(1) Pedal comfortable travel too large.
(2) Brake total pump internal brake fluid is deficient, or compensate hole obstruction, the total pump skin bowl, skin circle aging, swell, deformation or be trampled over.
(3) Brake total pump piston and cylinder body wear excessive and loose oil leakage, return valve seal bad, the valve Shang broken.
(4) The brake pump skin bowl aging, swelling, piston card lag, split pump piston and cylinder body wear excessive and loose oil spill.
(5) The brake shoe piece is worn severely, the brake gap is too large or the gap is reversed.
(6) Brake drum lost round, groove or wear too thin, brake shoe surface oil, ablation hardening, such as rivets revealed.
(7) The hydraulic braking system enters the air, or the braking system is too high, and the brake fluid in the pipeline is gasified, which constitutes the gas resistance.
(8) Tubing concave, joint loose leakage, brake hose aging, rupture or obstruction.