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Coach won’t raise to travel height
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It’s just a 90 degree elbow of standard
old crappy pipe hooked to an air/water separator and as Jon pointed
out, has nothing to do with ride height unless it’s a major leaker
effecting aux air buildup. My Royale had the same stuff.
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Scott,
Sorry I didn’t mean to hijack your thread, I just thought since we are both having similar problems that perhaps we can address them all in one thread.
That circled T area in my photo is the location of a small air leak.
However, today after starting the engine, the bus aired right up to drive height! Ghosts? But can still hear the air leaking out of the T.
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Our coaches share a suspension system logic that uses a number of Norgren spool valves. With a few exceptions the spool valves are activated by auxiliary air system air pressure which moves the internal spool to open or cloase the valve. That air pressure is controlled by the suspension control at the driver’s area. and that control operates solenoid valves which by being open or closed control the spool valves.
That’s a long winded way of saying that absent a leak in the air bags or suspension valves or connections when you operate the level low system controls you are actually using air pressure to move the spools to make the suspension do what you need it to do. If moisture has reached the system that moisture can evantually cause the internals of the spool valves (Norgrens) to corrode and gum up, eventually preventing them from functioning. Once they get messed up internally it is anyone’s guess as to why the bus suspension does or does not do what it is commanded to do.
Despite Georges good luck at having the coach go to the driving height, he now has a bus he cannot rely on to react correctly every time. It may work the next time, or it may never work again without repairs. Regardless the initial problem of moisture needs to be dealt with, and then the system needs to be checked. In this particular case I would suggest all air tanks get drained. Then the air dryer serviced. Then I would exercise every portion of the suspension system multiple times by alternately raising and lowering each corner fully to exhaust as much moisture as possible. If the air entering the auxiliary system is know to be dry, then filling and exhausing the air bags will help purge moisture. It will also exercise the Norgen valves. If they have an internal build up of the gray crud (a technical term) that is associated with moisture in the system that will not go away, but by exercising the valves at least they may not bind up.
If in exercising the bus suspension, both manually and by driving it something does fail to function then at least part of the problem has been isolated without requiring a lot of time consuming diagnosis.
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Being fully aware of the underlying problems with my pneumatic system, I am not falling into a false sense of security just because it aired up and seems to be staying there while the coach sits for the last 2 days.
Where exactly is the air dryer and should I do anything to make it healthier?
Would it be safe to drive it 100 miles to where it should go so that I may have a Prevost professional look at it? What are the chances of it just laying down on me while I drive it to that location?
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On my previous coaches the air dryer was located on the passenger side, ahead of the drive axle on the frame. On my current coach it is located left of center, on the bulkhead ahead of the drive axle.
If you are at ride height you can safely drive 100 miles or more. If your suspension components are beyond 10 years old I think you will not regret changing them out which will likely address the moisture problem as well as increasing your reliability for the long upcoming trip.
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Looking in the suspension section of my parts manual, I am unable to find the air dryer, would it be listed in another section?
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Georges,
My chassis vin # ends …1114 and is likely close to yours.
The air dryer on my coach is on the drivers side and located on a bracket just ahead of the tag axle and requires removal to service (which is easiest done on a bench).
All other instructions from Jon are correct …of course.
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Mine ends with 1096, our coaches look like twins (on the outside). Thanks.
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Hi Georges,
Like Chuck my 91 H3 has the dryer over the driver side drive axle.
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OK so it’s not something I can just remove and replace or clean, it requires someone to get under it or put it on a pit. Thanks.
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They put them in really tough spots Georges, making servicing them difficult. Mine is on the starboard side up high near the drive axle and almost impossible to reach laying on a creeper, while trying to spin off a filter that never wants to let go.
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I believe Georges air dryer is the type that has a cartridge that is held in place with a huge snap ring and three small bolts. It is not the spin on element type. Not the easiest type to service.
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