Great Wall Florid, Service Manual

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GWFLORID Maintenance Manual 96
Brake System Maintenance
Brake fluid inspection and replacement
Brake fluid directly influences the brake performance and the operating conditions and use life of the brake
system components. Brake fluid has very strong hygroscopic properties, and thus absorbs water easily,
which will then deteriorate the metal and rubber pieces. Polluted and deteriorated brake fluid or its mixture
would cause the brake fluid to boil and gasify, hence reduces braking efficiency. Therefore, pay attention to
the items below when filling or changing the brake fluid:
1. Containers used to hold brake fluid must be tightly closed and sealed
2. Brake fluid is poisonous and damaging to the paint. Hence if it gets on the vehicle surface, rub it
off at once
3. If water or other contaminates found in the brake fluid, and the brake master cylinder's piston seal
has been broken, then the brake fluid and all the rubber pieces inside the brake system including
the brake hose must be replaced
4. The correct brake fluid level in the reservoir must be between MAX and MIN. After the vehicle has
been driven for over 1000 km, check the brake fluid level in the reservoir. If the brake fluid level is
not up to regulation, more brake fluid should be added to the reservoir until it reaches MAX.
Hydraulic component inspection and system flushing
1. If the oil-based solvent gets into the hydraulic system, flush the whole system and change all of
the rubber pieces
2. Clean your hands before installing new rubber pieces or other components
3. Do not use regular solvents (kerosene, gas, etc.) when inspecting or cleaning hydraulic
components, instead use absorbing alcohol or brake fluid
4. After inspecting the components, drain the brake fluid from the system. Use new brake fluid to
flush the system. Afterwards, add new brake fluid to perform hydraulic system exhaust
5. Flushing completion sign: When the brake fluid flowing out of the dump valve is clear from any
contaminate.
Hydraulic pressure system drainage
If the brake fluid inside the whole hydraulic pressure system needs to be emptied, open all the bleed screws
with each connected to a hose, as to allow the brake fluid to flow into a container. Step on the pedal slowly
until only air flows out. During the whole procedure, make sure all the valves are open.
Hydraulic pressure system air bleeding
The hydraulic brake system must work under a vacuum environment. The air will cause spongy brake or
overall brake failure when it flows into the hydraulic system. It is extremely necessary to bleed system air
when performing any operation on the brake system or if any air inside the brake system is suspected.
1. Air bleeding sequence
If air inside the brake master cylinder is suspected, first perform air bleeding.
(a) If numerous valves are equipped, air bleed each valve
(b) Another sequence principle is: Air bleed from the wheel brake furthest away from the master cylinder.
The air bleeding sequence for the LHD modules is: rear right wheel - left rear wheel - front right wheel
- front left wheel, Right rudder vehicles: rear right wheel - left rear wheel - front left wheel - front right
wheel.
2. Air bleeding method
(1) Manual air bleeding
Use the brake pedal or pump as the air bleeding power source. When the air bleed screws are open, vent the
brake fluid containing the bubbles from the system. Usually this is simultaneously done by two people. One
steps on the brake pedal and the other operates the air bleed screws. Important points to take note of when
performing the operation:
(a) Place the ignition switch to the off position and step on the pedal repeatedly to remove the
vacuum pressure or hydraulic pressure.
(b) Before and after air bleeding, add clean brake fluid into the master cylinder until it reaches
the correct (stated) level.
(c) Check the fluid level frequently to make sure that more than half of the reservoir's capacity is
available.
(d) Bleed screws should only be opened when the pedal is pressed down, and closed before the
pedal is loosened. Meanwhile, check if the vented brake fluid has bubbles inside.