radaddict

Here's an interesting issue. I've had this 2002 CLK430 for a couple of months and have been battling front end vibration at highway speeds. I replaced worn components and tires, had the front end aligned and wheels balanced. While there was improvement, there is still vibration.

Some time ago I had read on a forum (may have been this one, but I don't recall) someone having similar issues and they wrapped a piece of tape around the hub to see it that would better center the wheel. I decided to try this. Low and behold, vibration is much reduced (not totally gone, but the tires could have some minor cupping at this point due to continued driving with vibration).

So then, what's the root cause of the front wheels not centering properly; worn hubs, worn wheels, worn rotors, worn lugs or even all of the above?

I'll likely start by replacing the rotors since there is a bit of front end shake when braking at highway speeds. I'll probably replace the lugs as well.

If that doesn't fix it, then I'll move on to the hubs leaving the replacement of the wheels for last.

Anyone else run into this issue or anyone have any thoughts or suggestions?

Thanks in advance.

radaddict

The more I think about this, the more I'm thinking the fundamental problem is the interface between the wheel center hole and the hub. It needs to be a tight, perfect fit. If it's not, the wheel won't center properly when the lugs are torqued, or it won't stay centered driving down the road.

So, that being the case, is the wear that's causing the wheel/hub interface to be out of spec on the wheel, or the hub (or both)? Since aluminum is softer than steel, the wheel is probably the culprit. However, I'm afraid the only way to fully address the problem is to replace the hubs and wheels. Bugger.

Gundo

Try some of these out

http://www.ebay.com/itm/HUB-CENTERING-RINGS-73-1-73mm-TO-66-56-66-56mm-HIGH-QUALITY-POLY-CARBONATE-/200968452892?pt=Motors_Car_Truck_Parts_Accessories&hash=item2ecaa73b1c&vxp=mtr

radaddict

Thanks, but those are for adapting aftermarket wheels. I've got factory AMG wheels. I would need a hub centering ring that would go from about 66.58 MM to 66.56. ;-)

My research continues and I'm not yet certain the problem is with the wheel/hub interface. It could just be corrosion on the face of the rotor where the wheel bolts.

From what I've found, wheels that are hub-centric are centered on the hub by the center wheel hole fitting snuggly to the hub. However, there are friction forces in play that hold the wheel tight to the face of the rotor by the clamping force of the lugs. So, that interface needs to be clean. Corrosion can act almost like a lubricant allowing the wheel to move by tiny amounts, causing vibration.

So, as a first step, I've cleaned the corrosion. I've not yet taken it for a test run. I'll report back what I find.

radaddict

Well, I'm happy to say that removing the corrosion from the face of the rotor where it interfaces with the wheel seems to have done the trick. Of course the corrosion will return, but at least now I'm certain the problem can be more permanently fixed by replacing just the rotors.

MarcusF

Two words: bearing grease.

A dab around the lip.

How often do you change rotors? On my car, the rotors are replaced every other brake job. They're typically out of spec and in the trash.

Then again, I'm in So Cal where the average annual rainfall is 14 inches (most of which occurs when I'm not in a car) so what do I know about corrosion? Did I mention the drought? Yeah, we're under 4 inches of rain for the past 12 months.

radaddict

A little dab 'l do ya, huh? ;-)

I typically replace rotors when needed and usually due to wear, not corrosion . I've had this car for only about a month and I wanted to diagnose and fully understand the problem before replacing parts. The car only has 66K miles on it and it's entirely possible the rotors are the original rotors.

Although cleaning the corrosion seems bloody obvious, the physics behind the corrosion causing vibration is not intuitive (to me at least), but it is interesting.