When you say its grinding, do you mean the ABS is actuating? It can feel like a grinding sort of vibration in the pedal. If thats the case and your abs is kicking on at times then was it happening before you had the struts done? Im thinking maybe an ABS sensor or the sensor reluctor wheel on the axle got damaged. Generally when that happens the ABS kicks on at times and it dosent always set a code or turn on the ABS light in the dash.