That Sinking Feeling - A6 Allroad air suspension problems

[54A4Avant]

I've just ordered a couple of the Aliexpress air springs. Wil post pics when it comes. Total outlay was $225 incl delivery for 2 and if they're no good I'll be using the buyer protection which seems to work as well as ebay's.

[bagpipingandy]

My A6 Allroad C6 appears to have this issue, it will sink to lowest setting if left overnight in automatic mode, I've just run it up to lift mode and will leave overnight to see if it sinks or not. I've read a lot of the previous threads but still have some Qs.

What's the significance of using jacking mode when testing whether the car sinks from dynamic or lift mode overnight? At present I'm testing with jacking mode off, do I need to repeat the tests with jacking mode on?

Chinese eBay (Aliexpress) has air springs for C6 at around 100 US dollars plus half as much again in shipping. Has anyone tried one of these Far East imports, or is it worth paying more than double for an eBay uk item (given its probably made in China anyway?!).

Hi the reason to use jacking mode is this disables the cars ecu from performing any adjusting, as the car will constantly try to keep the car level, so if you have a leak on one corner the car will adjust and let air out the other corner to keep the car level, so by applying jack mode, only any leaking corner will lower all the way to the bump stops. Note: the other corner may dip as they take the weight of the car but any leak will show by sinking all the way down to the bump stops in some cases a leak is obvious at a specific corner, in other cases it looks like both corners sink so then use jack mode to confirm if it is both corners or only one.

I buy mine direct from china,

best regards

Andy

[54A4Avant]

Thanks Andy. I had the opportunity to park the car up in dynamic mode with jacking mode on this morning and have been keeping an eye on the back corners. It's now been parked nearly 3 hours and the back left corner is almost down on the bump stops. Back right corner is a little higher, so I'm not sure if that one is also leaking or if it's the extra load from the other corner. Will watch it all day I guess and then I'll have my answer.

For changing the air bags, this video shows removal without un bolting the lower suspension arm and seems to imply the new bag can be fitted the same way: Audi A6/C6/4F Rear Air / Pneumatic Spring Change - YouTube not sure if this is a good idea but certainly less scary than taking the suspension arm off?

[jrenoc1]

I did mine without unbolting any arms.

once I had car on axle stands( in jacking mode) put a long extension bar with a 10 mm socket between 10mm bolt at top of shock and lower arm.
This will hold gap so easier to remove and refit be bag.IMG_0508.jpg


IMG_0509.jpg

[54A4Avant]

Thanks jrenoc1, I will have a look when doing mine to see if I can rig up something similar. Did you hit any problems in changing the air springs, or did it go fairly smoothly?

[jrenoc1]

Only really pain was the bolt in base , get a good quality spline bit . I sprayed some release oil on it before I started so it had time to work. It's really exposed to road crap under the arm so I also sprayed the bottom in wd40 and usd a small screwdriver to try and clear .Place in spline bit in bolt and give it a good whack with a rubber mallet, make sure it's seated properly before to try to undo it, far to easy to strip. When refitting air line I counted how many turns to remove nut on new bag and did up the same so that the green line was lined up .

Other than that I just took my time , radio on , a few brews and bacon sarnie .IMG_0524.jpg

[54A4Avant]

Thanks, I will take care with the spline bolt and take your tips of wedging something in the gap to keep the suspension arm lowered and count the turns on the air line nut. I have both sides to do so will at least know what I'm doing on the second side I guess.

Do do you know what torque setting to use when tightening the spline bolt?

[jrenoc1]

To be honest I did it by feel ( bad boy) I'm sure someone here has the correct figure .

Youre correct the 1st 1 is the hardest , once you've done that 1 the 2nd is easier.

Ive done 6 in total now on different cars , all my own cars. The failing air bags used as a bargaining tool.

also replaced the compressor on my current allroad as well, surprisingly easy job.

[54A4Avant]

Sounds like i have a fall back option of hiring you to do the job for me Just kidding, with all I've read up on how to do this it seems easy enough (famous last words.

One last Q - for the air line connection, do you simply screw the old fitting dry onto the new air bag, or is some kind of sealing compound or Ptfetape called for?

[jrenoc1]

The new airbag should come with a new collar and nut. Will have a white piece of plastic in it , I undid the nut then compressed the air bag and refitted .
This again helps with refitting the new bag.
With a new Stanley blade trim about 5-10mm off the air line, a nice clean straight cut, then put the nut and collar on line , push into airbag so that the collar is at the correct depth on line and tighten up nut.IMG_0511.jpgIMG_0515.jpg
easy !!!!!!