Brake System; Fault Diagnosis - Lifan 620 Maintenance Manual

The brake system is used to transform the force on the brake pedal from the driver to braking force
of all wheels. Then the hydraulic system will distribute the braking force to each wheel. The
vacuum brake booster is used to decrease the force from the pedal and increase the hydraulic
pressure. The parking brake operates by rear wheels and controls the operation manually.
LF620 sedan has two brake systems, namely driving brake system and parking brake system. The
driving brake system is an engine vacuum booster ABS hydraulic brake system. And the parking
brake is to control the rear brake by cable system which utilizes the self-adjusting ratchet and pawl
structure. The ABS is controlled by the hydraulic control unit (HCU) in the hydraulic system, and
only works when the vehicle speed sensor detects that the wheels are locked.
I. Fault Diagnosis
The fault elimination of brake system is shown in Table 2-4. The figures in the Table refer to the
sequence of possible faults. Check all components and parts in sequence. Replace related parts if
necessary.
Fault
Brake runs off or drifts
Red brake warning lamp is
lighted continuously
Vibration during brake action
Rapidly sunken
pedal
Slowly sunken pedal
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Section III Brake System
Table 2-4
Possible Cause
Alignment angle of wheels
Brake pad
Brake disc
Brake caliper
Brake fluid level sensor
Parking brake control device
Excessively worn brake pad
Main piston rod of braking master
pump
Brake pad
Brake caliper
Brake disc
With air in system
Braking master pump
Brake disc
Brake pad
Brake caliper
Brake master pump
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Actions
Check the alignment angle of wheels.
Check and install a new component if necessary.
Check and install a new component if necessary.
Check and install a new component if necessary.
Refer to WDS.
Release and adjust the parking brake.
Check and install a new component if necessary.
Install a new braking master pump.
Check and install a new component if necessary.
Check and install a new component if necessary.
Check and install a new component if necessary.
Discharge the air in system.
Check the braking master pump.
Check and install a new component if necessary.
Check and install a new component if necessary.
Check and install a new component if necessary.
Check the brake master pump.