[Richard]

I can't say if that is the supply line for the HCV. I just don't know.

Yes, the line goes from the six pack to the appropriate air tank via 1/4 or 3/8 tubing, then the air bag is connected to the tank via the 1 " hose. The purpose of the tank and the large hose is to use the tank as part of the air spring resulting in a lower spring rate aka softer ride.

Any idea how that settling rate compares to before?

Jon makes a good point for any followers of the thread. I have seen three different six pack manifolds on Newells, not to mentioned the non manifold setup on the classics. The first manifold has the solenoids equally spaced and the supply line comes into the top of the manifold about midway. On that manifold the up solenoid is in the middle. The second manifold, also with equally spaced solenoids has the supply line entering from the side. On that manifold, the solenoids on the end next the supply are the up solenoids. And the third manifold is like the one in Tom's pictures. The supply line comes into the back.

When I learned this last week, it made years of befuddlement about the solenoid arrangement make sense. I had seen diagrams of solenoid identification that disagreed with mine. I also had people tell me that a diagram I drew was wrong. I laughed when I discovered they comes in different flavors.

The point is that it may take a little detective work with energizing the different solenoids and using a steel washer to confirm which solenoids are travel, up, and down before a guru starts diagnosis on a leveling issue.