Freightliner Air Suspension Won't Rise (Cold Weather)

[OMMM4747]

Happened once last year and I attributed it to a glitch but it happened again this year ... 2022 Newmar Dutch Star on a Freightliner chassis.

I take my coach out once a month to "exercise it" (don't like having it in prolonged storage during the winter; run the generator w/a load for ~1.5 hrs during the drive). Outside Air Temp (OAT) was 25F. Had the engine block heater ON overnight. Came ready to take coach for a drive (engine was warm). Started the engine. Both air systems pressurized to 130-140 psi, but the air suspension didn't move (full down; not on jacks). Same thing happened last year and shutting down the engine and starting again got the suspension to rise right away, but not this year!

I then selected the chassis battery disconnect at the battery and inside the coach in an attempt to reboot any onboard systems and the ECU. Waited 2 minutes before reapplying power. Started the engine again and still nothing -- good air pressure but air bags won't inflate. Hmm??? Ran the AUTOLEVEL on the HWH leveling system, and although the jacks came down, I did not hear the usual air release during the leveling process. I presume this was normal as the air bags were already empty. I then retracted the jacks and attempted a MANUAL DUMP [of air]. I could hear a "clicking" which I presume was the system driving the dump valve to open to let the air out of the bags. Since the bags were empty (coach suspension full down/not inflated), nothing happened (as expected). I started the coach again and pressure on both systems still indicated 130-140 psi, only this time the coach started to rise and I was on my way 5 minutes later. But for approximately 20 minutes, I was dead in the water ... the coach just would not rise.

The only thing I can presume is that there is a valve -- somewhere -- that froze and would not allow the airbags to fill.

Note: I purged the 3 front axle air compressor lanyards and the Brake Sync lanyard before putting the coach into storage (November) and none expelled any water. If there's water in the system, it's not in the tanks and is elsewhere.

Any ideas as to what is going on here? Has only happened twice and both times when the OAT is below 32F.

Thanks!

[TomandGloria]

Try putting it in drive and move it forward a few inches. Had that happen to mine, but not in freezing weather and the air bags began inflating.

[alank]

Sure sounds like a moisture freezing problem. Hope you get it worked out. I would suggest a new desiccant filter for future operation.

[daveh5525]

I make it a habit to hit auto Retract. The hydraulic system bleeds down over time and doesn't have the preasure to close the valve to signal the system to air up the bags.

[Dutch Star Don]

Here's a couple of thoughts. When you put the coach away this time and last time, did you manually dump the air bags? If you did, you caused the system to skip a procedure and will cause what you experienced.

As others noted, you can often just put it in gear and that will cause it to air up.

If you are dumping the air manually when you park, just don't do it anymore. The coach will naturally lose air over a few days to a week, and you won't have the issue.

Lastly, exercising the generator is fine, but there is really no need to drive the coach. It can sit for several months and not be an issue. Sometimes you do more damage if the coach is not brought up to full temp for quite a while.

[Ray,IN]

Don mentioned the HWH system getting out of whack and that happened to my MH. When you manually dump the air via (12V electric solenoids) then turn off the engine, that leaves the dump valves open. They require another 12V signal to close, but the shutdown causes it to sorta lose its memory and not send the close signal.
The remedy is to auto-level after startup, and allow the system to complete, then store the jacks and shut down engine.

Repeat this process and this time the air springs should auto-inflate. That lesson cost me $165 in 2013 from a mobile truck repair service. He said he sees it every year at least 2-3 times from new owners.

[PanJH]

I had a similar issue this past summer. Would not air up. I pulled the touch pad for the jacks and cleaned the contacts on the connections. Still nothing. Next, under the generator hood, on the passenger side is the HWH hardware/valves. Going into that is a 32 pin connector. I removed it, sprayed with contact cleaner and re-installed. All worked fine at that point and has continued since.

[OMMM4747]

Thank you all for the great inputs! Based on what you’ve pointed out, here is what I believe I did wrong.

Dutch Star Don: Yup, I manually dumped last time I stored it. Won’t be doing that again! (thanks).

daveh5525: I manually dumped vs Retract (AUTO STORE on my coach) (thanks).

I don’t believe the problem was water/freezing related. A coincidence?

As many recommended, I did not try putting it into gear. It’s the one thing I didn’t try since I figured if it’s not on air, it shouldn’t be driven/put into gear. So at least I have this option in my bag of tricks should it ever happen again.

As for “exercising” the coach … my manufacturers, Newmar, Freightliner/Cummins, Allison (transmission), HWH (hydraulics) all recommend exercising. To that end, I take it on ~1.5-hr highway round trip every 30-45 days culminating w/a gas stop @ a Love’s about 10 miles away to leave the tank full before storing the coach again. Once I get back I run through a camp set-up and tear-down routine so as to run the slides and the leveling system, also recommended. I run the generator the entire time w/a load (HVACs/heat – ON). On the drive I keep an eye on engine and tire temps to ensure they all get to operating temp. In the Winter, the engine gets to operating temp within 10 mins after hitting the hwy (60 mph) and the tires about 30-45 mins thus, the engine (fluids and exhaust system are getting 1+ hrs at operating temp and the tires about 45 mins). In the Summer, I get to operating temps much quicker. Lastly, I store the coach on wooden blocks I built and place them at the 4 jacking points so the full weight of the coach is not on the tires/sidewalls but rather on the blocks. The tires rest on thick rubber mats purchased at Tractor Supply (not on the cold concrete). As recommended by HWH, I do not store the coach on jacks since there is the possibility it will introduce moisture into the now partially-filled hydraulic reservoir.

Agree or disagree, this is what my manuals recommend and I follow their guidance because I have no reason to doubt them. In fact, it makes perfect sense (to me). The 3-hrs and $35 in fuel is time and money well spent and forces me to go inspect the coach monthly and catch problems early. It doesn’t just exercise the coach, it also exercises my brain.

Once again, thank you all for the great inputs and any other which may follow. I like to understand how things work so I can work w/the system rather than against it and running the risk of causing avoidable damage and expenses.

Happy trails and stay safe out there!

[Dutch Star Don]

Depending on where you live, exercising the coach can be fine, as long as you're driving as far as you stated. I live out west, nothing gets cold and on occasion the coach may sit for several months.

The cold and wet weather is a big killer of generators. The windings get nasty. If I lived in cold and wet weather, I would exercise the generator regularly.

We've owned a Diesel Pusher since 2005. I've never exercised the generator on any of my three DP's, sometimes going 6 months to a year between use. The warm weather is gentler on them. I've never had a generator issue.