a_very_naudi_guy

Per MP's comment and the descriptions I've read many times throughout the forum regarding worn-out upper control arms, it certainly seems as though I need to replace mine. I am a bit confused about exactly what to replace, though; I have watched ltooz's videos on his replacement but, at the same time, the documentation is stating something about needing special tools to depress certain pistons or something on the air-ride suspension struts. I am not sure I was looking at the right information. His video made it look very easy indeed, and I hope it is so because as I go in to replace my brakes I figure I may as well do these if I can.

So I guess the question is - I replace the control arm on both left and right front sides, correct? Anything else I need such as new linkages, or anything else? What's the part number(s) for the part(s) required / what quantities?

Thanks

Jack88

Replacing upper control arms is easy. You need a new pinch bolt and nut if you haven't had it off before, but other than that, no additional parts are required. If the ball joint seems fine, you can get away with just replacing the bushings, which a shop can press in, at a fraction of the cost of a whole arm. It's easiest to remove the strut, held in on top with 3 16mm bolts and one 18mm bolt on the bottom, with one 16mm bolt removed from the sway bar link(before you jack anything up,) to make it easier to get out. With the pinch bolt removed and those things, the strut and arms come out as one, and it saves you from trying to finagle in the tight spaces the inboard bolts on the arm are.

a_very_naudi_guy

Thank you! A few more questions:

1) So there are two control arms per wheel? These are just the front wheels, correct? Do you have a part # on the control arm or a link to one (or a set)?
2) I suppose I should have my trusty local Meineke mechanic (they do a great job, they just aren't up on German teched out cars that much) check the ball joint and do the bushing press in then? Or should I just remove them and bring it to them for press and re-insert? I'm not 100% sure what I'd be looking at to determine if the ball joint is in an acceptable conditon.
3) Where do I obtain this pinch bolt and nut - do they come with the arms?

Sorry, I am not familiar with this part of the vehicle.

Thank you!

Jack88

Not every place will press in the bushings, you have to check. Still, there is nothing special about the four control arms per front wheel. Any regular shop can remove them, and any decent shop can replace the bushings or inspect the components. If you go to parts sites, like getaudiparts.com, you can see the diagrams and get all the part numbers you need for the applicably damaged parts. Feel free to shop around a little, but make sure you buy OEM parts, no one makes a good aftermarket suspension components. You need to order the pinch bolt and nut, I haven't got the part number for those offhand, but you can get them for any dealer.

MP4.2+6.0

1. Two UPPER control arms per front wheel. There are also two lower control arms. Normally issues are with (only) the uppers Thus, for uppers, four in total. All separate part #s and shapes, though all use same bushing part # regardless of location. Do NOT buy a set, since in all cases I know of the sets in turn will rely on dubious/no name suppliers. Search on the literally hundreds of posts that will say much the same thing. Use dealer OE or Lemforder as the OES supplier for less money. Lemforders are still expensive, but actually last 50-100K miles instead of a fraction of that that much of the junk does. For Lemforder, my oft go to site for actually buying as well as price comparisons is RM European. See here: https://www.rmeuropean.com/Make/Audi...?catalogID=016 To be clear, (among others) I regard both Karyln and especially Meyle as complete junk. Meyle also tends to imply or misrepresent that it is German, while it appears to more a distributor of China junk.

2. You can also find the upper control bushings from Lemforder on that same page. Again, they were the supplier to Audi for the arms and its separately available bushing. From my own experience, even if arms have 100K miles, the ball joint end wil still be solid. You are looking for ease of movement, absolutely no play, and no torn rubber seals. Torn seal and then movement getting balky are the most common issue with them when issues do come up. Torn rubber seal can be seen by simple inspection on car. All suspension mechanics will know what to check here, and in overlapping suspension parts (lower arms, tie rod ends, etc.)

2a. Not asked, but if you are doing upper control arms or bushings, also do the say bar links. Toward the very end of that RM web page. Again, Lemforder was the OES for those and now less than $18 per link. And yes, these do come from China now when you look at packaging, but Lemforder actually has some QC and is a true manufacturer (owned ultimately by ZF, the transmission and steering folks). You need two--one per side. Dealer price is literally 10x that. Sway bar link is probably second most common wear point, and they are usually worn/cracking/distorted in rubber bushing area by 100K miles. Incidental to #3 BTW, the Lemforder sway bar link does oddly come with one of the bolts, at least last time I bought them

3. Pinch bolt is dealer only and a separate piece part. They do not come with the arms, except in the (junk) kits. One of each per side. It is just above the hub, where the ball joint ends of the upper control arms bolt up to it. Definitely replace. You will probably pull the tie rod end too ,and then I usually replace those fasteners. They don't corrode and freeze up though like pinch bolt can. Be sure you/mechanic realize the pinch bolt is prone to freeze up, and you absolutely can NOT hammer on the hub area or try to pry open the area it spans. Hub is forged aluminum, and it will break if messed with. Then you are is a world of hurt, as a few owners have found over the years. You can do control arms either by dropping strut as Jack mentioned, or by pulling plastic fender liner that gets in way of the inner through bolts at the bushing side of the arms. If you do it the fender linder removal way, then also get new push (rivet) pins, which are also dealer only. About 5 per side. They often distort or get messed up on removal and are in the $1 or less range. More generally, when I do a job like this I usually buy the arms or bushings and similar parts from some place like rm, and then do a parallel parts order for the hardware bits from audiusaparts.com. If they are doing a free shipping deal, I throw in a oil filter, HVAC filter, wipers, etc, until I get to the minimum. Their prices on those tune up parts and incidentals are competitive with quality aftermarket anyway.

BTW, expect to get an alignment after the arms are replaced or bushings changed. While technically not required in theory IF car was never aligned after the bushings were worn some AND if a really careful church lady drove it on pristine roads, in practice any prior alignment (yet alone pot holes) with wear in bushings will have insidiously built that wear into the alignment settings. From practical experience, pre vs. post alignment is a nice "aha I fixed it" drive home, while it still feels fort of blah and older until aligned.

See my prior post here (and linked in auto sig) for lots of info on control arms. Some part #'s since probably superseded, but lots of background there. https://www.audiworld.com/forums/a8-.../#post24620404 Pinch bolt can be seen in the lower picture in my reply 17 there BTW.

PaulW

Here's my procedure:

https://www.audiworld.com/forums/a8-...ht=control+arm

LivinLong

Comments above are all good, but don't underestimate how awful the pinch bolts can be. I replaced my upper control arms a couple months ago. It's a cake job except that in my climate, road salt pretty much guarantees seized bolts. Took me 5 days of heating, penetrating oil, drilling, and a special pneumatic punch to get those suckers out. Also, everyone recommends replacing just the inboard bushings but beware that getting the arms off the vehicle to do that requires ball joint at outboard end be disconnected. It's very easy to damage those ball joints in the process.

Jack88

That's true, 2 of my ball joint boots were damaged from someone using heat to get the pinch bolt out, but it wasn't until I went to take out the arms that the damage became apparent. If you can get the pinch bolt out without use of heat, that would help.

LivinLong

Yes, heat should be considered a necessary evil and avoided if possible. However, the outboard ball joint shanks are tapered into the hub and one must use a picklefork, a 2- jaw puller, or a punch to the end of the shank to jar them loose. Chances are, the ball joint will not be unscathed after removal. Another case of - it worked great when we tried it in the engineering garage on a car with 2 miles on it. Did not go so well when attempted on a 14 year old example that had seen 120K miles on midwestern roads with de-icing salts present........

MP4.2+6.0

On the editorial side for those not familiar with the parts, two parts/portions of the suspension are getting jumbled here. The upper control arms are held by a pinch bolt, which is prone to corrosion (or rather electrolytic reaction probably) . But once the bolt is finally out of there, the shafts of the ball joints for the UPPER arms are straight vertical cylinders and they slide out easily. There when heat is being applied, it is presumably for the pinch bolt rather than to get the joint itself out of the steering knuckle/hub casting. By contrast, the LOWER control arms are the ones with the traditional taper ball joint ends that require a fork or other tool to exert enough pressure to get them to pop out, and may also need some heat or other persuasion to pop them free. And as soon as the fork type tools come out, yep the grease boots on the ball joints likely get torn or with heat they get cooked. Meantime, probably 90%+ the time, the arms that need attention are the upper ones.

Besides difficulty removing and always using a new pinch bolt, I always put antifreeze lubricant on the shaft of any pinch bolt when I am installing it to avoid the issue later. Fortunately being in coastal California plus using the aniseize paste, all the ones I have removed on both the D3 and C5 over a variety of suspension jobs (arms, CV boot and related hub pulls, bearings, etc.) have come out fairly easily. It is a stupid design though there you have no clean access to the threaded end (where the nut goes on) to simply hammer it out with a drift. On the D4, they made the threaded nut end easily accessible, though they otherwise continue to rely on the same dubious longevity general bushing set up for the upper arms.