: the car in motion, a foot or a few feet brake, brake pedal is stepped, braking suddenly.
1. no brake fluid in the master cylinder.
2. the master cylinder Cup is broken or taken.
3. damaged pump leather Cup up or down.
4. brake pipe severely cracked or connector line.
diagnosis: causes of poor braking efficiency of hydraulic braking systems may generally be under the brake pedal stroke (commonly known as the high and low), step on the brake pedal hard and soft feel, step on the brake pedal the stability and increased brake pedal height to judgement.
1. brake pedal height is too low, poor braking efficiency. Two feet or foot brake, pedal height increased braking effectiveness and improved instructions and friction of the brake drum or master cylinder push rod of the piston clearance is too large.
2. maintain braking, pedal height is either slow or rapid decrease note somewhere in the brake line ruptured, poor joints closed or pump Cup seal is bad, the return spring too soft or broken, total pump leather Cup, aprons or bad seal, return valve and the outlet valve is bad. First press the brake pedal and observe whether the brake fluid leakage. If outside normal, you should check the cylinder or the master cylinder failure.
3. for several feet when braking, pedal height is still too low, and after the second foot brake, master cylinder piston does not return, tap the brake pedal master cylinder push rod and piston impinging sound, is the total pump leather Cup cracked or return spring too soft.
4. brake pedal height slightly increased for several feet, and elastic, that permeates the air in the brake lines.
5. for a few feet, pedal is stepped, and pedal without force, shows laboratory brake fluid master cylinder reservoir fluid loss.
6. for several feet when braking, pedal height is low and soft, is the total liquid storage room in the oil inlet hole plug vent plug.
7. one foot or two feet when braking, pedal height fit, but too hard braking efficiency is poor. Should check the wheel friction and clearance is too small of a drum. If normal clearance, check the drum-wall friction and surface conditions. As normal, then check whether the brake shoe spring skills, master cylinder or pump leather Cup swelled, the piston and the cylinder wall tie is loose open. As is normal, you should check whether the brake hose aging is not clear.