MP4.2+6.0

FWIW, creaking can also be from the roll bar bushings and links.

MP4.2+6.0

Per my VIN for a 2006 W12, audiusaparts.com (Romney) confirmed my car has the 2MA suspension type, meaning it uses the A8 standard and sport part number as stock, rather than the S8 number that goes with 2MB. Still planning on shifting to S8 part #/type.

MP4.2+6.0

I pulled the front passenger wheel today for a close look. I have owned the car CPO since 15K in 2007 and know the whole service history--started as a car driven by the dealership owner as his personal ride. Short history for this purpose is rear upper arms are original, as are fronts apparently. Front arms were serviced for bushing issues, and apparently that is all they did (not the whole arm). I conclude that both because of the rear bushing condition (more in a minute), and that both arms have a manufacturing stamp of sometime in "05"; car was built in spring 2005.

Condition wise for inspections I also learned something. From what I saw I could make out that the fronts were starting to tear. I was not so sure on the rears. So, I pulled the pinch bolt to free them up at the ball joint end. Its a CA car, so indeed I had them free in minutes with simple hand tools. Once I did that--one at a time--I could really move them around and get a good look at the bushings and get a good feel for the ball joint. The front was partially torn but still held together from inner to outer rubber areas. It was the rear that surprised me. When I moved it, I could see tearing more than I could before I undid the ball joint side (looked arguably less torn earlier), but now I realized I could move the whole arm up or down a fair amount and it would not really spring back. The front one would, and it should if the bushing rubber is in one piece and acts like a winding spring. I concluded the rear bushing was actually fully torn out in the center of the rubber, but the bushing was still pretty firm. Net, it tended to confirm prior service was a bushing only repair to the front uppers, so the rears would have run the full 107K miles on vehicle. And, that rear is gone in my judgment, and front will be before too long. So, figure 100K on rear, and maybe half that since the front one was done once already.

I also tried to assess ball joints. No tearing of rubber boots at all, and no obvious free play. About what I expected and they seem adequately sized compared to some older subpar C5 era ones I dealt with before that later got sized up. But, they had a few kinks in the movement. Since the car was up on the front right side, I could get to the driver's side too (with wheel on still). There in grabbing the front upper arm, in moving it a bit (can be done since the bushing is designed to allow twisting), I could feel a bit of clicking. Very slight, but seemed to be from the ball side rather than the bushing side. Most would probably let it go, but if I am going to pul them anyway, it caused me to lean toward full arm replacement here.

I also looked for brand names, and there confirmed both lower arms are marked with Audi part numbers and TRW branding.

The upper arms do not have part numbers I could find at all, and are marked with what looks like a brand: LMO. I Googled that to find that either LMO or LME are signifiers for Lemfoerder (some spell Lemforder; there is an umlaut in German I think); they are the ZF controlled brand and the letters are parts of the Lemfoerder name in both cases.

MP4.2+6.0

Given my inspection where at least one ball joint could have some minor issues, I looked again at pricing for dealer/OE with audiusaparts.com. I was actually on the phone, so got further confirmation what I was seeing was true. Not surprisingly, the S8 bushings are somewhat more than the A8 bushings--$39 vs. $24, each. BUT, it reverses on the arms, where for front uppers as an example, you get $166 for the S8 complete arm, but $222 for the A8 one. Non-sensical, but what it was. Oddly for my direction, I liked the answer. Coupled with my prior research that the S8 arms also go into the heavier "armoured" W12's in Europe as well as the rough road suspension fitments in C6 A6's, likely the way I'm going, even more so if I go complete arms and the price then goes down, not up.

Rockauto.com shows Lemforder upper ams BTW, and lists the corresponding A8 part number. $135 each--$87 less than discounted dealer. But relative to S8 part #, they don't list them and the price spread there using the A8 arm price they have relative to dealer true S8 OE narrows to $31 each. They show Lemforder (#2931801) bushings for $14 each, but don't differentiate between the A8 and S8 underlying part numbers. For those on a tight budget trying to stay closest to OE on presumably A8 spec with ball joints in good shape, that would be a very rational choice, or $10 more for confirmed A8 fitment via the discounted dealer.

MP4.2+6.0

So, I got the Audi supplied S8 complete arms from audiusaparts.com. As expected, no obvious physical difference in the metal or shape at all. I have yet to line up the ball joints side by side to see if there is anything is different about ball sizing. I doubt it. As explained in my original post, oddly the S8 upper arms are a fair percentage less expensive than the A8 arms via the dealer, even though the S8 bushings by part number are more. Each replacement upper arm by the way clearly has the Lemforder trade symbol (triangle w/ owl in it) and "LMO"--common initials/abbreviation found with their parts. They also have the four rings and the older style small "checkerboard" boxes rectangle to mark the month of manufacture, with year cast in.

Where it gets odd is at the bushing itself. The S8 arms I got--confirmed with part numbers both on the packaging/tags and inkject printed on each arm--are clearly the "F" part numbers tied to the S8 suspension option code (2MB). But, because the arms are brand new, I can read the little part number on each of the four arms' worth of bushings. In every case it says 8D0 407 515C. BUT, that is the bushing number for the A8 (std. or sport (2MA) option), not the S8 bushing number of 4E0 407 515D.

I called Romney at audiusaparts, who promptly called Audi on the US parts side. Audi reported back quickly that they are aware of the bushing part number question and it is noted on some kind of internal screen or document they summarized. They report back that literally the same mold is supposedly used for the rubber of both bushings--thus the part number embedded with the rubber--and only the consistency of the material itself varies. Thus presumably stiffer/tougher in some way. That is there are two different actual parts that vary with the consistency of the rubber, but the part numbers marked on them are not distinguishable and they physically look identical in the rubber because it is exactly the same mold.

Question: For any board members who have bought/used the dealer supplied S8 bushings, do you have any memory or input on whether the bushing part number in the rubber matched or varied from the actual S8 number you thought you bought?

MP4.2+6.0

Basic mileage stats; I owned car since CPO in 2007 and know whole history:

Currently 107,800 and about 9 ½ years from build date. Changed front and rear upper arms on both sides, and sway bar links both sides.

Per service paperwork, all four control arm bushings were also changed at 34,595 miles at approx 4 years from car build date. Links were previously changed at 73,837 miles, and about 6 ½ years from build date.

Bushings this time were pretty shot, and more than I thought from what I saw visually when they were on the car. On the car I saw what looked like modest to moderate cracking. What I found was modest but noticeable cracking on parts of one, and moderate to severe cracking on the other three. One appeared to be fully torn through on the car, since I could rotate arm with it loose on the ball joint side and it would not spring back like it should (bushing side bolts were all tight). The other three still sprang back. None were to the point where the rubber starts to collapse and you can get metal to metal contact when it gets really bad. Had that on the 2000 A6 with junk Meyle parts.

Remembering the prior services when it was still under warranty, that time the upper arms were reused with new bushings pressed in at 35K miles. So, it ran about 70,000 miles on this set, vs. only 35,000 on the first set. The ones I pulled out had the current bushing part number rev on them, which agrees with my dealer work order. Original arms may have been on an older part revision number. BTW, dealer did not install 2 of the 4 bushings close to the way the OE replacement OE arms (S8 flavor) arms are done, nor per the documentation on the web. The holes in the bushings are supposed to be vertical +/- 5 degrees. Two of the arms are around 45 degrees off. I remember being aggressive pushing the dealer on the first set of arms since it was under 4/50 warranty and I figured I might later slide a second set under CPO. I did look at them hard as they rolled off CPO at about 80,000 miles on car at that time, but they were still visually okay--Audi says minor/cosmetic cracking okay, but not if it goes deep/through. I could have had them done originally at 50K instead (at end of 4/50 warranty), and then these would have run roughly 60K incrementally.

Not what I expected, but overall visually it was the REARS THAT WERE IN SOMEWHAT WORSE SHAPE-- Bushings clearly broken on both sides and both ways when you flex them. Front ones somewhat less so, and not yet consistently on both sides of a given bushing. Pictures to follow.

Control arm ball joints. The arms I pulled out are clearly the original ones. The arms have manufacturing dates in early 2005, and the bushing area is separately stamped with a week and year stamp from the first manufacture, slightly later than the cast date but still early 2005. Honestly, they seem generally quite tight and serviceable and rubber in good shape. I will probably take these to a shop and get new bushings put in--S8 again instead of A8 most likely. Job took longer than I thought (I will post on that separately), and I did it a side at a time. Dealing with the press type stuff in a home garage and no overall lift to do both sides at once would have been impratical for me.

Net on upper control arms: I would call the control arm bushings done as far as material cracking at 50-70K, now with two cycles under my belt. I would no longer distinguish between front and rear either. Dealer did both front and rear the first time, and I found the rears worse at the margin than fronts.

Sway bar links: Those were done at approx. 75K by dealer. They were starting to tear out some by then. This change was early, but since I used Lemforder quasi OES for a lot fewer $ than dealer (approx $65 total for parts and ship), I just did it together. Given what I saw--and have seen on my prior C5 Audi 4.2 with similar set up--I would say 75K miles as a normal cycle, or out to 100K pushing it more. Lemforder price point and ease of changing these reduces the decision hurdle.

Sway bar itself: Still doing fine on the bushings. Probably 85K since I swapped in the S8 bar. Can easily run until next control arm interval, maybe more.

Note, all upper arms are clearly Lemforder. They are marked in many ways, including even the bushings. If you are doing straight A8 bushings but want to do full arms, now a no brainer to buy the Lemforder upper arms instead of dealer. They price materially more than the other stuff out there I tend to regard as generally junk, but still only about 50-60% of discounted dealer. My switch to S8 was a one off. S8 (dealer) arms oddly are cheaper than dealer A8 ones, and I wanted a stiffer bushing given the wear issues. Upside down, since S8 bushings as a piece part cost more via the dealer. Lemforder has no separate listing for the S8, but excludes it from the A8 listing (as in, it knows it is a one off).

Last, attached as PDF's are the following which I will also link to:

Parts diagram from Euro EKTA, showing Audi part #'s. It's always the same diagram no matter which you have basically; the S8 number variants (the 2MB option) come up here and there: Audi - A8Q - 2006 - The front axle, transfer case, steering Teile Katalog (Pats Catalog)

Lemforder/ZF catalog. This is very lengthy, but pdf below is just a few page excerpt for D3 with both their part #'s and Audi's. https://mediaservices.zf.com/Redirec...WOR27COgg6I%3D Note the lower arms on mine are TRW, not Lemforder. I see little meaningful wear there and they are much stouter than the uppers to begin with. I plan no work there, likely past 200K miles if I still have it then.

MP4.2+6.0

1. As expected, pulling the fender liner was obviously the way to go. I am used to it now, so quick. It takes at least 4 push pin quasi sacrificial plastic rivets to replace, or 5 if you pull one on the felt liner right by the rear upper control arm bolt to get it out of the way.

2. Per some of the posts, loosening the 16mm bolts from under the hood that hold the large triangular shaped upper suspension arm attachment bracket makes a lot of sense. It makes it way easier to get the rear arm bolt out and back in (in absence of yet other obstructions--next point), and takes only about 5 minutes to loosen it per side.

3. It may be a W12 one off, but the driver's side was a real pain, and I had never come across info about it before. The front control arm bolt jambs hard against the ABS unit on the pump side. Really hard, and no way (or desire) to get too aggressive with it, nor of course to take it out with all the brake lines. I just barely got the bolt out and even then only by a combination of all of: a. loosening the strut unit (also somewhat hard on drivers side because W12 coolant bottle is back in plenum area and very close to the bolt behind the first plenum firewall; b. removing the small Torx bolts that hold the ABS unit bracket to the car in the underhood area; removing a few more small bolts underneath for similar ABS brackets (I never had it truly loose); and c. removing the 13 mm bolts from the small diagonal frame member that runs from the upper fender area down to the main framerail/bumper shock area. Only with all of that and some large screwdriver prying pressure to force the ABS pump a bit further away, while also rotating the shock unit slightly with upper arm bracket bolts loosened from the prior paragraph (it was still bolted to lower arm and air line and wiring fully in place) did I just barely work the bolt out at a pretty severe angle. No real way to get a mallet in there either, even if I wanted to. To get it in, I used a dummy short bolt though the opposite side of the arm bracket (side toward the strut unit where the nut goes) so the arm would stay there while I manhandled strut unit, pried some on ABS pump, and again just barely got bolt in at an angle. I never whacked on it or pried on the bolt face to try to force it in since it is going through a cast part. Another pair of hands would have been helpful for this step.

4. I took the time to tighten the bushings in the final suspension position carefully--both the upper arms and the sway bar links. First I reassembled it all, tightening the upper arm bushing bolts to where they would hold in a position if I swiveled them there, but could still be moved my hand w/ any force. Then I put the pinch bolt back and fully tightened the hub/ball joint side. I also installed the lower say bar link, but again just to where the bolts were going snug. I left the fender liner OFF at this time. I bolted up wheel and took car off jack completely, took it out of jack mode and set MMI screen back to my normal height--actually starting the motor, letting leveling system fully do its thing and moved car--out the driveway to the street the first time, and around the residential block on the final side. I brought it back to the garage and parked it at normal level height. I could still just barely reach in and get my 16mm wrenches on the inner bolts to tighten firmly, and did same with lower links. Only then did I jack it back up, remove wheel again, check arm bolts one more time, reinstall fender liner and then button it all up. A final test drive confirmed all was very tight and zero noise. Still plan to take it to the alignment place for a recheck with the work and swap out in case anything has been tweaked a bit. On the casual drive it all seemed on the money.

First picture below was my (one man) technique to pull strut unit down (with upper strut unit bolts loosened) that made it a lot easier to remove and replace bolts, especially the back one. The part numbers you see on the arms are how they look on the Audi OE arms currently sold, in this case the S8 numbers on the right/pasenger side. If you look toward the back--above where the tie rod is--you see the part of the body that protrudes and makes that bolt hard to get out and in if you don't pull the felt liner away (there is a plastic pop rivet right there) and drop the suspension arm bolt up bracket a bit. With those two steps it was pretty easy, other than my struggle with the ABS unit that may just be a W12 specific set up. Same suggested two helping steps on any A8/S8, regardless of motor.

Second picture below is of the same passenger side with car on the ground, at normal ride height--non-sport, about 10mm dropped via VCDS, with the 20" tires that also run another .3" bigger in radius than stock 18"s or 19"s. Still just enough room to get in there to do the final upper arm bolt tightening and have the bushings in their natural rest position; you can see the rear bolt pretty clearly, but not the front from this angle. Fender liner is still off, so you see more stuff back there that is normally covered up by the liner.

MP4.2+6.0

Each set of pictures is for the identified arm, flexing the bushing with a screwdriver one way and then the other. Look for the extent of the cracking.

MP4.2+6.0

Pictures up close of upper front left control arm bushing--the least worn of the bunch. Call this marginally "acceptable wear" per the Audi TSB type usage.

MP4.2+6.0

Upper rear left arm bushing--lots of cracking. Again, notice my rears were actually visually worse than my fronts.