They break good! First time replacing a vacuum pump and I was very surprised to see the spline and everything else in there being plastic. I guess thats good so it can shear and not break stuff in the case but still I was surprise. Think it's still usable? I'll tell you what the nut on the bottom left by the tach cable is absolutely a pain in the butt as is changing the filters behind the panel! But I have vacuum so all is good.