Seems a bit like a stupid comment, but I had a similar experience with my 97 Galant. I'm a mechanical engineer whose daily work consists of working with bearings in a chemical plant, so I should know my business. When I heard a noise from the left back it sounded 100% like a bearing. Dealer said it could only be replaced as a package, which would cost up to ?
600 ($ 675). After an inspection he came back with the solution: replace your rearwheeltyre... Like I dont know a bearing from a tyre!! As an unbeliever I silently changed tyres with the spare... the noise was gone !!! It appeared the tyre was "cupped" with enough profile to last another 20,000 km. Due to my drivingstyle (I think) or a bad tyre, the tyre has got "teeth" around sticking out, that make the same noise as a worn bearing.
It was the best solution though to get rid of the noise, and a lot cheaper.
Morale of the story.... be sure it's your bearing, before you end up with a costly repair that does not solve your problem....
Regards, Peter