fuel pump locking ring

The plastic lock ring does screw off, but it is very difficult. The biggest problem is that you can't get any leverage on it, due to it's location. You can purchase a lock ring removal tool for about thirty bucks, but that is alot in my mind. You can try taking a VERY dull chisel and a hammer, and place the chisel against the tabs on the lock ring, and gently tapping with the hammer. Sometimes this will loosen it enough that you can get it off. Before you remove it, however, you should vacuum any dirt and debris that has collected around it, or this is going to fall into your fuel tank.