Question about front wheel bearing adjustment on W210.
 

I was trying to get rid of a clunking noise coming from the front suspension on my 1997 E320 going over rough roads. I took off the bearing caps and was checking to see if there was any movement. When I hold the wheel at 12 and 6, there seems to be some noise emitting. I thought that I would try and tighten the wheel bearings. I loosened the allen cinch bolt and turned the nut finger tight. I then tightened the cinch bolt. Did I over tighten? I know I should have a dial indicator to check and verify this. I took it for a drive around the block and the noise is still there. I don't want to drive it anymore until I know if it is too tight.

Also, how would you test to know if the sway bar links would be making the noise?

TIA,
Steve

It's definitely not too tight and is probably too loose. The general rule of thumb, and the way most shops do it, is to tighten the nut while turning the wheel until you can't turn the wheel anymore, or nut whichever happens first. Then back up 1/3 of a turn and tighten the allen. Then, give the end of the axle a good whack with a hammer to release the bearings. When I changed my LBJ's I called all around and was given the same procedure from shops specializing in MB's as well as the MB dealership here.

Steve, did you ever find out what the problem was.. I have the same prob with mine.. I have replaces so far..:
1. Lower control arm bushing.
2. Lower ball joints.
3. Sway bar bushings.
4. Upper shock bushing..


Still same clunk. I just received my end links.. I will replace them sometime this weekend... Hope that solves it..
I am tired of replacing things..

It is definitely the end links. Very common problem. The local dealership stocks multiple sets. I replaced mine and all is quiet now.

Steve

I am going to replace them this weekend. I hope that is what the problem is. when I first noticed the problem the car was in for inspection and the tech said "Oh you need lower control arm bushing" I took them for there word, but I said I will do it myself. That cost me some extra money. The links were only $5 apiece..

Peter

What are the end links that you describe? Do they also go by any other name?

Thanks.

I am going to do the job tomorrow, I will document and post pictures...

Peter

bjcsc, the procedure you mentioned doesn't make sense. Back off 1/3 of a turn?... this would result in way too much axial play. Yes, you tighten the nut real hard - until the wheel is hard to turn - to seat the bearing and squeeze the excess grease from the contacting elements. But then you have to adjust the preload to 0.01 to 0.02 mm axial clearance. When I did mine using a dial gauge, the clearance was imperceptible by feel.

If I was to suggest a backyard way of setting preload after tightening the nut, I would back the nut until just loose, finger tighten, then lock the nut. Bearing preload is absolutely critical to bearing life, more so than grease. You'd be amazed how little grease a bearing needs to survive.

I don't like to hear that the shops around you are using this practise. I work in the bearing industry and one of our battles is dealing with service garages who don't know how to properly service a bearing. All too often, the user comes back and blames the bearing for inferior quality. Rarely is there anything intrinsically wrong with a bearing. The main problem is people who improperly install or service them. This is one of the reasons the American automotive and truck industry is moving toward unserviceable units that are so expensive to replace.

wheel bearing adjustment
 

Kestas, Unlike american cars, the threads on the bearing shaft of the mercedes are much finer and 1/3 turn is about the same as 1/8 turn on my US cars. I have used the 1/3 turn (120 degrees) on my bearings several times in the past and find it very satisfactory. For those of us who do not have the more sophisticated adjustment tools it works fine. You have to be sure that the bearings are packed well. Also, I would clean the allen bolt threads with some solvent and apply some blue lock tite, as I have had the experience of the bolts coming loose even when snugged well. If that happens, bye bye bearings. Regards.

PS I did not mean the shaft nut, for the locktite, just the allen bolt that locks it.