TM 9-2320-272-24-1
1-23. COMPRESSED AIR AND BRAKE SYSTEM OPERATION (Contd)
Key Item and Function
A SPRING BRAKE RELEASE CONTROL VALVE - This valve functions as an override when a
failure in the air supply system (causing spring brakes to engage) occurs. When valve is manually
pushed in, emergency air is supplied to the spring brake chambers. This releases the spring brakes,
allowing vehicle movement.
B PEDAL VALVE - Vents primary or secondary signal air pressure when pedal is released.
C FRONT BRAKE CHAMBER VENT - Vents air pressure inside chambers when pedal valve is
released.
D LIMITING VALVE - Vents signal air pressure going to front brake chambers so rear brakes apply
first.
E STEP BOX QUICK-RELEASE VALVE - Vents air pressure from spring brake chambers when
parking brake valve has been actuated.
F REAR BRAKE CHAMBERS - Vents ports on chambers to prevent air pressure buildup.
pedal is released. Vents signal air pressure through upper port in valve.
H AIR INTAKE STACK - Venting point for the vent system.
I
TRANSMISSION VENT - Vents internal air pressure buildup due to internal heat.
J SPRING PARKING BRAKE VALVE - Vents air pressure from air and doublecheck valves No. 3
and No. 4.
K TRANSFER CASE VENT - Vents internal air pressure buildup due to internal heat.
L FUEL TANK VENTS - Vent fuel vapors to prevent partial vacuum from stopping fuel flow.
1-69
