TM 9-2320-272-10
3-12.
AIR SYSTEM SHUTOFF VALVES
General. Primary and secondary air systems are provided with shutoff valves to isolate them from the rest of the
vehicle air system. These valves are closed by the operator only in an emergency situation.
(1)
The primary system air shutoff valve (1) on the M939/A1 series vehicles is located at the forward end of the
wet tank. On the M939A2 series vehicles, it is at the side of the wet tank reservoir. If air leaks in the primary system and
the vehicle must be driven, close air shutoff valve (1). Closing the primary system air shutoff valve (1) will isolate the
primary system and maintain air pressure to brake system components and enable operator to slow down or stop the
vehicle.
(2)
The secondary system air shutoff valve (2) is located on top of the wet tank reservoir. In the event of an air
leak in the secondary system and the vehicle must be driven, close air shutoff valve (2). Closing the secondary system
and air shutoff valve (2) will isolate the secondary system and maintain air pressure to brake system components and
enable operator to slow down or stop the vehicle.
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