Wheel Bearing Squeal or is it Brakes?
 

I have to replace the discs and pads on the rears, that I know. But I also get a squeal sometimes coming from what sounds like the rear when I approach higher speed turns (lane changes, off ramps). The front brakes are fine but they squeal when they come to a stop and it sounds almost like the same sound but fainter, so its difficult to say if its coming from the front or rear.

What kind of noise should I be hearing if the bearings are in need of attention?

"a bad wheel bearing will typically have a grinding, whining, or squealing noise, plus looseness or roughness that you will feel the moment you rotate the wheels." Jack up the rear and rotate the back tires to listen for the noise.

If the squeal only happens when braking, I would start there.

From the hundreds of customer narratives I've read that describe bad wheel bearings, the most typical are a grinding, growling, roaring, or whining noise, most noticable at 30-50 mph. Squealing is not part of the repertoire. Only in advanced failures will you feel roughness and looseness.

I agree that you should concentrate on the brakes.

ok good, thank you.

In my experience wheel bearings roar, and it gets louder the the faster you go. Sounds king of like being in an airplane. I'd start with brake pad. You will be able to tell if the are low just by pulling the wheel and looking at how much pad is left. Change both sides at the same time. You don't have to do front and back at the same time but left and right sides at the same time it critical.

A retired Mercedes mechanic just told me that the rear bearings don't go bad too often. Brakes and rotors first...

Thats what I've heard form several sources too. The bearings in the 123's a pretty tough.

this is all very good news.

i was researching rear wheel bearing work and it is very involved if i am correct. special tools to measure play to the .000 inch, something about crushable washers/seals? Bit of overwhelming DIYable job.