Pinkfloydd

Hey gang. I always preface my posts with an upfront thank you in advance. You all have saved me so much money and time answering questions for me. Here is my latest woe.

So over the last year or so, my car began to develop a slight vibration. It was mostly a sound annoyance as the phone craddle would rattle against the plastic of the armrest or the glove box would rattle stuff inside. Over time it got noticeably worse. I bought 4 brand new Goodyear Eagle's and had the tire store put them on. No differnece. I assume they balanced them. Im pretty concerned now as it has gotten pretty bad. The car accelearates and brakes normally and the gears seem to shift seemlessly up and down so I ruled out Transmission problems. Nevertheless at low and high speeds, there is a considerable shudder. At highway speed, I can let go of the sterring wheel and see it visibly shuddering like a cheap washing machine on spin cycle. There is no loud vibration sounds at all, just a glass in my cup holder or something in the door panels give it away. You can feel the shudder in your arms and back too. Can anyone give me a a list of a few probable things it could be or how I can go about testing ideas? I don't know much about mechanical work myself and fear a repair shop would give me the ol' "Oooo...your brake light fluid boot seal is worn..that'll be 2 grand please" and nothing gets fixed. I got my oil changed at Audobahn Performance the other day and they seemed very nice. Would taking it to a place like that get me answers, or would they just narrow it down to like 15 possibilites and kill me on labor figuring it out? thanks to all in advance! If you live in Atlanta and can drive it for a few miles give me your educated opinion, there is a free bottle of Glenlivet or Grey Goose in it for ya =)

--Chris


P.S. -- Whoever I passed the other day in the Silver colored 2003 S8, thanks for letting me cut over on the interstate, almost missed my exit eyeballing your ride!

2000A8blue

Really sounds like a warped brake rotor, but you should feel it in the pedal when you put on the brakes. Maybe only when you put them on HARD. Do you notice that it changes, gets better or worse, when you put on the brakes?

ryoung

<b>1</b>. If not, perhaps one of the wheels is bent. I doubt this would be the problem if you're running OE S8 wheels, they're built like tanks.

<b>2</b>. I've never heard of a warped S8 rotor (see <a href="http://www.stoptech.com/tech_info/wp_warped_brakedisk.shtml">The Warped Rotor Myth</a>), but it could be pad deposits on the rotor. If so, the vibration would normally be noticeably less when the brakes are cold, and gradually increase as the pad's coefficient of friction increases when the pad/rotor warms up. If this is the problem, try re-bedding the brakes. ... 3-4 back-to-back max effort braking from 70 to 5 mph (do NOT come to a complete stop), followed by driving a few miles to allow the brakes to cool down.

<b>3</b>. Long shot (but simple solution) ... Rust build-up on a wheel hub could result in vibration like a wobbling wheel. Mounting new tires wouldn't necessarily change anything. If this is the problem, pull the wheels, clean the hub with a wire brush, wipe it clean, remount and properly torque the wheels.

Good luck.

HIstateS8

Maybe the balance weights came off your wheel. It happened to me once.

Sleeper8

If that does not resolve it, next I would jack it up and spin the tires looking for a bent wheel, especially if they are non-OEM. Likely place to look is on the inside edge of the rim. It is helpful to if you have a dial indicator, run-out should generally be less than 2mm. Another way to trouble shoot is to rotate the tires (put front wheels on back &amp; vice versa). If the vibration in the steering wheel stops, it points some problem with the tires/wheels that were on the front.

If these items check out, I would have a reputable mechanic put it on the lift and check front control arms (8 total) and steering tie-rod ends. Any play in any joint can cause these symptoms. These parts seem to fail at about 100k miles (±25k). I personally would only use a mechanic who is willing to allow me to go under the car with him and show me any problems he finds.

Good luck!

TonyA8

Hi Pink, check the tightness of your suspension. Put it up on blocks and try to see how much play is in the wheels. Grab the wheel at the top and bottom and twist. Do the same but hold the wheel at the right and left. Try to see if there is any looseness on any of the 4 axles. The next thing which might also cause it is the drive axle to the rear wheel or any of the half shafts to the wheels. If it is out of balance, it will vibrate. That can only be checked while turning to see if it turns out of round. You can also see how much play they have (there should not be any).

One trick to try, have someone drive next to you and go to the speed where the problem is most acute. Have them look at each of the wheels to see if any of them vibrate. Have them drive around your car to check all 4 wheels. If any of them are vibrating, then it is just a bad wheel balance. If the problem occurs mostly when braking, then look to warped rotors and/or control arm.

TimD

I noticed you had different wheels. As with all things car related start with the cheap and easy things first.

Tires balanced? Free to $20

Check suspension and control arm bushings.

Check tie rod ends.

Axle maybe? Probably not, but check it.

Autobahn Performance is a good place. I doubt they will charge you if they cant figure out the problem. That being said...Im pretty sure they can figure out what it is. They have been around for awhile.

OneLong8

I had the exact same problem. The dealer did an alignment, etc. but I took off the wheels and found one rim bent. This was visible on the inside of the wheel, not visible from looking at the outside rim.

Tom

KYNZ

take it to a place that does ROAD FORCE Balancing...try that.

skiracer1313

exactly what it feels like. It's probably a front wheel- remove and visually inspect - I could easily see the flat spot- and replace w/ the full size spare to see if it goes away.

I'll be doing some wheel repair in the very near future- good luck!!