RR8S chassis leaning on air bags after shutdown

[ok-rver]

another update. Did get hold of the field guy for HCVs at Link. Good discussion. Submitted pictures to the distributor on the leakage at the HCV and they sent a new valve. Over the last few weeks, the 3 ride height air circuits have not leaked any significant amounts of air. Air tanks have gone to 30 psi over 36 hours but the check valve in the HCV keeps air from leaking back to the tank and our MH has stayed level for a week. Really nice to open the storage bay door and NOT have a MH leaning to the side. Well worth changing out the hoses and fittings going to the air bags.

[Dr4Film]

Great Job!

👍

[Georgia Mike]

My problem sounds very similar as Mikes. My Dynasty leaks down on the front drivers side in less than an hour. I replaced a valve in the rear and a fitting in the front generator compartment both you could hear but it still leaks down the same. I tried to listen underneath for any more hissing but don’t hear anything else. Next step is to start with the soapy water spraying on all the fittings. Is there any particular problem area that I should look at first?

[ok-rver]

G Mike, I plugged in the type of ur MH and it appears yours is 42' which probably should give you a tag axle. RR10x chassis ? You stated that the front drivers side leaked down and that at first had me questioning how that could happen. My assumption is that you have one height control valve at the front and one each side at the rear drive axle. the tag axles seem to have a single pressure regulator to supply both rear air bags. as the front and tag airbags should be connected side to side, they would not contribute to keeping the MH from leaning, air just moves from one side to the other thru the tubing from side to side. If your rear is not dropping, it may have something to do with the tag axle.

Measuring from plate to plate on top and bottom of the air bags on each side. this will give you some idea of where the tilting is coming from. If your MH is leaning in an hour, you have some major leaks. My first leak was the over pressure valve in my front air tank. $20 and less than an hour install and air leak went to less that 10 psi an hour. As big as your air leak is you should be able to hear as you have on a couple. I was going to change the rear safety valve but it does not have one on my MH. A leak this big could be causing your engine compressor to run excessively.

If you find that the driver rear is also tilting, there are maybe five obvious leak paths.  The fittings (#1) in the level circuit are:

straight QC fitting at HCV, airline from outlet to tee

two swivel tees on each side of a bulkhead fitting on the frame above the axle,  lines to these are air source from HCV, line to dump valve probably in engine compartment, line to each of the two air bags.

fittings in top of each air bag.

7 fittings to spray down under the MH. I have purchased DOT compression fittings and changing out the quick connects as I work thru the air lines. I could only find the swivel tees, tube x tube x npt, in a QC fitting.

While at the HCV (#2), spray all over the valve, both fittings in the top and the horizontal air tube about 3" long that is the exhaust. spray soap into the tubing to confirm the valve is not leaking to the exhaust. I found a new HCV was leaking at the 4 bolt flange that held this exhaust tube.

Look in your engine room to see if you can find your air dump valves(#3). If you can not find them, have some hit the dump valve switch while you are at the rear. You should be able to hear the air exhaust. spray the fitting and the exhaust of the valve. It should have a screened fitting that you can spray with soap. the screen keeps bugs out of the port.

 Another possibility is that you HCV check valve under the inlet fitting(#4), a ball and spring, is allowing air to back feed to the tank as it gets below around 70 psi. My engine compressor cycles the tank between 90 and 125 psi when the engine is running. air bags need around 60 to 70 psi to get to full ride height. I replaced the air lines and fittings on my driver rear two air bags. I believe there may have been a leak in the airline due to a previous owner tire blowout. Also replaced the HCV. My MH stays level for days even when the tank has gone to 30 psi in about 48 hours.

While not real common, air bags (#5) have been know to leak. takes lots of soap solution to really cover them.

While under the MH, u might take a good look at the rubber fittings on the links to the HCVs. Mine where full of cracks and about to separate. A broken fitting would disconnect from the HCV and would no longer be reading the correct ride height and would either fill or bleed air from the bags and be a major problem

Send me a PM if you have more questions and we can talk direct.

 

 

 

[Georgia Mike]

Mike, thanks for all of the information. I don’t understand fully how this air system works on this Motorhome I am still learning. My previous Motorhome was a Fleetwood Discovery with just 4 air bags and not as complex. I just came back from a trip and fortunately our site was level so I didn’t have any problems. I ordered some heavy duty jack stands and plan on going under soon to start looking for leaks. I have replaced two dump valves that were hissing bad and can’t hear any other audible leaks. The rear seams to stay up fine but the driver side starts to drop with in 30 min then the the entire front goes down in a few hours. My Thomas compressor isn’t working either so I plan on pulling that out as well. I have another one I ordered to replace. I will check all the areas you mentioned and hope I find something obvious.

[Dr4Film]

The HWH Air Leveling 6-Pack Valves are an area to not overlook. I had a similar problem for many years in the rear. I finally had Josam in Orlando evaluate the problem and they found two problems with the rear 6-pack valve assembly. Repaired them and now I am a Happy Camper!