The problem: Lost air in right rear air bags the other night. Last night lost air in the left rear air bags. The rear of the bus will not air up.
Bus is at a shop right now (24/7 service dept, kinda cool concept) and the technician says the rear air tanks are empty. Since it's a truck shop, they claim they dont have the right type of valves in stock, so they don't want to remove, inspect and clean, etc. any valve. If they break it, they can't fix it.
Bus has to be back in service by 10pm tomorrow to make it to the next venue.
Does anyone have a suggestion on which valve it might need? Or valves? I'm pouring through the parts manuals and I've never seen a piece of equipment, wheels or no wheels, that use more air valves than this thing.
Thanks,
Mark
Fill the rear tanks with a shop compressor it may start working again,you can always buy a compressor at H/D to keep the rear air up till you can get it to Prevost,it's not unsafe to do that all you are airing up are the auxiliary tanks.Aren't the Prevost a over engineered air system ???
Has your air dryer not been serviced for some time? There might be a lot of sludge in the system that is fouling up the transfer valves and check valves. The mechanics where you are at should be able to check the air dryer. Hopefully, there are connections on the rear tanks so you can air up.
You can remove the drain valve to air it up, the accessory tank is up front on the right side it may have another about the middle on the right side
I'm certain the dryer hasn't been serviced. I'll have them look at that.
Cliff, you got me thinking.... I wonder if I can get the tech to run a line from the front aux air tank to the rear tank that feeds the rear air bags. I think I saw that the air bag system has a pressure protection valve that limits it to 75 psi, or maybe it maintains a min of 75 psi. Now I need to reread that section of the manual.
I have spent three days convincing three different "mechanics" to think out of the box and just FIX it! If you can't get the part, then improvise. Example, they missed the shipping cut off so they "can't get the part tomorrow" (BTW, I gave them the part number they needed to order 5 hours before the shipping cut off, I insisted that they order it next day AM delivery, I was told they would order, but they didn't) . So....... I found someone in the area to get a Uber ride, pick up the part, then had the Uber driver drive it to shop. Just like that, the part they couldn't get, is there. Getting them to install it is a different matter.
run a line from the front aux air tank to the rear tank...
that could compound your troubles.
Clifford's suggestion to plumb an auxiliary compressor is best.
do you have an inverter ?
a $100 bill gets a pancake.
i would.
i have.
just don't return the compressor and tell about it here :)
Your problem is probably a norgren. valve - FWIW
The real problem is it is in a shop that services trucks and not a shop that actually understands Prevost suspension systems. It isn't rocket science, but some shops have the ability to think they know the system, or at least more than the bus owner and they will screw with the system, usually ignoring the true problem until the owner's wallet is empty.
The suspension air bags have NOTHING to do with the wet, primary or secondary air tank, except that they need to have air in them before the accessory tank gets air. The accessory tank is the source of air pressure for the suspension. Fill the accessory tank (only) from the schrader valve in the steer compartment, and with the key on and the suspension control set to the driving or road position the rear should air up. If it does not you likely have an issue with the solenoid valve in the center on the 5 valve manifold near the schrader valve. If it does air up, look at your compressor or protection valve.
Jon beat me to it. Mist have signal to center stack solenoid, front left lower steering compartment. what it does is change elect signal from switch to air signal that sends a air signal to norgren valve behind last bay bulkhead in front of rear axle. that valve either directs air to level low or manual leveling valves.. Also the front opens valve to fill aux tanks. Not unusual for this filter to be neglected to the point of plugged up. Go to prevostcommunity web site at top articles section go down till you get explanation of level low. I don't think you have to sign in to get there. Bob
PS all valves in that stack are interchangeable. If you may think the center is bad just switch solenoid from. another .
Mark, there is a regulator from the auxiliary tank at the right front corner not far from the tank they go bad too,what I was trying to say if you can equalize the pressure on both sides of the protection valve most of the time it will start working again.The entertainers coaches that come through here carry a box full of valve, fittings and lines to bypass some of the valves when they have a problem on the road,lol if I ever need a NG valve I just look for a entertainer coach
I ruled out solenoids because it would be rare for 2 to go out at the same time - FWIW
Any time there is an issue as described the only way to resolve it is to find out where there is a lack of flow. If you have aux pressure then you have to follow the air through both the manifold which is sending the command to the Norgren valves, but also to the air supply to the Norgren valves.
In a Prevost the air bags get air routed through 5 port Norgrens which are normally closed until they get an air signal from the manifold stack. Then based on the signal which is going to come from those solenoid valves the Norgren which is normally closed, is going to allow air flow through either the ride height valves, or by manually filling with commands through the level low system controls. Without leaving the driver's seat you can do part of the diagnosis by determining if you can get the rear to raise using one of the two methods. If it won't raise at all then you have to see if you have an issue with the air supply not reaching the 5 port Norgrens.
If the air system has not been maintained and the norgrens within the system are filled with moisture and aluminum oxide which becomes a paste almost you have a whole coach issue of fairly large proportions. But if the system is dry and has been maintained you may just have a problem with on valve.
He is lucky his is a 1997 model these new Prevost with the computerize air suspension are a nightmare.
A casino here has a H with the self closing door it take 4 Norgren valves to close 1 door and it is interlocked to the B500 and won't engage till the friggn door is closed why they do stuff like that is beyond me
I totally understand Clifford, recalling some of the air circuit boards on the frames of the dumps trucks in the mid 2000's with their electric over air relays controlled by the body control module. This was a real blessed learning curve, and with out the laptop and some software it was a pain at times. I had fun talking with a friend who work with the city trans busses and I felt lucky.
Floyd
Quote from: Jon on July 19, 2016, 08:09:13 AM
If the air system has not been maintained and the norgrens within the system are filled with moisture and aluminum oxide which becomes a paste almost you have a whole coach issue of fairly large proportions. But if the system is dry and has been maintained you may just have a problem with on valve.
As I said before, it is important to check the air dryer to see what state it is in, if it is all gunked up with gray paste, lack of dryer maintenance may have caused the whole miserable situation.
While I agree fully that a poorly maintained Prevost air system is a recipe for disaster, step one still should be to identify the cause of the current problem. If in fact it is that gray sludge affecting the operation of the suspension system valves, then it is likely the problems are widespread affecting all norgen valves, air bags likely have some water in them, protection valves probably may not work due to corrosion, and the brake chambers are likely rusting inside, prematurely wearing out or damaging the diaphragms.
Or it could just be as simple as a single bad valve.
So...back to square one....get air in the tank by any means possible...and run with your wallet to some place that knows what the heck they are doing...
If the Prevost is at a shop, air can be introduced to the accessory system only via the Schrader valve in the front steer compartment. If the brakes have air pressure and the accessory tank does not, and air has to be added the problem is a bad protection valve at the secondary tank. But if the accessory tank has air pressure the problem is elsewhere.
This shouldn't be difficult.
Its a bummer in any travels, but with the help from the site here I sure do see it a great resource.
I'm sure many of these newer coaches have these valve types below and we may look at them to gear up or deny them :)
Just kiddin, these here are neat but also can be a pita as mentioned when a frame is stacked with them. They been putting various sorts of these on trucks for quite awhile, and especially in safety options as doors "leveling" for un-loading of dumps, and you can imagine the designed stuff from people at the pencil desk ::)
https://imagehost.isoftdata.com/phpThumb.php?src=partimages/254076/&productcode=254076&id=395249&w=500
Multiplexing Architecture
Unlike the electrical systems on previous models, which utilized point-to-point wiring for all input signals and output loads, this system uses multiplex technology to provide control and communication between major functional areas of the vehicle.
Multiplexing simply means: communicating multiple pieces of information via a single twisted pair of wires (called the data link) without requiring a wire for each piece of information. This information could be gauge information such as engine oil pressure, or switch information that controls vehicle functions such as headlamps.
mechanics always thinking outside the real box dangit
Floyd
LOL I counted 5 of those boxes on Gary's 2010 Prevost RV chassis and 8 on the 2014 H model seated coach the casino owns
Yes Sir, exactly as I was just thinking I should have put in the post we made labels and turned them on with the laptop in whatever way was desired, on-of, signals, percentage whatever.
I thought it was bad with just the 2 of these on a dump frame, finding as you said they kept upping the game.
Floyd
Here's the update........
I pulled it from the shop it was at because they did not order the trans cooler when I told them it needed to be ordered. They charged $708 to diagnose the leaking trans cooler and inop air bags, despite the fact I told them was was leaking and gave them the part number for trans cooler. Total waste of money let alone precious time.
After the driver got the bus out of there, I drove to the bus in Boston last night and tried to figure out the air bag problem. I gave myself 30 minutes to diag the problem before I started on a work around. I crawled around under the bus, in the dark, deflated air bags and all, found the norgren valves for the rear axles. No air to either valve, and no air after them. I quit there and started on the Yankee Ingenuity repair. I ran a 1/4" nylon air line from the 115v air compressors regulated output to the rear. I removed the drain valves on the air bag tanks and installed nylon push lock fittings and a tee between the tanks and connected the air lines. I set the compressor's regulator to 60 psi and in 5 minutes it was up on air again. Done till it gets off this tour.
The tranny cooler leak was very small, dripping coolant once every 5 seconds. I had the driver remove the expansion tank cap the night before and the leak was minimal. I decided the leak was minor enough and sent it to the venue to pick up the band with 15 minutes to spare last night. Earlier in the evening I had ordered the norgrens and tranny cooler from Prevost in NJ. After the show last night, the driver got to Prevost in NJ at 7am to get the parts, then continued on to Philly to drop the band, then head to US Coach in Vineland. Well, 74 miles from Lukes the cooler blew on the NJ turnpike. All done. Rented two vans and got the band to Philly, then got raped by the tow company for the hook and drag to US Coach.
Luke got the bus at 2pm and Bill worked as hard as anyone could to get the cooler out and the new one in time for the bus to make it to Philly to drive the band to Detroit tonight. Thankfully the band had already decided to fly to Detroit tomorrow morning and hang out there during their "travel day" instead of riding in a bus, so that gave us an extra day at US Coach for them to finish the job.
I have to say I'm seriously impressed with Prevost's parts dept. 7am to 7pm CST, parts pickups till 11pm! Give them the last 8 of the VIN and they know EVERYTHING about your bus. Create an account and order away. Plus free ground shipping. And ordering the part direct was 50% less than the truck shop wanted... yes, a 50% markup above Prevost's over the counter price.
I also can't say enough about Luke and Bill at US Coach. They are great people, know what they are doing, and support us in a way that most of us will only realize when these two people retire. There is no one north of Vineland NJ doing what they do. Thank you Luke and Bill!
bunch of hoses on those norgrens. Been there. Mark good. would suggest good time to get rid of the push fittings. Glad your running again. I had a picture of that bank of them on rear compartment wall but it wouldn't post. To darn complicated--both the system and pic posting. Check and see if you have power to center solenoid on back wall of steering compartment drivers side. 5 Stack Key on.
I knew you could figure that out Mark BTDT try as hard as Prevost does people with common sense can get around all their complicated crap.
10-4 on Luke he came through with some studs for me MCI wanted $38.00 each he sold me some for $15.00 each such a good deal I bought 20 of the studs and now have plenty of extras I will never use ;D
Maybe at one time Clifford, but with the multiplex coaches without programming you cannot even change the type of light bulbs.
I wish the bus companies would go back to solid front axles, relays and circuit breakers. And skin that is held in place with rivets.
Maybe at one time Clifford, but with the multiplex coaches without programming you cannot even change the type of light bulbs.
I wish the bus companies would go back to solid front axles, relays and circuit breakers. And skin that is held in place with rivets.
Quote from: Jon on July 21, 2016, 10:55:52 AM
Maybe at one time Clifford, but with the multiplex coaches without programming you cannot even change the type of light bulbs.
I wish the bus companies would go back to solid front axles, relays and circuit breakers. And skin that is held in place with rivets.
Yea the chassis electrical is a different world Jon, first time I got into that was a changing a speedometer head Jon my H-41
Driver picked up the bus from Lukes at the end of the day and 20 miles later it started to over heat. It seems to be air locked. He's added 10 gallons or water so far but it still over heats after a few minutes.
Trying not to lose hope on this bus.....
I drive a 2016 Prevost H-345 passenger coach and the parking brake won't release until u raise it to ride height.
Quote from: billy6941 on July 21, 2016, 06:38:36 PM
I drive a 2016 Prevost H-345 passenger coach and the parking brake won't release until u raise it to ride height.
I may be wrong but I think a lot of the devices on current production coaches are built in because the intent is to protect us from ourselves. The problem is that by taking the ability to work around a problem away from the driver the bus gets far more complicated than necessary. How long will it be before the bus is controlled by a computer that disables it (like low DEF) until it is taken to a Prevost service facility where it must be serviced and the computer reset?
If google get their way the driver will be the next thing to go.
uncle ned
It has reached that point with commercial planes. Next year the co-pilot is being replaced with a monkey. The monkey is not a skilled pilot. His only job is to slap the pilot if the pilot should attempt to touch the controls.
He's overheating now. Trans cooler install gone bad?
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