If you want your brake to stop rattling forever:
-Go to your hardware store and get the smallest bolt you can fine that is 3" long. It will probably be 1/4" diameter. Get the strongest material they have it in (usually grade 8 black oxide coated steel). Also, get a nut that goes with it.
-Drill out your brake holes in your deck and brake to 1/4". 1/4" isn't too much bigger than the brake bolt so it shouldn't take long.
-Put everything back together. It will probably be harder than normal because it doesn't bend, but once it's in, you're scooter will be SILENT.
-Drop your scooter repetitively to show off to your friends that it sounds like a basketball.