Rear Air Suspension Leak/Replacement
 

Hi guys,

Chipping away at issues with this car, almost done! The next/last biggest problem is the rear air suspension leaks down after about 1 day. I'm assuming it is the air spring assembly leaking. What are my options? I see that Arnott makes replacements for around $800 a set, other aftermarket MFGs make a set for about $400. There are also entirely new rear strut assemblies from a company called ECCPP for about $800 - would that be an acceptable option? I dont really want to drop $3000 on OEM strut assemblies...

What do you guys think is the best budget method to repairing this system?

-Will

If you would like to end AS issues permanently, convert to steel spring suspension.

I recently ordered 3 Chinese air suspension bags from fleabay and have recieved the first package. I ordered a compressor as well a couple of months ago and it's installed and working fine. Obviously cannot vouch for longevity though. The OEM prices are just painful to see, as usual.

I definitely want to keep the AS, it is the best feature of the car. And it lasted 15 years/almost 200k miles so that isnt bad! Better than my bosses LR which eats AS parts...

Both sides as far as I can tell - When driving it is fine, it adjust to all levels fine but it leaks over a long period. It takes about one day currently to leak down fully. I will say this too - when it leaks down and you go up to the car and unlock it, the car (without even running) will self level by just the air held in the tank. Something for thought.

That is kind of my position. I'm all about OEM, etc but a lot of the time the OEM stuff is just rebranded "aftermarket" stuff anyway with a higher price tag. The compressor works fine and I'm trying to save it by not having it cycle as frequently due to the leakdown. Maybe I'll order those chinese bags. And let's be honest, I'd bet the only thing that really failed in my system is those two o rings anyway. I bet the bag is fine...

Ok so I dont want to be *that guy* but I found this..... I can get both rear *strut assemblies* for $100 shipped. Seems kinda crazy but it looks like they were discounted from ~$500. Clearing stock?

https://www.ebay.com/itm/New-Prime-C...sAAOSw2fRcU4DT

Honestly, for $100 I might roll the dice lol. Worst case I just steal the air parts... Still cheaper.

-Will

Although I see those have the electrical plug, will those shocks still retain the adjustable damping or is that a lie?

-Will

Let's say I get those cheap shocks for the time being - is it possible to get the OEM dampers/shocks (which I think are Bilstein) rebuilt? Meaning run the chinese struts for a while until I get the OEM's rebuilt, then just transfer the new air side components over?
Is rebuilding a shock even a thing anymore?

-Will

That's mind-bogglingly cheap :eek: - I'm actually glad they don't ship to Europe or I would be very annoyed that I just bought from someplace else.

Is that the valve that is on the airline inlet of the strut? I will tell you this, the air leak has gotten progressively worse as time has gone on. Meaning, I think there is a worn air system part more than a valve issue.

They were so cheap, I ordered a set regardless. ;) :roflmao: Worst case I'll just steal parts off of them.

So you placed the value on your life @ $49? Geez, the labor to change them is worth more than that....things that matter when your eating up concrete barrier @ 100mph.

Hahahaha! The labor costs me nothing (and the job is very easy in general). If they look/feel crap, I wont use them. Worst/best case I'll just steal the air parts off. I'm going to tell you right now, the parts I just bought are the exact same part that cardone, etc sells for ~$5-700. Other than OEM Bilstein factories, I doubt there is more than one Chinese factory that makes these parts. It is like saying your interstate battery is better than your autozone - news flash, there are only two main battery producers, they are probably the same. I will eventually figure out the best solution, but $80 bucks as an experiment is fine by me. Hell, the whole car is an experiment at this point... To each his own. You're the one implicating you drive 100mph....

I am sure your time is worth something. While you have some valid points on parts producers the difference is who the part manufacturer is selling them to and the spec it has to meet to satisfy that client and their quality/financial needs. The car doesn't have to be an experiment as they are proven great vehicles. Sounds like you are comfortable working on them and that's a big thing. Over the years I have seen the few instances of collateral damage from a reproduction wheel breaking or an airbag blowing while driving and it ain't pretty. If you didn't drive the PIG for what it's worth then you wouldn't have gotten one. I drive 100 whenever I can, I think that's a given.

Still I would be willing to bet on my limited knowledge that the bags are not the problem. You could always try some soapy water spray? Each strut has a dedicated air line that runs from the strut to the valve block. I don't see how both rear could bleed evenly without going through the valve block first. A lot of people misunderstand the purpose of the residual pressure valve at the top of the strut. It is not a check valve or one way valve. It simply flows both ways until the pressure on the strut side drops to a specific psi and will not let any more escape after that. I think it's around 2 bar. This is so the bag doesnt deflate completely because it can damage the bellows inside and still allows you to roll around with a fault. This is why the struts come from the factory pre-charged and strapped in a mid-extension position. A lot of thought went into this air ride system and compared to all the other big auto manufacturers I agree its really good if not one of the best. The only other leakage point at the strut is the o-ring at the top. I would find it hard to believe that both rears are leaking evenly at those two o-rings. Just some ideas for you.

Brave soul you are. I've had enough fitment/quality issues with Chinese crap to where I would never trust a $80 piece of garbage to carry me down the road. You would be amazed at ways they find to cut corners to save pennies, even within the same factory.

The control module will equalize them, that's how. The sucker periodically wakes up and checks... I guess same reason you're supposed to put the suspension in service mode before lifting the car, or the control box will start adjusting as you lift the car up even with key out of ignition.

If you want to test which side on the axle is leaking:
1. Measure ride height on each side from center of the wheel to the top of the arch.
2. Disconnect the control module.
3. Measure ride height after a couple of hours/days. The side that sagged more is the one with the leak.

Regardless, unless your car drops completely to the ground, the issue is not with the air bag itself. Residual pressure valve seems somewhat common failure point, as I've seen a number of threads for both Cayenne and AS equipped Touaregs on this. The valve frequently disintegrates when you attempt to remove it.