8.1 General Description
The brake system is the front two-wheel braking type consisting of a master
cylinder, wheel brakes and brake pedal mechanism.
8.2 Master Cylinder
The cylinder contains valve seat, check valve, return spring, primary cup, piston
and secondary cup, which are all kept in place with a stop washer and a stop wire. The
exterior of the cylinder is protected from dust by means of a rubber dust cover. The
piston is actuated through the push rod by operation of the brake pedal. As the brake
pedal is pressed, the push rod pushes the piston forwards. The brake fluid in the
cylinder flows back to the reserve tank through the return port until the primary cup
blocks up the return port. After the primary cup passes through the return port, the
brake fluid in the cylinder is pressurized and opens the check valve, flowing through
the brake pipeline to the operating cylinder. Thus, each operating cylinder piston is
forced outwards. This brings the friction pieces on the brake shoes into contact with
the brake drum and slows or stops the truck. Meanwhile, the cavity caused behind the
piston is filled with brake fluid led through the return port and inlet port. When the
brake pedal is released, the piston is forced back by the return spring. At the same
time, the brake fluid in each operating cylinder is pressurized by the return spring,
returning into the master cylinder through the check valve. With the piston in its
original position, the fluid in the master cylinder flows into the reserve tank through
the return port. The brake fluid in the brake pipelines and operating cylinders has a
residual pressure proportioned to the set pressure of the check valve, which makes
each operating cylinder piston cup securely seated to prevent oil leakage and
eliminates a possibility of air locking when the truck is sharply braked.
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