How did they find the volume of this Calc II volume problem?

It says, Find the volume of the solid generated by revolving the region bounded by the graphs of the given equation about the y-axis. x=y^2/4, x=0, y=-4 and y=4. The answer is 128/5(pi). I have the right denominator and pi, but I keep getting the wrong numerator. I always get 2000 something.Thanks!