*Manual adjustment:
The adjustment methods are basically the following:
1. Adjust the clearance by turning the adjustment cam against the brake shoe;
2. Adjust the clearance by turning the adjusting nut leaning on the end face of the support block or wheel cylinder to drive the screw and the connected pushrod to make axial displacement;
3. Adjust the clearance by turning the screw or nut on the adjustable pushrod between the primary and secondary collar hoof to change its length;
4. Adjust the gap by turning the nut on the adjustable parking brake pushrod to change its length.
*Auto adjustment:
The gap self-adjusting device can be divided into two types: one-time adjustment type and step type. Once the adjustment device performs braking every time, the gap in the brake will automatically return to the preset value; the step device needs to pass multiple braking before it is eliminated when the brake is applied or released.
The excessive gap of the brake is not completely caused by the wear of the friction pair, but also includes the gap caused by the thermal expansion of the brake drum and the elastic deformation of the shoe and the hub. However, the one-time gap self-adjusting device always eliminates excessive gaps according to the actual conditions of the brake at that time. If excessive thermal and mechanical deformation occurs at this time, the resulting gap exceeds the set gap. After the deformation is eliminated, the brake will stall or even lock. In order to avoid this phenomenon of "over-adjustment", a step-type self-adjusting device should be used.