2009 AUDI A4 CABRIOLET water pump

Braking
General information
What affects braking efficiency?
O pera tin g co ndition s and drivi ng h abit s
The brakes on today's automobiles are still subject to wear,
depending large ly on operating conditions and dr iving habits~
&­
On vehicles that are either driven mostly in stop -and -go city traffic
or are driven hard, the brake pads shou ld be checked by your autho­
rized Audi dealer more often than specified in the
W arr anty & Main ­
t e nanc e bo okle t.
Fai lure to have you r brake pads inspec ted ca n
resu lt in reduced brake performance.
On steep slopes, you shou ld use the braking effect of the engine.
This way, you prevent unnecessary wear on the brake system. If you must use your brakes, do not hold the brakes down continuous ly.
Pump the brakes at intervals.
Moi sture or road salt
If you are driv ing faster than 50 mph (80 km/h) and the windshie ld
wipers are on, the brake pads wi ll briefly touch the brake discs in
regu lar intervals so as to improve reaction time when braking on
wet surfaces. You, the driver, wil l not notice anything.
Under ce rta in conditions, for example, when dr iving through water
or very heavy rain, or even after washing your vehicle, the braking
effect can be reduced due to moisture (or in freezing conditions ice)
on the brake pads. A few cautious brake applications should dry off
the b rake pads or remove any ice coatings .
At speeds
over80 km/h and with the windshie ld wiper turned on, the
brake pads are app lied briefly to the brake discs. This occurs at
regu lar interva ls wi thout the driver not icing and provides for better
brake response time under wet conditions.
The effectiveness of the brakes can be reduced when the vehicle is driven on a sa lt-covered road and the brakes are not used. Likewise,
Controls and equip­
ment Safety first Vehicle operation
Int
ellig ent tec hnol ogy
you clean off accumulated sa lt coating from brake discs and pads
with a few ca utious applications of the brake ~
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Cor rosi on
There may be a tendency for dirt to build up on the brake pads and
corrosion to form on the discs if the car is not driven regularly or
only f or sho rt trips with little use of the brakes.
If the brakes are not used frequently, or if corrosion has formed on
the discs, it is advisable to clean off the pads and discs by braking
firm ly a few times from a moderately high speed~
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Fa ults in the brake system
If you shou ld notice a sudden increase in brake pedal trave l, then
one of the two brake circuits may have failed~
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Lo w brak e fluid l evel
Malfunctions can occur in the brake system i f the brake fluid level is
too low . The brake fluid level is monitored electronically .
Brake lining wear statu s
Brake lining wear may be checked by visua l inspection of the condi ­
tion o f the brake pads through the open ings in the wheel. If neces­
sary, the wheel may be removed for this inspection
~ page 293,
"Whee l change".
& WARNING
• You should perform braking maneuver s for the purpo se of
cl eani ng th e br ake sy stem onl y if ro ad condition s permit . Other
road u se rs mu st not be put a t ris k -you may cau se an accident!
• Before des cending a steep gr ade , reduce sp eed and sh ift tr ans ­
mi ssion into a lower gear or lower driving po sition . Do not ride the
brake s or hold the pedal d ow n too long or t oo often . This could
cau se the brake s to get hot and dimini sh brakin g efficien cy . _.
Vehicle care Do-it-yourself service Technical data

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& WARNING (continued)
• Do not "ride the brakes" by resting your foot on the pedal when
you do not intend to brake. This may cause the brakes to overheat, premature wear and increased stopping distance.
• Under certain climatic and operating conditions such as
passing through water, driving in heavy rain or after washing the
vehicle, the effectiveness of the brakes can be reduced. In winter,
ice can accumulate on the brake pads, linings, discs and drums .
Cautiously apply brakes for a test. Brakes will dry and ice coatings
will be cleaned off after a few cautious brake applications .
• Driving for an extended period of time on salt-covered roads
without using your brakes can also affect braking efficiency. Clean
off accumulated salt coating from brake discs and pads with a few
cautious brake applications.
• If you damage the front spoiler, or if you install a different
spoiler, be sure the air flow to the front brakes is not obstructed.
Otherwise the brake system could overheat reducing the effective ­
ness of the entire brake system.
• Failure of one brake circuit will impair the braking capability
resulting in an increased stopping distance. Avoid driving the
vehicle and have it towed to the nearest Audi dealer or qualified
workshop. u
Brake booster
The brake booster adds extra braking power.
The brake booster works with vacuum pressure which is created
only when the engine is running~ &.
& WARNING
• Never let the vehicle roll to a stop with the engine shut off.
• If the brake booster is not working, for example when towing
your vehicle, or because the brake booster has somehow been
& WARNING (continued)
damaged, the brake pedal must be pressed considerably harder to
make up for the lack of booster assistance. •
Functioning of Anti-Lock Brake System (ABS)
ABS prevents the wheels from locking up under braking.
The ABS contributes effectively to vehicle control since it prevents
the wheels from
locking when the brakes are applied. This means
that the vehicle remains steerable and is less likely to skid.
With ABS you do not need to pump the brake. Just hold the brake
pedal down.
However , do not expect that the ABS shortens braking distance
under
all circumstances. When driving on gravel or on newly fallen
snow on top of icy surfaces, braking distance may be even longer,
therefore, under these circumstances, it is especially important that
you drive slowly and with great care.
How the ABS system works
An automatic check is made when a speed of about 4 mph (6 km/h)
is reached. When this happens, a pumping noise can be heard.
If an individual wheel begins to rotate too slowly in relation to
vehicle speed and tends to lock, the ABS automatically reduces brake pressure to prevent that wheel from locking.
This automatic adjustment process will cause a
slight vibration of
the brake pedal and some noises to alert you that vehicle speed
must be adapted to existing road and traffic conditions.
& WARNING
Although the ABS is very effective, always remember that braking
capability is limited by tire traction . Always adjust your driving
speed according to the road and traffic conditions. Do not let the .,_