Air system schematic

[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

[IMG]file:///C:/Users/Jeff/Desktop/Six%20Pack.jpg[/IMG][IMG]file:///C:/Users/Jeff/Desktop/Six%20Pack.jpg[/IMG]

[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