Persistent vibration at 70-80 MPH and clunking at low speeds

[kday]

I've been trying to get to the bottom of this problem for over two years now. The vibration is moderate at highway speeds and I can feel it in the steering wheel. The clunking is noticeable at parking lot speeds when the ground is bumpy. I'm not sure if they're related but I'm looking for ideas. I replaced almost everything I can think of, in this order:

- All front lower control arms
- Brake rotors & pads
- Wheels and tires
- All front upper control arms
- Both front wheel bearings

I've verified that the top two steering rack bolts are tight. Nothing amiss from a visual inspection.

The vibration has improved stepwise with some of the parts replacements. The single biggest difference was the brake rotors, which cured the vibration under braking which was the original symptom (and may have led to the loosening or failure of whatever I'm dealing with now.) The RF wheel bearing and the RF straight lower control arm also made a noticeable difference

Any suggestions? I'm tempted to replace the tie rod ends, but the steering is tight and it seems unlikely that they would only get loose at high speed.

Subframe bushings maybe?

[Other_Erik]

I had clunking at low speeds around corners, turns out the car was too damn low, raised the suspension one notch on KWV3's (they were on the lowest setting), drives like a dream now! Also fixed the little bit of loose drift I had at highway speed from air pocket getting under the car and giving me a bit too much lift XD

O_E

[JSRS6]

I was thinking the same thing. I know that one issue is my driver front coil over is either not damping at all, or it is loose in the upper perch. Gonna disassemble tomorrow. But I have done almost everything you have done, to no avail. I have bilstein pss9's and my fronts are raised as much as possible. It's weird. The entire shock body should be a little taller I think. Or the neck should be longer under the tube.

[ben916]

The vibration has improved stepwise with some of the parts replacements. The single biggest difference was the brake rotors, which cured the vibration under braking which was the original symptom (and may have led to the loosening or failure of whatever I'm dealing with now.) The RF wheel bearing and the RF straight lower control arm also made a noticeable difference

Any suggestions? I'm tempted to replace the tie rod ends, but the steering is tight and it seems unlikely that they would only get loose at high speed.

Subframe bushings maybe?

Sounds like you have isolated "it" to the front right side.
some other things that you might look at are:
- Motor mounts
- Transmission mounts
- Rear diff mount (I noticed drive line lash and after I replaced it with the Apikol Blue, that lashing went away. 1 of the 4 rubber fins was cracked in half. With Wade's, 3 of the 4 were toast)
- There is a bearing that the front axles attach to on the front diff (I know where it is but am verbally challenged at the moment)
- when the rotors were replaced, was the mating surface wire wheeled off? Rotor might not be seating properly.
- OEM rims?

[SteveKen]

Sway bar mounts or end links?
Steering rack bolts?

[kday]

I replaced the sway bar dogbones too, but not the mounts to the subframe. I guess that's worth a shot.

I have not attempted to get to the lower steering rack bolt but the top two are tight.

Motor mounts -- vibration at 70 MPH?

Both sets of rims are OEM. The mating surfaces were cleaned.

[Dmb408]

I had this but I did control arm bushings and a strut (and a DRC recharge) all at the same time and there was a big difference.

[Dmb408]

But i have suspect summer wheels (and i did all this recent work with winter wheels which unfortunately i think are toast after just one winter with these potholes).

[BigD2500HD]

Axles? Happened on my a4. The audi dealer here couldn't figure it out so I finally came to the idea of just replacing front Axles and voila! It worked.

[Bigglezworth]

I would lean on it being a strut issue. Poor dampening will lead to a bouncing tire regardless of how well the tire is balanced. Do you have any cupping on the tire(s)? Clunking would suggest lack of dampening at low speeds also. OEM or aftermarket struts?

[JSRS6]

That's where I'm leaning on my situation. Makes sense for kday as well.

[kday]

I have the recalled DRC setup on my car. Has anyone else experienced DRC related vibration at speed?

The axle idea is interesting, I can imagine that causing a high speed vibration -- but not the clunking. Not to say there aren't two separate problems of course.

[BigD2500HD]

The vibration and clunking sorta go together. The clunking at low speeds is related to the vibration at high speed. The boot on my axle was torn and the grease was no longer prevalent. And the Cv's dried out causing rough contact of the joints. Clunking and vibrations were the same. Just reached differently depending on speed.

[kday]

Ok, good feedback, thanks. I have a 6 speed conversion in the works (which, admittedly, has been the case for going on 2 years) so I have to decide whether to replace the axles even though they'll go in the trash at conversion time...

[BigD2500HD]

On that note.... What's average price on the swap?

[ttboost]

On that note.... What's average price on the swap?

Depends who's doing it....you know...labor...$3k to $5k in parts and probably close to the same for labor...