Wheel bearing replacement.

[pezzy]

What will I need to replace the front left bearing on my car? I called the Mercedes dealership and they said I would need a bearing kit which would cost $89 and then another whatever labor it was to install. What is included in this bearing kit and do I need everything thats in it? Does anyone know the part number? Also I decided to replace the bearing because the front left sounds like I am driving on a monster truck tire and it doesnt sound like its good, is it ok to drive the car if the bearings is bad and whats the worse thing that could happen if the bearing just fails one day? Thanks for your help

Adam,

Are you sure the problem is a wheel bearing? These bearings are incredibly long lived. I have prepared to replace bearings before, only to find the noise coming from a tire.

Good luck,

[pezzy]

Well Im not really sure, the tires are about 2 weeks old. The noise doesnt change when I hit the brakes and the brake pad indicator light isnt on. I crawled under the car and the tire looked like it had plenty of clearance and I also checked the brake shield and it looked ok.

[Ted2222]

Pezzy,
Suggest you jack up the wheel in question. Once the tire is free of the ground, spin the wheel and listen closely for any grinding sound. You can also grasp the top and bottom of the tire and test for play in the wheel. There should be no play. If there is, then you will have to determine if it is in the suspension or the wheel hub. If in the wheel hub, you have a bearing problem.

If there is a bearing problem, do not delay getting it attended to. It could lead to some serious consequences.

Hope this helps. Good luck with it.

I would also listen for audible changes as you do turns to the left and right and load unload the wheel. The outside wheel in the turn is the more heavily loaded.

Concerning the bearing replacement, I have done plenty on other cars, but not the MB models yet, but should be virtually identical. Please use caution to prevent crushing your skull! Use wheel chocks, parking brake, good quality jack & jack stands. Do not put valuable body parts in harms way should there be mechanical failure in your jacking set up!

After the wheel is removed, remove the front caliper, remove the grease cover and undo the cotter pin and retaining nut, and outer bearing. The front disc and inner wheel bearing should come out as an assy. Remove the inner grease seal and discard, you will need a new replacement. If a bearing is truly bad, I would replace both inner and outer. The bearing races, which are driven into the disc, will need to be replaced as a set as well. Drive them out with a punch and carefully seat new ones. They will come with the new bearing. Lubricate the new bearing by putting a big spoon full of grease in your palm and knead the grease into the core of the bearing by pushing the open edge down into the grease in you palm. Smearing it around on the outside is not sufficient. Assembly with the new grease seal. While spinning the wheel, torque down the retaining nut, back off and then tighten to remove all free play in the wheel - bearing joint. Install cotter pin etc.

Good luck and be safe!

[Tobias MB]

Just confirming what Deezel says about replacing the whole bearing assembly. Do NOT just put the bearing in without its matching race because there are a number of bearing manufacturers and each have their own dimensions which do not interface with each other. 1/2 degree difference on surface contact will wipe out a new bearing rather quickly. Its like the boat trailer bearing kits you can buy at Wal-Mart etc. all made by who knows in Japan. Keep the bearing parts together. Good luck...

Tobias MB
4 MBs

[pezzy]

I have no knowledge of replacing bearings so I would probably have the Mercedes dealer do it. Also, I just found out the noise completely goes away when I go around a curve turning left, but if I turn right it stays the same as if I am going straight ahead. Is replacing a front bearing an easy task? If it is I might just go ahead and buy the cd from here and do it myself.

[P.E.Haiges]

Replacing the front wheel bearings is a simple job and if you get the bearings, cones and seal at a Kaman Bearing type store, it shouldn't cost more than $25 instead of $200 at the dealer. There should be one (bearing store) in your area, see yellow pages.

There probably isn't a cotter pin in a locknut. MB uses a contracting locknut that is tightened on the threads by an Allen head screw, 8mm I think.

If you keep driving, the bearing could seize on the spindle and you will need a torch to get it off (happened to me).

P E H

Pezzy, It really isn't hard. I would suggest that you invite a friend over that has some basic knowledge of cars and do it! The friend can help you interpret the uncertainties, such as am I packing the wheel bearings correctly, damaging the races during installation, etc. It will do you wonders for your mechanical confidence. If you really screw it up, there will be plenty of warnings before you crash and die, and the financial penalties for screw ups are really minimal, all things considered. Becareful witht he vehicle while it is on jacks!

Go ahead ands live on the edge. Do it and let us know how it works!

I would definitely suggest doing it yourself. I always replace both sides at the same time. The previous owner of my car had the bearings repacked at the place they bought the tires. I drove the car for a long time before I had a passenger tell me that the floor was vibrating at certain times. I had started to notice a strange noise and vibration. When I took a look at the wheel bearings, to my horror the retaining nut that holds the wheel on the car, was on backwards with the obvious rough(and it is rough) side towards the washer. The nut had completely unscrewed and was being held on by the grace of the grease cover. I could have had a major accident. I would never trust a shop unless it was familiar with German cars with my wheel bearings. It is worth doing yourself. Get some disposable rubber gloves from Walgreen's.

Our Safety Officer is back. I guess the pristine 450 has made it from Cal. to Ga. so he has time to start offering his great safety lectures again.

Welcome back and thanks for keeping everyone safe,

Aye aye, captain, I'm back. Work is caught up, kid's soccer is done and I have a new ride in the stable to reinvogorate me. I have some posts in the Vintage section describing the drive.

Concerning the ribber gloves......I do not agree, you loose sensitivity and it is not as good for the mechanic or the car! Wear your dirty finger mnails as a badge of honor! And there is no safety issues as long as you don't chew you nails!