: Oscillating front end hum



253ctsv
03-09-13, 06:58 PM
My car has a hum coming from the front end. It oscillates faster the faster I drive and is noticeable from about 40mph up. If I push the clutch in I can even kinda feel it in my foot. I just got new tires alignment etc and I thought it would fix it but it hasn't. Any ideas? Maybe bushings in the front end?

darkman
03-09-13, 07:13 PM
The bushings in the front react to changes in road surface such as bumps, so your symptoms do not sound like they are related to suspension bushings.

If the source is wheel related, such wheel bearings, or drivetrain related, such as clutch/transmission it will vary with road speed. The fact that you can feel it through the clutch pedals does point toward the drivetrain.

Can feel it through the brake pedal and/or steering wheel?

See: http://www.cadillacforums.com/forums/2004-2007-cadillac-cts-v-general/220606-troubleshooting-guide-vibrations.html#post3160797

253ctsv
03-09-13, 07:36 PM
Well it vibrates enough that I can hear it vibrate things in the cab so I thought maybe a worn bushing could be some metal on metal or something. I don't think it's drive train related because the vibration relates to the speed but not engine rpm. I figured anything Noticeable les schwab would have picked up on. It's not the biggest deal in the world but it annoys the crap out of me

darkman
03-09-13, 08:05 PM
If you have a vibration caused by a bent wheel or an out of balance tire it can be amplified by worn bushings, but bushings worn that badly would typically be making some noise when encountering bumps.

The drivetrain upstream of the transmission rotates based on engine speed but the components downstream rotate based on wheel speed. The clutch pedal can be senstive to either.

Most vibrations turn out to be tire or wheel related. These tires often require "force" balancing, because of the narrow sidewalls and a slightly bent wheel can be overlooked during a tire change. Finally, worn wheel bearings make a noise that I recognize, but cannot adequately describe.

Noise diagnosis over the internet is a crap shoot at best.

253ctsv
03-09-13, 08:23 PM
Lol. Thanks ill check out the links when I get home. Say it's a slightly bent rim. Can I do anything about that?

darkman
03-09-13, 08:26 PM
As far as I know the stock rims cannot be "unbent," but you can usually find one in the classifieds or on ebay.

253ctsv
03-09-13, 09:28 PM
I don't have a spare :/ guess ill start snooping around

253ctsv
03-10-13, 09:47 PM
So I snooped around google. Read about some guy with a Subaru that had a bad wheel bearing. And when he turned one way it wouldn't vibrate. So I tested it out and when I go around corners to the right the hum goes away! Sooooo. Wheel bearing right?

darkman
03-10-13, 10:03 PM
Could be. See attached.

POS VETT
03-11-13, 09:10 PM
Let me know if you want used hubs; I have a set from when I did lug conversion.

253ctsv
03-12-13, 08:00 AM
Let me know if you want used hubs; I have a set from when I did lug conversion.

How much?