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Coach 647, 2003
60 D
My coach has been sitting in my shop, with shop air, my gauges said i had 90 psi on brake and supply side.  The passenger side drve and tag was almost touching tires. I never heard any air leaks the hieght control valve is new.
If anyone has any ideas whats going on i would appreciate thoughts.
Thank you, James Price

[Gnawrocki1]

More information is likely required to help diagnose.

Although 90psi is the reading you have, I am going to guess that it is not enough to float your coach.

You could have a slow leak over a period of time that drops your coach.  

I would raise the pressure to 105 put the coach on travel mode and see if it raises up.

A slow leak given enough time will drop every coach.

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Ok i will try that. Also i started engine and released parkbrake couple times passenger side started airing up.
Could this have somethi g to do with park brake?

[Guy]

My coach is much older than yours, so we may not have much in common, but.. our Newell will not raise much with 90 PSI, especially in the rear. . What happens if you run your engine with your suspension in travel mode? Does your air come up to 120 and maintain ? Does your chassis look correct ? Good luck

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Guy, answer is yes to all questions. But when coach sets it leaks down with shop air after several days or week. Did not know if park break could be problem,release PBrake will go back to travel ready.

[Jack Houpe]

You may need to rebuild your 6 packs after rebuilding both of mine my coach stays up for weeks also both my tag axle air bags leaked, I did not replace them as they are only a few years old but put green slime tire sealant and it fixed them both.

[Richard]

It’s a wee bit difficult to understand exactly what is going on, since my interpretation is that the problem is not clearly defined. Is the problem, the coach settles when parked? Is the problem the coach does not rise immediately when cranked unless the P brake is released?

One of the hardest concepts to get your head wrapped around is that the air pressure while the coach is parked had NOTHING to do with the coach settling. NOTHING !!!!!

How could that be? Both the HWH systems and the Valid systems isolate the air bags from the coach though either the six pack or individual solenoids on the Valid. Unless those valves are leaking backwards into the air supply then the leak down is between the six pack all the way, and including the air bag. If one understands that it will save a lot of effort at understanding what is going on. The HCV is on the inlet side of the six pack or solenoid valves. Even if it leaks like a sieve, the coach should stay up while parked. The coach air pressure will go to nothing, but the coach should stay up. Forgive me for hammering the point, but MANY have spent futile hours and dollars chasing a settling coach because they did not understand the role of the six pack.

Before I get roasted, it is possible that one of the solenoids is leaking internally or externally and that will cause the coach to settle. It does happen and it’s easy to address with a rebuild kit of the solenoids, but it is not the common cause.

Let’s address the P brake issue, with due respect that there are a number of posts that mention this in far greater detail. So I will present the condensed version. On later year Ridewell suspension coaches that have the parking brake which activates both the drive axle and the tag axle brakes, application of the P brake inhibits the suspension from going up or down. If you look at the suspension design, the swing of the suspension up and down as the coach moves is in opposite direction for the drive and tag axle. Because the P brake locks the tire to the axle, it is not free to rotate as the suspension rotates about its pivot point. The drive tires “want” to rotate in one direction, and the tag tires “want” to rotate in the opposite with this suspension design. The P brake prevents the rotation. You can prove it to yourself by either raising or lowering the coach with the P brake on. When the P brake is released the rear of the coach will jump several inches.

If you have a leaking air bag situation, this will drive you nuts in the middle of the night as the coach tries to settle because you continually get pops and groans as the brakes try to prevent the settling.

And those that have commented that the rear of the coach requires greater than 100 psi of air pressure to raise are absolutely correct. It has to do with the weight of the rear and the diameter of the air bags that Newell specified.

[Richard]

I would highly recommend that any Newell owner read, and reread this manual until it makes sense.

https://www.hwhcorp.com/ml20635.pdf

[Jack Houpe]

This is the system we have for rear and tag axle? If so then how does the switch for raise and lower tag apply if we only have one 6 pack in the rear?

[Richard]

Yes, that is the correct diagram.

Of course Newell added some embellishment. One air line leaves the six pack, that tees to feed the tanks for the drive and tag. Before the tag line gets to the tag tank it has two three way electrical valves in it. One of the valves is plumbed to coach air on the third port. So that when the valve is actuated by the switch on the dash, it closes the path to the six pack and applies coach air to the tag. The second valve is plumbed so the third port is open to the atmosphere, so that when that valve is actuated, the path to the six pack is closed and the pressure is exhausted to the atmosphere.

The one thing that will throw you a loop is that you will see only ONE tag axle tank underneath the coach. That tank is bifurcated, meaning it has a plate welded in the middle. What appears to be one tag is actually two.

It took years to noodle this out, and Steve Bare @rheavn did the heavy lifting spending hours under his coach figuring it out.