2015 FORD F750 suspension

Connecting and Disconnecting a Trailer with Air Suspension and
Air Suspension Dump Switch
When connecting to a trailer:
•Press the lower portion of the switch to exhaust air from the air
suspension system.
•Press the upper portion of the switch, and then raise the landing gear
after making the connection to the trailer.
When disconnecting the trailer:
•Lower the landing gear, and then press the lower portion of the
switch.
•Disconnect the brake hoses, trailer-side and rear light connectors,
then pull the release lever on the fifth wheel.
You must press the upper portion of the switch before operating with a
trailer or operating in the bobtail mode.
Suspension Conversions
WARNING:When operating a loaded vehicle, the driver must
keep all adjustable axles on the ground at all times, supporting
their share of the vehicle’s load. Failure to do so can overload other
axles, tires, wheels, springs, steering components, brakes and frames,
resulting in early component failure, loss of vehicle control, possible
property damage and personal injury.
We do not recommend performing, or approve of, suspension
conversions. However, we understand that, on occasion, others install
aftermarket add-on suspensions on the truck chassis that allow operator
control for weight transfer from other axles (such as air lift axles).
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TOWING A TRAILER
WARNING:Do not exceed the GVWR or the GAWR specified on
the certification label.
WARNING:Towing trailers beyond the maximum recommended
gross trailer weight exceeds the limit of the vehicle and could
result in engine damage, transmission damage, structural damage, loss
of vehicle control, vehicle rollover and personal injury.
Your vehicle’s load capacity designation is by weight, not by volume, so
you cannot necessarily use all available space when loading a vehicle.
Second-unit bodies are not included in maximum trailer weight ratings.
You must subtract the weight of the extra body from the maximum
trailer weight.
Towing a trailer places an extra load on your vehicle’s engine,
transmission, axle, brakes, tires and suspension. Inspect these
components periodically during, and after, any towing operation.
Load Placement
To help minimize how trailer movement affects your vehicle when
driving:
•Load the heaviest items closest to the trailer floor.
•Load the heaviest items centered between the left and right side
trailer tires.
•Load the heaviest items above the trailer axles or just slightly forward
toward the trailer tongue. Do not allow the final trailer tongue weight
to go above or below 10–15% of the loaded trailer weight.
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Fuse/Relay
LocationFuse Amp
RatingProtected Circuits
16 15A High beams, Indicator
17 — Not used
18 5A Dimmer switch, Interior lighting
19 15A Engine control (diesel engine only)
20 5A Starting system
21 10A DRL resistor
22 15A Air horn, Air suspension dump, Two-speed
axle, Driver-controlled locking differential
23 10A Flasher relay
24 15A Hydraulic brakes relay, Fuel heater relay
(diesel engine only), Air dryer
25 10A Blower motor relay coil
26 10A Right-hand low beam headlight
27 — Not used
28 10A Left-hand low beam headlight
29 10A Cluster, GEM
30 15A Allison electronic transmission
31 15A Mirror fold relay
Relay 1 — Interior lamps
Relay 2 — Not used
Relay 3 — Horn
Relay 4 — Not used
Relay 5 — Not used
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Perform a complete inspection of the air induction system annually.
In areas where road salt is used, disassemble the joints of each aluminum
component and inspect for salt build-up and presence of chlorine that
can cause aluminum particles to flake off and enter the engine
combustion chambers. If evidence of corrosion is found (usually at the
pipe connections), use a wire brush to clean the inside of the pipes and
inside the rubber hoses.
If pitting is evident at the joint ends of the intake pipes, use Motorcraft
Silicone Gasket and Sealant TA-30 to seal the joints. Make sure no
excess material, which can pull into the engine, is on the inside of the
pipes. If the service condition of the pipes, hoses or clamps is
questionable, replace the defective part(s).
Make sure to clean all dust and debris out of the pipes and couplings
with a clean, damp rag before reassembly.
Chassis-mounted Charge Air Cooler
Visually inspect the core assembly for debris and clogging of external fins
with the engine off. Before engine operation, remove any debris blocking
the core.
•Turbocharger-to-charge air cooler
•Charge air cooler-to-intake manifold pipe
•Mounting bracket
•Chassis-mounted charge air cooler core
Inspect air intake piping:
•Check for accumulation of salt deposits (where applicable). If
present, disassemble and clean the complete air intake piping system.
If pitting is evident on the intake piping, use Motorcraft Silicone
Gasket and Sealant TA-30 to seal joints against leakage.
•Check for loose hoses and clamps.
•Check for ruptured or collapsed hoses.
•Check air cleaner housing for cracks.
Suspension Inspection
Note:Do not adjust air suspension height to any setting other than the
specified setting. Altering the height setting changes the driveline angle
and may result in unwarrantable component damage, such as
transmission component damage.
Verify drive axle air suspension height and height control valve
performance at engine oil change intervals.
206Maintenance
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Periodically check:
•Condition of spring leaves for evidence of fatigue, bending or
breakage.
•Condition of suspension mounting brackets and bushings.
•Torque rod mounting fasteners for tightness.
•For proper suspension alignment. Maintain proper alignment at all
times.
•U-bolts. After the chassis has been operating under load for
1000 miles (1600 kilometers) or six months (whichever comes first),
the U-bolt nuts must be re-torqued. Re-torque the U-bolt nuts every
36000 miles (60000 kilometers) thereafter. Clean and lubricate the
U-bolt and nut threads and seats to make sure a like new condition
when re-torqueing.
Note:SeeSpring U-bolt checklater in this chapter.
Supporting Your Vehicle for Service
WARNING: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.
Prepare your vehicle for service repairs by doing the following:
1. Park your vehicle on a level, concrete floor.
2. Set the parking brake and block the wheels to prevent your vehicle
from moving.
3. Select a jack with a rated capacity sufficient to lift and hold up your
vehicle.
4. Raise your vehicle with the jack applied to the axle(s). Do not use
the bumper as a lifting point.
5. Support your vehicle with floor stands under the axle(s). When
servicing the axle or the suspension, support your vehicle with floor
stands under the frame side-members, preferably between the axles.
Frame and Tow Hooks
Your vehicle’s chassis is manufactured with frame rails of either HSLA
steel or heat-treated steel. Handle each in a specific manner to make
sure maximum service life. Consult the service manual or an authorized
dealer before attempting frame repair or modification.
It is important, particularly on vehicles that use tow hooks frequently, to
inspect the front and rear tow hooks for damage or a loose mounting.
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SPRING U-BOLT CHECKS
Check U-bolt nuts and re-torque every 36000 miles (60000 kilometers)
after initial 1000-mile (1600 kilometer) re-torque. Clean and lubricate the
U-bolt and nut threads and seats to make sure they are in peak condition
when re-torqued.
U-bolt Nut Torque
Suspension ft-lb N•m
Front axle – 8500 lb (3856 kg) 180-200 244-271
Front axle – 10000 lb (4536 kg) and higher 260-300 353-407
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-torqueing and installation information below.
Air Suspension U-bolt Checks and Re-torqueing 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 you can turn any nuts with a
force below the specified torque.
3. Using the lowest discovered torqued nut as a starting point,
re-tighten 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.
BRAKE FLUID CHECK
WARNING:Brake fluid is toxic. If brake fluid contacts the eyes,
flush eyes with running water for 15 minutes. Seek medical
attention if irritation persists. If taken internally, drink water and induce
vomiting. Seek medical attention immediately.
220Maintenance
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•Always use a clean sponge or car wash mitt with plenty of water for
best results.
•Dry your vehicle with a chamois or soft, terry cloth towel in order to
eliminate water spotting.
•It is especially important to wash your vehicle regularly during the
winter months, as dirt and road salt are difficult to remove and cause
damage to the vehicle.
•Immediately remove items such as gasoline, diesel fuel, bird droppings
and insect deposits because they can cause damage to your vehicle’s
paintwork and trim over time. Use Motorcraft Bug and Tar Remover
(ZC-42), which is available from an authorized dealer.
•Remove any exterior accessories, such as antennas, before entering a
car wash.
•Suntan lotions and insect repellents can damage any painted surface;
if these substances come in contact with your vehicle, wash off as
soon as possible.
•If your vehicle is equipped with running boards, use Motorcraft Detail
Wash (ZC-3-A), and, as required, Motorcraft Bug and Tar Remover
(ZC-42), both as per the directions on the products’ labels. To
manually dry, use a clean, dry, lint-free towel. Do not use rubber,
plastic and vinyl protectant products on the running board surface, as
the area may become slippery.
Exterior Chrome
•Wash your vehicle first, using cool or lukewarm water and a neutral
pH shampoo, such as Motorcraft Detail Wash (ZC-3-A).
•Use Motorcraft Custom Bright Metal Cleaner (ZC-15), available from
an authorized dealer. Apply the product as you would a wax to clean
bumpers and other chrome parts; allow the cleaner to dry for a few
minutes, and then wipe off the haze with a clean, dry rag.
•Never use abrasive materials, such as steel wool or plastic pads, as
they can scratch the chrome surface.
Underbody
Flush the complete underside of your vehicle frequently. Keep body and
door drain holes free from packed dirt.
Rear suspension components may require regular cleaning with a power
washer or a thorough rinse with a strong stream of water if you operate
your vehicle in dusty or muddy environments. Rear leaf springs or other
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suspension components may emit squeak or popping noises while
operating your vehicle if particles, such as dirt, rocks, or other debris,
are present in the components.
Cleaning Plastic Exterior Parts
Use only approved products to clean plastic parts.
•For routine cleaning, use Motorcraft Detail Wash.
•If tar or grease spots are present, use Motorcraft Bug and Tar
Remover.
WAXING
Regular waxing is necessary to protect the paint on your car from the
elements. We recommend that you wash and wax the painted surface
once or twice a year.
When washing and waxing, park your vehicle in a shaded area out of
direct sunlight. Always wash your vehicle before applying wax.
•Use a quality wax that does not contain abrasives.
•Follow the manufacturer’s instructions to apply and remove the wax.
•Apply a small amount of wax in a back-and-forth motion, not in
circles.
•Do not allow wax to come in contact with any non-body (low-gloss
black) colored trim. The wax discolors or stains the parts over time,
such as:
•Bumpers
•Grained door handles
•Side mouldings
•Mirror housings
•Windshield cowl area.
•Do not apply wax to glass areas.
•After waxing, your car’s paint should feel smooth, and be free of
streaks and smudges.
REPAIRING MINOR PAINT DAMAGE
Your authorized dealer has touch-up paint to match your vehicle’s color.
Take your color code (printed on a sticker in the driver’s door jamb) to
an authorized dealer to make sure you get the correct color.
•Remove particles, such as bird droppings, tree sap, insect deposits, tar
spots, road salt and industrial fallout, before repairing paint chips.
•Always read the instructions before using the products.
236Vehicle Care
2015 F-650/750(f67)
Owners Guide gf(ownloose), 1st Printing, December 2013
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