Mine would crank a few times then everything would die. After a few mins, it would crank again. After a bit the brake light would turn on with one click if the ignition, but as soon as I went to crank, everything would go dead.
Turned out there was a wire loose at the solenoid - it would stay connected until I started to crank, then everything would go dead.
At any rate, there's no point in not just tightening everything down just to be sure - it doesn't cost anything.