Sways and vibrations have two different causes with different things to check. Weak front springs will let the car sway more when cornering at higher speeds. You'll also find that the ride height is low. There are published specs. That list the places to measure for each car model. Worn or broken anti-sway bar links and bushings will allow the body to lean more than normal during high-speed turns. You won't notice a problem in city driving. Broken links usually make a clanking noise too, especially over bumps.
Wheel bearings rarely cause a vibration. Most commonly they make a buzzing noise like an airplane engine that increases in pitch with increases in road speed.
If you can get a feel for how fast the vibration is occurring, it might help to figure out the cause. If it occurs once per tire revolution, it's almost always tire, wheel, or brake-related. If it feels like it might be three times faster than tire rotation, suspect an inner cv joint housing. A weak or collapsed engine mount can let one end of the drive train sag and change the angle and length of the half shaft. That puts the inner cv joint's rollers in a different area within the housing so they may be running beyond their previous wear areas. Slight imperfections worn into the rolling surfaces cause the rollers to bind, especially under the load of acceleration. When the shafts can't change length freely, they push on the spindle and steering system. That isn't typically felt at lower speeds or when cruising at a steady speed.
If your alignment mechanic isn't solving the problem, take him along on a test drive so you can point out exactly what you're experiencing. Find out what other solutions he suggests.
Monday, August 29th, 2011 AT 8:37 PM