2003 FORD F650 service

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 will
deplete air pressure faster and could result in loss of braking
capability.
Periodically check the air pressure
gauge while driving. Pressure should
range between approximately 724 to
930 kPa (105-135 psi). 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 414 kPa [60 psi]), 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 in this condition 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
All Ford air chamber push rods have orange stroke indicator stripes that
alert the operator when the braking system requires adjustment or
repair. The orange stripe is painted on the air chamber push rod at the
slack adjuster readjustment stroke dimension.
Air brake inspection and adjustment should be performed by a qualified
service technician in accordance with the instructions in the Ford Truck
Service Manual.
0 30 12090 60
150AIR
PRESSUREPSI
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Cam brakes—automatic slack adjusters
Standard air brakes (cam) are
equipped with automatic brake
adjusters. Automatic adjustment
occurs during forward and reverse
brake applications. Inspect brakes
for proper adjustment at the
intervals listed in the vehicle Service
Maintenance Guide.
Emergency air brake
All vehicles are equipped with a dual brake system. In the unlikely event
of a failure of one system, the second system will function for emergency
stopping. These systems are all controlled by the brake pedal in the
same manner as for normal stops.
Do not continue to operate the vehicle with a failure of one of
the systems. Take the vehicle to your dealer for service
immediately.
Anti-lock braking system (if equipped)
For information on the anti-lock braking system (ABS), refer to
Hydraulic brakesin this chapter.
Driving with ABS
Maintain a steady brake pedal application; you do not need to pump or
remove your foot from the pedal. The ABS keeps the wheels rolling
during braking to maintain control and reduce stopping distances. For
information on the anti-lock braking system (ABS), refer toHydraulic
brakesin this chapter.
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Parking brake
Do not use the gearshift selector in place of the parking brake.
Always set the parking brake fully AND make sure the gearshift
selector is in R (Reverse) for vehicles equipped with manual
transmission or N (Neutral) for vehicles with automatic transmission.
Unexpected and possible sudden vehicle movement may occur if
these precautions are not taken.
If the service brakes should fail to operate while the vehicle is in motion,
you can make an emergency stop with the parking brake. The stopping
distance, however, will be much greater than normal. Repairs should be
made immediately to an inoperative air brake system circuit.
Parking brake control
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
or N (Neutral) for automatic
transmission. Use of wheel chocks
is also recommended in hilly or
off-road usage.
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.PARKING
BRAKE
PULL TO
RELEASE
APPLY
PUSH TO
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System park
With both controls in for normal run modes, the parking brakes on both
tractor and trailer may be actuated by pulling the yellow control (parking
brake) out, which exhausts the air from the tractor spring brakes and
simultaneously causes the red control (trailer supply) to pop out,
applying the trailer brakes. This complies with federal regulations stating
one control must apply all the parking brakes on the vehicle.
Trailer charge
If both controls are out when parking the combination vehicle and it is
desired to recharge the trailer (leaving the tractor spring brakes
applied), the trailer air supply control may be pushed in, repressurizing
the trailer supply line. This mode could also be used to park a
combination vehicle with air actuated emergency brakes on the trailer to
provide demonstrated parking capability with tractor spring brakes only.
Automatic application
With both controls in (in the normal run configuration), if the supply
pressure to the push-pull valves is reduced to approximately 240 to 310
kPa (35-45 psi), the red control (trailer supply valve) must pop out,
applying the emergency or parking brakes on the trailer. If the red
control is held in manually and the pressure decreases to approximately
172 to 240 kPa (25-35 psi), a tripper piston within the MV-3 valve will
move upward. This will exhaust the trailer supply, causing the required
non-override feature. The yellow control (parking brake) will pop out at
approximately 138 to 207 kPa (20-30 psi).
Reservoir selection
The number one service reservoir will at all times be selected as the
primary supply source for the MV-3. This is accomplished automatically
by the function of the dual circuit supply valve contained in the body of
the MV-3. Only in the event of a pressure drop of more than 207 kPa (30
psi) below that of the number two service reservoir will the dual circuit
supply valve shuttle and establish the front service reservoir as the
supply.
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Exhaust brake (if equipped)
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
It is not available with automatic transmissions.
The exhaust brake is a butterfly
type valve mounted in the exhaust
pipe. When the operator’s foot is not
on the accelerator pedal and the
exhaust brake switch is in the ON
position, an air cylinder shuts the
butterfly valve, restricting the flow
of exhaust gases and retarding the
engine. This retarding action is
carried through the engine and drivetrain, slowing the vehicle and
reducing the need for frequent service brake applications.
Exhaust brakes are not intended for use as the primary braking system
during vehicle operation.
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Operation
Push the rocker switch up to turn
the exhaust brake on. The switch
will illuminate in the ON position.
Push the switch down to turn the
brake off.
Starting engine
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 temperatures.
Driving downhill
While approaching a steep grade, make sure that the exhaust brake
switch is in the ON position. The exhaust brake actuates as soon as you
remove your foot from the accelerator pedal. 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 would to ascend the hill.
Before descending a hill or steep grade always select the proper gear. If
the transmission is taken out of gear while descending it is possible that
you will not be able to select another gear because of maximum RPM
being governed.
Make sure the engine speed does not exceed the maximum allowable
engine RPM. Exceeding the maximum allowable engine RPM will 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.
The exhaust brake is not recommended for use on slippery or
low traction road surfaces. Under these conditions a loss of
vehicle control could possibly occur.
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Exhaust brake operating characteristics
When you remove your feet from both the accelerator and clutch pedals
and the exhaust brake switch is in the ON position, the exhaust brake is
activated. The following conditions should exist if the brake is operating
properly:
•A slight change in the sound of the engine when the exhaust brake is
activated.
•Exhaust smoke appears normal.
•Engine temperature remains in the normal operating range.
•Road speed usually decreases when the exhaust brake is applied
during a descent, except when the vehicle is carrying a heavy load or
the grade is extremely steep. In these instances, you may need to
apply the service brakes occasionally.
•During a descent, the tachometer usually shows a drop in RPM
depending on the grade and the vehicle load.
•Do not expect a retarding effect similar to sudden hard application of
the service brakes. The exhaust brake retards the vehicle with a
smooth braking effect.
•Depending on the grade and vehicle load, you may or may not feel the
retarding force acting against your body when the brake is applied.
The brake’s retarding force is actually preventing the vehicle from
going much faster.
Make sure the exhaust brake is turned off before shutting off the engine.
Installing an exhaust or auxiliary brake should never allow the
engine to exceed maximum governed speeds under any
conditions.
Air brake reservoir draining
Failure to drain air brake reservoirs can result in a reduction or
loss of braking ability due to fluid accumulation in the reservoir
and/or possible freeze-up during cold weather.
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Drain all the air brake reservoirs
daily, completely to 0 kPa/psi, by
opening the draincock at the bottom
of the tanks. Close draincock after
complete draining. Air tanks
equipped with automatic moisture
ejector valves may also be drained
manually as required to maintain a
dry air system. Contact your dealer
if you are unsure of the air reservoir
locations or the draining procedure.
STEERING
Your vehicle is equipped with power steering. Power steering uses energy
from the engine to decrease the driver’s effort in steering the vehicle.
Never hold the steering wheel to the extreme right or the extreme left
for more than a few seconds when the engine is running. This action
could damage the power steering pump.
Suspension and steering
The suspension and steering linkage in your vehicle should be inspected
periodically for the following:
•Spring leaf damage
•Spring sag
•Abnormal looseness
•Damaged seals
The following changes indicate a need to inspect and service your
vehicle:
•Changes in steering action
•Hard steering
•Excessive free play
•Unusual sounds when turning or parking
If the steering wanders or pulls
This condition can be caused by any of the following conditions:
•Underinflated tire(s) on any wheel(s)
•Front end out of alignment
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