Isolating Air Leaks

The past few months has been the time for me to pick away at life's little annoyances relative to the coach. I have extended my engine fuel primer, added a back-up water pump, added inverter by pass switches, upgraded the dash radio and added a CD changer with a large magazine, replaced my Norgren valves and rebuilt the solenoid valves, and most recently took the first step to find an auxiliary air leak that has all of a sudden shown up.

The bus auxiliary air system is essentially house components and bus components. On my coach the house or converter installed air operated items are the sliding floor, dump valves, bed lift, pocket doors, generator air bags, air horns, seat, etc. The bus auxiliary air components include the suspension, belt tensioners, etc.

As anyone can see isolating an air leak is a major task, and it is something that can require hours of effort. My first step in chasing leaks therefore is to be able to narrow the search. To do that I decided to cut my current and future effort in that regard in half. I added valves to the house or converter installed air lines so with all house air turned off I know if my leak is in the house side of things or the bus side. I could have added one valve for the entire house, but as long as all house air circuits were in one spot I added a valve for each circuit with the exception of the air horns. The air horn circuit has the solenoid valve right there easy to see and access so I did not feel I needed it.

The picture is of a Liberty, but in case other converters have used a manifold arrangement similar to this one, the concept would work for other coaches.

Since installing my shut off valves I know my aux system air leak is on the bus side of things.

Jon-

Please let me know if/when you get ready to sell this bus with all these neat modifications. I want it. Just wait a bit until I ditch the other 2 spare Prevosts I still have and am down to one.

Jon, it will be nice to get to TN this spring to check your improvments out. It's kinda looking like you steer bay is about full.

I'm waiting on the Parker valve rep. to come on the 10th of January. I'm hoping to get my level low system back together shortly after that.

Jon, that's a beautiful thing.

Change that tee and nipple to brass though for the show! :D

Nice job Jon...;)

The ugly Tee and nipple are going to stay. I don't know why, but it was a royal PITA to get my installed components and fittings leak free so I decided to leave the gauge fittings which I had installed previously alone.

I replaced all my Norgrens and the guts for the 5 solenoid valves and there had to be at least 100 fittings and I had no trouble with those, but for some reason this bit of plumbing was troblesome.

That's OK Jon, it's your bus and you can do what you want. You could paint it though. The galvanized is so gauche against all that brass. :D You could get the same blue as the valve handles and paint the gage too. :D

Jim......go buy a bus. NOW!

BTW, how many buses have you shopped? Inquiring minds want to know....me.

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Originally Posted by Jon Wehrenberg

Jim......go buy a bus. NOW!

BTW, how many buses have you shopped? Inquiring minds want to know....me.

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Three.:eek:

Here's a nice Prevost Country Coach conversion: http://www.parliamentcoach.com/PREOW...PHOTOSPECS.htm which I looked at just the other day at Parliament.

C'mon Jim, take the plunge, a guy only lives once.

Jim....pull the trigger. You are missing out on some fun, the market sure is a buyer's market, and you ain't getting any younger.

What do we have to do to convert you from a wannabe to a newbee?

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Originally Posted by Jon Wehrenberg

, the market sure is a buyer's market,

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How have things changed between what Jon said in January of 2008 and now with respect to it being a buyer's market? I've only been watching for a year or so.

It sure looks to me that prices are even lower for used coachs. But, there are signs that they are leveling off and maybe even starting to rise as the inventory of certain types of coachs is reduced. Even though the two main remaining converters are busy building again, It's a far cry from pre-recession numbers.

Based on the two that I bought and sold from late 2007 to early 2012, I think overall the market is softer now than it was in 2008, with the economy being the greatest contributing factor. Every time I start thinking prices are improving, they seem to continue to decline, but maybe, just maybe, we have hit bottom.

Dale, does that mean I'm entitled to a market rebate on my coach...

Yes Gil. Remind me the next time I see you, and I will give you half the profit I made on it.

I have to remember NEVER to poke at Dale.

Jon I have been slowly fighting the same problem I have to shut off my aux pump when sitting, I have found several small leaks found some major ones on the lines going to the gen airbags and replaced all the push on fittings with brass ferruled fittings, the coach stays level in manual but still cant turn on aux pump / I will keep looking you gave me a few more ideas,

Other common weak points ARE the drivers seat AND all the lumbar controles on the seat. The belt tensioners on the engine and that would include that regulator attatched to the control knob.

The Step slide this can leak a few different ways. One way is it can leak out the end of the cylinder where the ram comes out. You many or may not hear that at the step. Another way they OFTEN leak is like this.

That component the step slide is never "resting" it either has pressure pushing or pressure holding it closed. When that inner packing on the ram leaks internally the air will leak out at the exhaust port on the control (usually MAC control powder blue color) in the air distribution panel in the steering bay.


Brings a side note when these small square powder blue MAC controles that many of us have leak ot their exhaust port it is confounding. You will hear it clearly leaking much soapy water will not help because they shield that exhaust port with multiple baffles as so not to allow dirt and dust to migrate in at that poit damaging the control and that is why you can here it leaking but never find it with soapy water. You have to burry the entire component in soap suds to see bubbles risking shorting any of the many electrical components in there with it.

SEE this alot.. Recently I pulled the front stairs apart on Lewpops old bus to replace that cylinder that had an audible leak at the stairs as well. It was a Bimba cylinder I think that was the manufacturer and the cylinder they sent us was leaking out the seal for the ram bran new. Not bad but leaking none the less. NO GOOD Mr Bimba

On his Marathon the converter supplied a shutoff for that component right on the control in the stearing bay. Brought me to the conclusion that they were aware of the possibility of a problem and thought it important enough to allow it to be closed when not underway.

Larry on your Vantare there are multiple Mac controles behind a removable panel in the back wall of the closet in the bathroom. They signal all the pocket doors and the bed lift and I dono what else. Ever open up that panel and look in there for leaks. Watch it with the soapy water if you do and hear air lots of wires too. Remember what about leaks you can hear but not find on these controls and for sure watch all wiring end terminals as you look for leaks with soap and water.

Your bed lift cylinders IMO are also very suspect. Hope this helps and good luck.

With our bus I never got it completly air right on the aux air side but I did get the compressor down to cycling 2 or 3 times a day and that was managable IMO.

Nother thing I did once I got it to that point onours was changed the control switch for the aux compressor and added another manuall control for the compressor bypassing the regulator and right before bed Id turn it on manually and run the aux pressure up to 100 psi and at that pressure it would not drop to 60 psi and come on bothering some while sleeping.

Nother thing (sorry cant help it) where is the pressure set on the limit if it is at 100 thats unnessessary makes the pump run longer and more frequently.I see more buses that are at that unnessessary 100 psi setting on the aux compressor than not. Identify all the pnewmatic acessories and what kind of pressures they require and set the regulator for JUST 10lb greater than what you find. Usually 50 to 60 or 60 to 70psi is adiquate to opporate everything. Everything will be happier including you. Just the lower setting is sometimes enough to stop what were previously minor or small leaks and when it does come on it will only run half as long before stopping too.

Nother tid bit Even if your stuff is OK. I found a compressor in a Liberty a xl they put it in a box they build for sound and placed it behind the cruise air in that front compartment behind the bumper. Now it ran and worked. I was in there moving it to do things with the a/c and discovered that it had ran so long and hot that it melted its little plastic coolong impeller that is on the end of the motor shaft.

I rebuilt my aux pump last a year or two ago then it ran too long and the heat killed it so I ordered the biggest industrial 12v pump they made custom built the base about 6 to 8" longer and wired in a bilge blower fan right at the end of the motor fins so it kicks on and blows about 50mph wind across the air pump when running now it stays nice and cool I had to pat myself on the back for that one

Larry, I'm curious why a 12V compressor? My last plastic coach had a 12V compressor, which was far nosier than the cheap 110V unit I have in my Country Coach. We have so much inverter power available we really don't need a 12V compressor. Again, just curious,

If you want good capacity and QUIET, here's the real deal:
http://www.jun-air.com/product_detai...oductTypeID=50

There are always a few of them used on E-bay.