i would start with the rotors if they have 120k miles on them as you said
and not worry about the bearings now.

go to autozone and have them look up the part for the wheel bearing and
show it to you.  you will see that the bearings are made into the center
hub assy.  they are not a take a part and service type bearing, but a
sealed bearing unit.

these will wear out and cause the whole wheel to have a shake to it as
ou drive as well as stopping.  

now, if you are talking about a shudder only when you hit the brakes,
then you have rotors that are out of lateral.

this is caused by the manufacturing of the rotor itself and the hardness
of the metal varies so it doesn't wear at the same rate.  as a result
causes uneven spots on the rotors and when they rub over the brake pads
will translate into a rapid pulsing of brake pedal as the car stops.
you can take them off, take them to a machine shop and have them put a
peen finish on them, but because it is metal itself, the condition will
come back over time as the rotors wear.  replacement of the rotor will
usually get rid of this problem.  

if you do the work yourself, it won't cost a bundle.

hope this helps.

~ curtis

knowledge is power - growing old is mandatory - growing wise is optional    
"Many more men die with prostate cancer than of it. Growing old is
invariably fatal. Prostate cancer is only sometimes so."
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