The Dreaded Topic

[Jeffery Raymond]

http://www.nro.nao.ac.jp/~sofue/image/z_bike/lean.jpg

Motorcycles are intended to lean and I guess the Tower of Pisa.

But when your coach leans then that's something else.

Some good tips other than the use of a bottle of soapy water would be appreciated.

Thank you

[MangoMike]

Jeff,
I'm with you. I've already replaced one set of Norgren vavles, but still have reaccuring problems. Going to start working my way around the bus rebuilding and replacing.
Mike

By the way the pixs right in the post are very cool.

[Jon Wehrenberg]

The cynic in me sees the "leans" as a condition all of our coaches will experience, and those that choose to let someone else solve that problem will be sending some mechanic's kids to college.

There is an almost infinite number of potential areas of air leakage that will allow a coach to lean including the Norgren valves, air bags, solenoid valves, air line fittings, etc. You can look at your coach until you are cross eyed, but in the end, to fix the "leans" you have to methodically verify every single valve, hose, fitting and airbag is leak free.

To completely discourage anyone when my 1987 was about 10 years old it had a case of the "leans", especially in cold temperatures. I spent a few hours a night for almost a month under my coach. I replaced all air bags, rebuilt almost every Norgren valve and I replaced the Prevost valve pack (front lower compartment), and when I was done my coach would sit for a month and never sag or lean. All I learned was that over time it would start leaking air again. But for about 3 or 4 years it was as good as I could make it.

My current one has leaned twice since we have had it, but I think that was the result of a small leak in the auxiliary air system which has been fixed. You must maintain about 30 PSI in the aux system because below that some of the Norgren valves seem to dump air.

Note: this only applies to my Libertys. Other conversions may not have the same leveling systems.

[ken&ellen]

There is a small, Thomas, compressor in the drivers side compartment which operates at 12 VDC. The last couple of days I noticed it will, for lack of a technical discription, chirp. Upon closer inspection it is just cycling on/off without coming up to speed. If I flush the toilet, air flush, it will run and then shut down, but soon it is back to the " chirp". On the Liberty what does this unit support so that I can look for leaks? Ken

[Jon Wehrenberg]

Ken,

I have never had a system as you describe in my Libertys where I relied on a compressor for a toilet flush, but if I understand your description correctly a pressure drop from flushing for example starts the compressor and when pressure is restored it shuts off.

Then it "chirps" which means to me it runs very briefly and shuts down.

Thinking out loud here something is not right. A pneumatic pump like your compressor is controlled by a switch that senses a pressure drop and then powers the compressor until system pressure is restored. Unlike with hydraulics that usually takes a little time because as the name implies you are compressing air a few cubic inches at a time.

But you suggest that with a brief running time which I would assume is a few seconds the compressor shuts down. That acts like a hydraulic pump, which is not the case. I would consider you don't have a system leak, but maybe a pressure switch abnormality.

This can get to be a long issue to diagnose so if the pressure switch is not the culprit then there is something kicking the compressor on and off such as maybe a thermal overload switch or maybe the line to the pressure switch is water filled. It sounds wierd. Send an email if you want to see if we can puzzle through this.

[Jerry Winchester]

I noticed some months ago that when I had the aux compressor on, it would cycle more and more. Then after having the coach parked for a month with no air, it was leaning to the starboard side. I have to think the leaks have started, so I guess some soapy water, a drop light and a creeper are the tools to have when searching for them.

It would be nice if Jon could pen the "Newbie Air Leak Troubleshooter and Service Guide" for those of us neophites not totally familiar with the valves and their relative location on the coach. :)

[Jeffery Raymond]

On our Lib, and on most Lib Lady's and 'above,' there are even more things that run off air than some other coaches (Thanks guys).

There is a little valve on the right hand side of the sink in the bath. If that is messed up, then the bed lift doesn't work. The toilet also requires air (don't go there). On Elegant Ladys, for the Trump Crowd, the pocket doors on either side of the bath are also air operated.

In this case it is better to be poor than powered.

[Jon Wehrenberg]

On bus number one the sliding floor and the air lock was the only house stuff that operated by air. Now, in this one the aux. air operates the floor, pocket doors, bed air lift, generator air bags and the belt tensioners in the engine area. There may be more things because I am still trying to sort things out.

As Jeff will tell anybody, if you want to get really excited turn your coach over to Prevost and tell them you need your air leak fixed.

What makes this such a bad choice is that finding a leak which creates the leans for example can be anywhere. ANYWHERE! Pay close attention folks: the guy running around under your bus may know how Prevost put together the bus portion of your aux air system, but you are paying for his on the job training when the trouble shooting expands to include the converter portion. This will run the average bill up to a number that approaches the size of the national debt.

If you as an owner can get under your coach with a spray bottle of soapy water and a stethascope you can save enough money trouble shooting to be able to afford a contribution to my new bus fund. Cash only please, small unmarked bills.;)

[MangoMike]

Thanks to a heads up from Jon I have already replaced one Norgren valve located immediately in front of the drive wheels. However I'm now rear-sinking again and plan on "diving" to look for another leak.

A great start would be to diagram the location of each valve on our buses. Now I know each converter will probably have a different location for the Norgren's and the years would matter too - but we can start to build a database of valve location diagrams that would be incredibly helpful in the future. I'll get pen and paper.

Mike

[Jeffery Raymond]

Prevost has schematics by coach in Canada. I took our old bus up there and Voila! Out came the schematic. They also have a custom machine that they made (out of stainless steel) which pressurizes the coach and measures the air resistance. From that they can detect problems precisely. Of course, the exchange rate was about half of what it is now, so it was also fast, good AND cheap. Now it is only fast and good.

The converters version of the schematic isn't that difficult.

Anyone for an en masse trip to Canada this summer? Maybe we could invade Canada and take over? Of course, that movie has already been done, but it would be nice to get it right the first time.

[Jon Wehrenberg]

For those who are into punishment (like Mango) here are some things I figured out in my quest to eliminate the leans.

The problem with leans in the rear could be with a valve in the front. Do not rule out any valve.

Eliminate the hoses, airbags and hose fittings before you start messing with valves. Soapy water and your ears are the only tools needed for this phase of the repair.

You can replace entire valves, but Norgren valves are easily tested and rebuilt. If you go to a Norgren distributor you can buy the internal parts real cheap compared to buying a whole valve. I used to replace the entire valve until I ran out of money.

You can create a simple testing device with some tubing and a few brass fittings and valves from Lowes or Home Depot. All you have to do is remove the valve from the bus, and air into either end of the valve does the "switching" and then you just have to insure the valve seals when it is supposed to on the other ports. The schematic is on the valve and there are about a billion different variations on our coaches so you may have as many as two inlets and several air outlets.

You can test and rebuild the valves without removing them from the coach simply by removing the hoses going to them and/or removing an end cap. It is easier to remove the valve most of the time.

Curing the leans is something you should do when you want to get your mind off of everything else in life. If you need to concentrate on your business or solving the world's problems let the repairs wait or turn your bus and your bank accounts over to someone else. This is a project that will drive you nuts, but when you have solved the problem nothing else on the bus will be a challenge.

[lewpopp]

I guess I would be game for a trip to Canada this summer but not by air. We'll all need passports, won't we?:o