(1) The brake pedal has no free travel.
(2) The gap between the brake drum and the brake shoe friction plate is too small, the brake shoe return spring breaks or fatigue blows.
(3) The brake fluid is too dirty or the accuracy is too large, making it difficult to return oil.
(4) The return hole of the bypass hole of the master cylinder is blocked; the cup or apron of the master cylinder or the sub-cylinder is aging, deformed or swollen.
(5) The return spring of the master cylinder piston is too soft or broken or the piston is stuck.
Fault diagnosis and elimination:
First determine whether the vehicle is bite or individual bite according to the fault phenomenon, and then make further diagnosis.
(1) If the vehicle brakes bite: 1) Check if the brake pedal has free travel. 2) Open the lid of the liquid storage chamber and use "Continuous Step"
Brake pedal method, observe the oil return. If the oil return is slow or not, check whether the brake fluid is too dirty or the viscosity is too high. If the brake fluid is pure, at this time, after stepping on the brake once, release the brake pedal, and loosen any one of the cylinder bleed bolts, the brake fluid is sprayed out, and the brake bite phenomenon of the whole vehicle is eliminated.
(2) If individual wheels bite: 1) Support the wheel that brakes bite first, loosen the cylinder exhaust bolts, if the brake fluid is urgent
After the speed is ejected, the brake shoe moves back and check whether the brake oil pipe is blocked. 2) After the fluid is drained, if the brake shoe still cannot move back, check if the brake clearance is too small. 3) If the above inspections are normal, then disassemble and inspect the cylinder piston, leather cup, and other factors that cause poor return of the brake shoes.