BTW, if you don't have the "special tool" Mark talks about, a slim 10mm open end wrench will do .....
( If you don't have a slim one, make one with your grindstone and a $1 Chinese wrench. Paint it red when done to identify it and also prevent it from rusting. If you do this with a loooooong wrench, then it is a multipurpose tool for replacing the 'eyebrow' lights in the headlight assembly )