At the beginning of the brakes, drive the S camshaft adjustment arm turned clearance angle (C) and excess clearance angle (Ce), and accurate records produced by wear. At this point S cam angle stroke in the gap region, the gap area 
 
Braking torque characteristic is changed much. 
While continuing brakes, S rotary cam into elastic deformation zone, a sharp rise in braking torque until the car stops. Release the pedal, brake return, brake torque down, S cam angle stroke back gap region 
 
. According excessive gap adjustment arm when braking records, internal adjustment mechanism driven by S camshaft worm turned at an angle, thus completing the adjustment. 
Adjust the angle of the arm stroke when braking 
Brake adjustment arm angle stroke can be divided into three parts: 
The clearance angle, clearance corresponding to the brake drum and the normal friction linings; 
Excessive clearance angle corresponding to a result of increased friction lining wear gap; 
Flexible angle corresponds to the flexibility in transmission caused by a brake drums, brake linings and wheel cylinders and brake system dynamics.