1. Check whether there is too much soil in the brake pump, and the piston of the brake pump can not return to the position if it is stuck.
2. Check whether the brake fluid in the oil pipe is sufficient. The air in the brake pipe forms air resistance, which causes the brake pump piston to fail to return.
3. Check whether the brake shoes and brake discs are severely worn.
4. The free sag of the chain can be adjusted to 20-30mm, and a small amount of oil can be brushed on the chain for regular adjustment.
