i doubt they broke when he put the non abs axles in, the only dif between a abs and non-abs axle is the hub end on the abs has a ridged ring around it. if anything its dirty like the other guy said, dont just go replace your sensors cause your abs doesnt work. theres a number of things that could be wrong before you need to go replace something without knowing. and i believe their is a way to check your ABS light to get a code for whats wrong, ill look it up and let you know. may have just been the SRS