User Manual

CAUTION
Do not try to put the vehicle in motion
before
pressure in the system reaches
100 psi (689 kPa) because the wheels
are locked by the spring brake action.
Unnecessary stress and possible
brake malfunction could occur if the
vehicle is forced to move before the air
system reaches 100 psi (689 kPa).
Failure to comply may result in equip-
ment damage.
WARNING
If the air pressure falls below 60 psi
(414
kPa) the spring brakes may stop
the vehicle abruptly, which could
cause an accident resulting in person-
al injury or death. Observe the gauges.
If the warning alert comes on, do not
continue to drive the vehicle until it has
been properly repaired or serviced.
WARNING
Using the trailer hand brake or air
brakes
to hold a parked vehicle is dan-
gerous. Because they work with air
pressure, these brakes could come
loose. Your vehicle could roll, causing
an accident involving death or person-
al injury. Always set the parking
brakes. Never rely on the trailer hand
brake or truck air brakes to hold a
parked vehicle.
Vehicle/Trailer Air Supply Valve
Initial Charge
The red octagon knob controls the air
supply to the trailer. With the system
completely discharged, both the Red
(trailer air supply) and the Yellow (parking
brake) knobs are OUT; thus, vehicle and
the trailer parking (spring) brakes are
applied.
To supply air to the trailer system and
release the trailer parking brakes:
1. Allow the vehicle air system
pressure to build up to operating
level.
2. When system pressure reaches 50
psi (345 kPa) the Red knob may be
pushed IN.
3.
Hold the Red knob IN by hand until
the trailer air pressure builds to a
pre-set level, about 45 psi (310
kPa). At this point it will remain in,
charging the trailer system and
releasing only the trailer brakes.
4. The Yellow knob will remain OUT
(vehicle brakes ON).
Normal Run Position
• The Yellow knob (system park)
may now be pushed IN, which will
supply air to the vehicle spring
brakes, releasing them.
DRIVING - Air Brake System (option)
138 Y53-6113-1A1 (11/20)
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