So ive tried removing my freehub body from my old bike(Carrera) im rebuilding to make regreasing/replacing the bearings easier, but when i put my 10mm allen key inside its simply not biting to anything, yet i can see the shape inside for an allen key. It just goes straight through the wheel where the axle would be. Where am I going wrong? Ive watched endless 'how to' YT vids on it and they all suggest 10mm allen keys.. any help would be appreciated. Thanks!