Hi!

The front wheel bearing of my 85 380se makes this humming noise when I drive the car. The noise level increases with the speed.

I am thinking about repacking the grease inside the wheel cap. Will this fix the problem or I need to replace the bearing itself?

It seems to me that repacking the grease shouldn't be too hard. The manual says that I need to have a special tool to pull off the wheel cap, refill the grease and put the cap back.
Is the tool expensive? Can I get this tool from any auto part store or I need to get it from the Mercedes dealer?

If repacking the grease won't work and I need to replace the bearing, then how difficult this task will be? Is this task a do it yourself job? What steps I should pay attention to?

I appreciate your help.


Lin
85 380SE
Austin, TX

My first thought is that you need to purchase a good manual if you are going to attempt repairs. I think even a Haynes manual covers this with some pretty good pics.

Front wheel bearings are normally a good diyer job but understand that the way you tighten MB wheel brgs is a little different. If you pull the cover off of the hub (the special tool is a screwdriver and a rubber headed hammer) you should go ahead and do the brgs. The difference in the MB wheel brgs is that you have to make sure you put the proper amount of grease in there and you have to make sure you tighten the nut to the proper tightness prior to fastening it down. Even if you go with new wheel brgs the relatively inexpensive.

__________________
Jim

If you can hear it then it is too late for grease.

I have always suspected that the reason there is no service interval for greasing front wheel bearings is that the cost of such service would dwarf the cost of the bearings.

If you were to get a manual you might be scared off by all the special tools indicated. Actually the job can be done with simple tools. Its as straight forward as a Chevrolet and may even use the same bearings. The bearings can be bought from any parts store under the number "Set 3" and "Set 5". They are the same as numerous manuafcaturuers use. You will be surprised how cheap these bearings are.

The brake caliper will need to be removed, leave it connected (so you won't have to bleed the brakes afterward). Hang it with a coat hanger (not the rubber hose). Loosen the allen screw that locks the pinch nut holding the outer bearing (under the grease cap). Unscrew the pinch nut. Pull the assembly from the spindle, wasn't that easy! It will be in 75% of the instances. If you do both sides there is great likelyhood that one of the four bearings will stick to the spindle - not so easy).

After the outer bearing is removed I usually reinstall the pinch nut and then use it as a tool to pull the inner bearing and seal from the disc/flange combination. To do this you grab the disc on both sides and give a sudden pull. If the rear bearing isn't stuck the whole assy will come out about four inches and hit the pinch nut. The impact will drive the rear seal from the flange and leave the inner bearing and seal hanging from the spindle, discard both.

Unless a bearing sticks the hardest part of the job will be to remove the pressed in race of the bearings from the hub. You CAN"T just replace the rollers. The whole bearing (two pieces) must be replaced. There are special tools to do this but a long punch and hammer and tapping all around the circumference will work it out. Use the old race and a hammer to tap in the new race. DO NOT impact the face of the bearing. Be sure the race is fully seated.

Grease the bearing, NOT JUST EXTERNALLY. You must push the grease through the inners of the bearing. Without tools this requires a hand full of grease. Take the bearing in other hand and push the bearing sideways into the handfull of grease, shoving the grease sideways between the rollers until it comes out the other side.

Place the rear bearing into the hub and tap in the new seal. Install onto the spindle, wasn't that easy..... sometimes it won't go. uh-oh. Don't have much to say if it don't except to clean the spindle and try over concentrating on getting the bearing straight as you push in.

Place some grease in the middle but do not fill, MB would tell you to use xx grams of grease. Basically about half full. Install the outer bearing. Tightten the nut with a pair of pliers while turning the hub till fairly tight, somewhat more than hand tight; this is to be sure the bearing is fully seated. Back the nut off and tighten by hand. The bearing is not to be tight. It actually is supposed to be loose by about a few tenthousandths of an inch. Less than .001in. This can not be felt and even can hardly be measured with all the grease in the bearing. It is a thing of experience and feel.

One technique is to mount the tire and hit the tire with your fist as you tighten the nut. There is a rattle sound that occurs with each hit. When you reach the point of proper tention the rattle sound diappears. Unfortunately as good as this works it should be demonstrated for proper understanding. Just remember the bearing is NOT to be tight. That is the reason for the pinch nut. It can be tightened and will stay in place without physically being tight against the bearing as a bolt would be when tightened.

__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

Steve, you really should write a book of "helpful hints". I'm using too much printer ink trying to keep up with little "jewels" like this and others (not to mention my unique filing system for these tidbits).

__________________
The Golden Rule

1984 300SD (bought new, sold it in 1988, bought it back 13 yrs. later)

I suppose that I am.

I actually have kept about a hundred of my posts. I will eventually post them and many pictures I have been accumulating into some index system on my shop website: www.continentalimports.com . Currently we have three of the four professional articles I have wrote for "Import Car" magazine (a trade publication). Two of these appear here in the DIY section.

The posts that I have saved all were retrieved from mercedesshop archives as anyone else can do. I forget how at the moment; I always have to bang my way through computer procedures. One can see all the postings of any member, somehow.

I just love some of the pictures and some of the things I see. I just looked through some and thought I'd post this one for grins. This DIYer was a BMW DIYer so we can take solice. It gives new meaning to an socket extention.

I hope this comes out clear enough at this size here goes:

Attached Thumbnails

 

__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

Hi! Steve & Jim,

Thanks for the information. Your detailed information is
very helpful.
It seems to me that this front wheel bearing task is labor intensive and requires a lot of patience.
There are also rooms for mistake which will be very dangerous.
I might want to bring to the shop to have them do it.
Hope it's not too expensive.

Thanks for your help.

Lin

He used a deep socket and it's not a deep cycle battery. Isn't that his only mistake?

__________________
The Golden Rule

1984 300SD (bought new, sold it in 1988, bought it back 13 yrs. later)

I have found that a claw hammer with straight claws takes off the front hub caps ( not wheel covers) easily. ~~~~~~~~~~~PEH~~~~~~~~~

I've recently done my 85 380se's bearings. The hardest part was realizing that I needed something more solid than a screwdriver to drive out the races from the hub. Once I found my trusty socket extension, the task was pretty easy.

I removed the grease caps with a pair of channel locks. Wasn't too worried about damaging them, as new ones come in the bearing kit. Getting the new ones on was a pain until I realized that I was working against the hydraulic pressure of the grease from the cap being over filled.

Old king pins from a straight axle make a dandy punch, especially when you need something harder than brass. Have used king pins to drive out races for many years without worrying about buggering up sockets or extensions.

__________________
Mike Tangas
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72

'02 CLK320 Cabriolet - wifey's mid-life crisis

2012 VW Jetta Sportwagon TDI...at least its a diesel

Non illegitemae carborundum.

TXBILL:
I was just trying to distinguish hub caps as the part that goes on the end of the spindle and covers the axle nut and wheel bearings from wheel covers that cover the wheel and what most people incorrectly call hub caps. Dust covers, aren't they the aftermarket part that keeps brake dust off alloy wheels?
Anyway, the claw hammer might remove the wheel covers but a screw driver works better.
I can't understand why anyone say a wheel bearing job isn't a DIY. That is a job that is about as basic as it gets.
~~~~~~~~~~~~~~~~~~~~~~PEH~~~~~~~~~~~~~~~~~

Wheel bearings is a fun and easy job! You get to play with a fistful of creamy, delicious wheel bearing grease.

Far more fun than, say, having hot black diesel-soot motor oil run down your arm and pool in your armpit the very first time you change the motor oil, because you're 17 years old and don't know what you're doing (cough, that was a long time ago).

Or, say, taking a shower in warm yellow coolant because you forgot to loosen the drain plug in the block to drain out ALL the coolant at the appropriate time (cough, that wasn't really so long ago).

Yep. Changing wheel bearings isn'so bad.

- Nathan
'83 240D "Steiner"
'00 New Beetle TDI

TXBILL: I had an outer wheel bearing fail from lack of lubrication. The outer bearing spun on the spindle and welded itself to the shaft. I couldn't drive the 190D any farther so I had to get a ride home, get my acetylene torch set and some used parts from a junk car. I had to burn the bearing off the shaft and replace the bearings and the cone. I guess I fixed it OK because I never had any more trouble with that wheel bearing and the car lasted a few more years.
After that I made sure the wheel bearings had enough greaze.
~~~~~~~~~~~~~~~~~~~~PEH~~~~~~~~~~~~~~~~~~~

I need to replace front bearings on a W210 - Dealer said there is too much play in the bearings.

What is the trick in tightening these? The book mentions a gage that should be used to ensure the right amount of play.

Is there another way to accomplish this, is the gage really necessary?

apb: If there is too much play in the bearings all you do is to tighten them. You loosen the split spindle nut allen screw with an allen wrench (8mm I think) and tighten the spindle nut until there is no play in the spindle bearings. You can do this by feel: Just try shaking the wheel gently and you can feel any loosness. When all the free is play is gone you turn the spindle nut about 10 degrees more and then you retighten the split nut allen screw.

Front wheel bearings on a 2 wheel drive rear drive are not rocket science but front wheel bearings on a 4 wheel drive or front drive are more complicated. I don't believe any gage is needed for 2WD rear drive front wheel bearings. I have been doing them for 40 years and never used a gage.

If the bearings do not make any whining noise, they are OK. They rarely go bad as long as thay have enough grease. You might add some wheel bearing grease in the hub cap before you replace it which will push the grease into the wheel bearings.

P E H