I think I'm losing a wheel bearing... - PeachParts Mercedes-Benz Forum

The Warden · #1 12-14-2002, 04:28 AM

I'm hearing a growling noise that increases with vehicle speed and is independant of engine speed, although it quiets down a bit when I apply the brakes. I'm guessing this is a wheel bearing...any idea how to narrow it down to a specific wheel? Also, how difficult is it to replace the bearings? This is somewhat a "field repair" as I'm not home right now.

Thanks in advance!

#2 12-14-2002, 08:42 AM

Front wheel bearings are minor work.. However rear wheel bearings are major work.. You need some special tools.. You can make them or buy them.. I do my own rear bearings on my 123's but I also tell most people to take them to Mercedes or some one that workes on Mercedes all the time and has the tools.. Getting a bad job on the rear bearings will cost far more than paying some one to do it right the first time.. As far as the front.. They are straight forward and can be done by you if you carry enough tools or most any shop.. The bearings on the 123 are standard sizes and most parts stores have them.. However one never knows until you get there...

If you have come north from you place remember that up here in Northern Calif and Oregon we run studded tires and chains all winter and eat the roads down ..They are no longer smooth .. If you drive on our roads up here your car will sound like the bearings are out.. I am always amazed when I get down south and the tires are quite but then I start hearing all those sounds that I never hear..

Ken

The Warden · #3 12-14-2002, 04:35 PM

I went south, not north. I'm currently in Bakersfield, and will be driving to Lancaster later today. I think I have enough life on the wheel bearing to make it.

Again, any idea on how to narrow it down to a specific wheel? I don't want to imagine how much someone would charge to do it, but I guess if it's a rear, I won't have much of a choice...

Thanks!

Wasuchi · #4 12-14-2002, 05:16 PM

Might try giving the old feel or touch test when you're done driving it, to see if there is more heat in one of the wheels than the others.

Ridge · #5 12-14-2002, 06:03 PM

warden,

Why don't you just jack up each front wheel, one at a time, put one hand on the top of the wheel and the other on the bottom of the wheel and rock it back and forth from top to bottom. If i'ts loose, just tighten up the bearing lock nut. Then give the wheel a spin and listen for grunching noises. You can check the rear wheel bearings by the rocking method but it's much more difficult to change them than the front ones.

If memory serves me correctly, wheel bearing rotate at half the tire speed, thus the grunching noises would be half the tire speed.

By the way, did you ever find a Mercedes for your girl friend? If not, give me and email at gridge@sprynet.com when you're back in town. I've got a car that you can't refuse.

Ben
www.reproduce100s.com

#6 12-14-2002, 06:57 PM

Very, very often a roaring tire is mistaken for a bad wheel bearing. Your problem is very likely a tire rather than a wheel bearing.

You might try rotating the tires front to rear and see if the noise changes.

Good luck,

240 Ed · #7 12-15-2002, 09:48 AM

Hi Warden, long time.
I have been at the Vintage board lately, dealing with newly acquired 68 250S. It's not diesel, but I like her just the same.

She has a bearing going out too, and I had a devil of a time figuring out where the sound was coming from! I jacked up the car and had someone run the car while I crawled under it. (Pretty scary !)
I figured it was the transmission bearings, so I went off and bought a used one.

Then just to make sure, I went for another drive.

Now I am convinced it is the left rear wheel bearing! Sheesh.
As well as a noisy differential.

It aint easy huh?

One tip is to turn your head sideways while you are driving and you may isolate it as to front or rear...

BTW, Benzina is for sale, reluctantly, but I have to clear some room before the neighbors start their petitions! She is a beauty!

#8 12-15-2002, 07:28 PM

Ed

As I remember the 68 250S has the swing axle.. and the axle bearings are single and run with grease with seals to keep the axle oil away from them.. Changing bearings is not to hard and changing the left one is the easy one.. The other side is the same except you have to pick up the U-Joint when you install the axle..

Over the years I had rebuilt lots of old cars.. and just a year or so ago rebuilt the rear end on a 67 250S.. It went well but the gears were a little rough....Lots of miles and few oil changes..Not real bad but it still made noise after I finished it.. I used some Lucus Heavy Duty Oil Stabilizer in rear end (You can pick it up in most parts houses) after the rebuild and after a while it did quite down.. I have also rebuilt VW, Porsche,BMW and other mercedes rear ends and used this stuff and they quite down.. and when pulling them apart some time later the rough grear area is smooth .. I have also had the same luck with STP... I have no clue what is in this stuff.. It does in time quite rough gears and often they look like new when checked thousands of miles later... However if its bad bearings the only thing to do is replace them.. This stuff will not help..

Ken.

The Warden · #9 12-16-2002, 01:10 AM

Thanks for the suggestions! I'll try checking the play and rotating the tires...

Also, Ben, I sent you a PM regarding the car...

I'll reply with the results, hopefully in the next few days. BTW, got to Lancaster okay, although I'm making a conscious effort not to drive the car for the moment...just in case, eh?

The Warden · #10 12-17-2002, 02:19 AM

Quote:

Originally posted by LarryBible
Very, very often a roaring tire is mistaken for a bad wheel bearing. Your problem is very likely a tire rather than a wheel bearing.

I drove the car a bit today, and listened carefully, and it does sound like a big 4x4 off-road tire rolling along a paved road. I wasn't able to rotate the tires today, as it was raining cats and dogs.

Also, going at speed with no throttle (coasting), I heard what almost seemed like a throbbing. I could feel a bit of a vibration through the gearshift, as well.

If it is a roaring tire, how can this be remedied? Or is it even a real problem (as opposed to "just" an annoyance)? I can live with the noise if it's "okay". BTW, the tires are in pretty good shape, although I have a slow leak (I check and maintain the pressure regularly) in the left rear tire.

Thanks again!

240 Ed · #11 12-17-2002, 06:13 PM

Sounds like you have a combo problem.

One, your rear wheel bearing is getting rough.

Two, your center bearing or carrier, or both are probably original and could use replacing.

#12 12-18-2002, 07:24 AM

You remedy a roaring tire by replacing it. Tires do not usually develop this condition with a lot of tread depth remaining anyway.

Good luck,

P.E.Haiges · #13 12-18-2002, 10:44 AM

I had a '68 220D that had a humming noise that I was sure was a bad wheel bearing on the right front. After replacing the RF wheel bearings, the noise still persisted.

It turned out that it was a bad bearing in the drive shaft. Replacing the drive shaft with a used one I had solved the problem.

P E H