•Do not increase engine speed
until the oil pressure gauge
indicates normal pressure; this
should be indicated on the gauge
within 15 seconds after starting.
•Idle the engine for three to five
minutes before operating with a
full load.
•Try to limit engine idle to 10
minutes. Excessive idling reduces
fuel economy.
•When starting a cold engine, increase the engine speed (RPM) slowly
to make sure adequate lubrication is available to the bearings.
Cold weather operation
Do not use volatile starting aids such as ether, propane or
gasoline in the engine air intake system. Glow plugs may ignite
vapors which can cause engine damage or personal injury.
In order to operate the engine in temperatures of 32°F (0°C) or lower,
read the following instructions:
•Make sure that the batteries are of sufficient size and are fully
charged. Check other electrical components to make sure they’re in
optimum condition.
•Use a permanent-type engine coolant solution to protect the engine
against damage from freezing.
•If your vehicle is equipped with a water-fuel separator, drain it daily.
Fill the fuel tank at the end of daily operation to prevent condensation
in the fuel system.
•Make sure you use proper cold weather engine oil and that it is at its
proper level.
•At temperatures of –4°F (–20°C) or below, it is recommended that you
use a crankcase-mounted coolant heater to improve cold engine
starting.
•If operating in arctic temperatures of –20°F (–29°C) or lower, consult
your truck dealer for information about special cold weather
equipment and precautions.
Note:Idling in cold weather will not heat the engine to its normal
operating temperature. Long periods of idling in cold weather can cause
2008 F-650/750(f67)
Supplement
USA(fus)
Driving
87
a buildup of heavy deposits of carbon and rust on valve stems causing
them to stick which, in turn, can cause valvetrain damage.
Winter fronts
The use of winter fronts, or other air-restrictive devices mounted in front
of the radiator on vehicles with chassis-mounted charge air coolers, are
not recommended unless extremely cold weather conditions exist. Air
flow restriction can cause high exhaust temperatures, power loss,
excessive fan usage and a reduction in fuel economy. If you must use a
winter front, the device should have a permanent opening of at least 120
sq in. (774 sq. cm) directly in line with the fan hub.
Hot weather operation
•Keep the engine cooling system filled with a clean, permanent coolant
solution to protect against damage from overheating.
•Fill the fuel tank at the end of daily operation to prevent condensation
in the fuel system.
•Keep external surfaces of the engine, radiator, charge air cooler, A/C
condenser and accessories clean to avoid dirt build-up.
Above normal coolant temperatures could be experienced while driving
in a transmission gear ratio which lugs the engine. To correct this
problem, engine speed should be increased by downshifting in to the
next lower gear to increase engine RPM.
Starting a turbocharged engine with the vehicle on a steep grade
When starting a diesel engine when the loaded vehicle is on a grade, the
engine RPM will start to fall slightly when the clutch is engaged; do not
disengage the clutch and try to increase engine RPM as this may damage
driveline components. The engine will recover as the vehicle begins
moving.
Engine shutdown
Allow the engine to idle for three to five minutes before shutting it
down. The larger the engine, the greater the need for this idling period.
However, do not let the engine idle for more than 10 minutes.
Restarting after running out of fuel
The fuel system may need to be purged of air, refer toRunning out of
fuelin theMaintenance and Specificationschapter.
2008 F-650/750(f67)
Supplement
USA(fus)
Driving
88
If brakes do not grip well
•If you have been driving through deep water, gently apply the brakes
several times while the vehicle is moving slowly.
•Let the brakes cool if you have been using them excessively, as in
mountain driving or after several fast, high speed stops.
•Check brake adjustment.
•Check brake linings for excessive wear.
•Check system air pressure. (Air brakes only)
HYDRAULIC BRAKES (IF EQUIPPED)
HydroMax brake booster system
The HydroMax systems receive fluid pressure from the power steering
pump to provide power assist during braking.
The HydroMax booster receives back-up pressure from the reserve
system electric pump whenever the fluid in the power steering system is
not flowing. When the engine is off, the pump will turn on if the brake
pedal is applied, or if the ignition is turned to the ON position.
The sound of the pump operating or fluid flowing through the booster
may be heard; this is a normal characteristic of the system and should be
no reason for concern.
The reserve system provides reduced braking power, so the vehicle
should be operated under these conditions with caution, and only to seek
service repair and remove the vehicle from the roadway.
If braking performance or pedal response becomes very poor, even when
the pedal is strongly applied, this may indicate the presence of air in the
hydraulic system or fluid leakage. Stop the vehicle safely as soon as
possible and seek service immediately.
If the red BRAKE warning lamp in
the instrument cluster remains
illuminated after engine start up,
this indicates a system failure in the
master cylinder of the brake system. Stop the vehicle safely as soon as
possible and seek service immediately.
2008 F-650/750(f67)
Supplement
USA(fus)
Driving
92
Periodically check the air pressure
gauge while driving. Pressure should
range between approximately
100–125 psi (690–862 kPa). The air
compressor governor cut-in and
cut-out pressure settings are preset
at the factory and are not
adjustable.
When air pressure is insufficient
(below 60 psi [414 kPa]), a warning
light illuminates and a buzzer
sounds when the ignition is in the
ON position.
This condition may be caused by excessive brake applications depleting
the system air pressure. If this condition occurs, stop driving the vehicle
until the compressor has fully recharged the air system.
Do not move the vehicle when the air pressure is insufficient
because the brake system may be inoperative.
Select a gear ratio to help slow your vehicle before descending grades.
Supplement with brakes as required to safely slow the vehicle and avoid
overspeeding the engine.
Air chamber stroke indication
Air chamber push rods have orange stroke indicator markers that warn
when the braking system requires adjustment or repair. The orange
stripe is painted on the air chamber push rod at the slack adjuster stroke
dimension which requires service when visible during brake application.
Air brake inspection and adjustment or repairs should be performed by a
qualified service technician in accordance with the instructions in the
service manual.
2008 F-650/750(f67)
Supplement
USA(fus)
Driving
98
Parking brake control (knob)
Pull the yellow parking brake knob
out to apply the parking brake. Push
the knob in to release the parking
brake.
This control is used for
parking only. Do not leave
the vehicle unattended after
setting the parking brake without
placing the transmission in R
(Reverse) for manual
transmission, N (Neutral) for
automatic transmission (except
Allison 2200 transmission) or P
(Park) (Allison 2200
transmission). Use of wheel
chocks is also recommended in
hilly or off-road usage.
The parking BRAKE warning lamp
in the instrument cluster illuminates
and remains illuminated (when the
ignition is turned ON) until the
parking brake is released.
Releasing spring brake with air pressure
The air system in all vehicles with spring-actuated rear wheel parking
brakes is equipped with a tank valve located on the supply or service air
tank for connection to an outside air supply. The valve permits the
system to be recharged with air from an outside source, releasing the
spring-actuated parking brakes. The vehicle may then be towed in an
emergency.
An outside air source can be used only if the protected system is in
operating condition. If air pressure cannot be restored in the protected
air system, the spring-actuated brakes must be released manually.
P
BRAKE
2008 F-650/750(f67)
Supplement
USA(fus)
Driving
101
4. Turn the release stud one-quarter
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.
5. Tighten the nut until the spring is
fully caged and the brakes are
released. Do not loosen or remove
the release stud and nut unless the brake chamber is completely
assembled and is securely clamped.
6. When the air pressure is restored, unscrew and remove the release
stud and install in the carrying pocket. Install the access plug.
EXHAUST BRAKE (IF EQUIPPED)
Note:The exhaust brake is
intended to help control vehicle
speed; it is not a vehicle stopping
device.
An exhaust brake is an optional
auxiliary braking system that assists,
but does not replace, the primary
service brake system. An on-off
switch on the instrument panel, in
combination with the accelerator
and clutch pedal switches, allows the operator to make maximum use of
the exhaust brake in the following conditions:
•off-highway driving
•mountain driving
•heavy traffic
•high speed highway driving
2008 F-650/750(f67)
Supplement
USA(fus)
Driving
103
Note:Installing an exhaust or auxiliary brake does not necessarily
protect the engine from exceeding maximum governed speed. The
primary brakes should be used to never allow the engine to exceed
maximum governed speed under any conditions.
TRAILER BRAKE HAND CONTROL (IF EQUIPPED)
The hand control, located on the
right-hand side of the instrument
panel, is used to apply the trailer
service brakes which are
independent of the truck or tractor
service brakes.
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 operates a valve that provides gradual control of air
pressure applied; when the valve is only partially applied, the trailer
brakes can be overridden by pressing fully on the brake pedal.
To apply the trailer brakes using the hand control, move the lever
downward. The further the lever is pushed downward, the greater the air
pressure is applied to the brakes. The lever will remain in place until
manually moved.
To release the trailer brakes, move the lever upward completely.
2008 F-650/750(f67)
Supplement
USA(fus)
Driving
106
Aggressive driving in any road conditions can cause you to lose
control of your vehicle increasing the risk of severe personal
injury or property damage. The occurrence of a Traction Control
event is an indication that at least some of the tires have exceeded
their ability to grip the road; this may lead to an increased risk of loss
of vehicle control, vehicle rollover, personal injury and death. If you
experience a severe road event, SLOW DOWN.
AIR SUSPENSION (IF EQUIPPED)
Note:The vehicle must not be operated without air in the suspension
springs. Operating the vehicle without air in the air suspension springs
will damage the suspension, degrade ride performance and may cause
property damage.
The suspension system automatically adjusts to different loads to
maintain a constant frame height. The system allows for ease of vehicle
loading and provides improved vehicle ride and increased driver comfort.
Air suspension dump switch
The system is controlled by a switch
located on the instrument panel.
The switch will operate only when
the ignition is in the ACC
(Accessory) or IGNITION positions
and the air tanks have sufficient
pressure to fill the air springs. When
the ignition is turned off, the
suspension will remain in whatever
state it was last set.
Note:The suspension will dump air when the ignition is in the ACC or
IGNITION position, but will only fill when the ignition is in the IGNITION
position.
When the upper portion of the switch is pressed air supplied to the air
spring is exhausted, lowering the frame for loading. Pressing the lower
portion of the switch causes air to fill the air springs so the vehicle will
remain at normal ride height.
2008 F-650/750(f67)
Supplement
USA(fus)
Driving
113