Hey i have recently bought me a Rear Euro whiper to fit on my "zx5" euro focus, but discovered that the original whiper hole that fits over the screw coming out og the window have a (excuse my bad english

) but a tracked inside that fits on the same track on the nut in the window, but the new one is smooth inside and wouldnt go all the way in, i tryed to screw as hard as i could (haha you know what i mean right

) but there is still a gap between the windshield and the whiper :S is it suposed to be like that? or do i just have to screw harder?