How to adjust the brake drum?

How to adjust the brake drum?
1. Adjust the annular sleeve on the screw rod with a special wrench. When the Angle between sabah and the horizontal direction is about 45 degrees, the two sand belts hold the brake wheel tightly at the same time
2. Install adjusting screw washer, nut and cap to loosen the sabah, and adjust the sand belt hook when the Angle between sabah and the vertical direction is about 10 degrees;
3. Check the gap between sand belt block and brake wheel net with steel plate ruler to make the gap even.