If the system is disabled, normal
braking is still effective. If the
brake warning lamp illuminates
when you release the parking brake, have
the system checked by an authorized
dealer. It also illuminates momentarily
when you switch the ignition on to confirm
the lamp is functional. If it does not
illuminate when you switch the ignition on,
or begins to flash at any time, have the
system checked by an authorized dealer.
HINTS ON DRIVING WITH
ANTI-LOCK BRAKES
The anti-lock braking system does not
eliminate the risks when:
• You drive too closely to the vehicle in
front of you.
• Your vehicle is hydroplaning.
• You take corners too fast.
• The road surface is poor.
Note: If the system activates, the brake
pedal may pulse and may travel further.
Maintain pressure on the brake pedal. You
may also hear a noise from the system. This
is normal.
PARKING BRAKE
Hydraulic Brakes (If Equipped) WARNING:
Always set the parking
brake and leave your vehicle with the
transmission in park (P). WARNING:
This control is for
parking only. Do not leave the vehicle
unattended after setting the parking
brake without placing the transmission
in park (P). We recommend using wheel
chocks for hilly or off-road
circumstances. WARNING:
Unexpected and
possibly sudden vehicle movement may
occur if you do not take these
precautions. WARNING:
If the parking brake is
fully released, but the brake warning
lamp remains illuminated, the brakes
may not be working properly. Have your
vehicle checked as soon as possible.
Apply the parking brake whenever the
vehicle is parked. To set the parking brake,
pull the handle up until it snaps into the
locked position.
When the parking brake is out of
adjustment, seek service immediately. The parking brake warning lamp
in the instrument cluster
illuminates, and remains
illuminated (when you switch on the
ignition), until you release the parking
brake. 123
F650750 (TBC) , enUSA, Edition date: 201804, Second-Printing BrakesE209041 E208810 E210347
Push the palm release lever (A) on the
parking brake handle (B) and push down
as far as possible to release the brake.
Driving with the parking brake on causes
the brakes to wear out quickly and reduces
fuel economy.
We recommend you not use the parking
brake to stop a moving vehicle. However,
if the normal brakes fail, you can use the
parking brake to stop your vehicle in an
emergency. Since the parking brake only
applies retardation to the rear wheels, the
vehicle's stopping distance increases
greatly and the handling of your vehicle is
adversely affected.
Releasing Spring Manually
WARNING: Do not attempt to
disassemble the parking brake air
chamber under any circumstances as
this may cause serious injury. WARNING:
Block the wheels to
help prevent the vehicle from moving. WARNING:
Unexpected and
possibly sudden vehicle movement may
occur if you do not take these
precautions.
If you release hydraulic pressure from the
spring brake chamber, the power spring
applies the brake. If the hydraulic pressure
can be re-established, you must release
the spring brake in order to move your
vehicle. Air Brakes
(If Equipped) WARNING:
This control is for
parking only. Do not leave the vehicle
unattended after setting the parking
brake without placing the transmission
in park (P). We recommend using wheel
chocks for hilly or off-road
circumstances.
If the service brakes fail to operate while
your vehicle is moving, you can make an
emergency stop with the parking brake.
Since the parking brake only applies
stopping power to the rear wheels, your
vehicle ’s stopping distance greatly
increases and the handling of your vehicle
is adversely affected. Make repairs
immediately to an inoperative air brake
system circuit. Pull the yellow, dash-mounted parking
brake knob to apply the parking brake.
The parking brake light
illuminates and remains
illuminated (when you switch
the ignition to the on position) until you
release the parking brake.
124
F650750 (TBC) , enUSA, Edition date: 201804, Second-Printing BrakesE210341 E208810
Releasing the Parking Brake
WARNING: When your vehicle is
stationary, keep the brake pedal fully
pressed when shifting gears. Failure to
follow this instruction could result in
personal injury, death or property
damage.
Note: Read and understand the following
steps and perform them whenever you
prepare to drive the vehicle.
Note: The parking brake does not disengage
unless sufficient system air pressure is
available.
1. Press and hold the service brake pedal
while the engine is running.
2. Select the appropriate drive gear.
3. Push and hold the yellow dash-mounted parking brake knob until
the parking brake light turns off, then
release.
Parking Brake Light Illumination Due
to Low Air Pressure
If the air pressure becomes too low at any
time during vehicle operation, the parking
brake may apply and the parking brake
light turns on.
If the parking brake applies due to low air
pressure, immediate service is required to
the parking brake system.
Releasing Spring Brake with Air
Pressure
The air system in all vehicles with
spring-actuated rear wheel parking brakes
has a valve on the governor for connection
to an outside air supply. The valve lets you
recharge the system with air from an
outside source, releasing the
spring-actuated parking brakes. Your
vehicle is now ready to tow in an
emergency. You can only use an outside air source if
the protected system is in operating
condition. If you cannot restore air pressure
in the protected air system, you must
release the spring-actuated brakes
manually.
Releasing Spring Manually
Do not use impact wrenches as they may
damage the piston and prevent proper
caging of the spring. Do not apply more
than
50 lb.ft (68 Nm) to the release bolt
nut.
1. Remove the stud tool and nut from the
carrying pocket on the brake chamber
assembly. 2. Remove the access plug from the end
of the spring chamber.
3. Insert the release stud through the opening in the chamber and into the
spring pressure plate. 4.
Turn the release stud ¼ turn to engage
the stud tangs with the slot in the
pressure plate. Keep the stud engaged
and install the nut on the release stud.
125
F650750 (TBC) , enUSA, Edition date: 201804, Second-Printing BrakesE210365 E210366
•
A retarding force possibly felt acting
against your body during brake
application (depending on the grade
and vehicle load). This force prevents
the vehicle from going much faster.
• Engine temperatures remaining in the
normal operating range.
• A drop in engine RPM (depending on
grade and vehicle load) during a
descent.
• A decrease in road speed when
applying the exhaust brake during a
descent, except when your vehicle is
carrying a heavy load or the grade is
extremely steep. In these instances,
you may need to apply the service
brakes occasionally.
TRAILER BRAKES (IF EQUIPPED)
Trailer Brake Hand Control (If Equipped) WARNING:
The hand control
should never be used to apply the brakes
when the tractor and trailer are parked
unattended. Air may leak from the
system and the vehicle could possibly
move, resulting in possible property
damage, personal injury or death. The hand control is located on the
right-hand side of the instrument panel. It
applies the trailer service brakes, which are
independent of the truck or tractor service
brakes. It operates a valve that provides gradual
control of air pressure applied. When the
valve is only partially applied, you can
override the trailer brakes by pressing fully
on the brake pedal.
To apply the trailer brakes using the hand
control, move the lever downward. The
further you push the lever down, the
greater the air pressure is applied to the
brakes. The lever remains in place until
manually moved.
To release the trailer brakes, move the
lever up completely.
Trailer Air Supply and Parking
Brake Modular Controls
(If Equipped)
The trailer air supply valve delivers air to
the trailer supply and automatically pops
out, shutting off the trailer supply, if
pressure decreases to approximately 35 psi
(249 kPa)
.
129
F650750 (TBC) , enUSA, Edition date: 201804, Second-Printing BrakesE210339 E210340
A
B
12
A320
A E210341
The parking brake controls the spring
brakes on the tractor. When you pull the
knob out, it causes the trailer supply valve
to pop out, applying both the tractor and
trailer parking brakes. You can
independently release the trailer brakes by
pushing only the trailer air supply valve in.
Initial Charge With the air system completely discharged,
both knobs (A and B) are out. When the
air pressure reaches 70 psi (481 kPa), the
trailer air supply (A - red knob) may be
pushed in and should stay in, charging the
trailer air system and releasing the trailer
brakes. You can push in the parking brake (B -
yellow knob) and supply air to the tractor
spring brakes, releasing them.
Normal Driving Position
Push in both knobs (A and B) to supply air
to both trailer and tractor spring brakes,
releasing all brakes.
130
F650750 (TBC) , enUSA, Edition date: 201804, Second-Printing BrakesE210342 E210343 E210343
System Park
With both knobs (A and B) pushed in
(normal driving position), the parking
brakes for both the tractor and trailer can
be applied by pulling the parking brake
knob (B) out, exhausting air from the
tractor spring brakes, simultaneously
causing the trailer air supply valve to pop
out, applying the trailer brakes.
Trailer Charge
If both knobs (A and B) are out, and you
want to recharge the trailer while leaving
the tractor spring brakes applied, the trailer
air supply (A) can be pushed in to recharge
the trailer air supply line. You can also use
this mode to park a combination vehicle
with tractor spring brakes.
131
F650750 (TBC) , enUSA, Edition date: 201804, Second-Printing BrakesE210344 E210342
Automatic Application
If both knobs (A and B) are pushed in and
the brake system air pressure is reduced
to approximately 35 psi (249 kPa), the
trailer air supply (A) knob automatically
pops out applying the emergency or
parking brakes on the trailer. If the trailer
air supply (A) knob is manually held in and
the air pressure is reduced to
approximately
30 psi (207 kPa), a tripper
piston within the valve moves, exhausting
the trailer air supply, applying the trailer
brakes. Further reduction of air pressure,
while holding the trailer air supply knob in,
causes the parking brake knob to pop out
at
25 psi (172 kPa).
Actuation of Trailer Park (Emergency)
or Tractor Bobtail Position To actuate the trailer brakes only, pull out
the trailer air supply (A) knob. This applies
the trailer brakes whether the trailer uses
emergency or spring brakes.
You can also use this mode when the
tractor or truck with trailer is used during
bobtail operation.
132
F650750 (TBC) , enUSA, Edition date: 201804, Second-Printing BrakesE210345 E210345
•
Shift to a lower gear when driving down
a long or steep hill. Do not apply the
brakes continuously, as they may
overheat and become less effective.
• If your transmission is equipped with
the Tow/Haul feature, use this feature
when towing. This provides engine
braking and helps eliminate excessive
transmission shifting for optimum fuel
economy and transmission cooling.
• Allow more distance for stopping with
a trailer attached. Anticipate stops and
brake gradually.
FIFTH WHEEL OPERATION WARNING: Failure to follow the
fifth wheel manufacturer ’s instructions
for hooking and unhooking as well as
sliding the fifth wheel could result in an
accident, personal injury or death. WARNING:
When the tractor and
trailer are parked unattended, the trailer
brake hand control should never be used
to apply the brake, since air may leak
from the system, allowing vehicle
movement, resulting in possible property
damage, personal injury or death.
Before hook-up, make sure:
• The fifth wheel jaws are fully open.
• The fifth wheel is fully tilted back to
prevent body damage when the tractor
is backed under a trailer.
• You block the trailer wheels and adjust
and apply the trailer spring brakes.
Never chase a trailer.
• The brake hoses and light cords are
clear of the fifth wheel. Hook-up
1. Back the tractor squarely under the
trailer, engaging the fifth-wheel jaws
on the kingpin. Always back up slowly;
make sure the trailer is neither too high
nor too low. Avoid backing under the
trailer from an angle.
2. Connect the service and emergency brake hoses and trailer light connector.
3. Inspect the jaws of the fifth wheel to be sure they have fully closed on the
trailer kingpin and the trailer plate is
resting securely on the fifth wheel.
4. Make sure the coupler release lever is in the locked position.
5. Charge the trailer brake system. Set the trailer brakes, with either the hand
valve or tractor protection valve. Pull
against the trailer for an extra check of
proper hook-up. Do not pull hard
enough to damage or strain the
equipment.
6. Set the tractor parking brakes and fully
raise the trailer landing gear.
7. Check the operation of all trailer lights
and correct any lights that may be
faulty.
Un-hook
1. Try to keep the tractor and trailer in a straight line.
2. Apply the parking brakes.
3. Lower the trailer landing gear, making sure it is on solid, level ground. The
weight of the trailer is to be on the
landing gear.
4. Block the trailer wheels.
5. Disconnect the brake hoses and light cords. Be sure hoses and cords are
clear.
6. Pull coupler release lever to disengage
the fifth wheel jaws.
147
F650750 (TBC) , enUSA, Edition date: 201804, Second-Printing Towing