I need help diagnosing a new noise. It sounds a lot like the sound you make when you blow across an empty beer bottle… a low whhuuuu… with a slight vibrating feel to it.

This came up on my way down to the Northeast Gathering. I thought at first it was the front wheel bearings. Checked them and tightened them a tiny bit, but they weren’t loose at all. The sound came back after a few hours, mostly in the twisties on the final leg to the Poconos.

The sound usually happens only after a fairly long time driving. Once it starts it happens more and more frequently… Mostly only when turning- in either direction. And completely stops when I touch the brakes. When it’s happening a fell a very slight vibration though my feet.

Any ideas what it might be? Brake pads? Rear wheel bearings?

Thanks!
Tom

Is the beer bottle empty or full?

Did you inspect the front wheel bearings for galling or other damage?

Does it sound like the humm is coming from the front?

If it were my car I’d inspect the rear brakes. Particularly the ebrake adjustment gap. If it is swelling and binding a vibration and even sound could be happening. At least a place to look, like you had nothing better to do. @theer

all 4 wheel bearings are 50 years old.
CV joints also hum as early warning signal.

rich

Adjust rear brakes.
Check play in rear wheel bearings.
I'd lightly apply parking brake to see it that removed noise like hitting the brake pedal does. This will isolate it to the rear if it works.

I will "snake" car down a deserted road fairly violently. I'm trying to completely unload one side then the other. This will isolate to one side.

I'd do this under mild acceleration, mild deceleration, and with drivetrain turned off.

See if any of that makes a difference.

I'd check trans fluid level. spider gears in diff can make weird noises.

All the running gear is 50 years old.

In human equivalent it's a 170-year-old person...

dragging front calipers...push pistons back and forth a few times.. push pistons in step on pedal to extract push em back a few times,, uuse something thinner than pad when extracting..to stop piston travel.. worked for me 40 yrs ago..

Empty or almost empty, so pretty low frequency hum

I did not take the rotor off yet, but that’s next.

Sound & vibration does feel as if it’s coming from the front… also the fact that the noise comes and goes by turning the steering wheel makes me think it’s a front wheel issue.

Front wheel bearings are not that old- less than 10 years and not a lot of miles. Rears are probably original, though.

Thanks for all the suggestions. I’ll check it out and report back what find out.

Check the runout on your rotors.

Had a noise on turns similar to what you describe. and a slight pulsing when stopping, but only at the very end

Checked the runout and it was .015 on one front, .004 on all others

Thought a rotor was warped, so replaced the rotor. That wasn't it

Trued the hub in a lathe to check bearing races.

found the outer race was not seated correctly and caused the excessive runout.

Replaced the bearings and races in that hub making sure they were true, and the problem is solved.

Might not be your problem, but something else you can check.

These were 911 separate hub/rotor set up right?

Thanks for sharing.

I've never seen this, it's way weird, but having the knowledge that you've just provided is beneficial to me.

The mental toolbox is equally important as the physical toolbox...