2008 FORD F750 wheel

Check to make sure that the axle mounting U-bolt nuts, attaching or
mounting bolts and nuts are securely tightened. Regularly check front
axle for damage, binding, worn parts and adequate lubrication.
At regular intervals, or during other scheduled maintenance, (tire
rotation/service, wheel bearing service, alignment, etc.) the kingpins
should be checked for excessive wear. Refer to the service manual for
proper procedures.
Toe-in setting - general inspection
Inspecting steer axle tires in the first 3,000–10,000 service miles
(4,800–16,000 service km) will generally show if tires are wearing
normally.
Rapid outside shoulder wear on both tires indicates too much toe-in.
Rapid inside shoulder wear on both tires indicates too much toe-out. In
P&D-type service, left-to-right steer tire tread life differentials up to 40%
can be observed depending on routes and other variables.
Follow the tire manufacturer’s recommended cold inflation pressure for
the tire size, load range (ply rating) and steer axle loading typical for
their operation (each steer axle tire will equal
12steer axle loading).
Special applications may warrant a setting based on past experience with
the type of tire operating loads and conditions. Radial tires are more
sensitive to toe-in setting than bias ply tires. While not insensitive to
vehicle alignment, fine tuning school bus alignment to line-haul truck
standards will not drastically improve tire tread life.
It is essential that correct toe-in and tire pressure be maintained for
optimum tire wear.
Rear axle - general inspection
Check to make sure that the axle mounting U-bolts, attaching or
mounting bolts and nuts are securely tightened. Refer toU-bolt nut
torquein this chapter. Regularly check the rear axle for damaged,
binding or worn parts.
NoSpin Detroit Locker positive locking differential
Vehicles equipped with this type differential have the operator’s manual
supplied with the vehicle. Refer to this manual for maintenance checks.
Brake system - general inspection
Your vehicle is equipped with non-asbestos brake linings. However,
exposure to excessive amounts of brake material (whether asbestos or
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non-asbestos, fiberglass, mineral wool, aramid or carbon) may be a
potentially serious health hazard.
Note:Persons handling brake linings should follow all precautions listed
below:
1. Always wear a respirator approved by the National Institute of
Occupational Studies of Health (NIOSH) or Mine Safety and Appliance
(MSA) during all brake service procedures. Wear the respirator from
removal of the wheels through assembly.
2.Neveruse compressed air or dry brushing to clean brake parts or
assemblies.
3. Clean brake parts and assemblies in open air. During assembly,
carefully place all parts on the floor to avoid getting dust in the air. Use
an industrial vacuum cleaner with a HEPA filter system to clean dust
from the brake drums, backing plates and other brake parts. After using
the vacuum, remove any remaining dust with a rag soaked in water and
wrung until nearly dry.
4.Neveruse compressed air or dry sweeping to clean the work area.
Use an industrial vacuum cleaner with a HEPA filter system and rags
soaked in water until wrung until nearly dry. Dispose of used rags with
care to avoid getting dust in the air. Use an approved respirator when
emptying vacuum cleaners and handling used rags.
5.Worker clean-up:Wash your hands before eating, drinking or
smoking. Vacuum your work clothes after use and then launder them
separately, without shaking them, to prevent fiber dust getting into the
air.
Air brakes - inspection and adjustment
A regular schedule for periodic cleaning, lubrication and adjustment
inspection should be established based on the type of vehicle operation.
It is difficult to predetermine an exact maintenance interval (time or
mileage), since vehicles will be used in a wide variety of applications and
conditions. If you are uncertain of the proper schedule and procedures
for your vehicle, contact your dealer.
Periodic checking of push rod travel or brake adjustment is essential for
effective braking. Push rod travel should be checked every service
interval to determine if adjustment is correct. Brake chamber push rods
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Note:If brake fluid requires attention to maintain a proper master
cylinder level, this is an indication of either severe operation (pad wear)
or fluid system leakage. A more frequent and thorough brake inspection
will be required.
Hydraulic brakes - fluid precautions
The HydroMax brake system consists of two completely separate
hydraulic systems operating with two different and incompatible fluids;
power steering fluid and hydraulic brake fluid. Failure to observe
precautions preventing the contamination of either system with fluid
from the other will result in swelling and deterioration of rubber parts
leading to reduced brake performance and eventual brake failure.
To avoid fluid contamination, the following should always be observed:
1. Use only fluids specified (or equivalent) and properly identified.
2. Add fluids only to the following locations:
•Power steering fluid to the power steering fluid pump reservoir
•Brake fluid to the brake master cylinder
Hydraulic brakes - brake lines, hoses and fittings
Inspect these components every 4,000 miles (6,400 km).
•Check lines for kinks, dents, corrosion or rupture.
•Check hoses for abrasions, kinks, soft spots or rupture, collapse,
cracks, twists or loose frame supports. When replacing a hose, be sure
there is adequate clearance to the hose to avoid an abrasion to the
new hose.
•Examine all connections for leaks.
•Repair or replace brake line tubes, hoses or fittings as required.
Driveline parking brake
Parking brake adjustment should only be performed by a qualified
technician, and in accordance with the instructions in the service
manual.
Use wheel chocks and exercise caution when inspecting under
the vehicle. A vehicle roll-away could result in property damage,
personal injury or death.
Catalytic converter
If your diesel engine is equipped with a catalytic converter, it is
important to review the maintenance schedule to ensure proper
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The exhaust outlet assembly on your vehicle is a uniquely functioning
device that accompanies the DPF assembly. It is designed to help control
the temperature of the exhaust during the DPF regeneration process.Do
not modify or remove this device. Modification of the system
and/or additions of aftermarket devices can reduce the
effectiveness of the system, as well as cause damage to the
exhaust system and/or engine. Any modifications may also
invalidate the vehicle and/or engine warranties. See the vehicle
and engine warranty guides for more information.
The inlet holes in the side of the assembly are functional. These holes
allow outside air to be drawn into the outlet assembly. The holes need to
be kept clear of mud and other foreign material to maintain proper
functionality of the system. One way to keep the holes clear is to spray
the outlet assembly with a hose when washing the vehicle. Failure to
keep the functional holes clear of foreign material may result in the holes
becoming blocked or plugged.Blocked/plugged holes or
modification/removal of the outlet assembly could result in
elevated exhaust temperatures which may result in
vehicle/property damage and/or personal injury.
NOISE EMISSIONS – EXTERIOR
In order to comply with the federal exterior noise regulations, your
vehicle may be equipped with noise emission items. Depending on the
vehicle configuration, it may have all or some of the following items:
Air Intake System
•Air Cleaner:should be inspected and its location should not be
altered. Do not alter inlet and outlet piping.
Body
•Wheel Well:splash shields, cab shields and under-hood insulation
should be inspected for deterioration, dislocation, and orientation.
Cooling System
•Check the fan for damage to blades; replace, if damaged, with the
recommended parts. Inspect for fan to shroud interference, and any
damage to shroud such as cracks and holes.
•The fan ratio should not be changed and the fan spacer dimensions
and positions should not be altered.
•Inspect the fan clutch for proper operation, make sure that the fan is
disengaged when cooling of the engine is not required.
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Supporting your vehicle for service
When performing service repairs on your vehicle, first prepare the
vehicle by doing the following:
1. Park the vehicle on a level concrete floor.
2. Set the parking brake and block the wheels to prevent the vehicle
from moving.
3. Select a jack with a rated capacity sufficient to lift and hold up the
vehicle.
4. Raise the vehicle with the jack applied to the axle(s). DO NOT use the
bumper as a lifting point.
5. Support the vehicle with floor stands under the axle(s). If the axle or
the suspension are being serviced, support the vehicle with floor stands
under the frame side-members, preferably between the axles.
Do not use a jack when working under a vehicle. It may give way,
causing the vehicle to fall and result in property damage, personal
injury or death. Always use floor stands to support the vehicle.
FRAME AND TOW HOOKS
Your vehicles chassis is manufactured with frame rails of either HSLA
steel or heat-treated steel. Each must be handled in a specific manner to
ensure maximum service life. Before attempting frame repair or
modification, consult the service manual or your dealer.
It is important, particularly on vehicles where the tow hooks are used
frequently to inspect the front and rear tow hooks for damage or a loose
mounting.
U-BOLT NUT TORQUE
U-bolt diameter (nominal)
(all spring suspensions)U-bolt diameter (nominal)
Ft. lb. N•m
IROS Air w/15,500 lb. axles and
less260–300 353–407
IROS Air w/greater than 15,500 lb.
axles370–400 502–542
Hendrickson 23,000 lb. axle 370–400 502–542
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Your rear axle may be filled with an optional synthetic lubricant which
allows the use of extended service intervals. A tag on the filler plug will
identify the use of the synthetic lubricant.
Use only a lubricant that meets manufacturer specifications (refer to
Lubricant specificationsin this chapter).
Use of a non-approved rear axle lubricant may cause internal axle
component damage.
Checking the rear axle lubricant level
1. Park the vehicle on level ground.
2. Set the parking brake and shift into N (Neutral) (automatic
transmission) or 1 (First) (manual transmission) and turn the engine off.
3. Clean any dirt from around the rear axle filler plug.
4. Remove the filler plug and inspect the lubricant level.
5. The lubricant level should be up to the bottom of the filler plug
opening.
6. If necessary, add enough lubricant through the filler plug opening so
that the lubricant level is at the bottom of the opening.
7. Clean and install the filler plug securely.
Draining and refilling the rear axle lubricant
1. Drain the rear axle while the lubricant is warm.
2. Park the vehicle on level ground.
3. Set the parking brake and shift into N (Neutral) (automatic
transmission) or 1 (First) (manual transmission) and turn the engine off.
4. Clean any dirt from around the rear axle filler and drain plugs.
5. Remove the filler and drain plugs and drain the lubricant into a
suitable container. Dispose of all used automotive fluids in a responsible
manner following your local authorized standards.
6. Clean and install the drain plug securely.
7. Add enough lubricant through the filler plug opening so that the
lubricant level is up to the bottom of the opening.
8. Clean and install the filler plug securely.
WHEELS
General
Wheel bearings should be inspected, lubricated and adjusted at regular
intervals. This is especially important if operating in deep sand, mud, or
water. Refer toLubricant specificationsin this chapter.
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When installing wheel balance weights, they must be mounted on the
dome-side of the wheel only. Failure to do so may result in loss of wheel
weight and/or damage to brakes or wheels.
Important:Remember to replace the wheel air valves when the road
tires are replaced at the end of their useful life.
Oil lubricated front wheel bearings
During normal vehicle duty cycle, the lube and air inside the hub/wheel
cavity expands and if not vented, causes pressure build-up that could
cause accelerated seal wear.
There are two venting methods:
•a slit or small hole in the rubber check vent or
•the window
You can use either of these methods to prevent pressure build-up.
Normal maintenance
Over a period of time, if not routinely cleaned, a slight film of oil can
collect dirt around the rubber fill plug and face, which could appear to
be a leak. Routine cleaning ensures that the lube level can be easily
observed through the clear window as intended. In situations where the
window is clean on the outside but discolored on the inside, the lube
level may be checked by inserting a finger through the rubber check
vent hole.
The specified lube level for a clear window type hubcaps is from the
minimum line to + 5/16 inch above the minimum line.
If the lube level should suddenly drop dramatically below the minimum
level, see theWorkshop Manualfor diagnostic procedure.
Installation, tightening and alignment
When installing wheels, be certain that the threads on studs and nuts are
clean to permit correct torque. The mounting surfaces of rims, wheels,
spacer rings and clamps must be free of dirt, rust, lubricants or damage.
Use a wire brush to clean the mounting contact surfaces. Do not use
lubricant on threads.
After the rim or wheel has been properly tightened, it should be checked
for alignment. Rotate the wheel with a piece of chalk attached to a
steady, firm surface, and placed to just barely clear the outside surface of
the tire bead seat. This procedure will point out the high spot. A high
spot does not necessarily mean that the lug nuts have been unevenly
tightened. This condition or misalignment could be caused by a bent
wheel.
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Use the following installation procedure:
1. Slide inner rear or front tire and wheel in position over studs and push
it back as far as possible. Use care so that the threads on studs are not
damaged.
Disc wheel with flange nuts (hub-piloted)
Front wheel mounting of flange nut
system
1. Flange nut
2. Wheel(s)
3. Brake drum
4. Wheel stud (22 mm)
5. Wheel hub
2. Position the outer rear tire and wheel in place over the studs and
push it back as far as possible. Use care so that the threads on studs are
not damaged.
Rear wheel mounting of flange nut
system
1. Flange nut
2. Wheel(s)
3. Brake drum
4. Wheel stud (22 mm)
5. Wheel hub
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