2015 AUDI A8 brake

- the temperature of the engine coolant rises
due to th e heat bui ld-up from the engine in
the engine compartment, or
- the engine compartment heats up because
the vehicle is parked in intense sunlight.
.&_ WARNING
- To reduce the r isk of personal injury nev­
er touch the radiator fan.
- The auxiliary electr ic fan is temperature
controlled and can switch on sudden ly
even when the engine is not runn ing.
- The auxiliary radiator fan switches on au­ tomat ically when the engine coolant
reaches a certain temperature and will
continue to run until the coolant temper ­
at ure drops.
Brake fluid
Checking brake fluid level
The brake fluid level can be checked with a
quick glance.
N N
-N
i
F ig . 2 05 Eng ine co mpartmen t: cove r on the b rake f lui d
r eservo ir
Before you check anything in th e engine com­
partment,
alwa ys read and he ed all WARN­
INGS c::> .&. in Working in the engine compart­
ment on page 2 28.
~ Read the brake fluid level from the brake
fl uid reservo ir ~
fig . 205, c::> page 230. The
brake f luid leve l must be betwee n the "M IN"
and "M AX" marki ngs.
The location of the brake fl uid reservo ir can be
see n in t he engi ne comp artment illus trati on
c::> page 230.
Checkin g and fillin g 239
The fluid level may d rop slightly afte r some
time due to the automatic adjustment of the
brake pads . T his is not cause for alarm .
If the brake flu id leve l falls considerably be­
low the "MIN" mark, the brake warning/indi­
cator light . (U.S. models) . (Canadian
models) w ill come on
~ page 14 . Do not con­
tin ue to operate the vehicle . The complete
brake sys tem should be thoroughly checked
by an authorized Audi dea ler or other quali ­
fied facility and the cause corrected.
If the
brake f lu id leve l is too low, the brake warning/
indica tor ligh t will illumi nate. Conta ct an au­
thorized Aud i de aler
immediately .
Changing brake fluid
Have the brake fluid changed by an experi­
en ced technician.
B rake fluid absorbs moisture from the air . If
the water content in the brake fluid is too
high, co rrosion in the brake system may resu lt
after a pe riod of time. The boiling point of the
brake f lu id will also dec rease conside rably and
decrease brak ing performance.
T herefo re , the bra ke fluid must be changed
every tw o year s. Always use new br ake f lu id
which con forms to Federal Mo tor Veh icle
Standard " FMVSS 116 DOT 4".
T he bra ke fluid reservo ir can be d iff icu lt to
reach, the refore, we recommend that you
have the bra ke fluid changed by your author­
ized
Audi dealer. Your dealer has the cor rect
tools, the right brake fluid and the know -how
to do this for you.
A WARNING
---- Brake flu id is poisonous. It must be stor­
ed only in the closed or iginal container
out of the reach of children!
- Brake failure can resu lt from old or inap­
prop riate brake f lu id. Observe these pre­
cautions:
- U se only brake fluid tha t meets SAE
specificat ion
J 1703 and conforms to
Federa l Motor Vehicle Standard 116.

24 0 Ch eck ing and filling
Always check wi th your a uthorized Audi
dealer to make s ure you are using the
correct brake flu id. The correct type of
brake fluid is also indicated on the
brake fluid reservoir.
- The brake fluid must be new. Heavy use
of the brakes can cause a vapor lock if
the brake fluid is left in the system too
long. This can ser ious ly affect the effi­
ciency of the b ra kes as well as yo ur
safety. This could result in an acc ident.
(D Note
Brake flu id will damage the paint of your
veh icle.
@ For the sake of the environment
Because of the problem of proper d isposa l
of brake flu id as wel l as the special tools
requ ired and the necessary expert ise, we
recommend that you have the b rake fluid
changed by your author ized Audi dealer.
Battery
General information
Under
normal operating conditions, the bat­
tery in your Audi does not need any mainte­
n ance . With
high outside temperatures or
l ong daily dr ives we recommend that you have
the elec trolyte level checked by a service fa­
cili ty. The e lec trolyte level sho uld a lso be
checked each time the battery is charged
¢ page 242.
Have the b attery checked when you ta ke yo ur
ve hicl e in for service. Yo u are well adv ise d to
replace a battery that is older than S years .
W ith certa in types of airbag deployment, the
battery is d isconnected from the vehicle ele c­
tr ica l system for sa fety reasons¢
& in Re­
pair, care and disposal of the airbags on
page 165.
Disconnecting the battery terminals
Some veh icle func tions (power w indow regu­
l ato rs, for example) a re los t if the b attery ter- mina
ls are disconnected. These functions have
to be relearned after the battery termina ls are
connected aga in. To prevent th is, the battery
sho uld only be disconnected from the ve hicle
electrical system when abso lutely necessary
for repairs.
Vehicle s not driven for long peri ods
If you do not d rive your vehicle over a period
of several days or weeks, e lectr ica l compo ­
nents are gradually cut back or sw itched off.
This reduces energy consumption and ma in­
ta ins start ing capability over a longer period
¢
page 202. Some of the convenience func­
t ions may not ope rate, such as the inter ior
li gh ts or the power seat adjus tment. The con­
venience func tions will be ava ilable ag ain
when you switch on the ignition and start the
engine .
Winter operation D uring the winte r months, battery capac ity
tends to de crease as temperatures drop. This
is beca use more power is also consumed wh ile
sta rting, and the headlights, rear window de ­
fogger, etc ., are used more often .
Avoid unnecessary power consumpt ion, p ar­
t icu lar ly in city traffic or whe n traveling only
short distances. Let yo ur au thorized Aud i
dealer check the capacity of the vehicle bat ­
tery before winter sets in ¢
page 242. A well
charged battery will not on ly prevent starting
problems when the weather is cold, but will
also last longer.
(!) Tips
If your vehicle is left standing for several
weeks at extremely low temperatures, the
vehicle battery sho uld be removed and
stored where it w ill not freeze. This will
prevent it from be ing damaged and having
to be repla ced.

,....,
N ,....,
N
0 J:
'SI: ,...., \!) 1.1'1 ,...., 1.1'1 ,....,
Tires and wheels
Tires
General notes
Tires may be the least appreciated and most
abus ed parts of a motor vehicle .
Tires may be the least ap preciated and most
a b used parts of a motor vehicle . T ires are,
however, one of the most important parts of a
vehi cle, particularly considering the compara­
tively small patch of rubber on eac h tire that
assures that a ll- important contact between
you, you r vehicle and the road.
Ma intaining the correct tire pressure, mak ing
sure that your vehicle and its tires do not have
to carry mo re weight than they can safe ly han­
d le, avoiding damage from road ha za rds and
r eg ularly inspec ting t ires for damage i nclud­
ing cuts, slashes irreg ular wear and ove ra ll
condition are the most important things that
you can do to he lp avoid s udden tire failure in­
cluding tread separat ion and b lowouts.
Avoiding damage If you have to d rive ove r a curb or similar ob­
stacle, drive very slow ly and as close as possi ­
b le at a right angle to the curb.
A lways keep chemicals incl ud ing grease, o il ,
gasoline and brake fluid off the t ires .
I nspect the t ires regularly for damage (cuts,
cracks or b listers, e tc.). Remove any fo reign
bod ies embedde d in the t reads.
Storing tires Mark t ires when you remove them to indicate
the direction of rotation . T his ensures you to
be ab le to mount them correctly when you re­
in stall them .
When removed, the whee ls or t ires should be
sto red in a cool, d ry and preferably dark place .
Store tires in a vertical pos ition if they are not
mounted on r ims, in a horizontal pos it ion if
they are mounted on rims .
Tires an d wheel s 245
New tires
New tires h ave to be broken in ¢ & .
The tread depth of new t ires may va ry, accord­
ing to the type a nd make of t ire and the tread
pa tte rn.
Hidden damage
Damage to tires and r ims is ofte n not readily
visible . If you notice unusual v ib rat io n or the
vehicle p ulls to one s ide, th is may ind icate
that one of the t ires has been damaged . T he
tir es m ust be che cked immed iate ly by an au­
t horized Audi dea le r or q ua lified wor kshop .
Unidirectional tires
A un idirec tional tire can be identified by ar­
rows on the s idewa ll, that po int in the direc­
tion the t ire is desig ned to rotate. You mus t
f ol low the specified d irection o f rotation . T his
is necessary so that these tires can develop
their optimum characteristics regarding grip, road noise, wear and hydrop laning resistance.
For more information
¢ page 275.
A WARNING
New tires or t ires that are o ld, worn or
damaged can not provide maximum con­
trol and braking ability .
-
-New tires tend to be slippery and must
be broken in. To reduce the r isk of losing
contro l, a co llision and ser ious personal
in ju ries, d rive with special ca re fo r the
fi rst 350 m iles ( 560 km).
- Driving with worn or damaged tires can
le ad to loss of control, sudde n tire fail ­
ure, including a blowout and sud den de­
fla tion, c ras hes and se riou s personal in­
juries . Have wo rn or d amaged t ires re­
placed immediate ly.
- Ti res age even if they are no t being used
an d can fai l sudden ly, especially at hig h
spee ds. Tires that are more than 6 years
old can only be used in an emergency
and then w ith special care and at low
speed.
•
•

24 6 T ire s and whee ls
- Never mount used tires on yo ur vehicle if
you are not sure of their "previous histo­
ry." Old used tires may have been dam­
aged 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, al­
ways stop as soon as it is safe to do so and check the wheels and tires for dam­
age.
(D Note
- Please note that summer and winter
tires are designed for the cond itions that
a re typ ica l in those seasons. Aud i recom­
mends using w inter t ires d uring the win-
Glossary of tire and loading terminology
Accessory weight
means t he comb ined weight (in excess of
those standard items which may be rep laced)
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 t he ratio of the height to the width of
the tire in percent. Numbers of 55 or lower in­
d icate a low sidewall for improved steer ing re­
sponse and better overall handling on dry pavement .
Bead
means the pa rt of the tire t hat is made of
steel wires, wrapped or reinforced by ply cords
and that is shaped to fit the r im.
Bead separation
means a breakdown of the bond between
components in the bead.
Cord
means t he strands forming the plies in the
tire. ter months.
Low tempe ratu res signifi­
cantly decrease the elasticity of summer
tires, which affects traction and braking ability. If summer tires are used in very
co ld temperatures, cracks can form on
the tread bars, resu lting in permanent
tire damage that can cause loud driving noise and unbalanced tires. Aud i is not
responsib le for this type of damage.
- Burn ished, polished or chromed rims
must not be used in winter weather. The
surface of the rims does not have suff i­
c ien t corrosion protect io n for this and
cou ld be pe rmanently damaged by road
salt or simi lar substances. This damage
is not covered by war ranty.
Cold tire inflat ion pre ssure
means the t ire press ure recommended by the
vehicle manufacturer for a tire o f a des ignated
size that has not been driven for more than a
coup le of miles (ki lometers) at low speeds in
the three hour period before the tire press ure
is measured or adjusted.
Curb weight
means the weight of a motor vehicle w ith
standard equipment including the maximum
capacity of fuel, o il, and coolant, air cond i­
tion ing and additional weight of optiona l
equipment.
E x tra load tire
means a tire design to operate at higher loads
and at higher inflation pressures than the cor­
responding standard tire. Extra load tires may
be identified as "XL", "xl", "EXTRA LOAD", or
"RF" on the sidewall.
Gross A xle Weight Rating ("GAWR ")
means the load-carrying capacity of a single
axle system, measured at the tire-ground in -
terfaces.
IJ>,

,....,
N ,....,
N
0 J:
'SI: ,...., \!) 1.1"1 ,...., 1.1"1 ,....,
Tires and wheels 24 7
Gross Vehicle Weight Rating ("GVWR") Ply
means the maximum total loaded weight of
the vehicle .
Groove
means the space between two adjacent tread
ri bs.
Load rating (code)
means the maximum load that a tire is rated
to carry for a given inflat ion pressure . You
may not find this informat ion on all tires be­
cause it is not requ ired by law.
Maximum load rating
means the load rating for a t ire at the max i­
mum permissible inflation pressure for that
tire .
Maximum loaded vehicle weight
means the sum of:
(a) Curb weight
(b) Accesso ry weight
(c) Vehicle capacity weight, and
(d) Production opt ions we ight
Maximum (permissible) inflation pressure
means the maximum co ld inf lation pressure
to which a tire may be inflated . Also called
"maximum inflation press ure."
Normal occupant weight
means 150 lbs . (68 kilograms) times the
number of occupants seated in the vehicle up
to the tota l seating capacity of your vehicle.
Occupant distribution
means distribution of occupants in a veh icle.
Outer diameter
means the overall diameter of an inflated new
tire .
Overall width
means the linear distance between the exteri­
ors of the sidewalls of an inflated tire, includ­
ing e levations due to labeling, decorations, or
protective bands or ribs. means a layer of
rubber-coated parallel cords.
Production options weight
means the combined weight of those installed
regular production opt ions we ighing over 5
lbs. (2.3 kg) in excess of those standa rd items
which they replace, not previously considered
in curb weight or accessory weight, including
heavy duty brakes, ride levelers, roof rack,
heavy duty battery, and spec ial trim.
Radial ply tire
means a pneumatic tire in which the ply cords
that extend to the beads are laid at substan­
tially 90 degrees to the centerline of the
tread.
Recommended inflation pressure
see ~ page 246, Cold tire inflation pressure .
Reinforced tire
means a tire design to operate at higher loads
and at higher inflation pressures than t he cor­
responding standard tire. Reinforced tires
may be identified as "XL", "xl", "EXTRA LOAD",
or "RF" on the sidewal l.
Rim
means a metal support for a tire or a t ire and
tube assembly upo n which the tire beads are
seated .
Rim diamete r
means nominal diameter of the bead seat. If
you change your wheel s ize, you wi ll have to
purchase new tires to match the new r im di­
ameter .
Rim size designation
means rim diameter and width.
Rim width
means nominal distance between rim flanges.
Sidewall
means that portion of a t ire between the
tread and bead .
•
•

254 Tires and wheels
A WARNING
Overloading a vehicle can cause loss of ve­
hicle control, a crash or other accident, se­
rious personal injury, and even death.
- Carrying more weight than your vehicle
was designed to carry will prevent the
vehicle from handling properly and in­ crease the risk of the loss of vehicle con­
trol.
- The brakes on a vehicle that has been
overloaded may not be able to stop the
vehicle within a safe distance.
- Tires on a vehicle that has been overload­
ed can fail suddenly, including a blowout
and sudden deflation, causing loss of
control and a crash.
- Always make sure that the total load be­
ing transported -including the weight of
a trailer hitch and the tongue weight of a
loaded trailer -does not make the vehi­
cle heavier than the vehicle's Gross Vehi­
cle Weight Rating.
Determining correct load limit
Use the example below to cal­
culate the total weight of the
passengers and luggage or oth­
er things that you plan to trans­
port so that you can make sure
that your vehicle will not be
overloaded.
Steps for Determining
Correct Load Limit
1. Locate the statement "THE
COMBINED WEIGHT OF OC­
CUPANTS AND CARGO
SHOULD NEVER EXCEED XXX
KG OR XXX LBS" on your ve­
hicle's placard (tire inflation pressure label)
¢ page 249,
fig. 208.
2.
Determine the combined
weight of the driver and pas­
sengers that will be riding in
your vehicle.
3. Subtract the combined weight of the driver and pas­
sengers from
"XXX" kilo­
grams or
"XXX" pounds
shown on the sticker
c> page 249, fig. 208.
4. The resulting figure equals
the available amount of car­
go and luggage load capaci­
ty. For example, if the
"XXX"
amount equals 1400 lbs.
and there will be five 150
lbs. passengers in your vehi­
cle, the amount of available
cargo and luggage load ca­
pacity is 650 lbs. (1400-7 SO
(5
X 150) = 650 lbs.)
5. Determine the combined weight of luggage and cargo
being loaded on the vehicle.
That weight may not safely
exceed the available cargo
and luggage load capacity
calculated in Step 4.
6. If your vehicle will be towing
a trailer, load from your trail­
er will be transferred to your .,.

256 Tires and wheels
Incorrect wheel alignment
Incorrect wheel alignment can cause exces­
sive tire wear, impairing the safety of the vehi­
cle. If tires show excessive wear, have the
wheel alignment checked by an authorized
Audi dealer or qualified workshop.
All Wheel Drive
Vehicles with quattro must always have tires
of the same size, construction and tread type.
For details see Qpage 202 .
.&_ WARNING
Sudden tire failure can lead to loss of con­
trol, a crash and serious personal injury!
- Never drive a vehicle when the tread on
any tire is worn down to the wear indica­
tors.
- Worn tires are a safety hazard, they do
not grip well on wet roads and increase
your risk of"hydroplaning" and loss of
control.
- Always keep chemicals that can cause
tire damage, such as grease, oil, gasoline
and brake fluid away from tires.
- 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 lower speeds.
- Never mount used tires on your vehicle if
you are not sure of their "previous histo­
ry." Old used tires may have been dam­
aged even though the damage cannot be
seen that can lead to sudden tire failure
and loss of vehicle control.
New tires and replacing tires and wheels
New tires and wheels have to be broken in .
Fig. 212 Tir e specificat ion codes on the s idewall of a
t ire
No. Description
@ Nominal width of tire in millimeters
® Ratio of height to width (aspect ratio)
© Radial
® Rim diameter code
® Load index and speed rating
(J) U.S . DOT tire identification number
® Audi Original tire
® Sever snow conditions
@ Tire ply composition and materials
used
@ Maximum load rating
@ Treadwear, traction and temperature
grades
@ Maximum permissible inflation pres-
sure
The tires and rims are essential parts of the
vehicle's design . The tires and rims approved
by Audi are specially matched to the charac­
teristics of the vehicle and can make a major .,..

,....,
N ,....,
N
0 J:
'SI: ,...., \!) 1.1"1 ,...., 1.1"1 ,....,
Driving with different tires reduces vehi­
cle handling and can lead to a loss of
control.
- If the spare tire is not the same as the
tires that are mounted on the vehicle -
for example with winter tires -only use
the spare tire for a short period of time and drive with extra care. Refit the nor­
mal road wheel as soon as safely possi­
ble.
- Never drive faster than the maximum
speed for which the tires on your vehicle
are rated because tires that are driven
faster than their rated speed can fail
suddenly.
- Overloading tires cause heat build-up,
sudden tire failure, including a blowout
and sudden deflation and loss of control.
- Temperature grades apply to tires that
are properly inflated and not over or un­
deri nflated.
- For technical reasons it is not always
possible to use wheels from other
vehicles -in some cases not even wheels
from the same vehicle model.
- If you install wheel trim discs on the ve­
hicle wheels, make sure that the air flow
to the brakes is not blocked. Reduced air­
flow to the brakes can them to overheat, increasing stopping distances and caus­
ing a collision.
- Run flat tires may only be used on
vehicles that were equipped with them at the factory . The vehicle must have a
chassis designed for run flat tires. Incor­
rect use of run flat tires can lead to vehi­
cle damage or accidents. Check with an
authorized Audi dealer or tire specialist
to see if your vehicle can be equipped
with run flat tires. If run flat tires are used, they must be installed on all four
wheels. Mixing tire types is not permit­
ted.
(D Note
- For technical reasons, it is not generally
possible to use the wheel rims from oth-
Tires and wheels 259
er vehicles. This can hold true for wheels
of the same vehicle type.
- If the spare tire is different from the
tires that you have mounted on your ve­
hicle (for example winter tires or wide
profile tires), then use the spare tire for a
short period of time only and drive with
extra care. Replace the flat tire with the
tire matching the others on your vehicle
as soon as possible.
- Never drive without the valve stem cap .
The valves could get damaged .
(® For the sake of the environment
Dispose of old tires in accordance with the
local requirements.
Uniform tire quality grading
-Tread wear
- Tract ion AA A B C
- Temperature AB C
Quality grades can be found where applicable
on the tire side wall between tread shoulder
and maximum section width
c;, page 256,
fig. 212.
For example: Tread wear 200, Traction AA,
Temperature A.
All passenger car tires must conform to Feder­
al Safety Requirements in addition to these
grades.
Tread wear
The tread wear grade is a comparative rating
based on the wear rate of the tire when tested
under controlled conditions on a specified
government test course.
For example, a tire graded ISO would wear
one and one half (11/2) times as well on the
government course as a tire graded 100.
The relative performance of tires depends upon the actual conditions of their use, how­
ever, and may depart significantly from the
norm due to variations in driving habits, serv­
ice practices and differences in road character-
istics and climate.
ll-
•
•