[Richard]

Sorry for my misunderstanding. English is a second language for us South Carolina boys, and then you throw in that reading thing. I really missed that the coach will build pressure, and the rear stays up as long as the coach is running and the raise solenoid is activated. I totally agree with your conclusions that the air supplied to the raise solenoid is overpowering the tag solenoid leak. The reason RAISE will keep it up and TRAVEl will not is the decreased flow rate if the air comes through the HCV. I am going to attach a hand drawn picture of the rear setup. My apologies for getting totally out in left field. I will delete my previous post so that it doesn’t mislead someone in the future. Thank you for your patience.

   

I am working off the idea that the goal is get the coach safe to drive a short distance to a shop.

So let’s move to the front. The second picture is of the front setup. There are a couple of things to note. One, notice the line coming out of the HCV is singular and tees into two lines. One feeding the left travel solenoid and one feeding the right. There are NO check valves. Meaning that if both travel solenoids are open then both air bags see exactly the same pressure. After all their pressure originates at one source. This allows the front end to move side to side based upon the side to side in the rear.

   

Let me see if I got this right. If using RAISE on the leveling system both sides of the front will raise. Putting it in travel, results in the left front dropping and air escaping. The first thing that comes to mind is that the solenoid valves in the six pack for the left side have debris in them. The only way that the right can stay up and the left down is if the left travel solenoid does NOT open. The air escaping could be coming from the down solenoid stuck open. Again, using raise mode overpowers the leak.

Before tearing into the front six pack, I would try a Hail Mary. I suspect you have the very same HWH control system as I. There are some situations where my control system gets confused, and trys to put the coach in travel mode and level mode at the same time. It just won’t come to ride height. The solution for me is to turn off the HWH system by pressing the OFF button or Emergency stop button in the lower left corner. It seems to reset the brain. 

My approach at this point would be to gain access to the front six pack. Confirm that a critter has not eaten the wiring, confirm that the travel, lower, and raise solenoids are getting the signals when they are supposed to, and take the solenoid valves apart one at a time and clean them up. One thing to also look for is that some six packs have a pressure switch mounted to the back of the six pack for both the right and the left sides. Those switches can leak. 

Wow, this is tricky because the six pack is under the corner where the coach is dropping. You have a couple of options. Raise it all the way and crib up the front. Let me know if you need pictures of crib points for the front. Of, you may be able to get the six pack out for reasonable access. If you look on the front wall of the HWH compartment under the drivers feet, you will see two bolt heads about an 1 and half apart. Those two bolts affix the six pack to that wall. You can remove those bolts and the six pack will release. How far you can pull it out will depend on how many million zip ties are in place. It’s worth a try. If you remove it this way, get some threaded rod the same thread as the bolts you removed. Turn the bolt holes into protruding threaded studs. Why? Cause when you go to put the six pack back in, your arms will not be long enough to hold the six pack in place and thread in the bolts. It’s tedious two person job. Threaded studs make it a piece of cake.

[pestes]

One, notice the line coming out of the HCV is singular and tees into two lines. One feeding the left travel solenoid and one feeding the right.

Ugh, there goes my working theory.

The only way that the right can stay up and the left down is if the left travel solenoid does NOT open.

Except that turning the key off to disable travel mode stops the front left from falling any further. I suppose this could only be true if the dump solenoid is getting power in travel mode, which it obviously shouldn't. However, I would also expect the air escaping to be coming from the exhaust port on the 6-pack. It is not. It is coming from somewhere further under the coach.

I am about to head up to do some troubleshooting.

I have 2 working theories now.

Theory 1 is that the travel solenoid for the right side is stuck closed and not opening. The HCV is dumping air, and because the right side is all the way up, the HCV never reaches a point where it stops exhausting. But the left side is the only airbag connected as a result of the stuck solenoid, so it only dumps from the right.

Theory 2 is that I have a double failure scenario. A stuck travel solenoid on the right side and a faulty HCV.

I'm about to head up to the coach for some troubleshooting.

A couple thoughts on tests:
Start from fully dumped and see if the right side comes up to travel height.
Swap the 2 travel solenoids to see if the problem switches sides. After cribbing the front of the coach, of course.

Beyond that, it will be verifying that the proper solenoids are powered in each mode.

Fingers crossed for the stuck travel solenoid.

My rear air leak is also now fixed, so I can eliminate that extra odd variable. It was actually a cracked brass fitting, not the valve itself.

[pestes]

Ok, so had a bit of time to experiment.

First thing's first. After full timing in the coach for almost five years, we've been in a house and out of it for a few months, and it's shocking how fast you can forget some things.

While the coach was dropping down on the front left, it did not drop all the way down. I forgot how far all the way down really is. In any event, the front left is still down enough that tire will meet fiberglass on a turn.

I'm convinced there is not an air leak. I am also convinced that the air escape that I hear in the front is from the HCV exhaust port.

Swapping the solenoids would have been a pain, so I tried another experiment.

These scenarios now are all with the 6 packs wired normally both front and back and the rear air leak has been fixed.

Raise coach fully and disconnect both travel solenoids.
Put coach in travel.
Connect left travel solenoid only.
It takes about a minute for front left corner of the coach to drop to the point where the HCV stops exhausting and it stabilizes.

Raise coach fully and disconnect both travel solenoids
Put coach in travel.
Connect right travel solenoid only.
It takes multiple minutes (I unfortunately did not time it, but will do so in the morning) for the coach to drop to the point where the HCV stops exhausting and it stabilizes.

I am now thinking that there must be some blockage in the right travel portion of the six pack. Perhaps someone used PTFE tape at some point in the past and it has gotten caught up in there.

I'm trying to convince myself that the low flow path on the right side could shift the point of equilibrium to be such that the front left ends up quite a bit lower than the right. IE the front stops dropping as the HCV sees it as being too high. The left drops faster than the right due to faster exhaust rate.

I'm not sure I am all the way there yet, though, considering the pressure must be the same in both front bags at equilibrium. But the rear HCVs play a role here as well, so I'm not fully decided either way.

Tomorrow morning, I am planning to unbolt the six pack to where I can get the travel solenoids off for inspection. I'll also measure fiberglass to ground

[Richard]

Really helpful info.

Would you comment if my own words on summarizing the situation are correct. The coach raises in the front when in travel mode. However it is tilted with the left side lower.

If you lower the coach all the way down manually, does the front come back to the same ride height and the same difference from side to side. When adjusting ride height valves, the best practice is to lower the coach below ride height and allow the coach to raise to ride height before measuring.This is because of the minor hysteris in the HCV. If done the other way, raise above ride height manually and let travel return to the correct ride height, the results will be inconsistent.

Are the slides in or out? With my slides out, the front side to side cannot overcome the weight of the extended slides.

How much difference in inches is there from the left to the right side on the front? On the rear?

You have a great grasp of how the system works. Debris in the solenoid valves or HCV can give you fits, but if the corner is raising, partial blockage would cause slow response but eventually the corner would come to the proper ride height. If there is any flow path at all the pressurize will equalize over time.

[Richard]

One more related item. The toe in is VERY sensitive to the ride height. If you look at the suspension design, you can see why. One end of the tie rod is attached to the wheel end, and the other end is attached to a part that remains with the frame and the tie rod is on a slight angle.

My point is that if you adjust the ride height on the front, be aware the toe in may have to be adjusted.

[pestes]

Ok, so I've swapped travel solenoids, but no change.

Yes, your statements are correct. And the coach comes back to about the same position starting from low and letting travel raise it up or starting high and letting travel lower it down.

This is all with both slides in. I totally expect lean to the left with slides out.

When I do the test above where I raise the coach, disconnect the travel solenoids and then connect only 1 of the solenoids, it still takes 6 minutes for the right side to drop versus 1 minute for the left. I don't know if this is significant or if I am chasing zebras. It just seems like an excessive difference.

I also measured height from ground to fiberglass after everything is settled in travel mode:

Left Rear: 10.5 inches
Right rear: 11.75 inches
Left front: 7.5 inches
Right front: 11.5 inches

The left rear is about 1.25 inches lower than the right rear. Would that be enough on its own for the front left to drop 4.25 inches compared to the right?

I'm wondering if everyone's original assessment was correct all along and the left rear HCV simply needs adjustment. But it's not clear to me why that would have changed. I also climbed under the coach to scope it out and I can't imagine the arm length and body contortions that have to occur to make that adjustment.

[Richard]

It’s hard to believe 1.25 inches in the back would result in 4 inches in the front.

I am just going to throw out some ideas.

There have been a few occurrences where either the down solenoid stuck partially open, or the raise solenoid stayed partially open which resulted in odd behavior such as one side unexplainably low or unexplainably high. Tom had this happen to him on a trip. Debris in the solenoid could cause this.

It might not hurt to check to make sure the down solenoid on the left or the up solenoid on the right is not getting a signal from the HWH brain.

And take a look at the sway bar to make sure something isn’t amiss with the sway bar mounts.

I am impressed with your ability to carry out experiments to confirm your theories. I also appreciate your willingness to publish this adventure in real time. It may help others who are following, and someone who searches in the future to gain a deeper understanding of how the air suspension system works. I don’t have the statistics but it feels like this is an often repeated subject.

If you decide to adjust the rear HCV. Take a small amount of grease and a 5/16 nutdriver with you and slip between the drive and tag tires. Feel around on top of the drive axle and find where the vertical rod on the HCV attaches to a boss on top of the drive axle. Lubricate the end of the boss. Slip the rod off the boss, and pull it down. You should now be able to reach the clamp on the rubber “P” that holds the vertical rod in place. If you twist the rod and push or pull, you should be able to make the adjustment. It’s just about 1:1 in the rear. Move the rod in the direction you want the coach to go. Don’t forget to tighten the clamp when finished.

And I got the zebras reference.

[pestes]

So, as usual, no zebras.

With HCV adjusted, the front left corner is now at normal travel height.

So really, everyone's original proposal of coach tilt due to the rear HCV was the ultimate answer.

I think there were 2 factors that led me off into the weeds:
1. The broken brass fitting in the rear. That was what led me to try to force the raise solenoids open in the rear and when the front left of the coach still dipped, it made it seem like the front dip couldn't be due to the rear HCV. And, ultimately, I suppose, at that point - it wasn't.
2. The significant difference in the amount of time it was taking for the left side vs the right side to lower in travel mode. I'm not sure I ever waited long enough for things to reach equilibrium in this scenario. When the left dipped too far down to drive on and the right did not, it sure looked like something was wrong in the front, and I would move on to the next test without fully waiting. Ultimately, I suppose, something is still wrong in the front, but I haven't gotten back to investigating the slow response of the right side.

Thanks, as always, for everyone's help. And, as usual, your insights, Richard, have given me a much greater understanding of the systems here. Thank you for all of your thoughts and input.

[Richard]

Woo Hoo!!!! Glad it’s fixed.

[360]

So, as usual, no zebras.

I try to keep that mantra in my head now as well along with the whole "what's the last thing that was done".  Great job on getting to the bottom of it!