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Ride height major malfucntion HELP Please!
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If you have air into and from the ride height valve but it is not reaching the air bags when the arm is in a position to allow air to enter the air bags the 5 port norgren valve that allows you to fill the air bags via level low or the ride height valve is not shifting to open the path to the air bags.
The problem is not the ride height valve because as you stated air flows when the arm opens the valve.
The five port Norgren is mounted formward of the drive axle either on the bulkhead near the center of the coach or in front of the fender liner. Typically when the Norgren valves fail to shift it is because they have sludge in them or are hydraulically locked due to water in the system, both conditions typical of a pneumatic system that has not been maintained with moisture doing the damage to the valves through the system.
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Thanks all.
Yes, the air is flowing.
So, Jon, what you’re saying is if the air makes it to that point, it still has to travel on to the five port norgren where it will fill up the bags. So because I don’t hear any leaking, and the air is getting through the ride height valve, you would suggest I replace the five port norgren for the left side rear of the bus? There are two located on the bulkhead just in front of the drive axle, one for the left and one for the right. Replacing the left would be the next logical step I would take? Or are you referring to the norgren located in front of the steer axle?
And something tells me that isn’t a stock item at the truck repair here in Lubbock.
Does anyone have any ideas on the best place to get one shipped asap? We love Lubbock, but our plans call for us to go north to get out of this heat.
As for poorly maintained coach, you’re definitely onto something. We bought this one knowing we were likely in for some neglect from the previous owner(s). After completely gutting and rebuilding all of the interior systems, it looks like we’ll have an endless supply of new projects coming our way as we work our way through the rest of it. Where do you even start trying to clean out a gummed up air system? Or do you just have to wait for it to break and replace as you go.
Really, thanks to everyone for all of the input. This is definitely a learning moment for us.
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My fault as Bernie pointed out, I meant the left side.
If an an air bag is blown as you suspect, your engine compressor would never reach pressure (dryer wouldn’t sneeze) and you would see the aux gauge continuously cycling and never build any air. A few more things to check…
The left rear 5 port is controlled by the steering bay 5 port, I don’t remember which position for the coil/valve. The center is ride height, the bottom may be the left side. Jon?
Check the tag lift cyclinder to see if the diaphragm is blown and leaking
Check the 3 port mounted between the tag and drive tire
If you have an aux compressor, use that to put air into the aux tank, engine off, key on and see if you can hear a leak in the rear with the level low trying to pump up the left side
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Looking at the air schematic, it looks like the 5 port valve is pilot operated so if you feel you can take that valve off you should be able to remove the end caps of the valve without worrying about a spring popping out. You will need either a Phillips screwdriver or an Allen wrench, once you get the caps off making sure you maintain the orientation of each cap(take a picture). Once the caps are removed gently try to push the spool out, also maintaining the correct orientation. Clean the spool as best as possible and the inner body of the valve. Check that the o-rings if applicable are clean and absent of any rust or corrosion, once that is done apply a lite amount of Vaseline or lubriplate to the spool and the inner body of valve. When replacing the spool in the body make sure the spool is all the way to one side or the other. Replace both end caps and give it a go. This hopefully will get you up and going till you can get new valves.
GOOD LUCK
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Cheeef,
Read this excellent article Jon did on diagnosing the air suspension in the Article section, it will help you..
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cheeef
I have spares, air spring (bag), tag lift cyl, and replacement needles and solenoids for the five bank in the steering bay, norgens and ride height valves will be available at Mcwhorters or american equipment & trailer
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The five port Norgren is the switch point that opens the path to and from the ride height valve, or closes that path when the key is off, or opens the path so you can manually fill or exhaust air bag air.
On the valve you will see end caps with an air line in them. When you want the coach to air up through the ride height valves as you are attempting to do, air pressure coming through the manifold with the solenoid valves in the steer comparment (center solenoid valve) enters one of the end caps and pushed the internal spool sideways to open the path between the ride height valves and air bag.
That shows a 3 port valve and air would enter the end cap on the left top and push the spool in the valve body. The five port is similar in that that it has ends caps, springs and a spool. Verify you are getting air to the end cap (almost guaranteed because the other valves are getting air to actuate them). Remove the valve and either replace it (Prevost stocks them) or disassemble it and free up the center spool. The screws holding the end cap are often frozen because steel and aluminum parts will do that but if you can carefully remove them without breaking them you can clean and lubricate the valve. If it is corroded or filled with water or sludge it probably will leak but it will get you going.
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Good morning
unless it has been removed your coach has air over hyd cyls to raise the ride ht with tag picked up, only used for a couple of years 95 & 96. dont know that is a problem could be some of the linkage jammed on the system especially that you heard a loud noise when you picked up the tag. if you go back to McWhorters see if they will put it over the pit so can walk around under it
Call prevost RSM Jim Malcomb 1 800 837 7386 or ft worth scv center 817-685-0250 askfor Rosie she can tell you where Jim is.
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Just call me, let’s see if we can get you some help 806-828-4138
Glenn
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Glenn,
The system you refer to was called a “stabilzator” by Prevost. The only attachment was a pair of hydraulic cylinders that were attached to the drive axle in a near vertical position. Assuming the system was maintained (most weren’t) the cylinders could only hold the chassis up when the tag axle air bags were de-pressurized when tag lift was initiated. There is nothing in the system that could catch or lock the chassis down relative to the drive axle.
A lot of converters did not order shells with the feature and some who got shells with the feature disabled it.
The process of finding out why the coach will not rise on the left side is not complex, but is a simple step by step. I suggested checking the 5 port Norgren because that can prevent the flow of air in or out of the ride height valve we have been told will pass air. If the five port Norgren is not the problem then the next step is to determine if the drive axle air bags are pressurized indicating air is getting to them, but is possibly blocked at the 3 port valve between the drive andf tag air bags. That valve closes the path between the driver and tag bags when the tag is lifted, while exhausing tag axle air bag air. If the tag axle air bag is not inflating the problem can be the two drive axle bags alone are not able to lift the rear on the left side.
My guess remains with the 5 port Norgren as the next device to check.
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Jon
I appreciate the explanation on the hyd cyls and how the tag lift works, anyway cheeeef should be back on the road. I delivered an air bag to him this afternoon, I’ll let him tell the rest of the story, but involves not putting the nuts on
Cheers
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First of all – thank you thank you thank you to everyone who replied to this thread. I have learned so much about my coach.
As Glenn references above, we are all fixed up and ready to go – many thanks to Glenn for delivering a spare bag so we did not have to wait for one to be shipped in. Glenn – you rock, and it was great to meet you and your wife.
You were all correct – the culprit was the tag bag. The reason we could
not see or hear leaking was because of the severity of the damage. The air was flowing straight in and straight out the bottom of the bag. Now some backstory – A year ago we took the bus to Prevost Houston, and among other things, we had all of the air bags replaced. Prevost Houston did not put the nuts on the bolts of the bag, so the bag has been incorrectly attached for a year without us knowing anything about it. It finally broke, and air flowed out the bottom.
Just as I was at the shop, and we were about to start taking apart the norgren valves, one of the guys at McWhorters Truck Service in Lubbock – who I highly recommend, by the way – wanted to get all the way under the caliper and look up at the bag. He noticed the problem immediately. So basically, I also learned that you can’t rule out a hole in the airbag just because you don’t hear or see it leaking out. The hole could be so big that there is no resistance to the air flow at all.
Major lessons for us:
Never use the tag unless you’re desperate.
Carry some spares with you at all times.
Never take your bus to prevost houston. (Did I mention that I had to have the fire department meet me on the road after I left Prevost Houston the first time? And that they quoted me one price and then tried to bill me for $10,000 more – after keeping the bus six weeks longer than they said? I guess those are stories for another time.)
And finally, the Prevost Community is awesome! With the quick and thoughtful responses, the existing resources on the forum, and the hand delivery of exactly the part we needed, we’re back on the road.
Thank you!
Hope to see y’all out there.
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Glad everything worked out. Its interesting how often the least likely thing is the problem.
Fire Department story … please! Start a separate thread if you’d like!
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Cheeeef ,
Are You the one that done a You Tube documentary on Your interior rebuild ?
Cheif ?
Bsafe,
Rocky -
That’s inexcusable, and what happened was so far off the charts nobody trying to help diagnose your problem could have conceived an air bag installation could have been so completely screwed up as to create that problem and cause that damage.
Photos and an invoice to Prevost are justified and full compensation should be expected.
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