Anti-Lock Brake System (Abs); Using Abs - Ford Expedition 2003 Owner's Manual

Driving
"continuous squeal" sound is present while braking, the brake linings
may be worn-out and should be inspected by a qualified service
technician.
If you are driving down a long or steep hill, shift to a lower gear.
Do not apply your brakes continuously, as they may overheat
and become less effective.
Under normal operating conditions, brake dust may accumulate on the
wheels. Some brake dust is inevitable with use; this does not contribute
to brake noise. The use of modern friction materials with emphasis on
improved performance and environmental considerations can lead to
more dust than in the past. Brake dust can be cleaned by washing with
soapy water and a soft sponge. Heavier deposits can be removed with
Motorcraft Wheel and Tire Cleaner (ZC-37–A).

Anti-lock brake system (ABS)

On ABS-equipped vehicles, a noise from the hydraulic pump motor and
pulsation in the pedal may be observed during ABS braking events. Pedal
pulsation coupled with noise while braking under panic conditions or on
loose gravel, bumps, wet or snowy roads is normal and indicates proper
functioning of the vehicle's anti-lock brake system. The ABS performs a
self-check after you start the engine and begin to drive away. A brief
mechanical noise may be heard during this test. This is normal. If a
malfunction is found, the ABS warning light will come on. If the vehicle
has continuous vibration or shudder in the steering wheel while braking,
the vehicle should be inspected by a qualified service technician.
The ABS operates by detecting the onset of wheel lockup during brake
applications and compensates for this tendency. The wheels are
prevented from locking even when the brakes are firmly applied.

Using ABS

• In an emergency or when maximum efficiency from the four-wheel
ABS is required, apply continuous force on the brake. The four wheel
ABS will be activated immediately, thus allowing you to retain steering
control of your vehicle and, providing there is sufficient space, will
enable you to avoid obstacles and bring the vehicle to a controlled
stop.
• The anti-lock system does not always reduce stopping distance.
Always leave enough room between your vehicle and the vehicle in
front of you to stop.
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