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03 your driving environment – Volvo 2013 XC70 User Manual

Page 124

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03 Your driving environment

Brakes

03

122

The ABS system activates for more than
approximately a half second

In the event of sudden braking while the
vehicle is moving at speeds above approx-
imately 6 mph (10 km/h)

When the vehicle has come to a stop, the brake
lights and additional taillights remain on for as
long as the brake pedal is depressed or until
braking force on the vehicle is reduced.

Power brakes function only when the
engine is running

The power brakes utilize vacuum pressure
which is only created when the engine is run-
ning. Never let the vehicle roll to a stop with the
engine switched off.

If the power brakes are not working, consider-
ably higher pressure will be required on the
brake pedal to compensate for the lack of
power assistance. This can happen for exam-
ple when towing your vehicle or if the engine is
switched off when the vehicle is rolling. The
brake pedal feels harder than usual.

Water on brake discs and brake pads
affects braking

Driving in rain and slush or passing through an
automatic car wash can cause water to collect
on the brake discs and pads. This will cause a
delay in braking effect when the pedal is
depressed. To avoid such a delay when the

brakes are needed, depress the pedal occa-
sionally when driving through rain, slush, etc.
This will remove the water from the brakes.
Check that brake application feels normal. This
should also be done after washing or starting
in very damp or cold weather.

Severe strain on the brake system

The brakes will be subject to severe strain
when driving in mountains or hilly areas, or
when towing a trailer. Vehicle speed is usually
slower, which means that the cooling of the
brakes is less efficient than when driving on
level roads. To reduce the strain on the brakes,
shift into a lower gear and let the engine help
with the braking. Do not forget that if you are
towing a trailer, the brakes will be subjected to
a greater than normal load.

Anti-lock braking system (ABS)

The Anti-lock Braking System (ABS) helps to
improve vehicle control (stopping and steering)
during severe braking conditions by limiting
brake lockup. When the system "senses"
impending lockup, braking pressure is auto-
matically modulated in order to help prevent
lockup that could lead to a skid.

The system performs a brief self-diagnostic
test when the engine has been started and
driver releases the brake pedal. Another auto-
matic test may be performed when the vehicle
first reaches a speed of approximately 6 mph

(10 km/h). The brake pedal will pulsate several
times and a sound may be audible from the
ABS control module, which is normal.

Cleaning the brake discs

Coatings of dirt and water on the brake discs
may result in delayed brake function. This delay
is minimized by cleaning the brake linings.

Cleaning the brake pads is advisable in wet
weather, prior to long-term parking, and after
the vehicle has been washed. Do this by brak-
ing gently for a short period while the vehicle is
moving.

Emergency Brake Assistance

EBA is designed to provide full brake effect
immediately in the event of sudden, hard brak-
ing. The system is activated by the speed with
which the brake pedal is depressed.

When the EBA system is activated, the brake
pedal will go down and pressure in the brake
system immediately increases to the maximum
level. Maintain full pressure on the brake pedal
in order to utilize the system completely. EBA
is automatically deactivated when the brake
pedal is released.