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Hector Duplichen On Suspensions/Level low- Awesome
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Susan,
There is no correct answer about the use of the auxiliary air compressor. If your coach were approaching the air system integrity of Hector’s (he is our standard of excellence) you could leave the compressor on at all times and it would keep your belts tight, your generator air bags inflated, allow you to operate the air slide floor, pocket doors, bed lift, and all other air operated goodies, plus enable you to level your coach from time to time without starting the engine.
But if your aux air system has leaks and your air compressor cycles often to compensate I would suggest just turning it on when you want to level the coach. Folks with slides do not have the option because the air seal on slides has to be inflated otherwise there is a risk of rain water entering the coach and that is a bad thing. But unless you have devices that operate on air and they are critcal I would leave the compressor off until needed.
As a footnote it is unlikely if the camp site sloped the other way that your aux air compressor would generate enough PSI to lift a front end that is sagging so once you notice that happening it is probably time to consider fixing the cause of the “leans”.
BTW, Some questions are easy to answer on here because they are either generic and apply to all of our coaches, or the person answering has specific knowledge of your type conversion. Prevost chassis questions (such as this one) expect lots of good assistance, but for converter specific questions we cannot answer do not hesitate to speak to the folks at Pantera. They have a long history with Angola and can give you accurate information. Don’t hesitate to share information because knowledge helps all of us avoid the dread that goes with surprise problems.
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I’m reading old threads so that you don’t have to repeat yourself ad infinitum, Jon.
I spent time at Panterra last fall. They have been great about answering my call-in questions. I hate to interrupt the main technician’s momentum, though. He moves through work like a PacMan.
Many many thanks again, Jon.
Susan (tried sending a Reply earlier…hope this isn’t a Replay)
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Some may recall that my coach developed The Leans after I arrived at a park on the southern coast of Oregon. Jon kindly coached me through the diagnosis and suggested a stop-gap. He provided a wonderful white paper on the subject of fixing such problems. And Hector’s course material on the suspension system had been medicinal for my initial confusion.
The upshot was a fine workaround: simply turning the key and letting the coach re-level itself every other day, with the intention of getting the problem fixed at the first opportunity.
After a month or so of workaround, I left that park and drove an hour north to a park slightly more inland. Once parked, I noticed that the coach was a little high on the side with the lean. “Great, rather than level it I’ll just leave it like this and that side will gradually come down.”
But it never did.
I spent 5 days at that fun-house angle, then drove a couple hours north to my current location. I’m in the nice warm Willamette Valley. I decided to level the coach when I arrived. That was two weeks ago and the bubble is still perfectly within the circle. Not even a smidgeon to the left/right/up/down.
Thank goodness for angels like Jon and Hector, and also for the leak daemon.
Susan
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Since none of our coaches was delivered with the option that makes the bus repair itself usually when something is not working properly there is a repair required.
Having said that our suspensions can sometimes exhibit a problem that can reverse itself over time. For those of you struggling with the leans please don’t interpret that as meaning if you wait long enough the problem will go away. What I do mean is that for our suspensions to hold air thus keeping the bus level for long periods a lot of fittings and valves have to be leak free. Fittings usually are always going to leak once they start, but the Norgren valves can sometimes exhibit a problem that more frequent use can minimize, or a change in temperatures can affect. It is a given that a valve on the border of becoming a leaker will show a leak faster in colder temps than in warmer ones.
Another factor is if the auxiliary air system has not been maintained and moisture, even a little bit, finds its way into the system and the bus has been dormant for quite a while corrosion can occur inside the valve. That corrosion can inhibit the travel of the spools so the valve doesn’t completely seal, or the corrosion can impact the ability of the O rings to seal against the smooth bore of the valve. Frequent use and a dry auxiliary air system can enable the valves in some instances to move more freely and to repolish minor impediments to good sealing. More often however the reverse is true because the corrosion pits the smooth bore of the valves and the white corrosion of the aluminum bore of the valves builds up into a sludge and eventually screws up the opoeration of the valves.
Nice to know Susan is one of the lucky folks. Next time I play the lottery I am going to ask her to pick the numbers.
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All really good stuff and don’t forget, if your setting for extended periods using aux air for the toilet, doors, etc., the aux compressor can generate a lot of moisture and unless you have a means to drain, that moisture stays in the aux tank and can cause all sorts of problems as Jon pointed out. Moisture is the Norgren enemy.
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Thanks, Jon and Tom! I’ll ask the daemon if he/she’s available.
Susan
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I know this is a old thread, but I find it difficult to understand air system with a PDF only . Is it possible to reload Hectare’s Video cause it seems to be gone . Thank you in advance .
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I wish it still worked as well Al, Hector did a great job. We can’t get the video portion back unfortunately.
I’ll See if Hector is still supporting the video.
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Thank you Tom . As much as i try I just can’t seem to follow the path on the diagrams . I was able to isolate a air leak on the leans with the PDF but man if we could get the Video back that would make life much easier for us all . Thank s again .
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Hector did an amazing job and there is no downside to developing an understanding of the level low system.
But if the reason for wanting to understand the level low is to resolve issues with leaks (“the leans”) almost every single problem related to the leans is knowing where and how to look for leaks
We do not have a single suspension system. We have three independent systems, the front, left rear and right rear. We only need to look at one of them, depending on which way the coach leans. Each system shares an air supply, but other than that they are independent. For example if the coach leans to the left, isolate the leak seeking from the 5 port Norgren valve on the bulkhead in front of the drive axle, to the lines, fittings and valves going to the ride height valve and Norgren valves, and to the air bags themselves.
Hectors efforts were on the suspension his coach had. Prevost is always updating or changing designs so the details on Hector’s work are valid for his vintage and converter, but if you have another older or newer vintage some of your details are going to vary. My Liberty of a similar vintage to Hector’s CC had a similar level low system, but modified to a Liberty design.
Depending on your coach’s age and the age of the components you may find it far easier to replace air bags, fittings and or Norgrens and ride height valves.If you turn the responsibility for chasing leaks over to someone you are paying to do the work, just the cost of labor to isolate leaks may cost more than all the components because some leaks require system disassembly just to find them. A leak at the bottom metal “can” on an air bag is almost impossible to find unless the air bag is removed from the coach and then pressurized. The same goes for some Norgren valves.
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Understand, that is what i did for the lean I had. It turned out to be a fitting on top of the air tank going to a spring . Still would be nice to watch what so many enjoyed back in 2012 . Also I think his was a 96 or so and I thought mine being a 98 would be the same . Not so you say ? Thank you For the info Jon
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Al, I cannot say with conviction your coach is going to be the same or different from the system Hector defined. A change from a solid axle to an IFS brought some changes. I do not believe his coach had ping tanks for example which is a difference. Some systems are modified by the converter either by a small design change such as what Liberty does, or with the addition of a supplement to the system such as the HWH option. And as Prevost refined the system, design changes were made.
What I am saying is the over view of the system is all that is needed to chase leaks and simplify the process.
There was a time when owners who had leaks and the leans would pay someone or would themselves spend days (not an exaggeration) spraying soapy water on every air fitting on the bus to attempt to find a reason why the bus leaned to the right over night. Hector’s work helped a lot of people more efficiently find leaks that caused the problem.
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Thank you Jon , That is good to know . Would be nice to know some of the changes made over the years and what reasoning went into the changes .
The good news is unlike our years in the BB the information, and knowledge is still out there for us all . We only need to find it .
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I contacted Hector and he’s been through some pretty serious medical issues, but he’s going to see if he can resurrect the video. He said it died with the server it was on and maybe he can recover his file.
I’ll follow up…
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Al, I do not know any enthusiasts, Prevost owners or otherwise that can track the evolution of the level low system. I know some changes but the reasoning behind them would only be speculation.
Very early conversions did not even use Norgren valves. When the Norgrens appeared might be mid to late 80’s. At that point the accessory system had to be maintained to hold at least 30 to 35 PSI otherwise the Norgren valves between the drive and tag axles would dump air and the rear would drop.
Just after the mid 90’s Prevost came out with a change that allowed air locked in the air bags when the coach was shut down regardless of accessory system pressure. At that point it was not necessary to maintain the 30/35 PSI accessory pressure. There was a retrofit that could be applied to older coaches so how a coach is set up today could vary from the production design.
With the introduction of the IFS came ping tanks at each air bag plus the ride height valves were changed from delayed acting to instant acting.
I believe at or slightly after that point in time the Norgrens controlling the front had some changes that I think eliminated the 5 port Norgren in place of one or two 3 port Norgrens.
I think I know this because my 3 coaches went through those design changes. I might be wrong. What I do know is my Liberty modifications make my suspension system and controls unlike other conversions so what might be true for most coaches may not be true for my coaches. For example, instead of one three port Norgren controlling the exhausting of air for all three suspensions is not true for my Liberty in which each has its own dedicated 3 port Norgren for that function.
Over the years these changes were introduced without fanfare so someone with a greater depth of knowledge on the changes, when they were introduced and the reasons for them will have to fill in the gaps or correct my errors above.
If this is confusing, welcome to my world.
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