Front end rotational noise

[swiftrx8]

A 99 C4

It's tough to explain it's a rotational noise that almost sounds like either a tire rubbing slightly or a bad bearing? I don't know it doesn't get louder or change pitch at different speeds or throttle. I couldn't find a reason for it the tire to be rubbing.

Any thoughts?

[Loren]

Check to make sure you don't have a pebble ot two caught between the brake disc and the splash shield.

[swiftrx8]

Well the dust shield I had to trim off a little it was rubbing the brake rotor. I also found some sort of electronic condenser or something that melted through the plastic in the wheel well. It appeared that the tire had been rubbing on that. I relocated it up a little so it wouldn't be near the tire but still safe from the elements. However when I took it for a spin the noise was still there.

[GranburyChuck]

I had a slight grinding/rubbing sound on the front end of my car. Could really only hear it when doing 35 mph because road noise became more prominent at speeds higher than that. Turned out to be the wheel bearing. My car had 80k miles on it at that time. Never noticed the sound really change much when I would weave while driving at 35 mph. I only found this out because I was changing the front suspension and was pulling\pushing on the front\back of the brake rotor. Took it to the dealer to get fixed. Initially, he said it wasn't the problem because he grabbed it by the tire and didn't notice the play. Took the wheel off and was much more prominent. Anyway ~$400 later and no more sound.

[Geldgrube]

I had a similar noise on my 2003 C4S and it turned out to be the right carrier bearing on the front differential. The way I isolated it was to put the car on lift, start it up and put it in gear. I then held the right front wheel to stop it from turning; this eliminated the wheel bearing, brakes and CV-joint. I did the same for the left wheel to eliminate that side. The only thing left was the differential and when I tore it apart, sure enough, the carrier bearing was bad on the right side. I replaced the one on the left side as well. Total cost for parts was $98 including seals.

Good luck,

Ron

P.S. Out of interest, I called my local Porsche dealer to cost out the parts but they don't sell the bearings separately.....but they will sell you a new differential for $3,100!

[joyride5]

I had a similar noise on my 2003 C4S and it turned out to be the right carrier bearing on the front differential. The way I isolated it was to put the car on lift, start it up and put it in gear. I then held the right front wheel to stop it from turning; this eliminated the wheel bearing, brakes and CV-joint. I did the same for the left wheel to eliminate that side. The only thing left was the differential and when I tore it apart, sure enough, the carrier bearing was bad on the right side. I replaced the one on the left side as well. Total cost for parts was $98 including seals.

Good luck,

Ron

P.S. Out of interest, I called my local Porsche dealer to cost out the parts but they don't sell the bearings separately.....but they will sell you a new differential for $3,100!

Ron, thanks for this post!

Do you have the part numbers for the carrier bearing? Was it difficult?

Please let me know and thanks in advance!

[Geldgrube]

I had a similar noise on my 2003 C4S and it turned out to be the right carrier bearing on the front differential. The way I isolated it was to put the car on lift, start it up and put it in gear. I then held the right front wheel to stop it from turning; this eliminated the wheel bearing, brakes and CV-joint. I did the same for the left wheel to eliminate that side. The only thing left was the differential and when I tore it apart, sure enough, the carrier bearing was bad on the right side. I replaced the one on the left side as well. Total cost for parts was $98 including seals.

Good luck,

Ron

P.S. Out of interest, I called my local Porsche dealer to cost out the parts but they don't sell the bearings separately.....but they will sell you a new differential for $3,100!

Ron, thanks for this post!

Do you have the part numbers for the carrier bearing? Was it difficult?

Please let me know and thanks in advance!

I didn't take down the part numbers (there are two different bearings) but the numbers are stamped on the bearings and they are very common that are available through any parts supplier. The job itself wasn't difficult, it just takes some time to get the front diff off the car. Once it's off, it's dead easy to get to the bearings. Good luck!