Rotating around completely in 90 degree intervals

Rotating around completely in 90 degree intervals

I have a circular menu that rotates 90 degrees every time leftArrow_mc is
clicked but at 270 degrees the button stops working. Also will the
reseting the degrees back to 0 do anything for me?
import com.greensock.*;
import com.greensock.easing.*;
leftArrow_mc.addEventListener(MouseEvent.CLICK, rotateLeft1);
function rotateLeft1(event: MouseEvent):void {
if (bottomWheel_menu_mc.rotation==0) {
TweenLite.to(bottomWheel_menu_mc, 1, {rotation: 90,
ease:Bounce.easeOut});
} else if (bottomWheel_menu_mc.rotation == 90) {
TweenLite.to(bottomWheel_menu_mc, 1, {rotation: 180,
ease:Bounce.easeOut});
} else if (bottomWheel_menu_mc.rotation == 180) {
TweenLite.to(bottomWheel_menu_mc, 1, {rotation: 270,
ease:Bounce.easeOut});
} else if (bottomWheel_menu_mc.rotation == 270) {
TweenLite.to(bottomWheel_menu_mc, 1, {rotation: 360,
ease:Bounce.easeOut});
}
else if (bottomWheel_menu_mc.rotation == 360) {
bottomWheel_menu_mc.rotation == 0
}
}