There is a certain trick to extending the life of your pocketbike's brake pads.
If you have small, round button brake pads, the part that usually wears thin first is the inner pad bolted to the rear plate, next Undo the bolt, pull out the pad, and slip in a small washer over the threaded bolt welded to the back of the pad.
Now all you need to do is to reassembel the brake pad and you will have descent brakes again for a few weeks.
