Unity Animation: Rotating only One Axis

Hey folks, due to my lacking of animation skills I am using Unity to animate a crude robotic walk cycle. It works great for moving limbs, simply rotating them up and down/backward and forward. But oddly enough when I rotate the body to shift weight from one side to another and play it in the scene it uses the Animation's rotation rather than inheriting the Parent Container. So no matter which way I place the object, it always rotates to one specific direction.

Extra details: all four limbs are parented to the body, and the body parented to an Empty.

Two part question; why do my limbs rotate properly(relative to the parent) but not the body?

And two; is there a way to only animate the Z rotation axis? When i try to delete the X and Y curves it deletes all of them, and when I delete their key frames it still sets their values to 0 instead of inheriting the Parent rotations.

Thanks.