2014 WK2 Air Suspension

[kevm14]

Ha, I know this channel. He has an E63 and has many videos about it.

https://a.co/d/intttiW

Says same day delivery for me. I guess this is a common issue.

[rpaoness]

Those are cheaper, I just thought rmt seemed to have a decent rep. It lowered overnight and was cool so I soap bubble tested after starting/airing up but not touching anything else. No evidence of bubbles on either fitting.

[kevm14]

Oh I thought I sent the RMT ones. Guess not. Okay I replaced it with the correct RMT part. Of course it is situations like this where I wonder if the RMT part is just marked up Chinese part.

Did you try wiggling the fittings and hose?

[rpaoness]

I did. No leaks when wiggled, at least this morning.

[rpaoness]

I had replaced both fittings on top of the struts a while ago and had no ride height issues.

When below about 15 degF we had several "service air suspension immediately" warnings this winter, but always went away once warmer out.

Recently Cara has said she has seen the service air suspension warning 4 or 5 times in about the last two months, so I finally tried to do something about it.

Pulled codes and just got failure-to-achieve desired ride height and compressor-too-hot error codes. Reset codes.

My best guess, and it is just a guess, with no ride height/parked height changes indicating no leaks, is that some of the valves are sticky or contaminated with moisture or corrosion. The not-functional-when very cold is likely a moisture-in-the-system symptom.

Removed the right front wheel and fender liner, and I pulled all of the hoses off of the valve manifold. Sprayed WD40 in all of them and up each of the hoses so hopefully air movement will work it into the solenoid valves. Replaced all hoses.

Discharged the compressed air/nitrogen tank under the back seat. Uses a "standard" R134A fitting - It was at about 135 psi, I've heard that 175 psi is a typical target. Pulled a deep vacuum on it, filled to 3 psi with nitrogen and pulled back to deep vacuum three times to try to boil any moisture or other stuff in the system. Seemed to get a ton of water vapor out of the vacuum pump with each cycle, almost none on the last one. So I think I got it clean and dry in there. Recharged from my nitrogen bottle to 175 psi, and left it hooked up as I turned the ignition on to refill all of the bags.

Took a test drive and all seemed fine.

Pulled codes again and got a system air mass too high error message, which I assume is from while I had the bottle hooked up. Reset and haven't done anything since. Cara said she hasn't seen an error message now with 3 days of commuting. Hopefully that lasts.

[kevm14]

I always thought the "closed nitrogen" system they used was weird. I don't know if it has something to do with water fording. You certainly don't need to do that kind of maintenance operation on a Mercedes. Or at least I've never heard of it. Guess Jeep had to be different.

Found this: https://youtu.be/r_UtE9o6gPA?si=7bIMd_wSjB4Ey5wQ

This link describes the system in detail: https://jeepspecs.com/models/jeep-grand ... on-system/

The claim to fame in the "why is it closed" section is that it has a pressurized air tank. Uh, so do all my Mercedes. I'm still confused.

I suppose a system like GM's rear air shocks for load leveling were what they were referring but that's not a 4 corner system. Meh, marketing. I still don't understand the engineering reason. The only real difference is when my cars need to drop air pressure it exhausts to the atmosphere. But air for rising is pulled from the pressurized reservoir which the compressor merely tops up.

[rpaoness]

I don't think it's as "closed" as people think. I think it's all about starting dry and trying to stay that way as long as reasonable. No reason to start off with crappy shop air.

[kevm14]

Right but on Mercedes the compressor merely charges the air tank. I don't know why this can't happen with the Jeep.

[rpaoness]

Probably cheaper, less corrosion resistant system components. But maybe not.