[Johnnyboy]

I’m working on a 1987 classic with the tag axle. I noticed the rear tires spinning, actually very hard to move from a start. I have to try to ease in the pedal. My first guess is the tag pressure is to high and raising the drive tires enough to were they are not making enough contact with the payment.

My main question or were I need help is I read there is a adjustable regulator on the bulkhead, found it I think. I question if it’s installed correctly or if it needs to be a special type of regulator. The one in the middle of the picture was reading full air pressure 125psi. I tried to turn it down but it lowers the gauge below it also, is that ok. I’m thinking it’s plumbed wrong?

If anyone has or could provide a picture of their setup to compare or experience in how this thing is supposed to work. Greatly appreciated. Comments

[Johnnyboy]

Can anyone please provide a picture of their tag axle regulator and setup on the back wall.  Thanks

[Richard]

Johnny,

I am attaching a hand drawn sketch I made of set up similar to yours, but without a tag axle. Let's assume for a second that Newell simply duplicated the setup with the addition of the tag.
   
Then looking at my poorly drawn sketch, the regulator would limit the pressure of the supply air. The nameplate in your first photo suggests to set the pressure at 35 psi.

Have you tried backing off on the regulator and observing if the coach squats or the bulge on the tires changes indicating a weight transfer?

I don't know if  you could sweet talk someone to letting you place it on a scale, with drive tires on one section, and the tag on the other, while you tweaked the regulator?

Here is my shot at identifying the stuff in your picture. Mirror image for the left side. Always keep one thing in mind when looking at a Newell leveling system. The connection between the HCV and the air bag goes through the manifold. The HCV has it's own air supply line, but the HCV is blocked from the air bag by the manifold UNLESS the travel solenoid is opened. Otherwise, if you tried to level the coach with the air bags, the HCV would just as quickly undo the leveling.

   

[Johnnyboy]

Thank you Richard for getting me started. I do think the tag plumbing has been changed. I cannot see how this is supposed to work in its current configuration. I drew new arrows on the supply line coming in. If we assume the Travel valves are open at the top of my picture then the air flow can bi-pass the regulator and send full air pressure to the tag air bags.

Another note the top gauge is tee to the regulator, another words I just see it showing full air pressure, will not show regulated air, so it is useless in its current configuration.

I believe someone changed out the regulator and got confused how to reassemble it. I was hoping to see another older classic tag plumbing arrangement to confirm.

I understand your sketch on running the air system, I just don’t see how it will work the way it’s currently ran. May have to move some solenoids around.

Please see if you can look at my sketch and see if you agree it’s wrong

[Richard]

Go back and look at my labeling, the reason the tag bags would get full pressure is if the line coming from the unregulated supply is to RAISE the coach. You are thinking those top solenoids are travel, and I think they are raise. The only time the regulated air supply for the tags would be used is in Travel mode. If you didn’t have full air pressure to the tags in the Raise mode, it would be difficult to raise the rear with just 35 psi.

Perhaps you have already done this. This would help me help you, especially if you think the system has been altered. If you run the system through its’ paces, different solenoids will be energized when in travel, raise, and lower. I use a washer to check for magnetized solenoid coils. Can you do that? And label the solenoids as found. We can compare that to how they should be.

It would not be the first time this has happened. I won’t call any names, but a former owner had me on the phone with his “tech” who was working on the air system. The tech did not believe how it should be and declared it plumbed incorrectly despite my input. The next owner paid to have the previous incorrect plumbing fixed. The Newell system works, but it is counterintuitive to a lot of folks, including me.

The place to start is with the sanity check, let’s 100% confirm which solenoid is activated in each mode.

[Johnnyboy]

First off, thanks for your patience. Yes, I was stuck thinking the tag pressure  had to go through the raise and travel, like the rear axle. Seems not the case with the current plumbing. I have verified the solenoids are correct and the plumbing is also correct. 

That lead to my other question, the regulator. Now that I understand the system. I pulled the manifold loose enough to see the back side of the regulator. Ah ha moment, the regulator is installed incorrectly (backwards). Explains why I could not adjust the pressure. Also with the gauge on the top side teed into the supply air it showed full 125psi all the time, and trying to adjust the pressure down was INOP.

I will post with final results. Once I have confirmed I have fixed it.

[folivier]

Bingo! great catch, hopefully that is the problem and it works correctly after you redo it.

[Johnnyboy]

First off, thanks for your patience. Yes, I was stuck thinking the tag pressure  had to go through the raise and travel, like the rear axle. Seems not the case with the current plumbing. I have verified the solenoids are correct and the plumbing is also correct. 

That lead to my other question, the regulator. Now that I understand the system. I pulled the manifold loose enough to see the back side of the regulator. Ah ha moment, the regulator is installed incorrectly (backwards). Explains why I could not adjust the pressure. Also with the gauge on the top side teed into the supply air it showed full 125psi all the time, and trying to adjust the pressure down was INOP.

I will post with final results. Once I have confirmed I have fixed it.

[Johnnyboy]

Looks, that the regulator being installed incorrectly lead to my issues.

In summary, if anyone changes a tag pressure regulator, be sure to pay attention to the new regulator and check the direction the incoming air is positioned on the new regulator. Don’t assume the exhaust ports are in the correct position. Also fully understand the direction the air flows through the air system.

Thanks for the help from the group.