Ford F-650/750 (2018 year). Manual — part 55

as a stroke indicator to aid in
adjustment checks. If the push rod is
clean and the brakes are out of
adjustment, you can see the orange
marker protruding from the chamber
when the brakes are applied.

•

Checking the brake lining (every service
interval). When brake linings or blocks
wear within 0.063 in (1.6 mm) they
must be replaced.

•

Periodic checking (every service
interval) of the air compressor filter.
Check the filter minder and when the
indicator is near or on the red line
marked Service, replace the filter and
reset the service filter minder.

Do not back off or disconnect the front
brakes so that they are less effective,
letting the rear brakes do all the stopping
of your vehicle. Do not overlook the brakes
on the trailer either. Brake condition on the
trailer is just as important as the tractor.
Proper brake balance on trucks and
tractor-trailers is essential for effective
braking.

Once a year, inspect the entire brake
system:
•

Rubber components for deterioration.
A qualified technician should inspect
these components and replace them
as necessary. Replacement intervals
vary according to the severity and
length of vehicle service.

•

Condition of brake drums, brake
chambers and slack adjusters.

•

System for air leaks.

•

Hose or pipes for rust, damage and
deterioration.

•

Operation of service and parking
brakes.

Periodically inspect parts such as air brake
chamber diaphragm, air compressor and
air cleaner. Replace any parts if you can
consider them unserviceable.

Air Dryer

Climactic conditions affect performance
of desiccant or after-cooler type air dryers.
You must establish a maintenance
schedule for each specific operation.

The use of an air dryer on a vehicle does
not eliminate the need to drain the air
reservoirs periodically.

Inspect for moisture in the air system by
opening reservoirs, draincocks or valves
and checking for presence of water. The
presence of small amounts of water due
to condensation is normal and is not an
indication that the dryer is not functioning
properly.

Replace or rebuild the desiccant cartridge
when you determine that the desiccant is
contaminated and does not have adequate
water absorption capacity. The desiccant
change interval may vary. A general
recommendation is to replace the
desiccant every 12 months (yearly). If
experience has shown that extended or
shortened life has resulted for a particular
installation, then the yearly interval can be
increased or decreased accordingly.

Draining the Air Brake Reservoir

WARNING

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.

Completely drain all the air brake reservoirs
daily by opening the draincock at the ends
of the tanks. (Where accessible.
Pull-chains are used when the drains are
undercab or otherwise inaccessible.) Close
the draincock after draining. Manually drain

any air tanks equipped with automatic
moisture ejector valves, as required, to
maintain a dry air system. Contact an
authorized dealer if you are unsure of the
air reservoir locations or the draining
procedure.

Hydraulic Brakes

Establish a regular schedule for periodic
cleaning, lubrication and adjustment
inspection based on vehicle use. Exact
maintenance intervals are difficult to
predetermine due to vehicle applications
and operating conditions. If you are
uncertain of the proper schedule for your
vehicle, contact an authorized dealer.

Regular inspections should include:
•

Checking the brake lining (every service
interval). Establish inspection intervals
that provide for lining replacement
before damage to the disc occurs.
Excessive lining wear may expose the
backing plate to the disc causing
scoring of the disc faces. A qualified
technician should perform this

inspection and keep to instructions
provided by the service manual.
Hydraulic brake systems are
power-assisted. There is a great
reduction in braking capabilities
without engine assist.

•

Proper fluid level. The level should be
at the bottom edge of the ring on each
reservoir fill port. Do not fill the master
cylinder to the top of the reservoir. If
fluid level requires attention to
maintain a proper master cylinder level,
this is an indication of either severe
operation (pad wear) or fluid leakage.
A more frequent and thorough brake
inspection is required.

•

Brake lines, hoses and fittings. Repair
or replace brake line tubes, hoses or
fittings as required. Inspect these
components every 4,000 mi
(6,000 km) for the following.
•

Lines for kinks, dents, corrosion or
rupture.

•

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.

•

All connections for leaks.

Driveline Parking Brake

WARNING

Use wheel chocks and exercise
caution when inspecting under the
vehicle. A vehicle roll-away could

result in property damage, personal injury
or death.

A qualified technician should adjust the
parking brake and keep to the instructions
in the service manual.

AXLE INSPECTION

Front Axle

Maintaining the front axle alignment to
specifications is very important. A qualified
technician should check and maintain the
alignment.

Regular inspections should include:
•

Toe-in inspection and adjustment (if
necessary), particularly with radial
tires.

•

Checking for proper tightness of axle
mounting U-bolt nuts, attaching or
mounting bolts and nuts.

•

Checking the axle for damage, binding,
worn parts and adequate lubrication.

•

Checking the kingpins for excessive
wear. Also, perform this check during
other scheduled maintenance, for
example as tire rotation or service,
wheel bearing service and alignment.
See the workshop manual for proper
procedures.

Toe-in

It is essential to maintain correct toe-in
and tire pressure for optimum tire wear.

Inspecting steer axle tires in the first
3,000–10,000 mi (5,000–16,000 km)
generally shows 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, there can be a
left-to-right steer tire tread life differential
up to 40% 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 equals ½ steer axle
loading).

Special applications may warrant a setting
based on experience with the type of tire
operating loads and conditions. Radial tires
are more sensitive to toe-in setting than
bias ply tires. Fine tuning school bus
alignment to line-haul truck standards
does not drastically improve tire tread life.

STEERING SYSTEM
INSPECTION

WARNING

Failure to maintain the steering
system in proper condition can cause
reduced steering ability resulting in

property damage, personal injury or death.

Note: Have any steering problems
immediately corrected by a qualified service
technician.

Ask your service technician to examine the
steering mechanism. Only minor
adjustments may be necessary.

Regular inspections should include:
•

Checking the tie rod, drag link end
clamp bolts and ball joints for proper
tightness.

•

Checking for installation and spread of
cotter pins and tightness of nuts at
both ends of the tie rod and drag link.

•

Checking that the pitman arm (steering
arm at steering gear) mounting is tight
and locked. Check system for leaks or
hose chafing. Repair immediately, if
necessary.

•

Maintaining proper steering gear and
power steering pump lubricant levels.

•

Checking steering column joint bolts
and steering linkage, particularly for
body-to-chassis clearance.

Steering Column Joint Bolts

As a good maintenance practice, check
steering column joint bolt tightness every
60,000 mi (96,000 km) or annually,
whichever occurs first. Do not overtighten
the bolts.

Hydraulic System

Whenever draining and refilling the power
steering's hydraulic system for any reason,
bleed air from the system before returning
the vehicle to service. Failure to bleed the
hydraulic system properly can result in
degradation of power system performance.

Consult an authorized dealer who is aware
of the proper procedures for filling and
bleeding the system.

SUSPENSION SYSTEM
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.

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 1,000 mi
(1,600 km) or six months (whichever
comes first), the U-bolt nuts must be
re-torqued. Re-torque the U-bolt nuts
every 37,000 mi (60,000 km)
thereafter. Clean and lubricate the
U-bolt and nut threads and seats to
make sure a like new condition when
re-torqueing. See Spring U-Bolt
Check (page 228).

FRAME AND TOW HOOK
INSPECTION

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.

REAR AXLE FLUID CHECK

Your rear axle may have an optional
synthetic lubricant that 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. Only use a
lubricant that meets manufacturer
specifications. Use of a non-approved rear
axle lubricant may cause internal axle
component damage. See Capacities and
Specifications (page 269).