[77newell]

Something like that certainly could be and somehow changing the tubing caused it to disappear. Logically that would require a chunk that somehow operated like a check valve since in the dump mode that side dropped as fast as the other side despite filling slower from the raise valve but filling just as fast from the travel valves. If it is debris I sure hope it is displaced forever, this was a real pain to figure out. I did learn a lot about the HWH system while working on this so all is not wasted, just my sense of pride.

Thanks for all that participated, exercising the mind supposedly delays dementia so we're all good for some time now.

[77newell]

Well goodness Richard was right again (not surprising really); a problem like this is never solved until proven over time. Upon arrival back home in Michigan the inability to raise the left rear with the leveling controls re-emerged. DRAT!

While it was still misbehaving I cross-connected the leads to the two rear "raise' solenoids and the problem stayed with the left rear so that proved it was not an electrical signal problem. I then undid that and cross-connected the tubes coming out of the 6-pack and attempted to raise the rear, the left rear didn't come up much so that proved the problem was downstream of the 6 pack. Well, I had already changed the tubing between the 6-pack and the ping tank for the left rear and the problem persisted so that wasn't the problem. All that remained were the ping tank, the hoses to the air bags and the air bags. Since I couldn't conjure up a way the ping tank or air bags could cause this on-again off-again behavior I chose to change the hoses. While sitting in the driveway the problem has not reoccurred, but as Richard so smartly says: "it isn't over until you've been down the road a bit".

Here is why I think the problem has been solved. A visual inspection of the hose from the ping tank to the tee that feeds the air bags showed a sliver of rubber showing at the end of the steel insert that goes into the hose as part of the end fitting assembly. The old hose was destroyed in the process of installing new hoses. I suspect the rubber inner liner of that hose had a small leak in it that allowed compressed air to pressurize the outside of the liner. That only became a problem when the pressure inside the liner dropped to the point the liner collapsed. Once collapsed the pressure in the ping tank had to be substantially reduced for quite awhile for the air outside the liner to leak away and the liner then returned to its proper position. This logic explains why the leveling raised properly following my replacement of the tubing from the 6-pack to the ping tank which took several hours with that side completely depressurized and then had the problem re-emerge later when the system had been pressurized for a long time.

[bestgenman]

I think what you are describing is what I call a flapper.  When the steel insert of the end fitting is threaded into the rubber (with overall steel braid) , it cuts the rubber and makes a really nice check valve which always works when you don't want it to work.  I can't count the times I've made up a hose with a flapper and about the only fix is to cut the end of the hose off and start again.  My experience is mostly with fuel lines but air suffers from the same malady.

[77newell]

Well, well, well, ain't we got fun. A couple days a go I tried to run the rear up and down, guess what the left refuses to raise to the occasion. Sooooo, I pressurized each side separately, the right to about 100psi, and the left to 110 psi as measured at the outlet to the 6-pack. The left side still stayed down. Using proper safeguards I climbed under the coach and gave a firm smack with a hammer to the right and left side air bags. The left side bags resounded with a slightly higher pitch than the right side, this would be consistent with the higher pressure supplied at the 6-pack. Therefore the bags are properly inflating but the coach ain't arising. Hmmmmm.

I'm wondering if the shock absorber is hanging up and mechanically restraining the rise but not the lowering. Anyone have any thoughts about that?

[Richard]

Shock could be frozen, or bushing in suspension.

[77newell]

That's what I was thinking. I've not heard of a shock siezing. If so it must put a heck of a lot of strain on it, wow. I'm leaning towards the shock only because I just can't imagine a bushing could be siezed enough, but my imagination has been wrong a lot with this issue. Tomorrow I am going to bring the air pressure up on the air bags and then give the side of the shock a firm smack in the side and see if it moves. Otherwise I'll need to pull the wheels for access to free the top end and then try the air pressure to see what happens.

[Richard]

I thought of something last night. Will it lower? If so, the suspension is not frozen, something else is the culprit.

[77newell]

Yes it will go down but not up despite high pressure in the bags. It's as if that side is suddenly carrying an extra load. I pulled the shock and it is just fine darn it. So all that stands between the coach and the axle are the suspension parts; the air bags (which are pressurizing) , the track bar and the Ridewell radius arms. Something about at least one of those is not functioning properly. My imagination has hit a wall, it's time to stop, relax and muse for awhile.

[Fulltiming]

I presume you have verified that air is actually going into the bags, ie the bags are actually inflating (getting harder) as the solenoid opens. If they aren't getting harder, they aren't getting any/enough air pressure. If they are, something must be binding badly.

[77newell]

Micheal; yup the bags are inflated, intentionally more so than the right side. When smacked with a hammer they resound with a higher pitch than the right side. All that is consistent with higher inflation.