Mercedes: E430 vibration & mysterious steering wheel alignment behavior, steering wheel alignment, bad wheel bearing

Question
QUESTION: Hello Robert, I pray that you can help…

I have a 2000 Mercedes E430 (130k miles) with a couple strange behaviors, maybe related.

1.  Fairly high frequency vibration coming through the steering wheel and the car in general from 45 – 55 mph.  Vibration diminishes very significantly above 55 and more as speed increases. Doesn’t matter if I’m accelerating or coasting.  Problem has persisted through new tires (different brand), wheel balancing and alignment.  Seems to be the worst at the beginning of a trip and varies with different types of pavement…..strange.

2.  After a suspension alignment the steering wheel will be straight as the car tracks straight...everything fine....until I rotate the tires. The car will still track straight but the steering wheel is no longer perfectly level...currently slanted slightly to the right. The problem occurs whether I swap the tires front to back & right to left or simply front to back. What could be happening?????

Thanks, Matt


ANSWER: Matt,
You may have a bad wheel bearing or loose wheel bearing race. As you accelerate you pass through a harmonic vibration based on a slight imbalance along the center-line of the wheel. The faster the wheel rotates the more gyroscopic effect you have on the center line of the wheel, and smoothing out of the vibration. Bad rotors can also sometime cause vibration if they are out of round or warped.

This same wheel bearing may be causing the steering wheel tilt as well.
When new tires are placed on the vehicle they learn to be comfortable to the slight differences in wheel geometry. Usually by wearing in.
I was once told by a wheel expert that tires should be rebalanced after 1500 miles because during installation, each tire is new to the rim. Within that first 1500 miles the tire are seated in their rims and the side walls are set in.
My 420 has always had a tilt, I too had it four wheel aligned, because it wanted to drift left. It is a pain to always apply slight pressure to keep it center in the lane. Because of road crown, the car is quite sensitive to running out of the lane. Toward the left in the fast lane, and toward the shoulder in the slow lane.
If you have ball joint ware, it to will cause odd behavior with the steering.
Good Luck
Let me know if this helps.
Rob

---------- FOLLOW-UP ----------

QUESTION: Rob,

Good insight, got me thinking.  A while back I replaced the original rotors with aftermarket rotors because of a low speed sound/friction coming through the front end (accelerating or decelerating), turned out to be tires.  Tires were also cupping which I attributed to a broken suspension spring which was replaced. Also replace shocks.  Anyway, I wonder if these aftermarket rotors are the problem. Could I test by swapping rotors front to rear? Rear rotors are still original.

Also, what is the procedure for checking wheel bearing and bearing race wear? Something I can do at home or must it be a shop. FYI, I'm a mechanical engineer and motorcycle roadracer so I'm fairly mechanically inclined but have limited tools.

Thanks again, Matt

Answer
Matt,
I suspect that the rear rotors are different from the front. To check the wheel bearings,  you need to jack the vehicle so suspension is off the floor. Use Jack Stands for safety.
Either all four at once or front then rear.
with the wheels free, you can check the various joints. By gripping the front and rear of the tire as you face it try to rock the tire. Then try the top and bottom. There should be very little play.
Spin the tire and listen for unusual noise or or rattle. If the wheel shakes or rattles during the spin then the wheel bearing may need tightening.
To tighten the wheel nut is not too complicated. You need to remove the wheel spindle nut cap. It will be pretty greasy. If the bearing shows leakage on the back of the spindle hub, that is an indication that the seal is gone and should be replaced. This keep water from penetrating the bearing as well as keeping the grease in place. The should be either a cotter pin, or a flap washer to keep the wheel nut from rotating.
Straighten and remove the pin and the nut keeper if there is one. Take a large wrench and tighten the. You will need to research or phone a Mercedes mechanic, dealer or front end shop to find out the correct torque. You can type Mercedes Forums in to Google, and it will bring up a Mercedes Club site. There is a wealthy of information on just about any of the Mercedes vehicles.
There will probable be a torque too setting then a back off certain degree to properly adjust the run in on the bearing. Be sure and rotate the wheel while pulling the torque so as to allow the race to seat properly. Install the flap washer and cotter pin if the washer or pin will not line up, move the nut toward counter clock wise just enough to allow you to insert the pin.

If you are sure that the bearing are OK now shake the wheel as before but with enough effort to effect the steering joints.
You may see something worn that may be the problem. Do the process on each wheel.



It is a rear wheel drive vehicle right?


If the rear has independent suspension with U joints in the axle, then there is also a possibility of a dry U joint bearing that is if it has bearings and not the synthetic rubber disk, could cause the vibration.
With the vehicle in park or first if it is a stick. take the wheel and rock it against the pinion gear. have someone hold the other wheel during these operations. Look and feel for play in a U joint.
If the axles check OK the also try the same with the drive shaft.
Good Luck
Rob