Low moan at speed? - PeachParts Mercedes-Benz Forum

cewyattjr · #1 09-10-2008, 07:08 AM

So at maybe 40 miles and above, I'm hearing a moan that sounds somewhat like a small squadron of corsairs.

I had thought it might be a wheel bearing, though I figured that would be a high pitched noise. Sure enough I needed a bearing replacement. That's now been done, bvut the noise is still there.

I've put the transmission in neutral while cruising. It doesn't seem to effect the sound. Turning the wheel from side to side does seem to make a difference in volume. Tire noise? The tires are only about 4k old, and the noise became noticable only maybe the last 1k miles (?). Drive shaft? Tie rods?

Thanks!!

Chuck

Paulc66t · #2 09-10-2008, 08:21 AM

Usually the side to side noise change indicates a wheel bearing. Did you change the right one? Could another bearing be bad. With the help of a friend try to isolate the sound front to back and left to right.

babymog · #3 09-10-2008, 09:06 AM

Agreed, sounds like a wheel bearing again.

cewyattjr · #4 09-10-2008, 09:09 AM

So wheel bearing does a low frequency "moan" sound? This is kind of like an airplane engine noise. I notice it more if I bear stearing to the right on an off ramp curve, for example.

Thanks folks!

jt20 · #5 09-10-2008, 09:14 AM

check your differential, change the fluid

cewyattjr · #6 09-10-2008, 09:38 AM

I wondered about the differential. Would the noise resonate from the front and be affected by steering?

babymog · #7 09-10-2008, 09:51 AM

Sounds exactly like a prop-airplane. Right turn usually implies left bearing, could be front or rear.

cewyattjr · #8 09-10-2008, 09:35 PM

So that makes sense. The front passenger side was replaced, but the left-hand driver's side was not. Makes the noise if I just bear right on a curve. Also I "wiggle" tested the wheels and felt more from the passenger side, and the mechanic said we'd just replace the one side and "see how it goes." Hmmm.

Anyway, is bearing replacement a DIY job anyway? I looked in the shop manual, and I had thought it required a big press of some sort, but maybe there is a drop in bearing kit?

-Chuck

Paulc66t · #9 09-11-2008, 08:27 AM

It can be easily done if you don't need to replace the races.I think the races need to be pressed out of the hub. I did one on my 81 and just replaced the bearings which fixed the problem. 1 hr or less of time.

cewyattjr · #10 09-11-2008, 09:22 AM

Thanks, Paul! If I bought the bearing kit, wouldn't it be bearings-in-races, so I wouldn't have to worry about it either way? I'm looking on Fastlane and see a bearing kit for front, around $40.