Intermittent noise from front end while driving
 

Hi All,

During the last year, I've been hearing an intermittent noise from the front of my 1987 Carrera while driving. It usually happens after about 30-50 minutes of highway driving.

Today, it happened while driving to the last Cars and Coffee event at EASY in Emeryville, CA within 45 minutes of driving on the highway. On the way home, it happened within 15-20 minutes of driving on the highway.

The noise is sort of a low howl. When I tap the brakes or steer quickly from side to side the noise stops and then often returns intermittently.

Originally, I thought it might be something related to the front brakes, which work fine. Now, I am thinking it might be a wheel bearing.

Any thoughts on what would cause this? THANKS!

Repack your front wheel bearings...

Wheel bearings. My ‘87 did the same thing, and I could make the sound disappear when when I turned the wheel back and forth while driving.

Thanks for the feedback about the front bearings. I've never repacked or replaced front bearings a 911. Does this require any special tools? Is it a complicated procedure? Thanks.

Hi maclaren65, I agree with the folks above, that sounds like wheel bearings.

Here's a part of my full suspension rebuild where I show how to re-grease your bearings. It's a pretty straight forward job. Here's the thread:

http://forums.pelicanparts.com/porsche-911-technical-forum/726309-78-sc-elephant-racing-suspension-rebuild-14.html#post7270758

Here's another part of the building showing more details on greasing the front wheel bearings. I used the wrong grease, but you can see the procedure, and my previous post shows the proper grease:

http://forums.pelicanparts.com/porsche-911-technical-forum/726309-78-sc-elephant-racing-suspension-rebuild-12.html#post7252730

Craig, Thank you! I'll check out your post. -- Richard

check the adjustment if you don't want to get into the rebuild right away, you might even grease the outer bearing

If you want a real quick check, grab the front wheel and shake it cross car. If you have a bearing that's loosening up, you should feel a slight tap-tap of the play in it.

An autocross tech inspection pointed slight play out in my car at one of the first events I took it to. I reset the nut torque and it hasn't come back since.

Thanks! I'll check to see if there is any play in the wheel and bearing.

What's the torque spec for the lug nuts? I am using steel lug nuts installed a few years ago when I did some track days.

- Richard

Bet you have some. Turning the wheel and the noise stops is the classic identifier.

If you have cupped or scalloped tires the noise can be about the same but will not change much when you induce a side load.

I remember 92 foot pounds but I will search and confirm.

Edit: Just a wee bit off. 96.

http://forums.pelicanparts.com/porsche-911-technical-forum/599354-lug-nut-torque.html

not sure if I was clear, I meant the nut torque for the wheel bearing.

https://www.pelicanparts.com/techarticles/Porsche_911/SUSPEN-Front_Wheel_Bearing_Replacement/SUSPEN-Front_Wheel_Bearing_Replacement.htm

On my car the races still looked great and the grease looked brand new - like it had been recently serviced. I only tightened the axle nut per the second to last step in this link.

Nick's instructions from the PP how-to article:
Followup from the Pelican Staff: When adjusting. I have always loosened the clamping screw, then loosened the bearing nut by 1/4 turn. Next, rotate the brake rotor while tightening the bearing nut in small increments. Keep doing this until washer can barely be moved back and forth using a small flathead screwdriver. - Nick at Pelican Parts