The pressure switch works on air pressure. If you have replaced the bearings, presumably you had to virtually strip down the machine. The pressure switch will be higher than or level with the top of the drum, usually attached to the side of the machine. It is unlikely to be the switch that is the problem. A clear plastic tube connects from the switch to the bottom of the drum. As the machine fills, the water creates air pressure in the tube, which eventually causes a membrane in the switch to bellow out, thus operating the switch and closing the inlet valve. Most likeley the tube is damaged, or possibly you have not re-connected it. If the tube is connected, take it off the bottom of the drum, blow up it and you shuld hear the switch 'click' as it operates. Alternatively, when you locate the switch check that none of the electrical connections have come loose. Hope this helps.
Paul Higgins, April 2006