(1) Air inlet port
(2) Tandem housing
(3) Wheel spindle housing
(3) Wheel spindle housing
(4) Duo-Cone seal
(8) Wheel spindle
(10) Brake hub
(11) Air piston
(12) Air compartment
(13) Revolving discs
(14) Stationary discs
Power from the differential flows through the drive chain to sprocket (7). Inside wheel spindle housing (3), the sprocket turns wheel spindle (8), brake hub (10), and revolving discs (13). The drive wheels are connected to the wheel spindle.
There is one disc type brake in each wheel spindle housing (3). The four disc type brakes are used for the service brake system. The brakes are cooled through the oil in tandem housing (2). The service brakes are activated by pressure air from the air control valve for the service brakes. There is a Duo-Cone seal (4) that is located between the wheel spindle (8) and the wheel spindle housing. The Duo-Cone seal will seal in the oil. The Duo-Cone seal will also keep out the dirt, the water, and the other contaminants.
Stationary discs (14) are splined into wheel spindle housing (3). Revolving discs (13) are splined onto brake hub (10). The brake hub is splined onto wheel spindle (8).
(15) Air pressure gauge
Location of Air Control Valve for the Service Brakes
(16) Air control valve for the service brakes
Air from each section of the air tank flows into the respective air pressure gauge (15) and to air control valve (16) for the service brakes.
When you depress the service brake control (pedal), a rod actuates air control valve (16). Then, the air control valve for the service brakes will send pressure air from the air tank to the service brakes. The position of the pedal regulates the amount of pressure air to the brakes.
Pressure air flows through air inlet port (1) into air compartment (12). Air then moves air piston (11) against stationary discs (14) and revolving discs (13). The air piston pushes the discs against cover (6). As the air pressure increases, the air piston is forced against the discs. This will cause friction between the discs. As the friction increases, the revolving discs, brake hub (10), and wheel spindle (8) will start to slow down, since the stationary discs and wheel spindle housing (3) cannot turn. The brakes are in BRAKE ON position, but the brakes are not fully engaged.
If the operator continues to depress the pedal downward, the air pressure will increase in air compartment (12). The friction between the discs will then become great enough to stop revolving discs (13), brake hub (10), and wheel spindle (8). Air pressure is held in the brakes in order to keep the brakes in the BRAKE ON position.
When the operator releases the pedal, the pressure air in air compartment (12) is released through air inlet port (1) to the air control valve (16). Then, springs (5) force air piston (11) back to the BRAKE OFF position. Revolving discs (13) are again free to turn between stationary discs (14) .
The wear of the friction discs can be checked by observing the amount of piston travel. Before you inspect the brake pack for wear, refer to Testing and Adjusting, "Brake Disc Wear - Check". The information is in this manual.