AIR AND BRAKES
Refer to TM 5-3805-264-14&P for dump truck MCS circuitry.
The air system consists of the air compressor, air holding tanks, and various air lines. Also included in the air
system are the air pressure gages located on the dashboard for the purpose of monitoring the air pressure for safe
operation of all air-operated components of the vehicle.
The dual air brake system consists of two independent air brake systems that use a single set of brake controls.
Each system has its own reservoirs, plumbing, and brake chambers. The primary system operates the service brakes on
the rear axle; the secondary system operates the service brakes on the front axle. Service brake signals from both
systems are sent to the trailer.
Loss of air pressure In the primary system causes the rear service brakes to become inoperative; front brakes will
continue to be operated by the secondary system air pressure. In addition, trailer brakes will be operated by the
secondary system. Loss of secondary system air pressure causes the front axle brakes to become Inoperative; rear
service brakes and trailer brakes will be operated by the primary system.
The warning light and buzzer come on If air pressure drops below 64-76 psi (441-524 kPa) in either system. If
this happens, check the dual system air pressure gage to determine which system has low air pressure. Although the
vehicle's speed can be reduced using the foot brake
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