TSHong

I just hit 105k and having some suspension issues. Looks like it's like clockwork for us D3ers.

My front had dropped while I was replacing my leaking washer pumps. We did it on a lift so all four tires were off the ground. But it pump backed up to normal levels after start up. Kind of concerned me but everything seemed fine. After a month or so My front seemed like it was 1/2 inch down up front and 1/2 inch up in the rear. Finally triggered a the suspension light. Pulled codes and had the usual, lead detected, compressor over temp shut off, lower limit exceeded, and implausible g291 signal. Cleared codes but they have showed up again.


I sprayed soapy water on the front struts and the valve block with no bubbles. I figure the front struts are leaking while i drive so I ordered though one of my parts distributor two front rebuild Arnott front struts. My real question is the implausible G291 signal concerns me. Do you think I might need a valve block as well? The last three days, no light and the suspension seems to be working correctly but I do see it pumping up after shut off on all corners.

Or could it be just the valve block by itself. The front struts are such an issue that am I fixating on those unnecessarily? Seems like not too many people have changed the valve blocks?

MP4.2+6.0

My valve block tested fine when I did a thorough soap test, but I did test it. Unlike struts that are hard to leak test in center area under dust cover, you can definitely bathe the whole valve block, especially if you unscrew the retaining bracket.

I think dual strut failure is really rare. Thus I doubled back first on valve block. Dealer parts guy (Romney at audiusaparts) said their techs there definitely do pull valve blocks from parts counter to replace, though a good amount less often than struts.

If you only see something in a month, sounds hard to find. When mine dumped, it would drop front pretty fully in 1-2 days. They key was watching it in the opening 6-12 hours on mine, where at first I could make out that the right front corner was headed down earlier and more. Later on both sides were down and you couldn't be sure which, but in those partially down earlier hours I was maybe 90% sure I could see it, and always on right seeming lower in mid drop time zone. I think once a corner loses it, it puts enough weight both directly and across the roll bar to pull the other one down with it, hence second corner does go down in sympathy. Having leak tested valve block and found nothing, I felt comfortable enough to surgically order one new front right strut via dealer part, as opposed to two rebuilt Arnotts for similar money. The fairly educated guess worked out, and other three struts, valve block and main pump are still the originals at 135K on a Spring 2005 build (early) 2006.

TSHong

I did not pull the valve body off si it could be it. The reason why I was questioning the valve body was that both front seem to drop vs one side consistently but I do see your point about one side bringing the other side. Mine do not take a month but it does take a day to lower the front end. That is why I was resigned to do the front struts.

I would prefer OEM but they are more expensive today. Audiusaparts is who I normally use for OE parts, and they are $1557 each right now. Through my one of my parts vendors, the Arnott struts are close to $525 or so plus shipping. Also if ever i need to warranty one out, I can use them for that. They will take car of me since I spend at least $10K a month with that vendor.

I also plan to do all upper control arm bushings, and the right side CV axles because my inner boot is seeping now. I might just go ahead and do the left CV axle while I'm in. Also probably will do lower bushings? Any thoughts on those?

Thanks as usual MP

MP4.2+6.0

Hmmm, sounds like OE price is up, and Arnott down $ wise. Did you mean the original style Arnott rebuilt, or newer Arnott house design alternative replacement? If the latter, be sure you read the threads on those. I would buy rebuilt if on a budget, high miles or scenarios like that, but would not personally buy the alternate design that removed the tuning/ride firmness aspect IIRC.

Inner CV boot seeping--saw that on W12 too, rather than the usual old Audi cracking stuff. I did inner and outer w/ parts kit from audiusaparts. Rebuilt it myself; as usual with the newer design, hardest part is just getting axle off outer joint, plus the usual grease mess that is about a roll of paper towels per axle. New ones are really durable looking material not like the older closer to rubber stuff. Definitely do upper control arms/bushings while in there. Piece of cake to pull off strut assembly once you have it out anyway. If you do upper bushings, consider the S8 ones. Dealer only, like audiusaparts. Can't get from Lemforder catalog or any # either. Supposedly a stiffer material, though I had a hard time seeing any delta visually. It is a distinct part # though in Audi's system. The bushing is the only apparent difference from A8 to S8 for arm.

I saw no sign of wear on lowers ever, and would probably do tie rods before lowers. But having done tie rods, the design is a lot beefier in the various ball diameters than in past, and the ones I pulled at 100K from same type W12 like you were still in near new condition as best I could tell. I would however do sway bar links if never done before. Easy. Lemforder OES for like $65 shipped for the pair, at least from RM European. The sum of upper bushings/arms and links plus decent alignment really cleaned mine up again last I did it. And the little shimmy I had in some braking scenarios was apparently in those upper bushings--which is why I had gone for tie rod ends earlier.

TSHong

Yes, the rebuild Arnotts with adaptive dampening. Although the dampening part is not replaced or touched as part of the rebuild, there seems to no issues with them. I did read about the hydraulic/standard type shock with air level control with their NEW struts. I did verify that was the case with the Arnott rep here in ATL. He did confirm that they are not adaptive damping with the new units.

All the bushings were going to be ordered from Jim Ellis Audi here locally. That is interesting with the S8 bushings, I will order S8 uppers. I can also get whole CV axles for cheap so I think I will do both sides. I can keep my old ones if I need them later.

Again thanks for your insight.

Has anyone tried a new aftermarket valve block just in case I need one? There are less than half price but not sure if they are worth gambling with?

richard-tx

I used RMT rebuilt struts on my 2006 A8L. I am very happy.

Their rebuilt struts come with all the parts needed including rubber grommets and new o rings.

Rebuild Master Tech Air Suspension, Engine Parts & More...

Their shipping is dirt cheap. I don't know how they negotiated such a low price with FedEx.

tjf

To OP. You mentioned this happened when it was up on a lift? Was it in jack mode? If not, it may have let air out thinking the suspension was to high. When weight was put back on it, there was not enough press to hold it. The car is supposed to detect being on a lift automatically, but maybe it didn't.
As far as preventative maintenance of rebuilding before failure, I just did that at all 4 corners. ...wish I hadn't. I used RMT. Each strut had to be returned at least one time because of poor quality control on their part. They did make it right, but it took a lot of time on my part.

TSHong

Yes, I put it into jack mode and only the fronts were down and the rears were the same height as before the lift.

I did consider the RMT struts but i do remember reading about your experience and my local vendor carries the Arnott struts so I with the Arnott struts. If i need to warranty them out, I just call my parts supplier and let him deal with it.

richard-tx

Don't forget that the "new" Arnott shocks are NOT electrically dampened like the original shocks. That means that while the ride height is still adjustable, the ride stiffness is no longer adjustable. In other words, comfort mode does nothing except change the ride height.

Junius

Yeah and that's one thing that I would not like for my A8 to ride like. It's amazing how different the A8 rides in dynamic and comfort modes. I usually ride around in dynamic, since I like the look of it lowered, but the past two days I have driven in comfort mode, and it's like riding on the German magic carpet. I missed comfort mode very badly lol. Who would imagine that an 11 year old car with 197,000 miles would drive better than a car half its age. I remember at 120,000, the ride quality in my A4 was deteriorating. So I would just beware of Arnott's new set of air struts