Wobbly/shakey steering

A6 All/ S6 All
#1

About a week ago, I starting noticing this. At first, I thought maybe my wheels needed rebalancing, but that’s not it.

The steering wheel wobbles slightly at all speeds (anything from 2mph-80mph), and it’s wobbling at the same rate as the tires are spinning.

At 60mph and faster, the wobble turns into shaking, the car vibrates enough that’s it’s uncomfortable to drive at that speed.

It’s not accompanied by any unusual noise.

I popped my head out the window and it doesn’t appear that the wheels themselves are doing anything unusual.

What should I look for? I had the whole front suspension rebuilt with new parts 9 months ago, so it’s very unlikely to be control arms or anything like that.

#2

Back when I had my C5 A6 I had aftermarket wheels on it that needed centering rings in order to make the inner bore of the rim fit the outer diameter of the hub… I had a very similar shimmy occur at almost the same speeds you’re indicating. I wound up ditching the aftermarket rims for some OEM ones.

Aside from that I’d re-check to make sure everything is torqued down properly on the suspension along with the wheel bolts.

#3

I’ve got OEM wheels on there currently, and I don’t think they’ve taken on any damage or anything. I’ll drive my car onto some ramps tonight and take a look to see if anything appears loose. Thanks

#4

It’s very possible that you could have had a wheel weight come off. Tire shops put the wheel weights on the inside of the rim and from time to time its possible for them to fall off. The feeling your describing is a drive train issue from the sound of it.

#5

That’s what I thought, but I checked and all the wheel weights are still there.

I’m hoping it’s nothing too serious - I still haven’t had a chance to get underneath and take a look, hopefully I have some time at work today

#6

I had this type of shaking. Kinda like a 2nd order vibration. Really speed dependant on my car, say around 120km/hr (70ish MPH) it would go away. Any faster or slower and the intensity would pick up.

I replaced my lower rear control arm as the bushing was shot, but the vibration was still there.

Check the hubcentric ring… it was missing… replaced it. Vibration was still there.

Checked Tire for inbalance, tried other wheels… Vibration still there.

Finally looked and say that the inner boot on the CV joint was torn and the joint was loose. Replaced axle, and vibration is now gone.

Sorry for the story but that’s the process I went through to find the problem source.

Hope that helps.

#7

Maybe check that axle replacement thread started today.

#8

That’s a good thread. Its worth looking into C.scott. check the axel shaft for play and the CV boot for grease

#9

Found the problem. After narrowing down the problem to the front left corner, I took the wheel off and had a look.

The good news is, mechanically the front end is fine. The CV boots look brand new (JHM must have replaced them last summer, it wasn’t on my invoice but JHM is awesome like that ;D), and all the bushings and everything look brand new, no slop in the axle at all. The only thing really left to check was the tire/wheel.

I did a very scientific test. I rolled the tire down the driveway, to look for wobble.

Bingo. Tire had what appears to be a “high spot”. Upon closer inspection, it was tread separation.

The tires, despite my putting 30k miles on them since I bought the car, and who knows how many miles on them before that, had pretty decent tread life left on them. Unfortunately, my fender liners weren’t really secured properly, and have been rubbing on the inside edge of both front tires for some time now. Enough that it exposed metal in both tires on the inside corners.

So now I’ve got 3 problems to fix, on a budget. First, my fender liners are trashed. Next, my front tires are trashed. And 3rd, all 4 wheels are trashed (for unrelated reasons).

Now I need to figure out how to go about resolving those 3 issues as inexpensively as possible. I might just have to forego the new wheels and rear tires for now, and just get the fronts done. Can I have just the front tires done, if the rears still have halfway decent tread-life remaining? Tires shops I know ALWAYS say you have to do all 4 tires at once in an AWD car, but I really don’t want to get 4 new tires right now.

#10

Glad you found the problem! Ironically I thought about your problem today after having a flashback of my brother getting his first car back in like 99 which had a similar problem - a high spot in the driver’s side rear tire that made a “thumping” sound at all speeds.

As far as replacing all 4 at the same time, I think that’s them doing their thing and trying to sell you more than what you need. Personally, I’m of the opinion that you should replace tires on the same axle. So in your case at least both fronts. If the rears appear to have enough tread left in them I’d say use them up till they reach the wear bars.

#11

After doing quite a bit of research this morning, I found my solution, for uber cheap. Found a website that sells quality used tires, you can buy them in matched pairs with an indicated remaining tread depth to match your existing tires. Free shipping, even. So, for $105, I bought a pair of front tires that match the remaining tread depth of my rears (7/32"). Just need to get them mounted and balanced when they arrive.

I’m thrilled that I found an affordable solution, because I did NOT want to spend $1000 on new tires to go on my factory wheels that I plan to upgrade soon anyways but can’t afford yet

#12

Nice! Are you talking about bestusedtires.com? I’ve hit them up before when looking for a set for my M6… which sadly needs new rears AGAIN. I had the luxury of being pretty local to them so I swung by one day and brought the wheels with me and they mounted and balanced them there.

#13

Yep, that’s the place! Very well done website, and incredible prices… I might never buy brand new tires again

#14

Finally getting around to putting my summer wheels/tires on this w/e (it is Michigan…it could snow in June).
Doing an inspection of the everything and what do I see–both L&R inner CV boots are shot. First (3) pics are of the LF, but can’t easily see where its cracked. Not much grease left by the looks of what I cleaned up. The last pic shows the RF with the small diameter portion completed separated around the entire circumference. Checked them in October. Not sure when it happened, but I guess I know what I’m doing next w/e.

I was going to buy the axle replacement hardware kit (8E0407643AKT; ~$35/ea) and the inner CV boot kit (4E0498301; ~$52/ea) from ECS to tackle this. Any other thoughts on this job? Any special tools required? I’m assuming it’s within my reach. Thankfully I just bought the Bentley CD, but haven’t had a chance to install on the ancient laptop I got from my dad running the old Windows.

While I’m at it I was going to replace both upper control arms on both L/R sides.

#15

Not a terrible job to do.

Depending on where you live, the pinch bolt can be a real pita to remove but if you’re in the southern states it’s usually not too bad.

As for tools, you’ll need a triple square for the axle to transmission bolt (can’t remember what size, either M8 or M10) and you’ll need a 17mm or so Allan impact for the axle nut. Key is to break that loose with the wheels on the ground.

Might also need a pickle fork to separate ball joints.

#16

Figured I’d post an update. Been in Europe most of the last couple months, but finally got the chance to put the “new” tires on the front. Problem solved. Old tires were trashed, probably from driving 25k miles with a bad front suspension before JHM rebuilt it last summer. Tread was separating, I’m surprised I didn’t have a blowout.

Anyways, new tires are great, problem solved for < $200, so I’d call that a success.