Ford F 750 Owners Manual

							WARNING
Sudden accelerations on slippery
surfaces could cause the wheels to
spin, the vehicle to turn sideways on
a crowned road surface or in a turn,
possibly resulting in loss of vehicle control
and personal injury. Activating the Locking Differential
You can lock and unlock the differential
when your vehicle is moving at a constant
speed of less than 25 mph (40 km/h) and
while the wheels are not slipping. Do not
lock the differential when your vehicle is
traveling down steep grades and when
traction is minimal.
The differential lock and differential lock
light automatically disengage at speeds
above 25 mph (40 km/h). The differential
lock remains off until either you restart your
vehicle or you turn the differential lock
switch off then back on.
Servicing a Vehicle with a Locking
Differential
Turn the engine off and raise all drive
wheels of the locker differential axle in
order to prevent your vehicle from moving
when servicing the wheels, tires or brakes.
Axles equipped with a driver-controlled
differential deliver power to both wheels
even when only one wheel is on the ground. WARNING
Failure to raise all drive wheels with
this type of differential could cause
the vehicle to move unexpectedly,
resulting in property damage, personal
injury or death. 2-SPEED REAR AXLE
 (If Equipped)
WARNING
Never shift a two-speed axle when
descending a steep grade as this
may cause loss of vehicle control and
result in personal injury. Note:
Do not shift between ranges when
the speed control is on.
A two-speed rear axle allows the driver to
select a low range for greater pulling power
and a high range for greater road speed
and fuel economy. You can also use these
ranges to provide extra steps between
transmission shifts when driving on steep
grades or fuel economy may be factors.
Axle Shifting Note:
Do not shift the axle to LOW when
your vehicle is moving. Use LOW when you
drive a fully loaded vehicle on a severe grade
or in congested traffic. Use HIGH for all
normal driving conditions with a lightly
loaded or partially loaded vehicle.
Note: The axle is set to HIGH by default.
To shift the axle between HIGH and LOW
with the vehicle stopped, place the
transmission in position N, then press and
hold the button for two seconds.
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							GENERAL INFORMATION
WARNINGS
Do not drive with your foot resting on
the brake pedal. This results in
abnormally high brake temperatures,
excessive lining wear and increased
stopping distance. Continuous application of the brakes
causes the brakes to overheat,
resulting in temporary loss of braking.
Note:
Occasional brake noise is normal. If
a metal-to-metal, continuous grinding or
continuous squeal sound is present, the
brake linings may be worn-out. Have the
system checked by an authorized dealer. If
your vehicle has continuous vibration or
shudder in the steering wheel while braking,
have it checked by an authorized dealer.
All standard equipment brakes are
self-adjusting. Automatic adjustment,
when required, occurs whenever you apply
and release the brakes during forward or
reverse operation.
Know the required stopping distances for
all driving conditions you may encounter.
For longer brake lining life, take full
advantage of engine braking power when
coming to a stop. See Warning Lamps and
Indicators (page 58).
Wet brakes result in reduced braking
efficiency. Gently press the brake pedal a
few times when driving from a car wash or
standing water to dry the brakes.
If brakes do not grip well:
• Check brake adjustment.
• Check brake linings for excessive wear.
• Check system air pressure on vehicle
equipped with air brakes. •
Let the brakes cool if you have been
using them excessively, as in mountain
driving or after several fast, high-speed
stops.
• If you have been driving through deep
water, gently apply the brakes several
times while your vehicle is moving
slowly.
Brake Over Accelerator
In the event the accelerator pedal
becomes stuck or entrapped, apply steady
and firm pressure to the brake pedal to
slow the vehicle and reduce engine power.
If you experience this condition, apply the
brakes and bring your vehicle to a safe
stop. Move the transmission to park (P),
switch the engine off and apply the parking
brake. Inspect the accelerator pedal for
any interference. If none are found and the
condition persists, have your vehicle towed
to the nearest authorized dealer
Anti-lock Brake System
This system helps you maintain steering
control during emergency stops by keeping
the brakes from locking. This lamp momentarily
illuminates when you turn the
ignition on. If the light does not
illuminate during start up, remains on or
flashes, the system may be disabled. Have
the system checked by an authorized
dealer. 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.
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							If you connect a PLC trailer with
the ignition on, the trailer ABS
light also illuminates. If the light
fails to illuminate, if it remains on after you
start the vehicle or continues to flash, have
the system serviced immediately.
HINTS ON DRIVING WITH
ANTI-LOCK BRAKES
Note: When the system is operating, 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.
The anti-lock braking system will 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.
PARKING BRAKE
Hydraulic Brakes WARNINGS
Always set the parking brake and
leave your vehicle with the
transmission in park (P).
When doing this procedure, you need
to take the transmission out of park
(P) which means your vehicle can
roll freely. To avoid unwanted vehicle
movement, always fully set the parking
brake prior to doing this procedure. Use
wheels chocks if appropriate. Unexpected and possibly sudden
vehicle movement may occur if you
do not take these precautions. WARNINGS
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. 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.
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							Releasing Spring Manually
WARNINGS
Do not attempt to disassemble the
parking brake air chamber under any
circumstances as this may cause
serious injury. Block the wheels to help prevent the
vehicle from moving.
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
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.
Releasing the Parking Brake WARNING
Hold the brake pedal down when
moving the gearshift lever. If you do
not hold down the brake pedal, the
vehicle may move unexpectedly, resulting
in property damage, personal injury or
death. 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.
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							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.
5. Tighten the nut until the spring is fully caged and brakes released. Do not
loosen or remove the release stud and
nut unless you completely assemble
and securely clamp the brake chamber.
6. After restoring the air pressure, unscrew and remove the release stud
and install in the carrying pocket. Install
the access plug.
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							FULL POWER BRAKE
WARNING
If the brake warning lamp in the
instrument cluster remains
illuminated after engine start up, this
indicates a system failure in the Full Power
Brake system. Stop the vehicle safely as
soon as possible and seek service
immediately. This system incorporates standard braking,
an anti-lock braking system (ABS) and
optional Power Park Brake into one fully
integrated hydraulic brake system. With
the Full Power Brake system, braking
energy is stored, similar to an air brake
system, resulting in faster response times
and shorter stopping distances. This is
accomplished using motor and pump
assemblies that pressurize the system by
pumping brake fluid into accumulators.
This is similar to the air compressor of an
air brake system pressurizing the air tanks.
The system includes a master cylinder that
provides the normal pedal feel and
transfers the pedal force, via brake fluid,
to the main components of the system.
Note:
The motor and pumps run
momentarily with the ignition switch in the
on or run position, or in the off position with
the brake pedal pressed.
Note: During normal driving, you may hear
the pump and motors replenishing the
accumulators. This is a normal function of
the system. AIR BRAKES WARNINGS
Do not drive or continue to drive if the
low air pressure buzzer is sounding
or the brake warning light is lit. These
warnings indicate that air pressure is not
to normal operating level. Continued use
of the vehicle could result in loss of braking
ability. Avoid repeated light application of
the brake pedal. This depletes air
pressure faster and could result in
loss of braking capability. Do not move the vehicle when the
air pressure is insufficient because
the brake system may be inoperative.
After starting the engine, give the air
compressor time to build up the air
pressure to 60 psi (414 kPa) before moving
your vehicle. Periodically check the air pressure gauge
while driving. Pressure should range
between approximately 100 psi (690 kPa)
to 
130 psi (896 kPa). The air compressor
governor cut-in and cutout pressure
settings are set at the factory and are not
adjustable.
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							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 may happen because
excessive brake applications are depleting
the system air pressure. If this condition
occurs, stop driving your vehicle until the
compressor has fully recharged the air
system.
Select a gear ratio to help slow your vehicle
before descending grades. Supplementing
with brakes, as required, help to safely slow
the vehicle and avoids 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 painted orange indicator is on
the air chamber push rod at the slack
adjuster stroke dimension that requires
service when visible during brake
application.
A qualified service technician should
perform air brake inspection and
adjustment or repairs keeping to the
instructions in the service manual.
Cam Brakes - Automatic Slack
Adjusters WARNING
Do not manually adjust the
automatic slack adjusters to correct
excessive push rod stroke as it may
result in reduced brake effectiveness and
a vehicle crash. Excessive push rod stroke
indicates that a problem exists with the
automatic adjuster, with the installation
of the adjuster, or with foundation brake
components that manual adjustment does
not remedy. Seek service from a qualified
facility for excessive push rod stroke. Standard air brakes (cam) are equipped
with automatic brake adjusters. Automatic
adjustment occurs during brake
applications. Inspect brakes for proper
adjustment at the specified intervals.  See
Scheduled Maintenance
 (page 316).
Emergency Air Brake WARNING
Do not continue to operate the
vehicle with a failure of one of the
brake systems. Take the vehicle to
your dealer for service immediately. All vehicles are equipped with a dual brake
system. In the unlikely event of a failure of
one system, the second system functions
for emergency stopping. The brake pedal
controls all these systems in the same
manner as for normal stops.
EXHAUST BRAKE
WARNING
The exhaust brake is not
recommended for use on slippery or
low traction road surfaces. Under
these conditions a loss of vehicle control
could occur. 124
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							Note:
Installing an exhaust or auxiliary
brake does not necessarily protect the
engine from exceeding maximum governed
speed. Use the primary brakes to make sure
the engine never exceeds maximum
governed speed under any circumstance.
Note: Before starting the engine, make sure
that the exhaust brake switch is in the off
position. Do not turn the exhaust brake on
until the engine has reached normal
operating temperature.
Note: Maximum exhaust brake
performance relates to the type of
transmission your vehicle has.
Note: Engine speed has a major influence
of retarding performance. When engine
speed stays at the maximum allowable
level, the exhaust brake operates at peak
performance.
Note: Exhaust brakes operate effectively
with automatic transmissions, but
performance varies with engine speed and
the gear selected by the transmission.
An exhaust brake is an auxiliary braking
system that assists, but does not replace,
the primary service brake system. It helps
control vehicle speed; it is not a
vehicle-stopping device. A switch on the instrument panel, in
combination with the accelerator and
clutch pedal, allow 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.
To switch the brake on, push the switch
up. Push the switch down to turn it off.
While approaching a steep grade, make
sure that the exhaust brake switch is in the
on position. The exhaust brake begins
working as soon as you remove your foot
from the accelerator pedal.
Before descending a hill or steep grade,
always select the proper gear. If you take
the transmission out of gear while
descending, it is possible that you cannot
select another gear because of maximum
governed RPM.
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							Make sure the engine speed does not
exceed the maximum allowable engine
RPM. Exceeding the maximum allowable
engine RPM can result in damage to the
engine. Apply the service brakes to reduce
the engine RPM or make a slower descent
by using a lower gear.
While going down the grade, use a low
enough gear to descend safely with a
minimum application of the service brakes.
As a general guideline, use the same gear
as you use to ascend the hill.
Exhaust Brake Operating
Characteristics
The exhaust brake turns on when you
remove your feet from both the accelerator
and clutch pedals and the exhaust brake
switch is in the on position. The following
conditions exist if the brake is operating
properly:
•
A slight change in engine sound when
the exhaust brake turns on.
• A smooth braking effect. Do not expect
a retarding effect similar to sudden,
hard application of the service brakes.
• The retarding force possibly felt acting
against your body during brake
application (depending on the grade
and vehicle load). This force is actually
preventing the vehicle from going much
faster.
• Engine temperature remaining in the
normal operating range.
• The tachometer showing 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
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.
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							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)
. 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.
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B
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