd looked at "air line driers" but they ran in the hundreds of dollars. While they probably would work better in a professional type setup, these little water separators might just be perfect for my "once in a while" needs.

I'm really hesitant to use things in the air system that could further deteriorate the bags. After looking into these dryer products, all use some form of alcohol, which does deteriorate rubber. It seems that methanol (air brake line dryer) is more detrimental than iso, but neither is exactly good, at least in liquid form. I don't know what all in that air system is rubber, but I suspect at least the bags are. They're probably ok to use occasionally, and certainly a necessity if you're  stuck somewhere with frozen valves; but for sitting around in a rv park, they may be overkill. I'll see how successful I am with the water separator mod, first. I'm also going to look into one of those iso based line dryer add-ons (for when we're driving the coach in freezing weather). In vapor form, I believe alcohol is much less damaging.

Anyway, thanks all again for the very useful info. I've got some additional things to think about, and I suppose some shopping to do, lol. I wish we were still back in KC, there was a harbor freight 5 minutes away from us. Amazon seems to have those separators, but they're  more expensive and have so-so reviews. I suspect it'll be a bit of trial and error till I find one that works and doesn't itself introduce a leak

Thanks
George

[Dave5Cs]

George just get you some cable pull drains. One for each tank. Unscrew the drain that you have to open by hand and install the pull cable drain in it's place. Mine were 1/4 pipe thread. I would bet yours are also. Run the cable out to somewhere where you can reach it without have to go under the bus to use it. Have something to hold it open and let it drain good every so often after driving somewhere. If it is from the shop air then yep get that dryer in there. 

Dave5Cs

[Larry B]

Hello George-- When i park my bus I prefere to keep it at the  normal ride height or close to. I feel it is better for the bags. Also the rubber bushings inside the radius arms are tightened when the bus is at normal ride height, so anything out of that position and the rubber bushings are trying to move the body and axle back to that neutal position. I would think over long period of time this would have an effect on rubber bushings. ( I believe GM and MCI have same type radius rods for axle alignment) I accomplish this with blocks, short pieces of 8X8 with a few shims. The bus is parked in same spot so pile never changes. As far as drain points I added 12 volt air solinoids (6) at drain locations to switchs near driver seat. I knew I would not climb underneath as offen as I should to drain. It happens on a regular base with switches. Solinoids from Princess Auto $25.00 each --rated at 140psi
             Larry B

[Oonrahnjay]

...   As far as drain points I added 12 volt air solinoids (6) at drain locations to switchs near driver seat. I knew I would not climb underneath as offen as I should to drain. It happens on a regular base with switches. Solinoids from Princess Auto $25.00 each --rated at 140psi
             Larry B 

      Or for simpler and cheaper (and maybe more reliable??), you could put in a plain 1/4" NPT thread coupling to 1/4" DOT nylon tube instead of the on-tank drain.  Then put a plain 90 degree twist valve someplace easy to reach on the end of the DOT tube.  The water/crud will settle to the low point in the tank and be pushed out the remote drain.   All mechanical, no electrics - simple.

[luvrbus]

With freezing weather all metal shrinks and hot air pumped into a system the air turns cold all buses leak more in freezing weather and I am not a big fan of the cable pull drains

Like Bruce said just remote mount the drains in a easy spot and then use the little Propane tank bleeder valves 4 bucks each, you need to enlarge the bleeder hole on those but they work like a charm  

If Jon can keep a Prevost leak free a GM should be a cake walk I remember when Prevost said they were changing from the Humphrey valve to the less trouble free Norgren valve boy did they miss that one

[Oonrahnjay]

... I am not a big fan of the cable pull drains

    My issue is the they work like a charm when you pull the cable.  The problem is that they often stick (I'm guessing on a bit of trash or sludge) when you're trying to get them to close.  Sometimes it takes a couple of tries of pulling them and letting them "snap closed".  IMO, just not a perfect system.

... just remote mount the drains in a easy spot and then use the little Propane tank bleeder valves 4 bucks each...

    I like this thought because I don't want anyone to say "oh, my drains are too hard to get to, I have to kinda half-crawl under my bus and it's raining, I'll do it tomorrow .."  And tomorrow turns into next week, and then it's been a month, and before long it's a couple of months.   Not good - get a simple, reliable system to drain,  we all need it and we need to drain those tanks.

[PP]

Happy New Year everyone!

I have several 12V solenoid type LP gas valves that should be rated for 300 PSI. I wonder if I can use them for drain valves instead of having to slide underneath all the time? Even setting on blocks, I don't like releasing air from anything while I'm 'down under'. Any opinions on this use of the valves?

Thanks, Will

I forgot to add-they have 1/4" female pipe thread fittings in and out.

[Dave5Cs]

Well then I aman army of one because I like the cable drains. Never had a problem with them sticking and like Bruce said just give it another tug. I like your idea Clifford but on my 5c the two tanks are in the front wheel well in the middle, so if I ran copper 1/4' line from the drain on the bottom of the tank with a drain on the end to get any slope on it 1/4 per foot it would have to be 6 inches off the ground by the time it got to where I could reach it so wouldn't work on mine. My luck I would catch it on a curb and rip out the tanks, lOL

Dave5Cs

[daddyoften]

A remote drain does not need to be lower than the tank. It just needs to leave from the bottom of the tank. I use this setup on my service truck and works great. I have elbows installed on the bottom of the tanks with a rubber hose run out to the edge of the box with a quarter turn ball valve with another elbow so it points at the ground. The one on my main air compressor actually is above the bottom of the tank by about 6".  It is so easy to reach down about knee level, turn the valve, let it spray out the water and close it! Done! :-)  

Also, you can leave it open to completely drain the tanks....

Sent from my DROID RAZR HD using Tapatalk

[buswarrior]

Please use methyl hydrate in the air system for antifreeze purposes if you choose. Isopropyl isn't for the job.

Air systems leak worse in the cold.

The best defense is dry air 24/7/365. Catch the moisture before it gets in there

Bags up or down, environmental decay of the material is our problem.

Happy coaching!
buswarrior

[Beesme]

 So what it sounds like to me is ...if I were to eliminate my level valves my bus would stay inflated....as long as I installed manual valves to adjust coach... My lines are new and my airbags are new.... I can't hear air leaking ... Overnite coache is sitting on stops.....

[buswarrior]

Or renewed your leveling valves...

Happy coaching!
buswarrior

[John316]

Well then I aman army of one because I like the cable drains. Never had a problem with them sticking and like Bruce said just give it another tug.
Dave5Cs

Lol, sorry to break the news to you Dave, but you can't comment on this thread. You live in California, where it never snows, and rarely rains. So you don't have mud and slush to foul them up. Basically your cable drains are living in a natural museum. So yeah. They should work well. The rest of us that have (or had) buses, usually use them in less then ideal conditions. Hence why they sometimes have issues.



And for those of you who don't know how Dave and I roll, I'm guessing he is chuckling just as much reading it, as I did writing it. That is a tongue in cheek explanation of why they might work for some and not others.

Happy New Year! May this next year be filled with cheap fuel and many happy times.

[Dave5Cs]

No, No,No my OK friend John, yours might have clogged up from torn up road tar if yas know what I mean, LOL,

Ok you got me there Dang-it. you were the only one to catch that!...But I still have a lot of old Camel Dung I haven't got out of the system as well as the Tailings from the Gold Bars that were hauled in the sand from Aramco.
Yep I almost lost my keyboard when I was reading it. Lemonade doesn't work well in it as you know.

Take care you Buslessnut,  

Dave5Cs

[solodon]

Earlier in this thread one mentioned the effects of letting a car sit on flat tires and what it would do to the tires.  This is a relatively true state however the analogy is incorrect.  If there are bump stops the bags will still have some air in them, and the weight of the bus is not on the bag but on the stops so there is no additional stress on the bag.  A tire without air is no problem if there is no weight on it.  Check the spare in a lot of cars.  That's my thought anyway.  Happy New Year all.  Don