Odd squealing / high pitched noise on highway?

[bmwman91]

I replaced my brakes about a month ago and all went well.  For the past 2 weeks though I have been hearing a really loud, high pitched squeal/screech coming from my wheels.  It goes away when I press the brakes, and if I rock the steering left to right it disappears when the car is loaded from the left side.  It also comes and goes when I drive over bumps on the highway.  THe noise only seems to become apparent above 45mph.

So, could this be brakes, or wheel bearings?  I want to yank wheels and look around, but I am just far too busy lately...taking a leak is almost hard to schedule in.  The rear wheel bearings were replaced 2 Decembers ago.  The fronts...I have no idea when or IF they ever have.  Do wheel bearings squael when they are going south?  I thought they just made a lot of low frequency noise & vibration.

Thanks all!

[phredphish]

I had a similar noise and it turned out to be a sticking front brake caliper. I bought two rebuild kits and replaced the guide bolts on both sides. No more sticking caliper, no more noise! I let mine go a little bit too long and ended up with a slightly warped disc.

Lift your car and spin the wheels...you should be able to feel if its a wheel bearing or just sticking brakes --- a wheel bearing will make the wheel spin roughly, a brake problem will only make it difficult to spin the wheel (and add some noise, likely).

[bmwman91]

Alrighty, I will check it out.  I rebuilt the calipers when I did my brakes, so I sure hope they are not sticking.  This is not my first caliper rebuild either.  Maybe this is why my car feels slow and I swear it pulls every so slightly to the right (though it could be the road, or my imagination).  Thanks!

PS
Where is the cheapest place to get the front wheel bearing/hubs?  Those suckers are $$$!!!

[e30s4evr]

Just asking the obvious... You have checked for stuff lodged between the rotor and backing plates right?

[bmwman91]

I have not actually.  I will try that.  A couple weeks ago I pulled the pads and gave them a thick coating of anti-squeal goo.  It quieted the squeal down a bunch, but now it is as bad as ever.  Could using new pads on old, un-surfaced rotors be the problem?  I am tempted to pull the rotors & have them turned.  They have more than enough metal left for it.