Recently my 1999 A4 Avant sat undriven for a few days, and when I next drove it I was greeted with a noise/vibration combination coming from the front driver's side wheel well. The sound is a sort of dull 'thud', that occurs rythmically according to the speed of the car. Below about 20mph there is no noise, but above that speed the noise is present, with the intervals between 'thuds' decreasing as speed increases. The noise is easily audible, and each 'thud' is accompanied by a more subtle vibration in the drivers side floor pan. The noise immediately disappears upon application of brakes at any speed.

I recently (about 100 miles ago) had the rear brakes worked on, and was told that the front had only about 10% left until it would need new pads & rotors. When this noise appeared I replaced the front drivers side pads & rotor, but the problem remains. Have others experienced this, or have any ideas regarding a solution? Thank you!

 

check your tires for a bubble along the walls. same thing happened to me and i had to get new tires.

 

could be an un-balanced wheel.

 

i had something like what you are describing, but it was coming from the rear passenger side. i was getting vibrations that would increase in freq. as i sped up... turned out to be a bad bearing

 

I experience a low vibration noise when I (even slightly) press the accelerator. It seems to be easier to produce when I'm in 3rd gear or higher (~35mph or greater). You can also feel it a bit in the pedals and dead pedal. Also if the cars suspension is floating it goes in and out.

From a quick drive, my mechanic wasn't sure what the problem was, but guessed it might be a differential problem and suggested I get my tires replaced. I had a slow flat tire for a while and the noise was more pronouced when the tire was low. I think uneven tire pressure has caused this problem for me. I've sinced replaced the tires and the problem is less pronouced but I can still produce it. Next oil change I'll change the front differential oil.

 

dude changing the diff oil might not help but its worht a shot,,,, sounds like u got something that is hittin someplace, i suggest u try to get all 4 wheels off the ground and then run the car as driving and see if it does it then too....and in regards to u replacing only the driver side brakes..i hope u dod the pass too

 

Let me know what you find about this. I changed brakes, tires, balanced and aligned. Didnt work. Mine still doing it, but, I havent got time to bring it to the shop. The guys here told me to look at the bearings.

Let me know......

 

look at this subject:

loud noise + vibration

 

Constant velocity joints are usually reliable and largely trouble-free. The two main failures are wear and partial seizure.

Wear in the outer joint usually shows up as vibration at certain speeds, a bit like the vibration caused by an unbalanced wheel. To determine if the joint is worn, find a big empty car park and drive the car slowly in tight circles, left and right. Worn joints will make a rhythmic clicking or cracking noise. Wear in the inner joints shows up as a "clunk" when applying power, or if severe, when lifting off the throttle.

Partial seizure causes a strange "pattering" sensation through the suspension. It is caused by the joint overheating, which in turn is usually caused by the outer joint gaiter having split, allowing the joint to throw out its grease. If caught in time, you can clean the joint carefully, repack with grease and replace the gaiter. Kits which include the grease, gaiter and retaining clips are available from most motor factors. Some universal gaiters are split lengthwise enabling them to be fitted without having to disassemble the wheel hub and CV joint

http://en.wikipedia.org/wiki/Constant-velocity_joint

 

This sounds more like tread separation on the tire, or possibly, that you have thrown a wheel weight and your tire is no longer balanced. The other problem could of course be a loose wheel or remotely a failing wheel bearing.

Move the tire to the rear of the car. If the noise goes to the rear, then you have isolated the problem to the tire. If it remains in the front, have it checked out.