Driving noise from Audi A6 2000 2.5 TDi Quattro

[veghard]

Hello

My car has started making an annoying vibration sound from the front. It has gradually become worse with time and it gets worse with velocity or when turning. I have just replaced both frontal CV joints without any sound improvement (they had begun clicking though).

In addition, I have replaced both break discs and pads on both sides without any luck. At this stage I suspect caliper slider rubbers, wheel bearings and wheel hubs, but I don't feel like ordering anything new until I'm a little more certain of the issue.

Do you guys have any idea of what might causing this or what my next steps should be?

Please check this video I just recorded: https://dl.dropboxusercontent.com/u/995985/a6_noise.mp4
0:25 in to the video I increase speed to get more sound and a slow down at end.

 

[Tyler29]

What a6 is it?

 

[veghard]

Audi A6 year 2000 2.5 TDi AKE quattro wagon. 4B,C5.

 

[veghard]

Today I tilted the car to debug a little more. In the following video the noise is noticeable till 0:11 when I leave the car.

I also tried the 12-6 and 9-3 o'clock twitching to test the wheel bearing, but it seems to be alright. At this stage I suspect some sort of bearing for the frontal drive train or the differential. Hence, its worse than I thought

Any suggestions regarding this issue?

 

[Tyler29]

What's the sound like under braking does it get worse better? If you coast the car in neutral what happens then?

 

[two left feet]

Tyre balancing may be out.
My last set of new tyres did this about a month after new. The noise got worse soon aftere fitting.
After re-balance and i was good to go.
Otherwise wheel bearings may be on the way out.
If the vibration is in the seat, then the Prop shaft may be the source. I am currently chasing this Gremlin too, i bought a new support bearing, just waiting for the time to install)
good luck

 

[veghard]

What's the sound like under braking does it get worse better? If you coast the car in neutral what happens then?

Sound is same during brake except that braking reduces speed thus sound. If i drive with the sound present and put the car in neutral the car makes the same noise.

Tyre balancing may be out.
My last set of new tyres did this about a month after new. The noise got worse soon aftere fitting.
After re-balance and i was good to go.
Otherwise wheel bearings may be on the way out.
If the vibration is in the seat, then the Prop shaft may be the source. I am currently chasing this Gremlin too, i bought a new support bearing, just waiting for the time to install)
good luck

Not sure if its in the seat as the seats are quite good. I feel it in the wheel and pedals. Will feel closer though.

Also, I will try to lift the car again and remove the tires to rule out tire balance. Next natural step after that is to unmount drive shaft and to determine if its wheel bearings or not.

Thanks for your suggestions guys. I appreciate it.

 

[Tyler29]

Just a thought but have you inspected the mud/dust guards for the break calipers? They often rust and loosen enough to rub on the break disk worth a check, if the sound is present whilst in neutral it's unlikely a gearbox issue, as its isolated to the front driver side have hou had the wheel checked for buckles? start with the cheap easy fixes and work up,

 

[veghard]

So I lifted the car up again:

1. Removed the wheel - same sound.
2. Removed caliper and break disc - same sound.
3. Unmounted axle from gearbox - silence.

Conclusion: wheel bearings.

I have ordered new bearings (both sides) and assume it will fix the issue. I will change topic to solved once verified.

Thanks for all the help though.

 

[two left feet]

Veghard, what happened next ?

 

[veghard]

I have just replaced both bearings and the car is now back in shape.

 

[two left feet]

Congrats!