I've searched and some threads say the bearings only can be replaced by buying a new hub assembly. Other say you need special tools to get the races out of the hub. Others say you don't need any special tools and they are easily replacable. What's the deal?

I have some play and "clunk" in my front wheels when I rock them. I also hear a low pitched drone while driving.. I think they need to be replaced ASAP.

I've never done front wheel bearings before.. the procedure I am worried about is setting the bearing preload. I've read that you torque the nut down until you can't freely turn the rotor, then back it off 130 degrees and you should be set. Any help is greatly appreciated!

From what you describe, it sounds like you do have a bad wheel bearing. I'm not intimately familiar with the bearing setup on your W210, but I assume a lot is the same as the W124. Assuming that you properly replaced the bearings, preload is set by first tightening the hub nut until it's hard to turn the rotor. This seats the races firmly inside the hub and squeezes excess grease from the race surfaces. Then back off the hub nut only until slack.

If using a dial gauge, tighten the hub nut until axial play is within specification. Double-check the play after tightening the hub nut clamp.

If you're setting the play without a dial gauge, tighten the hub nut finger tight, then tighten the hub nut clamp.

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95 E320 Cabriolet, 159K

These are sold as a wheel bearing kit with seals. about 35$ to replace each if you do it yourself. I looked on a website for the price.
Steve

Here is a photo..



Pardon my ignorance, I assume once I get in there, these will be pressed in the hub.. how do I get them out? Do I seat them back in by tapping? What's the proper procedure for packing the bearings with grease? Thanks!

The races are seated by a press fit. Tap them out with a long straight punch and 2lb hammer fro the other side. I use a aluminum bearing race driver set to reinstall them. These are available from snap on or Mac tools or others. To pack the new bearings, I like the plastic cone packer sold at auto parts stores that hooks to your grease gun. Pack until grease spews out of the bearing. NLGI 2 wheel bearing grease is used. The seal is pried out with a prybar and reinstalled with the race driver.

I bought two front bearing kits today, but before I went to install them, I thought I should try to tighten the outer bearing first.

I loosened the clamp, pulled out the outer bearing, cleaned it, repacked it, reinstalled. Bearing and race looked fine. I finger tightened the clamp then tightened it to about 100 degrees. With the rim on, it will do two-three complete rotations. Lateral play is gone now, but I am still getting an intermittant low drone "humm".

Whats your thoughts?

Chances are if the outer bearing was loose it may have uneven wear. If you are sure that the noise is coming from the bearings and not from the tires or road then replacing the bearings and races might be the fix.

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Ray
1998 Mercedes E320, 200K Miles
2001 Acura 3.2TL, 178K Miles
1992 Chevy Astro, 205K Miles

Proceed with replacement of the bearings. You can't see wear on these.
Steve

How were you able to inspect the inner rings? The unremovable rollers preclude a good inspection. I've seen spalls as small as 2mm cause a good hum. This plus the fact that this bearing is an outer rotating design puts a lot of stress on the loaded side of the inner ring when compared with the outer ring. Did you see any soft dents on any of the races?

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95 E320 Cabriolet, 159K

To aid in the installation, put the bearing races in the freezer for several hours before installing.

Haasman

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'03 E320 Wagon-Sold
'95 E320 Wagon-Went to Ex
'93 190E 2.6-Wrecked
'91 300E-Went to Ex
'65 911 Coupe (#302580)