Testing for bad wheel bearings is pretty straightforward most of the time.
My two tricks are , one, to swerve  gently at about 35 mph, listening for
the noise to stay the same or increase swerving in one direction,
and get quitter swerving the other direction.
 If it's bad right side wheel bearings, the noise/vibration will be less in
a right swerve  as swerving toward the bad bearings lessens the load on
them, and they make less noise then.
The other one is to run it in the air, and listen at the wheel bearing
housings with a hardwood listening stick held to your ear.
Lots of nice rumbly sounds stand out with that method, often.
Do at least consider CV joints.

The big nuts holding on the flanges are well tightened ?
As another poster said, if it's brake noise, usually operating the brakes
will make the sound happen, or go away .....or change.
And with the parking brake, you can operate the rears independently of the
fronts of course.

On vanagon rear wheel bearings, I've personally have never seen any that
were obviously shot to hell.  What I find is maybe they are making noise,
there's a little play, you have 160+ thousand miles on them or whatever, and
you just know they are due.  Sometimes/usually the right side wears more,
but not always.

----- Original Message -----
From: "neil N" <musomuso@GMAIL.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Wednesday, September 09, 2009 8:51 PM
Subject: Re: need help identifying cause of noise

On Wed, Sep 9, 2009 at 7:02 PM, Troy <colorworks@gci.net> wrote:
> Yes, I did have the drums off last week and did not see anything obvious
> that would be making a noise. The trailing shoe did have some movement up
> and down (I think it's supposed to to center inside the drum) but both
> shoes
> were attached properly to the backing plate. All of the springs seem to be
> in the proper places, nothing detached. I certainly can take it apart
> again
> and look closer. If it was brakes, why would a load make a difference? No
> noise when up on the rack if you recall from my first message--does that
> make sense to you? I thought there might be some correlation with braking
> and the noise but I cannot say for certain as it did not seem to be
> consistent. Even the mechanic did not not know for sure what was causing
> the
> noise, but at least was honest about it. They have 2.5hrs into at at this
> point. Let's see what other people have to say, but so far it still
> remains
> a mystery. I can say the noise comes and goes, which makes me wonder about
> bearings. I would think that would be a steady noise, whereas if it was in
> the brakes it could possibly come and go, but then there is the load
> issue.
> Why no noise when not under load?

If possible, get another person to drive with you. You drive, then
swap seats and compare notes.

See if noise is coming from just one side.

Maybe find a way to coast and brake w/engine off. Reducing ambient
noise might help you hear it better.

You could also turn circles in a parking lot with the other driver.
(engine on or off up to you!)

Neil.

--
Neil Nicholson '81 VanaJetta 2.0 "Jaco"

http://tubaneil.googlepages.com/

http://groups.google.com/group/vanagons-with-vw-inline-4-cylinder-gas-engines