FORD F750 2012 12.G Owners Manual

Suspension ft-lb N•m
Rear axle with multi-leaf 260-300 353-407
Rear axle with IROS air suspension 370-400 502-542
Rear axle with Hendrickson air suspension 400–450 542–610
See air suspension U-bolt re-torquing and installation information below.
Air suspension U-bolt checks and re-torquing procedures
1. Inspect the threads of the U-bolt and nut for rust and debris. Clean
the threads if contaminated.
2. Using a torque wrench, determine if any nuts can be turned with a
force below the specified torque.
3. Using the lowest discovered torqued nut as a starting point, retighten
the nuts using the sequence listed underAir suspension U-bolt and
U-bolt nut installation.
Air suspension U-bolt and U-bolt nut installation
1. Inspect the threads of the U-bolt and nut for rust and debris. Clean
the threads if contaminated.
2. Install the U-bolts and nuts and torque the nuts to seat the cap flat
which is about 18 ft-lb (25 N•m) using a diagonal pattern. Use the same
diagonal pattern for each of the following U-bolt nut re-torque steps.
3. Tighten U-bolt nuts in increments of 74 ft-lb (100 N•m) until
tightened to final torque for the particular suspension.
DRIVESHAFT
Check the universal joints for any evidence of wear or looseness at the
regular lubrication interval. Stop the vehicle immediately, should
driveshaft vibrations occur, to avoid possible hazardous consequences or
damage to other components.
REAR AXLE LUBRICANT
Refer to theScheduled Maintenance Guidechapter for rear axle
lubricant level check/change intervals.
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
identifies the use of the synthetic lubricant.
Only use 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.
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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; it should be up
to the bottom of the filler plug opening.
5. Add lubricant, if necessary, through the filler plug opening.
6. 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 lubricant through the filler plug 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.
Mount wheel balance weights 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.
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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 that can be
used to prevent pressure build-up:
•a slit or small hole in the rubber check vent or
•the window
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 the
Workshop Manualfor diagnostic procedure.
Installation, tightening and alignment
Verify the threads on studs and nuts are clean to permit correct torque
when installing wheels. 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.
Check the rim or wheel for proper alignment after it has been properly
tightened. 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 points out the high spot. A high spot does
not necessarily mean that the lug nuts have been unevenly tightened,
but could be the result of a bent wheel.
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.
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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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Aluminum rear disc wheel with flange nuts (hub-piloted)
1. Flange nut
2. Wheel(s)
3. Brake drum
4. Wheel stud (22 mm)
5. Wheel hub
6. Wheel locator pad
Note for aluminum wheels:Clean each wheel locator pad on the hub
from all dirt, rust and foreign material prior to re-installing rear
aluminum hub-piloted wheels. Apply a light coat of chassis grease,
never-seize or disc brake corrosion control grease, only to the wheel
locator pad.
3. Run the nuts on the studs until they contact the wheel(s). Rotate the
wheel assembly a half-turn to permit the parts to seat.
4. Draw-up the nuts alternately following the crisscross sequence
illustrated under the following wheel tightening sequence illustrations.
Do not fully tighten the nuts. This allows uniform seating of the nuts and
ensure even face-to-face contact of the wheel and hub.
1
6
5
4
32
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Wheel tightening sequence:
8–lug wheel
10–lug wheel
5. Continue tightening the nuts to the torque specifications in the torque
chart using the same crisscross sequence shown.
6. After operating the vehicle approximately 50 miles (80 km), check the
nuts for tightness; some natural seating of parts may be encountered and
the torque on the nuts will drop. Retighten all nuts to specifications.
Once a week, inspect and retighten the wheel stud nuts.
Note:Make sure the tire valve stem clears the brake caliper when
installing the tire and rim assembly on disc-brake equipped axles. The
use of a tire manufacturer’s stem forming tool is the only acceptable
method of obtaining clearance when necessary.
Proper torque
It is important to tighten and maintain wheel and rim mounting nuts to
the proper torque. Loose nuts or over-tightened nuts can lead to
premature wear and possible failure of the wheel and/or mounting
hardware.
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Changing wheel types
Consult your dealer or wheel/rim distributor before attempting any wheel
or fastener changes.
WARNING:Use only the same type and style wheels and
mounting hardware to replace original parts. Failure to do so
may result in an assembly that looks fine, but does not fit together
properly. This could possibly cause wheel or fastener failures which
could result in property damage, personal injury or death.
Note:Do not attempt to mix stud-piloted wheels or fasteners with
hub-piloted wheels or fasteners.
Note:Do not change from aluminum wheels to steel wheels or
vice-versa without changing the mounting hardware required or, with
flange-nut mounting systems, changing the hub and stud assembly.
WHEEL NUT TORQUE
Size Nut mountingTorque
ft-lb N•m
22 mm Flange 450–500 610–678
Note:Do not use lubrication on dry threads. Where excessive corrosion
exists, a light coat of lubricant on the first three threads of the stud bolt
is permitted. Keep lubricant away from:
•Hex nut and rim clamp contact surfaces.
•Cap nut ball face and ball seat on the disc wheel.
•Flange nut washer surface and flat on the disc wheel.
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TIRE INFORMATION
Inflation
WARNING:Always maintain your tires in good condition.
Frequently check and maintain correct inflation pressures as
specified by tire manufacturers. Inspect periodically for abnormal wear
patterns and repair/replace cut or broken tire casing. Always use
experienced, trained personnel with proper equipment and correct
procedures to mount or remove tires and wheels. Failure to adhere to
these warnings could result in wheel or tire malfunction, damage to
your vehicle, personal injury, or death.
WARNING:To avoid personal injury or death, always follow
these instructions when mounting radial tires on wheels:
•Only personnel that have had proper training and experience should
mount or remove tires from rims or wheels.
•Use only heavy-duty rims or approved rims for radial tires. It may be
necessary to contact your wheel and rim distributor to determine if
your rims are approved for radial tires.
•If a tube is to be used, make sure special radial tire tubes are used
because of the increased flexing of the sidewalls on radial tires.
•Never use anti-freeze, silicones, or petroleum based lubricants when
mounting radial tires. Only an approved lubricant should be used as
an aid for mounting tires.
•Always inflate tires in a safety cage.
•Do not attempt to mix stud piloted wheels or fasteners with hub
piloted wheels or fasteners. To do so may cause premature wheel
failure resulting in property damage, personal injury, or death.
•Do not mix foreign (not made in North America) wheel mounting
parts with domestic (made in North America) parts. Many foreign
wheel components look similar to, but not exactly the same as
domestic made components. Mixing components could cause wheel or
fastener failures and result in property damage, personal injury, or
death.
•Do not change from aluminum wheels to steel wheels or vice-versa
without changing the mounting hardware where required or, in some
cases with flange nut mounting systems, changing the hub and stud
assembly. Mixing components could cause wheel or fastener failures
and result in property damage, personal injury, or death.
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All tires with Steel Carcass Plies (if equipped):
This type of tire utilizes steel cords in the sidewalls. As such, they
cannot be treated like normal light truck tires. Tire service, including
adjusting the air pressure, must be performed by personnel trained,
supervised and equipped according to Federal Occupational Safety and
Health Administration (OSHA) regulations. For example, during any
procedure involving tire inflation, the technician or individual must
utilize a remote inflation device, and ensure that all persons are clear of
the trajectory area.
WARNING: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.
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Stay out of the trajectory (1) as indicated in the illustration.
WARNING:Do not mount tube type tires on tubeless wheels or
tubeless tires on tube type wheels. To do so could result in tire
or wheel failure and cause property damage, personal injury or death.
Preserving proper inflation pressure is a very important maintenance
practice to insure safe vehicle operation and long life for the tires.
Failure to maintain correct inflation pressure may result in sudden tire
destruction, improper vehicle handling, and may cause rapid and
irregular tire wear. Therefore, inflation pressures should be checked daily
and always before long distance trips.
Follow the tire manufacturer’s recommended cold inflation pressure for
the tire size, type, load range (ply rating) and axle loading typical for
your operation. (Each steer axle tire load equals
12steer axle loading;
each drive tire load is14the axle loading if fitted with four tires).
Checking inflation
Always check inflation pressure when tires are cold. Never bleed air from
hot tires to relieve normal pressure build-up. Normal increases in
pressure due to service conditions is 10–15 psi (69–103 kPa), which is
allowable in truck tires.
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