W124 400E with a whining noise at rear left axle
 

This year I heard a slight whining noise at the rear right left side.
It has comes and goes with every turn of the wheel and it does not matter if I am on a curvy road or straight run. The frequency of the oscillating, whining sound is solely depending on the speed of the car.
The whining sound has become much louder over the summer.
As I think it comes from the left side I was checking if I can find something wrong at the left rear brake but nothing was wrong there.
Also I checked the differential oil level and all is good here as well.

My suspicion is that this might be the wheel bearing?

What do you think?

Thanks, Martin

get the rear wheels off the ground , see is either wheel has excess play, if you can tell which side is making the naise go around a curve (UNLOADING) the side that nakes noise may help pinpointing which side is noisy , its going to be a wheel bearing rear , or change both sides

Hi nulu,

There is no change in noise from driving straight or cornering the car..... otherwise the diagnosis would be easier.
The whining sound is the same no matter the load on the wheels.
I checked the rear end on the lift and there is no noticeable play at all but I remember that it is very hard to detect the condition of the bearings unless they are very much run down.
Martin

then try a stethescope on my 94 124 wagon one side was slightly loose , i replace that bearing , but noise still there, ended up changing both noise now gone

Noises can be so confusing. I guess I am planning on replacing both sides.
I cannot sense any extended play but something is obviously off and I need to act.
What special tools are needed for the job?

Best, Martin

Check your differential

Your not going to change the rear bearings with out a hydraulic press, its best to remove whole flange/spindle and take to a machine shop let them do it , even with the factory tools mine wouldnt come free until press loaded And more pressure to push the flange off, it let go with a bang and pieces flying, dont even think of doing the whole job at home!

Hi Professor,
How do I check the differential?

Thanks, Martin

Hi Nulu,
Oh...painful!
I guess you had the cast steel axle flange (that holds the rear bearing) still in place and tried to extract the bearings with the factory tool.

Probably gas/heat would help to break the corrosion and get the bearings out?

Martin

The factory tool wouldnt release the wheel flange from the bearing, if it did , then i could
of used the other tool to remove the bearing from the spindle, normal on a sedan 124 ball bearings allow just the wheel hub to separate with halve of the double row bearings, but the wagon has roller bearings, i applied more force to the hub by using the press to loosen everthing, then remove the circlip thats hidden between the hub and spindle , on all other cars double row ball bearings are used

Lift the car up and put your steto to it while in gear

Thanks everyone.

I found something new and maybe this is a hint.

When I am driving normal speeds even on 'curvy' roads there is no noticeable difference in noise.
However when my wife is not present I can go faster and I noticed during harder cornering that the noise is changing. In sharp left turn curves the noise is diminishing or partially gone and it sharp right turns the noise is getting stronger.

Does that point to the wheel bearing?

Best, Martin

yes, but on my 94 wagon the bearing was opposite of expected side left turn ( NOISE WAS LESS)unloading left side noise diminished, but turned out to be the right side, however the wagons have roller bearings instead of ball bearings , usually turning left above 35 mph and noise goes away indicates left rear is bad as weight is transfer to right side, and turning right noise gets louder indicates left rear is bad

Hi Nulu

thanks a lot. I am not sure why your T-wagon is different (noise changes with opposite turn direction relative to the sedan)with a different kind of bearing (roller vs cone)

You are saying: "...usually turning left above 35 mph and noise goes away indicates left rear is bad as weight is transfer to right side, and turning right noise gets louder indicates left rear is bad"

So I was experiencing the same symptoms (left turn - less noise and right turn- more noise) but so far I am assuming the noise is coming from right rear....grrr.

I am hoping to catch the correct side when I am working on this problem in February/March of next year.

Best Martin

i went for the obvious, replace the loose right rear bearing , even the brake pads were wearing uneven, but noise still there , then also replace left rear and noise gone, stethoscope dosent work because of no way to hear with weight not on car, and wheel spinning , when its a lot worse stethoscope may be better