Interesting question. I also own an air suspension Treg (08' V8) which is coming up on 130K miles and have been wondering if I should do anything, proactive. The only area I am considering is the air pump (under the frame/passenger side) as I've seen a few YouTube videos about the seal on the pump failing. I think replacing the upper and lower control arms is a good call. I personally replaced my lower control arms at 99K miles and they were shot to hell. When I decide to step up and replace the upper control arms, I would inspect the ride-height sensors and repair or replace, and I would also replace the brass air valve attached to the strut since they would have to be removed in order to remove the strut. I don't think you need to buy close to $6K (parts only) for the fancy new Bilstein air struts but that's up to your wallet. Or, if your struts are looking corroded, due to salty roads traveled, then I'd probably replace them. However, I would try to source used air-struts from the inter-webs to keep the cost down.
I can't think of anything else but hopefully others will chime in with help or opinions. Let us know what you decide and how it turns out.
Good luck! 🍻

 

Interesting question. I also own an air suspension Treg (08' V8) which is coming up on 130K miles and have been wondering if I should do anything, proactive. The only area I am considering is the air pump (under the frame/passenger side) as I've seen a few YouTube videos about the seal on the pump failing. I think replacing the upper and lower control arms is a good call. I personally replaced my lower control arms at 99K miles and they were shot to hell. When I decide to step up and replace the upper control arms, I would inspect the ride-height sensors and repair or replace, and I would also replace the brass air valve attached to the strut since they would have to be removed in order to remove the strut. I don't think you need to buy close to $6K (parts only) for the fancy new Bilstein air struts but that's up to your wallet. Or, if your struts are looking corroded, due to salty roads traveled, then I'd probably replace them. However, I would try to source used air-struts from the inter-webs to keep the cost down.
I can't think of anything else but hopefully others will chime in with help or opinions. Let us know what you decide and how it turns out.
Good luck! 🍻

Thanks, this is a Texas Treg so luckily no significant corrosion to speak of. It looks like the brass valves are a good candidate for preventive replacement either way, even if the struts are fine. I will still do upper and lower control arms at the same time, and probably add the sway bar links to the list.

Appreciate the heads-up on the pump! I will look into that.

 

I replaced the front shocks on mine about 18 months ago with the Bilsteins and the upper and lower control arms around 20 months ago. Bilsteins have been good so far. Only changed them as they were leaking. Don't think I'd change thevshocks as a preventative measure. But would consider changing the valves or at least keeping some in the car. Now it's time for the rear bushes😔.

 

Do you wish you would have replaced front shocks at the same time as the control arms since they ended up leaking a couple months later? Hindsight is 20/20, but I am trying to avoid this scenario and am wondering what the risk of it is.

Any difference in the ride of the Bilsteins compared to original suspension? I have run similar Bilstein shocks on A4 platform VWs and they have a very comfortable ride.

I appreciate the note about valves, I will add some to my road kit!

 

I see people like throwing money around here haha. If your shocks are not leaking, No need to replace it for new shock. I have 08 V8 w/Air Suspension.

So a couple of things:

1) If it ain't broke, don't fix it. These air springs are ROBUST. They are not just going to fail like that. I've heard of very few failures, in fact less than 5 failures since I've had these and have been keeping up with it. I'm sure there are definitely more.

2) If you have no leak and want to do some preventative maintenance, I would first replace the residual pressure attached to the air springs.

3) For the air suspensions models, the only way to replace upper control arms is to complete remove the air shock/strut assemblies. So while at it, another preventative maintenance would be to replace the 2 o-rings in assembly (picture below #5 and #7). You can also replace the shock mount (#4)

4) The level sensor cannot be repaired. If it ain't broke don't fix it. The only time you should ever need to replace one is when the sensor goes out, indicated by VCDS. The actual linkage should be able to be repaired, but I tried that and I ended up with new sensors with linkages.

5) There are o-rings at each line at the valve block under the passenger side when you remove the long cover underneath the car. You can replace those.

6) The compressor can also be rebuilt with new o-ring, cylinder head and piston ring. The kit can be purchased on eBay.

7) I have done all of these, with new TRW upper and TRW Porsche lower control arms. The porsche arm has rear solid bushing, while the VW spec is fluid-filled which fails to quikcly.

 

Thanks for your input, Micheld7. The o-rings are an interesting option for preventive maintenance on the struts, in addition to the brass fittings mentioned earlier. Seems like a lot of work though, and I am not sure how easy it would be to tear down and rebuild the units without issues.

While I typically agree that things should not be replaced unnecessarily, in this case we are talking about a vehicle that is my road-trip and overland vehicle. Replacing suspension components that could fail, leaving me stranded in a remote area of Texas, is simply insurance. Everyone chooses their own risk tolerance, but the objective of this thread is to identify maintenance that should be performed on a T2 with over 100K miles when upper control arms are being replaced due to ball joint or bushing wear.

Since we don't know the failure rate or distribution of service lifespans before failures, I am being cautious. A search on the topic of Touareg air suspension problems certainly turns up plenty of results, and I don't want to end up writing one of those posts.

I was able to locate the Running Gear Workshop Manual, and while it doesn't say anything about service interval of the air struts, it does say that after 200K km (~125K miles) if either air spring leaks, both air springs should be replaced. If the shock absorbers leak, the whole air strut assembly is supposed to be replaced because the oil can damage the bellows. However, the manual says the residual pressure valves should only be replaced if they are leaking or stuck. Both sealing rings (#1 and #8) are supposed to be replaced if air springs are replaced, but so is the boot (#6).

Looks like upper and lower control arms should be done together if either is needed, and air struts should only be replaced if the shocks leak, otherwise left and right air springs should be replaced if a leak develops in either. I will look into the Porsche LCA bushings and compare with the Meyle HD option. Thanks!

 

The #1 and #8 from your diagram are the o-rings (#5 and #7 on my diagram). I have done these two o-rings on two separate Touaregs, my previous 05 and my current 08 which has just crossed 150K mile. I have done full front end suspension refresh, no parts spared. I have always re-used the bellow. If there are no tears or holes, no need to replace. Its just there to keep debris/dust out. There are couple of youtube videos on replacing those o-rings.

Yes if the air bags leak, the whole assembly has to be replaced because the air bag itself if not sold separately from the shock absorber itself.
I do agree that if one control is bad, it is smart to do the other one as it is surely not far behind, i think it is far fetched to replace both air spring if just one is leaking.

 

@bhsramz

how to replace the o-rings

 

Thanks for the link @Micheld7!