Specifications

44
5. Brake system
Type of brake system
Front two-wheel braking, internal expansion,
hydraulic type
Pedal ratio
5.66
Master cylinder bore
19.05mm
Wheel brake
2t, 2.5t
3t, 3.5t
Type
Duo-servo type with parking brake
Operating cylinder bore
28.58mm
Size, friction pieces (L×W×T)
324×60×7 (mm)
348×76×8 (mm)
Area, friction pieces
194.4cm
2
×4
264cm
2
×4
Inner diameter of brake drum
310mm
314mm
Parking brake
Front two-wheel braking, internal expansion,
hydraulic type
5.1 General description
The brake system is the front two-wheel braking type consisting of a master
cylinder, wheel brakes and brake pedal mechanism.
5.2 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 downward. The brake fluid in
the cylinder flows back to the reserve tank through the return port until primary cup
blocks up the return port. After the primary cup passes through the return port, the
brake fluid in the lower cavity of 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
come into contact with the brake drum and slows or stops the truck. Meanwhile, the
cavity 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.