Our coach has been parked for a while cuz of you-know-what. It had been naturally settling lower on the suspension from gradual system air leakage. Yesterday I noticed it was sitting kinda high on the right front corner. Wanting to avoid the dread "cracked windshield from twisted frame" problem common to GVs, I decided to investigate. Got in the coach, turned the leveling system on, and tried to release air from the "high" corner. The DOWN arrows didn't seem to have any effect. So, using my onboard 110V air compressor I pumped the air system up to 120psi. I then raised the front end all the way up to the stops - that worked fine. But when I tried to let it back down, none of the leveling panel buttons would make it drop. HMMmmm
I have often advised Forum members, when having leveling system problems, to go directly to The Book. I decided to take my own advice, and pulled up my online copy of the HWH 600 Series Service Manual (link provided below).
https://www.hwhcorp.com/ml19048.pdf
Starting at the beginning of the trouble shooting steps, I performed each test exactly as directed. Everything was good until Step 4, where I hit a snag. The front UP and DOWN arrows would work in the UP direction, but not in the DOWN direction. I could raise the front of the coach, but could not lower it.
"Test each set of up and down arrows checking that the appropriate air bags will inflate and deflate and that the auxiliary compressor will run during the raise function. If there is any malfunction see Part 4 of the REPAIR STEPS."
Going to Part 4 of the REPAIR STEPS, Step A, I found my exact problem described:
A. Front bag will not deflate when pushing a front or side down arrow.
Reading across to the "SOLUTIONS" column, the first suggestion says:
"Check that the exhaust ports of the air manifold are not plugged."
This morning, while it was still "kinda" cool, I put the coach up on my safety stands (all 8 of them). Rolled under the front end on my creeper, and took a look at the the front 6-pack. Guess what I found? Both exhaust ports totally plugged. I have often read on the Forum about this problem happening to other members, but this is the first time I have personally had the problem.
Got out a few small tools, and started digging the hard obstruction out of the holes. It was surprisingly tough! When you think about it, those plugs were holding in place against 120 psi air pressure trying to blow them out. Pretty darn impressive engineering! The material I removed is a combination of green plant material and some kind of dense, yellow, waxy material. I did not see any obvious sign of a larva or egg, so I'm not clear on the purpose of the plug.
Once I got most of the crap dug out, went inside the coach and tried the front end DOWN arrow. Heard the welcome sound of air blowing out the exhaust ports. Went back underneath and finished cleaning the ports with a wet Q-Tip. Problem solved!
One safety tip: If you use a sharp tool to dig the plug out, be careful not to poke directly in the center of the port. You can see in the photos of the cleaned out ports that the blue sealing surface on the solenoid valve plunger is visible through the hole at the bottom of the exhaust port. Poking a sharp tool through the hole could possibly damage the seal.
More Photos:
I've wondered about adding a sintered filter or something on the exhaust ports to prevent this but not sure if it will cause problems by restricting the exhaust. Any thoughts?
Quickun Pneumatic Muffler Silencer, 1/4" Male Thread Brass Air Exhaust... (https://www.amazon.com/Quickun-Pneumatic-Silencer-Sintered-Mufflers/dp/B07WWJMLL1/ref=sr_1_5?dchild=1&keywords=1%2F4%22+exhaust+muffler&qid=1593367511&rnid=2941120011&s=industrial&sr=1-5)
Chuck, I don't think that is a wasps nest or anything to do with wasps. That is a growth from a spore, I find those growths in tubes and small pipes on the property. It is a plant seed that grows in tight places.
Folivier, I don't think using them would be a problem but you can also get the ones that stick out to give more surface area if you thought it was needed
Chris
I think I may have found a explanation for the troublesome plugs in my 6-pack. A Google search turned up some interesting info on Mason Bees. See the article linked below. Seems to fit what I found stuffed in the exhaust ports. The waxy yellow stuff is basically pollen. There is supposedly a egg laid on top of the pollen plug. The egg is covered with a protective cap - in this case it was made of green leaf material. In my photos of the stuff I removed you can actually see some small leaves that are still intact.
I must have missed seeing the egg when I dug the plug out. Don't know how big they are... Perhaps I mashed the egg with my digging tool?
Anyway, now that I know we have these critters around here, I will have to be more observant. Like I said in my initial post, this is the first time I've had this problem in the 7+ years we've owned our coach. Perhaps these bees are new arrivals in our neighborhood? I can imagine lots of other small holes all over our coach where they might make a nest and cause malfunctions.
Mason bee - Wikipedia (https://en.wikipedia.org/wiki/Mason_bee)
I must have them too then. Never bothered the coach, but in other places on the property. I'll try to take a photo the next time I find one.