2003 FORD F750 tires

•Total vehicle out of alignment (i.e. rear axle[s] out of alignment with
front axle)
•Improper adjustment in the steering gear
•Vehicle overloaded or unevenly loaded
•High crosswinds
•High crown in center of road
•Components in steering linkage loose or worn
•Wheel bearings improperly adjusted
•Excessive lash in steering shaft or universal joints
If the vehicle steers hard
Hard steering can be caused by any of the following conditions:
•Underinflated tire(s) on any wheel(s)
•Vehicle overload
•Misalignment of the front tires
•Lack of lubricant in the front spindle bearings or linkage components
•Low oil level in the power steering system
•Broken or loose power steering pump direct drive connection
•Malfunctioning relief valve in power steering gear or steering pump
•Malfunctioning power steering pump
•Restriction in power steering lines
•Improperly set turn stops
•Air entrapped in power steering system fluid
AIR SUSPENSION SYSTEM (IF EQUIPPED)
The on-highway air suspension system is designed to provide a superior
ride, outstanding driver comfort while minimizing wear on the cab, frame
and payload.
The height control valve automatically keeps the vehicle at a constant
level due to load changes and uneven road surfaces.
Air suspension-equipped vehicles are equipped with a dryer module
which needs to be opened monthly to remove moisture from the system.
Driving
131

MAXIMUM VEHICLE LOADING
Every vehicle manufactured by Ford
Motor Company is supplied with
information on the Vehicle Rating
Decal listing the maximum loading
for the vehicle (GVWR), and its axle
systems (GAWR) at the tire to
ground interface.
Under no circumstances should your vehicle be loaded in excess of the
GVWR or GAWR. It is the operator’s responsibility to assure that neither
the axle capacities, spring capacities, tire capacities nor the vehicle rated
GVWR is exceeded. For tire capacities, refer toMaintenance and
specificationschapter.
Unloaded or lightly loaded vehicles
The braking system has been designed to safely stop your vehicle when
fully loaded to its GVWR.
When operating empty or lightly loaded, sudden or hard braking
may induce wheel lockup with loss of vehicle control and the
possibility of accident and serious injury, especially on wet or slippery
road surfaces.
MFD. BY FORD MOTOR CO. IN U.S.A.
WB TYPE/GVW BODY TRANS AXLE EXT PNT DSO
XXX XXXXXX XXX XXX XXX XXXX XXXXXX
∇FOHT-15294A10-GA
DATE: XXXXX GVWR:XXXXX LB/ XXXXX KGFGAWR: XXXXXX/XXXXXXX RGAWR: XXXXXXX/XXXXXXX
XXXXXXXXXXXX W/TIRES XXXXXXXXXXXX W/TIRES
XXXXXXXXX RIMS XXXXXXXXX RIMS
AT XXX PSI COLD AT XXX PSI COLD
THIS VEHICLE CONFORMS TO ALL APPLICABLE FEDERAL
MOTOR VEHICLE SAFETY STANDARDS IN EFFECT ON THE
DATE OF MANUFACTURE SHOWN ABOVE.
VIN: XXXXXXXXXXXXXXXXX REAR REAR GAWR
TYPE: XXXXXXXXXXXXXXXXXX XXXXXXX/XXXXXXX
Driving
149

11. Inspect the air induction system for loose fitting, damaged or missing
components and repair as necessary.
SERVICING YOUR WHEELS AND TIRES
Wheel assembly
Your vehicle is fitted with hub
piloted wheels and two-element
swiveling lug nuts (20 & 22 mm).
Do not use taper type wheels or ball
seat wheel nuts.
•Do not paint the mating face of the hub/drum.
•Do not paint the two-element swiveling lug nuts or wheel stud.
•Do not allow an excessive thickness of paint to build between the disc
wheel mounting surfaces.
•Do not install disc wheels where the paint has not fully cured.
•At wheel changes, ensure mounting faces are clean and free of rust,
dirt and excess paint.
If fasteners are needed, use only Ford recommended replacement parts.
•To maintain the desired
torque/tension relation between
nut body and flange, it is
necessary to use clean engine oil
meeting Ford specification
WSS-M2C153-G between nut body and flange. Lubricate the nut body
and flange any time a wheel is removed.
The M20 & M22 wheel nuts are right-hand threads. Refer to the
following chart for approved wheel lug nut torque.
Wheel type Bolt size Wheel nut torque
10-hole disc 285.75
mm bolt circleM22 (22 by 1.5 mm) 610-677 Nm (450-500
lb-ft)
8-hole disc 19.5x6.75
mm bolt circleM20 (20 by 1.5 mm) 610-677 Nm (450-500
lb-ft)
The disc wheel nuts on your vehicle were tightened before delivery.
Recheck torque of nuts at 160 km (100 miles) and 800 km (500 miles) of
new vehicle operation or any time a wheel is removed. Reset to
recommended torque levels.
Maintenance and Specifications
210

Tires are one of the weaker weight carrying components of the
vehicle. Do not overload the vehicle beyond safe load carrying
capacity.
Avoid hammering rim with steel hammers.
Never run the engine with one wheel off the ground.
Failure to retighten wheel lug nuts as required could allow the
wheel to come off while the vehicle is in motion, possibly causing
loss of vehicle control and collision. Loose wheel studs may also cause
shimmy and vibration.
Use of aftermarket wheel assemblies is not recommended; they
may be incompatible with your vehicle and may result in
equipment failure and possible injury. Replacement with used wheels is
not advised; they may have been treated harshly or have high mileage
and could fail without warning.
A wheel or tire of the wrong size or type may adversely affect
such things as load carrying capacity, wheel and bearing life,
brake cooling, speedometer/odometer calibration, stopping ability,
headlight aim, bumper height, vehicle ground clearance and tire or tire
chain clearance to the body and chassis.
Maintenance and Specifications
211

•10–hole disc
•8–hole disc
Always tighten wheel lug nuts
alternately in the sequence shown.
Make sure the wheel is drawn
evenly against the hub or drum.
Check for damage that would affect
the runout of the wheels. Wobble or
shimmy caused by a damaged wheel
will eventually damage the wheel
bearings. Stones or lumps of mud
wedged between a wheel and drum
or between dual wheels can unbalance a wheel and tire.
Servicing your tires
Inspect the tire treads and remove stones, nails, glass or other objects
that may be wedged in the tread grooves. Check for holes or cuts that
may permit air leakage from the tire and make the necessary repairs.
Inspect the tire sidewalls for cuts, bruises and other damage. If internal
damage to the tire is suspected, have the tire removed from wheel and
inspected.
Check the pressure regularly. Maintain the recommended air pressure for
your vehicle, load, tires and rims or wheels. Check the tire valve for air
leaks and replace the valve if necessary. If the valve cap is missing,
install a new cap. Refer toTire/Wheel Rim Selection and Inflation
Pressuresor theVehicle Certification Labelin this chapter.
5310
1
8
6
4
9 2 7
1
3 4
27 6
5 8
Maintenance and Specifications
212

An inflated tire and rim can be very dangerous if improperly
used, serviced or maintained. To avoid serious injury, never
attempt to re-inflate a tire which has been run flat or seriously
under-inflated without first removing the tire from the wheel assembly
for inspection. Do not attempt to add air to tires or replace tires or
wheels without first taking precautions to protect persons and
property.
Refer to the Ford Service Manual or the regulations of the Occupational
Safety and Health Administration (OSHA) for appropriate procedures
and cautions.
Tire inflation pressure must not exceed the recommendations of
the axle, tire and/or wheel rim manufacturer for the specific
load, speed and application. The inflation pressures on the tire sidewall
do not take the wheel rim capabilities into consideration.
Never use a rim of different manufacture or any different size or
type than original rims.
Try to replace tires in pairs on the same axle shaft. Tires larger or
smaller than originally installed may affect the accuracy of the
speedometer. Consult your dealer about the need to change the switch
setting on the back of the speedometer.
Front wheel alignment
If abnormal tire wear or ride and handling characteristics such as vehicle
lead or wander are experienced with properly inflated tires, the front
end alignment should be checked.
Wheel bearing care
Front and rear wheel bearings are adjustable to correct for bearing and
spindle wear. Long bearing life depends upon proper adjustment and
correct lubrication. If bearings are adjusted too tightly (preloaded) they
will overheat and wear rapidly. Loose adjustment will cause pounding
and will contribute to uneven tire wear, steering difficulties and
inefficient brake operation.
Refer to the Ford Service Manual applicable to your vehicle for proper
tightening procedures and torque specifications.
Periodically check the oil level on oil filled front bearing hubs. If
necessary, add oil through the filler plug so the oil level is between the
Maintenance and Specifications
213

Vehicle Rating Decal - Sample
The National Highway Traffic Safety Administration Regulations require
that a Certification Label be affixed to a vehicle and prescribe where the
Certification Label may be located. Where Ford Motor Company is the
sole manufacturer of the vehicle, the Certification Label is located on the
front door latch pillar on the driver’s side. In many instances, the vehicle
is sold by Ford Motor Company to an intermediate or final stage
manufacturer who is required to affix the Compliance Label. In these
cases, the completed vehicle is manufactured in two (or more) stages by
two (or more) separate manufacturers, with the manufacture of the
completed vehicle occurring at a later date than the manufacture of the
chassis or incomplete vehicle. Consequently, the model year of the
completed vehicle may be later than the model year of the incomplete
vehicle or chassis.
MFD. BY FORD MOTOR CO. IN U.S.A.
WB TYPE/GVW BODY TRANS AXLE EXT PNT DSO
XXX XXXXXX XXX XXX XXX XXXX XXXXXX
∇FOHT-15294A10-GA
DATE: XXXXX GVWR:XXXXX LB/ XXXXX KGFGAWR: XXXXXX/XXXXXXX RGAWR: XXXXXXX/XXXXXXX
XXXXXXXXXXXX W/TIRES XXXXXXXXXXXX W/TIRES
XXXXXXXXX RIMS XXXXXXXXX RIMS
AT XXX PSI COLD AT XXX PSI COLD
THIS VEHICLE CONFORMS TO ALL APPLICABLE FEDERAL
MOTOR VEHICLE SAFETY STANDARDS IN EFFECT ON THE
DATE OF MANUFACTURE SHOWN ABOVE.
VIN: XXXXXXXXXXXXXXXXX REAR REAR GAWR
TYPE: XXXXXXXXXXXXXXXXXX XXXXXXX/XXXXXXX
Maintenance and Specifications
223

Daily Owner Checks Engine system
Check the air filter restriction indicator
Check the engine oil
Inspect the coolant level - for Powerstroke
engine (for Caterpillar and Cummins engines,
refer to the Owner’s Manual)
Brake system
Drain the air brake system reservoir - manual
valve
Check the air brake system reservoir
automatic drain valve operation
Transmission system
Visually check the automatic transmission for
fluid leakage
Steering system
Check the power steering pump fluid level and
check the system for leaks
Check the entire vehicle for evidence of fluid
leaks
U.S. Department of Transportation,
Federal Highway Administration
requirements (ensure that the entire
system is functioning properly)
Check the service brakes
Check the parking brake
Check the steering mechanism
Check the lighting devices and reflectors
Check the tires
Check the horn
Check the windshield wipers
Check the rear vision mirrors
Check the wheels and rims
Check the emergency equipment
General Maintenance Information
232