brake AUDI S6 2008 Repair Manual

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Speed
The higher the speed, the more difficult it becomes for the driver to
control the rig. Do not drive at the maximum permissible speed. Reduce your speed even more if load, weather or wind conditions
are unfavorable -particularly when going downhi ll.
Reduce vehicle speed
im med ia tel y if the trailer shows the slightest
sign of swaying.
Do not try to s top the swayi ng by accelerating.
Observe speed limits. In some areas, speeds for vehicles towing
trai lers are lower than for regular vehicles .
Always apply brakes ear ly. When driving downhill, shift into a lower
gear to use the engine braking effect to slow the vehicle. Use of the
brakes a lone can cause them to overheat and fail.
C ool ant t emp era tur e
The coolant temperature gauge=> page 13 must be observed care­
fully. If the needle moves close to the upper end of the scale, reduce
speed immed iately and/or turn off the air conditioner.
If the coolant temperature warning light in the instrument cluster
starts flashing
- F- , pull off the road, stop and let the engine idle for
about two minutes to prevent heat build-up.
& WARNING
A nyo ne n ot properly re str aine d in a moving vehi cle i s at a mu ch
g re ater ri sk in an accident . Never let any on e r ide in y our car who
is n ot pr operl y wea ring th e re stra ints pr ovided b y Audi . •
Trailer towing tips
Important to know
Your vehicle handles differently when towing a trailer because of
the additional weight and different weight distribution. Safety, performance and economy will greatly depend on how carefully you
l
oad your trailer and operate your r ig.
Before you actually tow your trailer, practice turning, stopping and
backing up in an area away from traffic . Keep practicing unti l you
have become comp letely familiar with the way your vehicle-trai ler
combination behaves and responds.
Back ing up is difficult and requires practice. Backing up with a
trailer generally requires steering action opposite to that when backing up your vehic le without a tra iler.
Ma intain a greater distance between your veh ic le and the one in
front of you . You will need more room to stop. To compensate for
the trai ler, you w ill need a larger than norma l turning radius.
When passing, remember that you cannot accelerate as fast as you nor mally wou ld because of the added load . Make su re you have
enough room to pass. After passing, allow plenty of room for your
trai ler befo re changing lanes again .
Avoid jerky starts, sharp turns or rapid lane changes.
[ i ] T ips
• Do not tow a trailer during the break -in period of your vehicle.
• I f you tow a trailer, your Audi may require more frequent main te­
nance due to the extra load=>
page 366. •
Parking on a slope
Do not park on a slope with a trailer. If it cann ot be
avoi ded, do so only after d oing the followi ng:
When p arking :
-Apply the foot brake.
- Have someone p lace chocks under both the vehicle and
the trailer wheels. ._

-Wit h chocks i n place, slowly release the brakes until the
wheel chocks absorb the load .
- Turn the wheels towards the curb.
- Apply the parking brake.
- Move the selector lever to
P.
Wh en r est arting aft er parking :
-Apply the foot brake.
- Start the engine.
- Move the selector lever to
D .
- Release the parking brake and slowly pull out and away
f rom the whee l chocks.
- Stop and have someone retrieve the wheel chocks .
[ i ) Tip s
If you move the selector lever of the automatic transmission to P
befor e applying th e parking brake and before blocking th e wheels ,
you may have to use more force later to move the lever out of the
P
position .
Controls and equip­ ment Safety first Vehicle operation
Tr
aile r t owing
Vehicle care Do-it-yourself service Technical data

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Cleaning and protection
General information
Regular care preserves vehicle value.
Any automobile is exposed to industrial fumes, corrosive road salt,
muddy dog feet, etc . A well cared for Audi can look like new many
years a fter purchase. Regu lar a nd correct ca re will co ntribu te to
maintaining the beauty and value of your Audi.
Furthermore, good care may be a condition for substantiating a
war ranty claim should co rros ion damage or paint defect s occur .
Your authorized Audi dealer has a variety of dedicated vehicle- care
product s
and can adv ise whic h ones to use for clea ning the e xter ior
and interior of your vehicle.
Whethe r you use p roducts recommended by Audi or other c ommer ­
cia lly availab le cleaning agents , please make sure you apply them
correctly.
& WARNING
• Cleaning agents may be poisonous. Keep them out of the reach
of ch ildren .
• Heed all caution label s.
• Always read directions on the contai ner before using any
product. Follow the di rection s carefully .
• Most chemical cleaners are concentrated and have to be
d iluted.
• Use spot removing fluids only in well ventilated area s.
• Do not use gasoline , kerosene , die sel fuel , nail polish remover
or other volatile fluids . They may be toxic , flammable or hazardous
in other way s. Do not wash , wa x or dry the vehicle w ith the igni ­
tion on or the engine running.
& WARNING (continued )
• Do not clean the under side s of chassis , fenders , wheel cove rs,
etc . without protecting your hands and arms. You may cut yourself
on sharp -edg ed metal parts .
• Moisture and ice on brakes may impair braking effi ciency
=> page 261 , "General info rmation ". Test the brake s carefully each
time you wa sh the vehicle.
~ For the sake of the environment
Se lect only enviro nmenta lly friend ly c leaning products . Leftover
clean ing products should not disposed of in the household waste. •
Care of exterior
Washing
Frequen t washing pro tects the vehi cle.
Th e bes t protection against envi ronmental influences is frequent
washing and waxing . How often this is required depends on:
• Ho w much the vehic le is used
• Where the vehic le is parked (garage, in the open under trees,
etc.)
• T he seasonal and weather conditions
• Environmenta l influences
T he longer bird droppings, insects, tree resin, road and industrial
gri me, tar, soot, road salt and ot her materials rema in on the ve hicle
body, the more lasting their destruc tive effects will be . High temper ­
atu res caused by exp osu re to in tense s un ligh t inte nsify the c orro -
sive effect, particularly when humidity is high as well.
~

llffll __ C_ le_ a _ n_i_n ~g _ a_ n_ d __ p_r _o _t _e _c_ t_ i_o _n ___________________________________________ _
brake dust is also corrosive. If left on for too long, brake dust can
cause pitting.
Use on ly specia l
acid-free cleaners formulated for a lloy r ims . Safe
products are available at your Audi dealer. Never leave the cleaner
on the ri ms longer than specified on the label. If not rinsed of f
promptly, the acid contained in some c leaners can attack the
threads o n the wheel bo lts .
Never use abrasive or metal po lishing c leaning agents. If the protec ­
tive coating has been chipped, e.g . by kicked up road dirt, touch i t
up as soon as poss ible .
& WARNING
• Moisture and i ce on b rake s may affe ct b raking effi cien cy
~ page 261 , "General information ". Te st the brake s carefully ea ch
t ime you wa sh the vehi cle .
• Always read and heed all WARNINGS and other information
~ pag e 278. •
Body cavity sealing
The body cavity sealing does not nee d to be checked .
All body cavities which could be affected by corrosion have been
t horoughly pr otected a t the factory .
This sealing does not require any inspection or additional treat ­
ment . If any wax should seep out of the cavity when the ambient
temperature is high, it can be removed with a plastic scraper and a suitable solvent .
& WARNING
Solvents can be dangerous.
• Ben zine is fla mmab le and to xic . If you use be nzine fo r removing
the wax , keep sparks, f lame and lighted cigarettes away . Never
& W ARN ING (continued )
dump benz ine on the ground , into open streams or down sewage
dra in s.
• Be sure to observe all safety and env ironmental regulat ions .
Follow all in struction s on the cont ainer .
• Alway s read and heed all WARNINGS and other inform ation
~ page 278 .•
Chassis
Have the u nderc oating c hecked for dama ge from tim e to
time.
T he lower body shell of your Audi is also thoroughly protected
aga inst corrosion .
Any damage to the undercoat ing caused by road hazards shou ld be
repaired promptly.
& WARNING
Too much undercoating in the wrong place s can cau se a fire .
• Do not app ly addition al undercoating or rustproofing on or
near the exhaust manifold, exhau st pipe s, catalytic converter or
he at shield s. While dr iving , the sub stance used for underco ating
could overhe at and cau se a fire .
• Alwa ys read and heed all WARNINGS and other info rm ation
=> page278 .•

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•
Closing the engine hood
- Pull the hood down until the pressure from the struts is
reduced .
- Let the hood
drop down and latch in place. Do not try to
push it shut;
it may fail to engage => &.
& WARNING
A hood that is not completely latched could fly up and block your
view while driving.
• When you close the engine hood, check it to make sure the
safety catch has properly engaged. The hood should be flush with
the surrounding vehicle body parts.
• If you notice while driving that the hood is not secured prop­
erly, stop at once and close it. •
Working in the engine compartment
Be especially careful whenever you work in the engine
compartment.
Whenever you must perform any work in the engine compartment,
for example checking and filling different fluids, there is a risk of injury, burns and accidents. To prevent personal injury always
observe the following WARNINGS. The engine compartment of any
vehicle is a hazardous area
~ & .
& WARNING
To help avoid injury, before you check anything under the hood :
• Turn off the engine.
• Remove the ignition key.
• Apply the parking brake .
& WARNING (continued)
• Move selector lever to "P" (Park).
• Always let the engine cool down. Hot components will burn
skin on contact.
• To reduce the risk of being burned, never open the hood if you
see or hear steam or coolant escaping from the engine compart­
ment. Wait until no steam or coolant can be seen or heard before
carefully opening the hood.
• Keep children away from the engine compartment .
• Never spill fluids on hot engine components. They can cause a
fire.
• Never touch the radiator fan. The auxiliary electric fan is
temperature controlled and can switch on suddenly.
• Never open the coolant reservoir cap when the engine is still
warm . The coolant system is pressurized and hot coolant could
spray out.
• Protect your face, hands and arm from steam or hot engine
coolant by placing a thick rag over the cap when you open the
coolant reservoir.
• If work on the fuel system or the electrical system is necessary :
- Always disconnect the battery.
- Never smoke or work near heaters or open flames . Fluids in
the engine compartment could start a fire.
- Keep an approved fire extinguisher immediately available.
• To avoid electrical shock and personal injury while the engine
is running or being started, never touch:
- Ignition cables
- Other components of the high voltage electronic ignition system.
• If you must perform a check or repair with the engine running: -First, fully apply the parking brake, move selector lever to "P"
(Park). .,
Vehicle care
I t •

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0 Not e
• Coolant pollutes the environment and cou ld cause an engine
fire. Excess coolant will be forced out through the pressure relief
valve in the cap when the engine becomes hot.
• If, in an emergency, only water can be added, the correct ratio
between water and antifreeze ~
page 303 must be restored as soon
as possible .
ci> For the sake of the environment
Dra ined coolant should not be reused . Always dispose of used
coolant whi le observing all environmental regulations. •
Radiator fan
The radiator fan switches on automatically by itself.
The rad iator fan is driven by the eng ine v ia the V-be lt . The v iscous
clutch regulates the speed of the fan according to the tempera ture
of the coo lant .
An auxiliary electric radiator fan * swi tches on and off depending on
coo lant temperature and other vehicle operating conditions.
After you switch the engine off, the auxiliary fan can continue running for up to 10 minut es -even with th e igni tion o ff. It can even
switch o n again later by itself~ & , if
• the temperature of the engine coo lant rises due to the heat
bui ld -up from the engine in the engine compartment, o r
• the engine compartment heats up because the vehic le is parked
in intense sun light.
& WARNING
• To reduce the ri sk of per sonal injury never tou ch the radiator
f a n.
& W AR N ING (continu ed )
• The auxiliary e le ctri c fan i s temperature controlled and can
s w itch on suddenly even when the engine is not running .
• The auxiliary radiator fan swit ches on automatically when the
engine coolant reache s a ce rtain temperature and will con tinue to
run until the coolant t emperatur e drop s. •
Brake fluid
Checking brake fluid level
Th e brake fluid level c an be checked with a quick glance.
Fig . 23 6 En gin e
co mp art m ent : B ra ke
fl uid re servoir
Befo re yo u c heck anything in th e en gin e compar tme nt,
always read and heed all WARNINGS~ & in "Working in
the eng ine compartment" on
page 297 .
Rea d the brake fl uid level from the bra ke fluid reservoir
~ fig . 236. T he b rake fluid leve l must be betwee n the
" M IN " and "MAX" markings.
The brake fluid reservoir is located at the rear parti tion of the engine
compartment on the left side~
page 298. .,_

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•
T he fluid level may drop slightly after some time due to the auto­
m atic adjustment of the brake pads. This is not cause for alarm .
If the brake fluid level fal ls
considerably below the "MIN" mark , the
brake warning/indicator light (U.S. models :
BRAKE, Canadian models:
{(j))) will come on~ page 23 and ~ page 32. Do not continue to
operate the vehic le. The complete brake system should be thor ­
oughly checked by an authorized Audi dealer or other qua lified
facili ty and the cause corrected . If the brake fluid level is too low, the
brake warning/indicator l ight will illuminate. Contact an au thorized
Audi dea ler
immediate ly .•
Changing brake fluid
Have the brake fl uid changed by an experienced techni­
ci an.
Brake fluid absorbs moisture from the air. If the water content in the
brake fluid is too h igh, corrosion in the brake system may result
after a period of time. The boiling point of the brake fluid will also
decrease considerab ly and decrease braking performance .
Therefore , the brake fluid must be changed
e v ery tw o year s. Always
use new brake fluid which conforms to Federal Motor Vehic le Stan ­
dard "FMVSS 116 DOT 4".
T he brake fluid res ervoir can b e difficult to reach, th erefore, we
recommend that you have the brake fluid changed by your autho ­
rized
Audi de aler . Your dealer has the correct tools, the right brake
fl uid and the know -how to do t his fo r you .
& WARNING
• Brake fluid is poi sonous . It mu st be stored onl y in the clo sed
o riginal cont ainer out of the rea ch of children!
• Brake failure c an re sult from old or inappropri ate br ake flu id .
Obs erv e the se pre caution s:
& WAR N IN G (c ontinued )
-Use only brake fluid that meet s SAE specification J 1703 and
c onfo rm s to Feder al Moto r Vehicle St andard 116 . Al wa ys check
w ith your authori zed Audi dealer to make sure you are u sin g
the corre ct b rake flu id. The cor rect type of br ake fluid is als o
indic ated on the brake fl uid reservoir .
- The brake fluid mus t be ne w. Heav y use of th e brake s can
ca use a vapor lock if the bra ke fluid i s left in the sy stem too
long . Thi s can seriou sly affect the efficiency of the brake s as
w ell as your s afety . This could r esult in an a ccident .
0 Note
Brake fluid will damage the paint of your vehicle .
Because of the p rob lem of proper disposal of brake fluid as well as
the special too ls required and the necessary expertise, we recom­
mend that you have the brake fluid changed by your authori zed Audi
dea ler .•
Battery
General information
Und er n ormal operating conditions, the battery in your Audi does
not need any maintenance. With
high outside temperatures or long
daily drives we recommend that you have the electrolyte level
checked by a se rvice facility . The e lectrolyte level should a lso be
checked each time the battery is charged~
page 310 .
Have the batte ry checked when you take your vehic le in for service.
You are well advised to replace a battery that is o lder than 5 years . _,,
Vehicle care I t •

Tires a nd wh eels -
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•
Tires and wheels
Tires
General notes
Tires may be the least appreciated and most abused parts
of a motor vehicle.
Tires may be the least appreciated and most abused parts of a
motor vehicle. Tires are, however, one of the most important parts
of a vehicle, particularly considering the comparative ly sma ll patch
of rubber on each tire that assures that all- important contact
between you, your vehicle and the road .
Maintaining the correct tire pressure, making sure that your vehicle
and its tires do not have to carry more weight than they can safely
handle, avoiding damage from road hazards and regu lar ly
inspecting tires for damage inc luding cuts , slashes irregular wear
and overa ll condition are the most important things that you can do
to help avoid sudden tire failure including tread separation and
b lowouts .
Avoiding dama ge
If you have to drive over a curb or similar obstacle, drive very slow ly
and as close as possible at a right angle to the curb.
A lways keep chemica ls includ ing grease, oil, gasoline and brake
f luid off the tires.
I nspec t the tires regularly for damage (cuts, cracks or blis ters, etc.l.
Remove any foreign bodies embedded in the treads.
Storing tires
Mark tires when you remove them to indicate the direction of rota ­
tion . This ensu res you to be ab le to mount them correctly when you
reinstal l them. When removed, the wheels or tires shou
ld be stored in a coo l, dry
and preferably dark place.
St ore t ires in a vertical posit ion if they a re not mounted on rims, in
a horizontal position if they are mounted on rims.
New tire s
New tires have to be broken in~&.
The tread dep th of new tires may va ry, according to the type and
make of tire and the tread pattern.
Hidden d ama ge
Damage to tires and rims is often not readily visible. If you notice
unusua l vibration or the vehicle pul ls to one side, this may indicate
that one of the tires has been damaged . The tires must be checked
immed iately by an authorized Audi dealer or qualified workshop .
Unidire ction al tir es
A unidirectio nal tire can be iden tif ied by arrows on the s idewa ll, that
point in the direction the tire is designed to rotate. You must follow
the specified direction of ro tation . This is necessary so that these
tires can deve lop their optimum characteristics regarding grip, road
noise, wear and hydroplaning resistance . For more information
~ page 344.
in. WARNING
Ne w tire s or tire s that are old , worn or damaged cann ot pro vide
m aximum cont rol and braking ability.
• New tire s tend to be slippe ry and m ust be broken in . To redu ce
the risk of losing control, a colli sion and seriou s per sonal injurie s,
drive with speci al care for t he fi rst 350 m ile s ( 560 km l.
• Driving with worn or damaged t ire s can lead to lo ss of co ntrol ,
s udd en tire failure , in clu ding a blowout a nd sudden deflation , .,,_
Vehicle care
I t •

-~_T_ ir_e_ s_ a_ n_d _ w_ h_ e_e _l_s _________________________________________________ _
& WARNING (continued)
crashes and serious personal injuries . Have worn or damaged tires
replaced immediately.
• Tires age even if they are not being used and can fail suddenly,
especially at high speeds. Tires that are more than 6 years old can
only be used in an emergency and then with special care and at
low speed.
Glossary of tire and loading terminology
Accessory weight
means the combined weight (in excess of those standard items
which may be replaced) of automatic transmission, power steering,
power brakes, power windows, power seats, radio, and heater, to
the extent that these items are available as factory-installed equip­
ment (whether installed or not).
Aspect ratio means the ratio of the height to the width of the tire in percent.
Numb ers of 55 or lower indicate a low sidewall for improved
steering response and better overall handling on dry pavement.
Bead
means the part of the tire that is made of steel wires, wrapped or reinforced by ply cords and that is shaped to fit the rim.
Bead separation means a breakdown of the bond between components in the bead.
Cord
means the strands forming the plies in the tire.
& WARNING (continued)
• Never mount used tires on your vehicle if you are not sure of
their "previous history." Old used tires may have been damaged
even though the damage cannot be seen that can lead to sudden
tire failure and loss of vehicle control.
• If you notice unusual vibration or if the vehicle pulls to one side
when driving, always stop as soon as it is safe to do so and check
the wheels and tires for damage . •
Cold tire inflation pressure
means the tire pressure recommended by the vehicle manufacturer
for a tire of a designated size that has not been driven for more than
a couple of miles (kilometers) at low speeds in the three hour period
before the tire pressure is measured or adjusted .
Curb weight means the weight of a motor vehicle with standard equipment
including the maximum capacity of fuel, oil, and coolant, air condi­
tioning and additional weight of optional equipment.
Extra load tire
means a tire designed to operate at higher loads and at higher infla ­
tion pressures than the corresponding standard tire . Extra load tires
my be identified as "XL",
"xi", "EXTRA LOAD", or "RF" on the side ­
wall.
Gross Axle Weight Rating ("GAWR")
means the load-carrying capacity of a single axle system, measured
at the tire -ground interfaces .
Gross Vehicle Weight Rating ("GVWR"l
means the maximum total loaded weight of the vehicle.

Tires a nd wh eels -
----------------
•
Groove
means the space between two adjacent tread ribs.
Load ra ting (code)
means the maximum load that a tire is rated to carry for a given
inflation pressure. You may not find this information on all tires
because it is not required by law.
M ax im um l oad ra tin g
means the load rating for a tire at the maximum permissib le infla­
tion pressure for that tire.
Ma ximum l oaded v ehi cle weigh t
means the sum of:
(a) Curb weight
(b) Accessory weight
(c) Vehic le capacity weight, and
(ct) Production options weight
M ax im um (p er mi ssibl e) infl ati on pr essur e
means the maximum cold inflation pressure to wh ich a tire may be
inflated. Also ca lled "maximum inflation pressure."
Normal occ upa nt wei ght
means 150 lbs. (68 kilograms) times the number of occupants
seated in the vehicle up to the to tal seating capacity of your vehicle.
O ccupant di stributi on
means distribution of occupants in a vehicle .
Outer di am eter
means the overall diameter of an inflated new tire.
O ve rall wi dth
means the linear distance between the exteriors of the sidewa lls of
an inflated tire, includ ing elevations due to labeling, decorations, or
protective bands or ribs.
Pl y
means a layer of rubber -coated para lle l cords.
P rodu ction opt io ns wei ght
means the combined weight of those installed regular production
options weighing over 5 lbs . (2.3 kg) in excess of those standard
i t ems wh ich they replace, not previously considered in curb weigh t
or accessory weight, including heavy duty brakes, ride levelers, roof
rack, heavy duty battery, and specia l trim .
Radi al p ly tire
means a pneumatic tire in which the ply cords that extend to the
beads are laid at substantially 90 degrees to the centerline of the
tread .
Reco mm ended infl ati on pr essu re
see => page 314, "Cold tire inflation pressure".
Rein force d tir e
means a tire designed to operate at higher loads and at higher infla ­
tion pressures than the corresponding standard tire. Reinforced
t ires my be identified as "XL", "xi", "EXTRA LOAD", or "RF" on the
sidewall.
R im
means a metal support for a tire or a tire and tube assembly upon
wh ich the t ire beads are seated.
Rim di amet er
means nominal diameter of the bead seat. If you change your whee l
size, you wi ll have to purchase new tires to match the new rim diam ­
eter .
Rim siz e de sig nation
means rim diameter and width.
Rim wid th
means nominal distance between rim flanges.
Vehicle care I t •