have a look at your brake disc on the inside ..if you have old style disc the abs exciter is cast in to it ,1 or more will be corroded ..if ok check wheel bearings for excess play,make sure all sensors are fully home ,check sensors for shorting to earth and their resistance ...if the discs are at fault ,before refitting the hubs make sure the sensors are free to move ..it not renew sensors and cage ,
norb, March 2011