Air system schematic

[Richard and Rhonda]

Do any of you have an air system schematic? Either from Newell or one you have deduced yourself?

I am trying to figure out how the air system works to help pinpoint the likely causes of leaks. The coach is a 95 model.

Yes I know a spray bottle of soapy water is my best tool in this quest, but I have a natural curiosity about the workings of the leveling system.

I would be happy if someone could just explain the six solenoid valves on the "six pack" and what each one of them is supposed to do.

Thanks

Richard

[fulltiming]

The six pack for air manifold for the front axle contains six solenoids, four of these are for the leveling system when parked: left front raise, left front lower, right front raise, right front lower, The two remaining solenoids control the travel height (raise and lower). The drive axle six pack and the tag axle six pack are similar to the front axle six pack.

The travel solenoids are controlled by the three ride height valves, center of front axle, right side of drive axle and left side of drive axle. The leveling solenoids are controlled by the level sensor, typically located in the center of the bay, near the center of the coach mounted to the ceiling of the bay.

Each six pack has a single air supply line going into it and air lines that go to the corresponding air bags and to an air release valve.

[encantotom]

the manifold for the front solenoids on mine is directly under the drivers side headlight.

the manifold for the rear on mine is on the passenger side engine firewall.

tom

[Richard and Rhonda]

I knew you guys would come through. I found both of them, and had the bride hit some leveling switchs so I could see hear which ones were connected to which switch. Michael filled in the pieces of the puzzle.

Mine doesn't have an automatic system. You can control each corner with a toggle switch at the driver's console. I am assuming that the MASTER switch that allows you to raise/lower the overall height temporarily overides the travel height solenoids.

Let me run my thinking by both of you. We can do this via PM, but if we use the forum, then the next guy will be able to find this info.

Anyway, the right rear will squat after one day with no compressors running. The other three corners stay up. There is NO system pressure by then. So, there must be check valves on the air bags when in leveling mode ????? Or is the leveling solenoid the only device in the pressure path for leveling? I am trying to understand what is happening that results in the system pressure leaking to zero and only one corner dropping. BTW, the check valves that isolate the brake system are holding, since the brake pressure hangs in there around 115.

[fulltiming]

I agree that discussing problems on the board rather than through PM's is of benefit to more people since they can see the solutions and later search for the information.

If the right rear is losing air, I would check 1) the dump/lower solenoid at the six pack for that axle to see if it is fully closing, 2) the air connections to the solenoids for that corner at the six pack, 3) the nipple going into the right rear air bag, and 4) the air bags on that corner for excessive cracking or crazing.

The solenoids do tend to start leaking by not fully seating with time. A year ago I replaced all 18 of my solenoids just due to age, well that and the fact that one of the dump valve was sticking closed so the right rear would not always drop.

This year I had to replace the left rear ride height valve due to the crack in the valve body. I was losing 20 psi in 12 minutes. The leak didn't show up by spraying soapy water on it. So much air was leaking out that it physically blew the water away from the valve instead of bubbling.

Your comment about the pressure staying up on the brake tanks is important. If anyone starts seeing the pressure of one or both of the brake supply tanks dropping with the main supply tank get it fixed ASAP. There is a check valve in each of the lines that come off the main supply tank. Losing brake air is a bad deal. I had leaks in both of my brake check valves. The longer the coach sits without being used the more likely the check valves will fail. If the coach has small air leaks, and they all do, and the system pressure goes to zero, outside damp air can get into the tanks over time and cause rust, especially in the check valves.

If anyone is interested, I can post photos of the crack in the travel valve and/or the defective brake check valves.

[encantotom]

i believe that if the air connections were leaking, you would be able to easily see bubbles using windex. the same for the nipple going into the airbag. the leak you are talking about is a slow one and not fast like fulltiming describes. i had one fast leak that lowerd the right front only in leveling mode (mine is manual like yours and totally fabricated by newell) and it showed it self by air coming out of the ride height control valve centered on the front axle. it was a bad solenoid that was letting air escape through the control valve.

if you cant see leaks on the airbags themselves along with the other places listed above, my guess is you have a bad solenoid. i am cheaper than Michael and only replaced the 3 solenoids that i had that were bad. the other two just didnt work. i keep one spare with me now, but at 80 bucks a pop i will replace them as they go bad. i can change one now in about ten minutes or less and it is easy.

i agree with michael on the air brake pressure. the thing we all have to remember is at a certain brake pressure loss, the wheels will lock up.

i had a leak on the air brake dryer and bought the rebuild kit and it fixed it easy.

[encantotom]

i believe that if the air connections were leaking, you would be able to easily see bubbles using windex. the same for the nipple going into the airbag. the leak you are talking about is a slow one and not fast like fulltiming describes. i had one fast leak that lowerd the right front only in leveling mode (mine is manual like yours and totally fabricated by newell) and it showed it self by air coming out of the ride height control valve centered on the front axle. it was a bad solenoid that was letting air escape through the control valve.

if you cant see leaks on the airbags themselves along with the other places listed above, my guess is you have a bad solenoid. i am cheaper than Michael and only replaced the 3 solenoids that i had that were bad. the other two just didnt work. i keep one spare with me now, but at 80 bucks a pop i will replace them as they go bad. i can change one now in about ten minutes or less and it is easy.

i agree with michael on the air brake pressure. the thing we all have to remember is at a certain brake pressure loss, the wheels will lock up.

i had a leak on the air brake dryer and bought the rebuild kit and it fixed it easy.

tom

[Richard and Rhonda]

I used enough soapy water this weekend to wash the street :D

Anyway, I only found one leak, at that was on the control valve for sliding the generator in and out. It was bubbling pretty good, so we'll see the impact of fixing that.

With your input, I did get a much better idea of how the air system works, and especially how you can get front to back, or side to side leveling. I didn't have a good understanding of how the ride height system worked with the leveling system. Now I do. When in ride height mode, the ride height solenoid opens to allow air to flow to the ride height valve, which in turns pressurizes or depressurizes the appropriate bag. When in leveling mode those solenoids are closed, and the up/down solenoids pressurize the appropriate tank which feeds the bag.

My biggest lack of understanding came from the wrong assumption. I had a picture of how the air system worked on my Mountain Aire. It only had one front tank and one rear tank, and the leveling was done with hydraulic jacks. The breakthrough in comprehension came when I saw that each set of air bags for an axle has it's unique tank. So, the air piping and valving to work that way is completely different than what I was thinking. The moral of the story.......there is NO substitute for crawling around under your coach.

I had my bride actuate the leveling toggles to help me identify which solenoid was connected to which toggle. I used a very sophisticated and expensive device to determine which solenoid was firing. An steel nail. When the solenoid fires it is magnetized.

[Richard and Rhonda]

It's good news and bad news. The good news is I found a big air leak where a line went into one of the press on fittings. It was on a solenoid WAY up under the coach hidden along the frame rail. I used a compression fitting to replace the one that was leaking. The line looked like it was under a little sideways stress which the press lok fittings don't like.

The bad news? I had hoped to draw a complete schematic of the air system for my own benefit. That didn't happen because the air lines are all bundled together making it impossible to physically trace individual air lines. If I get bored or industrious, I'll snip all the zip ties and trace them out.

[RussWhite]

The solenoids do tend to start leaking by not fully seating with time. A year ago I replaced all 18 of my solenoids just due to age, well that and the fact that one of the dump valve was sticking closed so the right rear would not always drop.

This year I had to replace the left rear ride height valve due to the crack in the valve body. I was losing 20 psi in 12 minutes. The leak didn't show up by spraying soapy water on it. So much air was leaking out that it physically blew the water away from the valve instead of bubbling.
.

Michael,
Dredging up an old thread I would like to pose a question. You have replaced all 18 solenoids. I am curious just what parts that includes, surely more than just the electrical coil itself. Here is what Newell just told me about what one receives when the "solenoid" is ordered. Please just comment some more on what tends to fail with age. I want to be prepared to fix a failed valve on the road. Thanks - Newell says "
THE SOLENOID NC-5391 THAT I’M TALKING ABOUT IS MADE BY HWH THERE SIX OF THEM ON A ALUMINUM BLOCK IT INCLUDES THE COIL ,2 WIRES , ORINGS IT IS 12V ,9.5 WATTS ,PSI125 , ORIF: 3/32 ALL METAL TYPE SOLENOID ! "
By the way, the price as of 9/2010 is $103.18.

[prairieschooner]

Russ,
The good news is that we can most likely troubleshoot the system.
Please describe what the problem is, from there maybe we can help.

[folivier]

I recently had one leveling solenoid leaking through the exhaust port. Ordered 2 from Newell expecting to replace one and have a spare. When I pulled the solenoid off I noticed that the o-ring was not seated. I seated it and it now works fine. I guess the moral is don't overlook the simple stuff.

[encantotom]

hi russ,

when you get the 103 dollar solenoid, you get the little unit that screws into the 6 pack with 2 wires coming out of it. it is one expensive puppy.

tom in frankfurt

[RussWhite]

Hi Forest,

I have observed on two occasions my right rear leveling valve exhausting when the system was not in the travel mode. That should be a failure of the Travel solenoid on the associated six pack. My interest in ordering the very expensive solenoid kit ( calling it a kit may be generous ) is to have one on hand should I suffer a hard failure while on the road. Does this sound reasonable to you?
Thanks, Russ

[Ron Skeen]

Hi Russ,
You can rebuild the solenoids as Richard has stated in a earlier post. I have rebuilt 8 of mine and they seem to work fine. The main thing that fails is usually the seat which can be replace with.

[Ron Skeen]

I'm sorry I did not complete my response. I rebuilt the solenoid rubber seat inside the valve that behind the spring. I used Permatex Ultra Grey Rigid High-Torque RTV Silicone which I purchase from Auto Supply. I dug the old seats out and replace with the silicone and allow to cure for 7 days and then sanded down. I bought 2 from newell and save the old ones which I have rebuilt over the last five years. Richard is the one how put me on this process, he is the Guru!

[Richard and Rhonda]

Russ, not necessarily, on your conclusion that air exhausting from the leveling valve means a leaking solenoid.

Study the HWH manual carefull on the schematic. Coach air goes to the leveling valve, through the solenoids, and on to the air bags. If the valve body is leaking, then the solenoid has no effect. The coach supply air will drain quickly. Your brake air should stay up because of the check valves between the systems.

[RussWhite]

Richard,

If you are referring to the valve body of the leveling valve, I agree. Some kind of internal failure in the leveing valve could cause it to exchaust when it should not. I have discounted that in my case as the valve is new and the problem was observed after valve replacement. I have tried to attach the HWH schematic although it is not correct for my particular coach which has only two six packs and the tag is supported through the six pack for the drive axle. Thanks, Russ

[Richard and Rhonda]

Russ,

I have the same setup with only one sixpack for the rear. I couldn't find anyone at Newell who could tell me exactly how that setup worked with particular regard to adding or removing air from the tag bags. If anyone out there knows exactly how that works or has a schematic, I would love to see it.

[HoosierDaddy]

Just based on my experience with my set-up (6 pak for each axle) the only reason for a 6 pak on the tag is to allow it to take more or less load than the main axle to allow shorter turning radius or as an aid in low traction conditions (less weight on the tag) or for "fooling" axle scales (more weight on the tag).
Regarding the one 6 pak for the rear setups, my guess is that the raise and lower valves are plumbed to both axles equally. The tag would be plumbed in with the main on the travel valve as well except there would be an air pressure regulator in the air supply line to the tag.

[Richard and Rhonda]

Dean,

That's not my understanding of how the tag is plumbed. The switch on the dash is supposed to add or subtract air from the tag bags to put more weight on the tag for scale purposes, or to put more weight on the drive for traction or tight turns.

With one six pack, in the normal mode air to both drive and tag is regulated by the height valve. I just don't understand what happens when the switch on the dash is activated. I don't understand what kind of device it activates that would isolate the tag bags, and raise or lower pressure in them. When I asked about this in detail at Newell, the guy in the chassis shop guessed at something like a "4 way valve" but he didn't say it with confidence.

Also with the one six pack setup, mine does not have a pressure regulator for the tags. If a coach is equipped with a two six pack set up, it has a pressure regulator for the tag.

[HoosierDaddy]

It appears on mine that the HCV only controls the main axle and the tag just helps carry the load via the regulated air pressure. If I'm reading the schematic that Russ posted correctly that is how that system would work as well. If you have the tag axle switch and only have one 6 pak there has to be another valve system on it somewhere. Also if they are both working through one HCV (which would eliminate the need for a tag axle pressure regulator....I think) the main and tag have to be isolated in order to load/unload the tag via the dash switch. Maybe that is what the 4 way valve does.
When I bought my coach the whole 6 pak system was bypassed and it had a schrader valve in the engine compartment to "air up" the rear bags. They had put screws in the exhaust ports to keep air from leaking out. It took months of "stand and stare" along with valuable advice and encouragement from you-all on this board to figure it out. Apparently there has been a number of running changes in how our various systems operate over the years as well. Originally my main axle 6 pak was a series of square solenoid valves that Newell tried for a few units and abandoned. They sent me a replacement valve block that would accept the more common round HWH style solenoid valves.

[Wally Arntzen]

I really don't know what valves are activated when I flip the tag switch on the dash, but I do know that the air is depleted from the bags when I do it.
You can tell the difference of the empty bags when backing up with sharp turns. My friend at a bus repair garage informed me that you should always deplete the bags when backing up if making any turns which will allow you to get into a spot eaiser and also saves wear on the tag tires.
On the older coaches there is a lateral arm shock above the tag and on mine when I got the shock was bad and we had to replace it. My friend informed me that it was from long time backing without fliping the tag switch when using reverse.
The Prevost coaches have a tag system that lifts up the wheels when activated and the Newells dropping the air serves the same purpose.

[jmacstack]

Tom, You mentioned in one of your threads that you had an air dryer leak and that you bought the rebuild kit. I too have a leak in my air dryer and need some advice on where to get a kit and what if anything I should know before I tear into it. I also have a leak in one of my front solenoids. It seems to be leaking(spewing) from the hose fitting,(no hose and never has been) on the bottom side of the solenoid. I will remove it and check out the "O"ring situation. Thanks, Jennifer

[encantotom]

hi, i copied this from an old email to myself. if your air dryer is a brakemaster cr68 this applies. i have also changed the pressure blowoff assembly on the bottom. it wasnt much more.

i talked to mike at skf cr brakemaster and he gave me the part numbers

the local dealer is fleetpride and i talked to richard. number is 480 834 5004

i ordered the 240 filter service kit. 31 bucks.....43 bucks retail.

tom

[Summersgal]

Hello,

I too have been trying to understand when and how to use the 3 position TAG switch on the dash. Here's what I found out today. I hooked up a couple of digital pressure sensors, one on the tag and the other on the drive axle.

With the coach running and in travel mode and switch in center position.
Main-70psi
Tag-70psi
Height (from my measuring points)-40 1/4"

With the coach running and in travel mode and switch in down position.
Main-96psi
Tag-0psi
Time to reach 0psi on tag - 2min 43sec
Time to return to 70 psi on tag - 1min 50sec
Height-39 3/4"

With the coach running and in travel mode and switch in up position.
Main-57psi
Tag104psi
Time to reach 104psi from 70psi on tag - 1min 5sec
Time to return to 70psi on tag - 57sec
Height - 41 5/8"

As soon as the switch is returned to the center position the tag returns to the same pressure as the main. The down position of the switch does not force the tag down, it lowers the pressure. The same for the up position, it increases the pressure thus forcing the tag axle down. I plan on adding three Parker MPS-P31N-PCI Pressure sensors and mounting them around the dash area some where. I will have one for the front, main and tag air bags. These sensors also have programmable outputs, N.O/N.C and a 4-20ma analog output. I will use these to set high and low alarms so I don't forget and leave the switch in the up or down position. It's odd, but right now, if the switch is in the up position an alarm sounds. In the down position there is no alarm. I am still trying to learn my air system (the hard way). I unhook air lines and see what drops, Pam flips switches and push's buttons while I try to find witch solenoid is energizing. The solenoids for my tag are mounted to the drivers side inside frame above the rear end. There are two solenoids here, one for up and one for down, very difficult to see and reach. It would have really been nice if Newell would have put these some where close to the sixpack. If I ever have to replace them they will get moved! The link below shows the sensors I will be using.

http://www.flo-products.com/floprod/partrpemps31.html

Jeff

[Richard and Rhonda]

Jeff,

You are the man !!!!

Quick question, do you have one six pack or two six pack solenoids for the rear?

And could you describe in a little more detail the two solenoids for up and down on the tag and exactly where you found them? I have been looking for those devils for two years.

[RussWhite]

Jeff - Way to go! Very interesting.

I'll just add some observations from my '99 and some questions.
Newell told me the air to the tag bags when through a "proportioning valve". You pressure readings do not seem to support that, or if you have that proportioning valve it is set to 100%.
I was unable to get the transmission to select a gear with the tag axle switch in the up ( bags full of air ) position and this seems to agree with your alarm.
I am wondering why when the switch is in the up position you did not get a higher pressure in the bags. I will assume that your system air pressure was higher than 104 psi. So where did the 104 come from? Maybe an air pressure regulator set to that maximum. Maybe if you had waited longer would it have gone higher?
Please keep us informed as you get more information from your pressure transducers. It seems that using the switch in the down position for taking load of the tag axle when making tight turns might be possible as there was not a large change in ride height. Again, Thanks - Russ

[Summersgal]

Richard,

I have one six pack for the rear, I have them identified as far as what solenoid does what. I will take pictures and add additional info this evening. I will also take pictures of the tag valves and show you their location.

Jeff

[Richard and Rhonda]

Then it makes perfect sense. When you dump the tag bags, the RHV will automatically put air into the drive bags to keep the ride hide at the set point. When you inflate the tag bag the RHV dumps air from the drive bags to keep the ride height about the same.
There has to be some sort of valving that kicks in when the tag axle switch is activated that isolates the tag from drive. Your data shows they are normally connected when the switch is in the middle.

[Summersgal]

Here is a picture of my Six Pack. This is the way I understand it so far. For all left and right references below: Right = passenger side. Left = Drivers side.

When the button for rear of coach UP is pressed on the HWH controller, both valves 1 and 4 are energized.

When the button for rear of coach DOWN is pressed on the HWH controller, both valves 2 and 5 are energized.

When the button for right side of coach UP is pressed on the HWH controller, valve 4 is energized. (along with front valve not identified yet).

When the button for left side of coach UP is pressed on the HWH controller, valve 1 is energized. (along with front valve not identified yet).

When the button for right side of coach DOWN is pressed on the HWH controller, valve 5 is energized. (along with front valve not identified yet).

When the button for left side of coach DOWN is pressed on the HWH controller, valve 2 is energized. (along with front valve not identified yet).

Solenoid valves 3 and 6 are only energized when the coach is running. I believe these supply air to the RHV's on each side. (not yet verified). I do know that if the coach is not running (valve 6 DE-energized) and you remove the air line from the right tag air bag, the right main air bags will also be depleted.

Russ,

The max pressure achieved in the tag air bags was 104psi. I have not checked my max supply pressure yet, I believe it is between 115 and 120psi, I will check it. I will also see if there is a regulator somewhere that is keeping the max tag pressure at 104psi.



Jeff

file:///C:/Users/Jeff/Desktop/Six%20Pack.jpgfile:///C:/Users/Jeff/Desktop/Six%20Pack.jpg

[Summersgal]

Here are a couple of pictures of the Tag Solenoids.

Jeff

P.S. HAPPY BIRTHDAY CLARKE!!!!!

[tuga]

I have some leveling solenoid gremlins in my coach. Last week my front p/s would loose air while parked w/engine off. It would be on the ground in about 4 hours. I called the factory and they told me that my DOWN leveling valves were probably leaking internally. So I ordered 2 HWH #RAP1940 leveling solenoid valves (Newell part #5391).

Took a trip to Asheville, NC for a week; the 120v auxillary air pump kept the front up by kicking on for 3 minutes about every couple of hours. Supply air stayed at 90 psi.

When I returned home - I turned off the 120v auxillary air pump and waited for the front to drop. IT HAS BEEN 24 HOURS & I'M STILL WAITING - it hasn't dropped an inch!

Should I change the solenids or just keep the new solenoids as spares?

[folivier]

Could have been a bit of trash that caused the leak. I had one last year that did similar and ended up just changing the o-ring.

[tuga]

Forest,

Did you buy the o ring locally or from HWH?

[folivier]

I think (which is dangerous) I found it locally. Kept the new solenoid as a spare.

[prairieschooner]

O-Rings are all standard Sizes. More importantly is what the composition is BUNA-N? This would be Oil Resistant!

[Richard and Rhonda]

Tuga,

I bought a hundred of each from McMaster Carr in the exact sizes, because they come a hundred to the bag. How many do you want?

[tuga]

Richard,

Thanks for the offer; a few would be fine.

Just throw them in an envelop and mail:

206 Comanche Dr.
Houma, LA 70360

Now that I have found someone who has the O rings my solenoids are holding air tight!

That's about my luck! I guess the grit or dirt that was causing them to leak air has been majically cleaned away by the "Air Leak Jenie".

Thanks again, Richard.

[GORDON HUMMEL]

Richard,

Could you post the part# so I can get some
thanks

[Richard and Rhonda]

Will do, it will be a couple of weeks. The rings are at the coach, which is stored remotely. I am traveling for two weeks.

[encantotom]

richard, someone gave me a couple of bags of these at one of the rallys we had. i think it was ron gookin.

one bag says 2-028 Buna-N 70D Black this is the big one on the outer ring.

other bag says 2-015 Buna N 70D Black this is the small one.

they both say for kip air valve, but they appear to be the same as on my rap1940 hwh replacement solenoid. but i have not tried them yet.

out of curiosity, how did you measure them to pick out the new ones?

tom

[Richard and Rhonda]

I measured the diameter of the o ring with calipers. I measured the ID of the groove on the valve body to get the ID of the oring.

Sorry that I havent responded with the size but I have not been to the coach, and I won't get there for another two weeks.

[Richard and Rhonda]

Sorry for the wait you know I love you if I typed this on my phone

The inner one is a size 15. 9452k59
The outer is a size 28. 9452k115.

The last numbers are mcmaster Carr catalog numbers

[GORDON HUMMEL]

Richard

Thanks