mike4211
24-11-2011, 09:28 PM
In case it's helpful, here's my experience of what front n/s wheel bearing failure sounds like on a 56 plate A4 S-line Avant 170 bhp @ 100,500 miles.
The only symptom was a resonant droning sound, like a distant propeller, which came on quickly within ~50 miles of motorway driving. It was hard to work out where the noise was coming from- the sound started above 30 mph and increased with speed, and did not vary with engine revs or clutch position. At 70 mph + the noise was loud enough to be heard above the radio. Braking, cornering, swerving or acceleration did not cause any variation in the sound, only road speed.
I checked for movement in the wheel bearings by jacking the car up and rocking each wheel in turn, but there was not even a hint of play in any wheel.
Lots of threads mention that saw- tooth wear on the rear tyres of estate cars can cause wheel bearing-like noise. I checked this out and although there was some, it didn't seem enough to be the cause of the noise (maybe 1-2mm max difference tip to trough).
I then changed both front tyres as they were down to the wear indicators anyway, but this made no difference either.
So I asked the local garage to take a look at it and they took it for a test drive with the two of them in it so they could try to pin down the noise. Their best guess was that it was the n/s front wheel bearing, although they couldn't be sure. Anyway, it turned out this was the problem- they said the bearing was rusty inside :confused: (and also very difficult to withdraw from the hub carrier). Bearing was replaced (£150 inc. parts) and the noise is thankfully no more :D
The only symptom was a resonant droning sound, like a distant propeller, which came on quickly within ~50 miles of motorway driving. It was hard to work out where the noise was coming from- the sound started above 30 mph and increased with speed, and did not vary with engine revs or clutch position. At 70 mph + the noise was loud enough to be heard above the radio. Braking, cornering, swerving or acceleration did not cause any variation in the sound, only road speed.
I checked for movement in the wheel bearings by jacking the car up and rocking each wheel in turn, but there was not even a hint of play in any wheel.
Lots of threads mention that saw- tooth wear on the rear tyres of estate cars can cause wheel bearing-like noise. I checked this out and although there was some, it didn't seem enough to be the cause of the noise (maybe 1-2mm max difference tip to trough).
I then changed both front tyres as they were down to the wear indicators anyway, but this made no difference either.
So I asked the local garage to take a look at it and they took it for a test drive with the two of them in it so they could try to pin down the noise. Their best guess was that it was the n/s front wheel bearing, although they couldn't be sure. Anyway, it turned out this was the problem- they said the bearing was rusty inside :confused: (and also very difficult to withdraw from the hub carrier). Bearing was replaced (£150 inc. parts) and the noise is thankfully no more :D