My '93 4x4 toyota truck had the center support bearing repolace a few weeks ago. Soon after the rear wheels started to make a thumping noise, similar to tire chains without the jingle. The mechanic says it is the rear wheel bearings. He wants me to open my purse for another 900.00 bucks. My brakes seem to be soft and also I feel a buzz under my foot when I apply the brakes. Is my mechanics diagnosis correct? Or should I get another opinion? The brakes were getting down and I asked him to check them a service ago with no comment.