TM 9-2320-272-24-1
1-23. COMPRESSED AIR AND BRAKE SYSTEM OPERATION (Contd)
Key Item and Function
A FRONT EMERGENCY COUPLING -When vehicle is being towed, coupling receives compressed
air from towing vehicle's brake system to charge its own brake system.
B PRIMARY AIR RESERVOIR - Stores sufficient air pressure to allow operator to make normal
brake applications if system pressure fails or engine stalls.
C PRIMARY FEED CUTOFF - Manually-operated valve used to isolate pressure leaks in primary air
system from draining wet tank (TM 9-2320-272-10).
D PRIMARY AIR RESERVOIR CHECKVALVE - Prevents backflow of air from primary tank if wet
system develops a leak.
E SECONDARY FEED CUTOFF - Manually-operated valve used to isolate pressure leaks in
secondary air system from draining wet tank (TM 9-2320-272-10).
F SECONDARY AIR RESERVOIR CHECKVALVE - Prevents backflow of air from secondary tank if
wet system develops a leak.
G REAR EMERGENCY COUPLING - When towing another vehicle, coupling allows pressurized air
from wet tank to charge towed vehicle's wet tank.
H SECONDARY AIR RESERVOIR - Stores enough air pressure in case constant pressure system
fails or engine stalls. The operator can make normal brake application before running out of air.
PRESSURE PROTECTION VALVE - Performs two functions:
I
(1) Allows air pressure to build to 60-65 psi (414-448 kPa) before supplying air to auxiliary air-
powered equipment.
(2) Closes off auxiliary air system from other systems if an accessory fails and prevents loss of air
from secondary reservoir.
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