brake fluid and bolt question

[klauder88]

so ive been fixing my bike, just replaced a lot and i noticed that the rear brake lever is missing the bolt to connect to the brake line. does anyone know the size and/or recommend a better type to sustain pressure and my brake fluid leaked but have to refill it. anyone have any opinions on type. i only have internet on my phone, not at home so i cant see the manuel above[confused] thanks!