REar wheel bearing I think! - PeachParts Mercedes-Benz Forum

Pook · #1 08-02-2006, 03:52 PM

This may sound strange, but I've been trying to diagnose this noise for years.

this 83 300SD has had a noise comming from the rear end area since it was purchaseed from its PO 3 years ago. Since then, 30k have been put on it, but the noise is the same.

The usual drive line suspects were replaced- the only things left are the CV's, and the rear bearings.

I was crawling under there the other day to replace the exhaust donuts which fell off (btw, MB carries new redesigned ones now, they dont fall off nearly as easily!). I grabbed the CV- and was able to slide it in and out.

This seemed a bit odd, as i cant do that on the other side.

The noise: The noise seems to be a very loud oscilating type noise- almost like something is out of balance. It is worst between 20mph and 60mph. It changes noise depending on if your on the gas or if your coasting.

It also doesnt make a difference if Im in neutral or not.

I can make the noise disappear- if I match the RPM of the vehicle to produce no load on the drive wheels- aka, just enough to remove tension on the driveline.

This seems like it could almost be a wheel bearing- but it also seems like the majority of the noise is from the CV itself, not spinning balanced.

I have a reman CV I will be putting in. I've searched, the short answer I get is, "dont try to do it myself, bring it to a shop". I'll do that, I just want to make sure where the noise is acutally comming from, and if the noise im describing is the rear wheel bearing.

rrgrassi · #2 08-02-2006, 03:57 PM

Raise the rear up, remove the brake calipers, and spin the wheels by hand. Also check for lateral play.

kerry · #3 08-02-2006, 04:05 PM

Had same problem with my 300td and took it to StarTech here in Denver. I thought it was a wheel bearing, but they diagnosed it as a dry cv joint and suggested filling the boots with grease and readjusting the rear hydraulic suspension so that the CV joints were at a different angle. Fixed it. The diagnosis was based on sliding the axle shafts side to side. Left slide fine, right was sticky. Noise was on the right.

Pook · #4 08-02-2006, 06:17 PM

ok, it definately isnt the tire- I've rotated, rebalanced, and replaced both rear tires.

So your telling me it is supposed to slide in and out?

If it is, that means that my right left is normal, and my rear right is tight-

This may/may not be the case- it would appear as if the PO might have replaced the CV/cv boot, as the right side is more aged than the left....

dkveuro · #5 08-02-2006, 06:24 PM

With the wheel off the ground...brake off...the axle shaft should dive in and out easily.
If not, this indicates either very dry joint or a joint begining to wear badly.

IMPORTANT..Never get under a vehicle without solid support of locking axle stands under the jack point/s.

.

Pook · #6 08-02-2006, 09:06 PM

ahh, gotcha. The one that l have on the left looks newer (the boot has no cracks) and goes in and out easily. The one on the right... cracks, but no leak.

I got a LLT replacement one from autozone for 65. it needed to be rebooted at the least, but if this is found to be the problem.. wow, I'll be so happy.

Does the noise im describing sound like the issue?

I've passed through at least 5 mechanics on test drives. I've gotten all sorts of answers, none of which was CV.

I've gotten,

"Front wheel bearings"
"Drive shaft"
"motor mounts"
"flex discs"
and my favorite, "this happens all the time, you have to replace your whole rear diff."

I've had this same noise on this car for 30k- This car currently has 166k.