Rear Air Suspension Issue

[msd3075]

I've spent the last hour or so searching all different places to see if anyone has experienced what is happening with my X5, but I've yet to find the exact issue so I figured I'd just post about it instead

I have a '14 xDrive35i with the 3rd row/air suspension option. Currently at 58K miles. Within the last year, I've had both rear air springs replaced because of the normal leaks that are typical with this suspension. I experienced the normal sag/etc that happens when the air springs begin the leak.

With that being said, over the last few months, the suspension will just randomly completely deflate upon start-up. No gradual leak. No hissing. No sagging. Within a minute or so after start-up, it'll go from normal ride height to being completely deflated. It'll operate normally for several days/weeks without doing this and then just randomally decide it wants to completely deflate. If I lock the car and let it sit for 5-10 minutes, it'll inflate right away after start-up and then act normal after that. My issue is that now it deflated and won't go back up. I can hear the compressor kick on if I open the door after I wake the car up, but it runs for maybe 20 seconds or so and the shuts off with no effect on ride height.

It doesn't sound like a typical leak because it happens so suddenly and also because both air aprings are pratically new (<5K miles). Can a valve be stuck open somewhere? If there a sensor somewhere that could be on the fritz that's randomly telling the car that the ride high is too high so it deflates?

Just wondering if anyone else out there has had a similar issue.

[ajshanny]

There are only a few components in the system: the air bags (which you already replaced), the control module for the air suspension, the pump (which includes the valves), and the air lines. It seems likely to me that the problem would be either the control module or leaky valves.

[msd3075]

Originally Posted by ajshanny

There are only a few components in the system: the air bags (which you already replaced), the control module for the air suspension, the pump (which includes the valves), and the air lines. It seems likely to me that the problem would be either the control module or leaky valves.

I let the car sit overnight and started it up this morning to see what would happen. As soon as I opened the driver's door, I could hear the compressor kick on, but the rear end did not raise up. It was still bottomed out. I started up the engine, but even after a few minutes of waiting, nothing happened. I shut off the engine, locked it, and let it sit for 10 minutes. When I opened the door again, the compressor again kicked on, so I knelt down on the ground on the passenger side by the compressor. I could hear a faint hissing noise coming from that area. Not sure if that's normal (I'm assuming not) or if it's one of the valves by the compressor leaking and/or stuck open.

Everything is pretty much on a pseudo-lockdown around here because of Hurricane Laura, so I can't exactly bring it into the shop to get them to look at it (nor do I want to if this ends up like what we went through with Ike back in '08). I'm mostly posting on here to see if anyone has had a similar experience.

[msd3075]

Finally solved this suspension issue after spending quite a bit of time trying to figure it out.

The culprit was a corroded pressure valve located on the black cylinder piece that's a part of the air compressor unit. It's directly inline with decadent beads, so it looks like humidity/moisture from the bad decadent beads caused the corrosion.

It took a huge amount of force to remove the valve. When it finally did pop out, the metal shaft was seized inside the valve, pretty much making the valve stuck wide open. I unseized the center metal shaft and cleaned everything up enough to where it could freely move again. Put everything back together again, and now it works perfectly.

I've attached a pic showing the location of the valve as wells as a pic of the corrosion on the valve after I worked the shaft out but before I cleaned it all up.

Hopefully this helps everyone out if/when they have this same problem.

[ixlr8]

Glad you found the problem, thanks for the update.

[TheMane]

Great detective work and thanks for the update!

[ajshanny]

Nice job!

[F15GorDe]

Thanks for following thru on this.

[lokomoto87]

I have a 2015 F15 with a about 35K miles on it. Recently, I find the rear of the car lowered after being parked in the garage overnight. Can I have the same issue as you did. Is it a quick fix? As soon as I touch the door handle the car levels off and its all good until its been parked for several hours. Can someone help me please.

[msd3075]

Originally Posted by lokomoto87

I have a 2015 F15 with a about 35K miles on it. Recently, I find the rear of the car lowered after being parked in the garage overnight. Can I have the same issue as you did. Is it a quick fix? As soon as I touch the door handle the car levels off and its all good until its been parked for several hours. Can someone help me please.

That doesn't sound like the issue I had with the pressure valve. With my situation, the car would hold air for days while parked but would dump all the air out very, very quick after the car is started.

It sounds like you have a small leak somewhere in the system. From reading on hear over the last month or so, it sounds like 99% of the time our our cars that the issue with a small leak is a leaky air spring. You'll lose pressure slowly, and the air compressor will kick on when you unlock the car to fill the bags back up.

[Maverik259]

Nice work. This is exactly what the forum is about!

[chumbedi]

Originally Posted by msd3075

Finally solved this suspension issue after spending quite a bit of time trying to figure it out.

The culprit was a corroded pressure valve located on the black cylinder piece that's a part of the air compressor unit. It's directly inline with decadent beads, so it looks like humidity/moisture from the bad decadent beads caused the corrosion.

It took a huge amount of force to remove the valve. When it finally did pop out, the metal shaft was seized inside the valve, pretty much making the valve stuck wide open. I unseized the center metal shaft and cleaned everything up enough to where it could freely move again. Put everything back together again, and now it works perfectly.

I've attached a pic showing the location of the valve as wells as a pic of the corrosion on the valve after I worked the shaft out but before I cleaned it all up.

Hopefully this helps everyone out if/when they have this same problem.

Did you dry the beads or filled new ones ?
Hope you put new rubber seals, otherwise the repair won't last.
Thanks for info

[msd3075]

Originally Posted by chumbedi

Did you dry the beads or filled new ones ?
Hope you put new rubber seals, otherwise the repair won't last.
Thanks for info

I originally replaced the beads thinking that was the original problem. They were soaked. Lovely Houston humidity.

When that didn't work, I assumed the compressor was weak/dying so I bought an aftermarket one online (included the bead canister and pressure sensor). I couldn't get my car to recognize the new sensor without throwing a Chassis Malfunction code, so I cleaned/lubed up the old sensor and used it with the new compressor and bead canister unit.

[E30toF30]

Originally Posted by msd3075

I originally replaced the beads thinking that was the original problem. They were soaked. Lovely Houston humidity.

When that didn't work, I assumed the compressor was weak/dying so I bought an aftermarket one online (included the bead canister and pressure sensor). I couldn't get my car to recognize the new sensor without throwing a Chassis Malfunction code, so I cleaned/lubed up the old sensor and used it with the new compressor and bead canister unit.

Thanks for sharing this. I am in the process of searching for posts related to suspension sag (like I'm sure many of you are/have!!) and wanted to do my DD before posting something new.

But like you, I had both airbags replaced on my 2014 F15 back in the beginning of March, 2020. But the issue returned about 3 weeks ago, so the bags are 8ish months and maybe 1500 miles old. So still pretty much new!

However, my issues this time is not so much inconsistent working/not working airbags. This time, the suspension just stays down. The other MAJOR difference is that in March, I was still under extended warranty (thank god), but during covid, my car exceeded 100,000km which ended my extended warranty (ARGH!!).

I did drop the car off at the dealer on Monday this past week, and they diagnosed it for me and concluded that it was the compressor that needed to be replaced. Their diagnosis was based on the following inspection - Checked the fuse, noticed it was blown. Changed to a new fuse, and the new fuse blew right away. So something with the compressor is causing the fuse to blow and not even giving it a chance to inflate the bags.

I don't have time to pull the current compressor out to check it so I'm likely just going to order a new aftermarket replacement compressor first. Then when I pull the current one out, i'll take a peak at this valve you are referring to.

Also, you mentioned you used the old sensor with the new replacement compressor. Can you let me know which sensor that is? It sounds like I might come into that same problem?

Also, which replacement compressor did you buy? I'm likely going with one by Aerosus (I think that is the name?). There are some other cheaper generic brands, but it seems at least this brand is a bit more reputable based on their website?
https://aerosus.net/bmw/x5/f15/bmw-x...essor-901.html
https://aerosus.net/2013-2018/bmw-x5...h-bracket.html

Another thing Im not sure about is that the Aerosus setup linked above comes with a replacement relay.
However, some of the other generic units come with a replacement Valve block, but no replacement relay.

Im reading that you would want to replace the relay when changing the compressor, but what about this valve block? Do we need to replace that? If so, I assume I need to source one of these valve blocks with the Aerosus setup?

[OzzieF15]

Hi E30toF30
Hope your problem got resolved. When I was blowing through fuses, it was the relay that was faulty. Replaced it (A$30) and problem gone. Didn't have to replace the compressor, though I did open it and replace the desiccant beads. Hope this helps.

[genuineguy]

The discharge valve has a removable metal shaft. The shaft will have some salt deposit due to moisture in the system. However, I would like to clarify that the metal shaft is not the moving element of the valve. The tip of the metal shaft has a plastic black color attachment. The real valve is inside the this plastic tip. You need to put some WD40 and clean the inside of the tip.

Cleaning the metal shaft of the salt deposit/corrosion may help with its magnetism and in turn help the plastic tip mechanism ( moving valve parts inside)

[raducris]

Originally Posted by msd3075

Finally solved this suspension issue after spending quite a bit of time trying to figure it out.

The culprit was a corroded pressure valve located on the black cylinder piece that's a part of the air compressor unit. It's directly inline with decadent beads, so it looks like humidity/moisture from the bad decadent beads caused the corrosion.

Did you have any error codes in ISTA?

[lowlaw99]

I have the opposite problem with my BMW. The suspension is much higher than normal. My suspension was deflated and I removed the pump and dried out the beads. That resolved the issue but the suspension pumped up past the normal height and will not go down. The is also a message on the dashboard, “chassis function restricted”

[nomi1902]

Originally Posted by lowlaw99

I have the opposite problem with my BMW. The suspension is much higher than normal. My suspension was deflated and I removed the pump and dried out the beads. That resolved the issue but the suspension pumped up past the normal height and will not go down. The is also a message on the dashboard, “chassis function restricted”

Have you found solution for that problem. Please update. Thanks.

[mrfochon]

Had the issue today. Totally down for 100km. Very stiff and bumpy drive.
Now have to replace the parts. Any reco in Europe ? (Thought fcp euro was an option but it’s only on the us??)