brake AUDI A8 2018 Service Manual

Checking and Filling
Cl osing the ho od
~ Push the hood down until you override the
force of the strut .
~ Let the hood fall light ly into the latch. Do not
press it in.
c::> .&_ .
A WARNING
-Never open the hood when there is steam or
coolant escaping from the engine compart­
ment, because there is a risk that you could
be burned. Wait until no steam or coolant is
escaping.
Engine compartment overview
The most important check points .
-For safety reasons, the hood must always be
closed securely while driv ing. Because of
this, always check the hood after closing it
to make sure it is latched correctly . The
hood is latched if the front corners cannot
be lifted.
-If you notice that the hood is not latched
while you are driving, stop immed iate ly and
close
it, because d riving when the hood is
not latched increases the r is k of an accident.
Fig. 258 Typical locatio n of the rese rvoir and the engi ne o il fille r open ing
(D Washer fluid reservoir (Q) c::> page 281
@ J ump start point(-) with hex head screw
c::> page 280, c::> page 32 7
® Jump start point(+) under a cover
c::> page 280, c::> page 32 7
@ Engine oil label * w ith VW standard
c::> page 2 75
274
® Engine oil filler opening ( page 2 76
@ Brake fl uid reservo ir ((0)) c::> page 2 79
(J) Coolant reservoir (-L) c::> page 2 78
The engine oil filling opening (item @) may be
l ocated in a different area depending on the en-
gine version.
.,.

lL
_& WARNING
-The cooling system is under pressure. Do
not open the coolant expansion tank cap
when the engine is hot. This increases the
risk of burns .
- The coolant additive and the coolant can be dangerous to your health. For this reason,
keep the coolant in the original container
and away from children. There is a risk of
poisoning.
- When working in the engine compartment,
remember that the radiator fan can switch
on even if the ignition is switched off, which
increases the risk of injury.
CD Note
Do not add coolant if the expansion tank is
empty. Air could enter the cooling system and
damage the engine. If this is the case, do not
continue driving. See an authorized Audi deal­
er or authorized Audi Service Facility for assis­
tance.
Brake fluid
N N
-N
" co IX)
Fig. 261 Engine compartment: cap on brake flu id reservoir
Observe the safety precautions ~&. in Working
in the engine compartment on page 2
72.
Checking the brake fluid level
.. Read the brake fluid level on the brake fluid
reservoir
~ page 274, fig. 258. The brake fluid
level must be between the MIN and MAX mark­
ings~&. -
~ The brake fluid level is monitored automatically .
...... N ...... 0 0 :c ' Checking and Filling
Changing the brake fluid
Have the brake fluid changed regularly by an au­
thorized Audi dealer or authorized Audi Service
Facility.
_& WARNING
-
- If the brake fluid level is below the MIN
marking, it can impair the braking effect
and driving safety, which increase the risk of
an accident . Do not continue driving . See an
authorized Audi dealer or authorized Audi
Service Facility for assistance.
- If the brake fluid is old, bubbles may form
in the brake system during heavy braking.
This would impair braking performance and
driving safety, which increases the risk of an
accident.
- To ensure the brake system functions cor­
rectly, only use brake fluids that comply
with VW standard 50114 or FMVSS-116 DOT 4.
CD Note
- If the brake fluid level is above the MAX
marking, brake fluid may leak out over the
edge of the reservoir and result in damage
to the vehicle.
- Do not get any brake fluid on the vehicle
paint, because it will corrode the paint.
Battery
General warnings about batteries
Because of the complex power supply, all work
on batteries such as disconnecting, replacing,
etc., should
only be performed by an authorized
Audi dealer or authorized Audi Service Facility
~ .&. .
The term "vehicle battery" refers to the 12 Volt
battery in your vehicle.
Detailed warnings for the vehicle battery:
® Wear eye protection.
b. Bat~ery acid is highly corrosive. Wear pro-
~ tect1ve gloves and eye protection. Ill>-
279

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"' -N .... N
-0
0
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® Mud and snow capability
"M/S" or "M+S" indicates the tire
has properties making it suitable
to drive in mud or
snow .~ indi­
cates a winter tire .
@ Composition of the tire cord
and m aterials
The number of plies indicates the
number of rubberized fabric lay­
ers in the tire. In general : the
more layers, the more weight a
tire can carry . Tire manufacturers
must also specify the materials
used in the tire . These include
steel, nylon, polyester and other
materials .
@Maximum permitted load
This number indicates the maxi­
mum load in kilograms and
pounds that the tire can carry .
@Uniform ti re quality grade
standards for treadwear,
traction and temperature resistance
Treadwear , traction and tempera­
ture
ranges¢ page 299 .
@ Running direction
The arrows indicate the running
direction of unidirectional tires .
You must always follow the speci- fied running direction
¢
page 319.
@ Maximum permitted
inflation p ressure
Wh eel s
This number indicates the maxi­
mum pressure to which a tire can
be inflated under normal operat­
ing conditions.
Glossary of tire and loading
terminology
Accessory weight
means the combined weight (in
excess of those standard items
which may be replaced) of auto­ matic transmission, power steer­
ing, power brakes, power win ­
dows, power seats, radio, and
heater, to the extent that these
items are available as factory-in­
stalled equipment (whether in­
stalled or not) .
Aspect ratio
means the ratio of the height to
the width of the tire in percent .
Numbers of 55 or lower indicate a
low sidewall for improved steer­
ing response and better overall
handling on dry pavement .
285

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(a) Curb weight
(b) Accessory weight
(c) Vehicle capacity weight, and
(d) Production options weight
Ma ximum (permissible }
inflation pres sure
means the maximum cold infla­
tion pressure to which a t ire may
be inflated . Also called "maxi ­
mum inflation pressure."
Normal occupant weight
means 150 l bs. (68 kilograms)
times the number of occupants
seated in the veh icle up to the to­
tal seating capacity of your vehi­
c le.
Occupant distribution
means distribution of occupants
in a vehicle.
Outer diameter
means the overall diameter of an
inflated new tire .
Overall width
means the linear distance be­
tween the exteriors of the side­
walls of an inflated tire, including
elevations due to labeling, deco­
rations, or protective bands or
ribs .
Wheels
Ply
means a layer of rubber-coated
parallel cords .
Production options weight
means the combined weight of
those installed regular production
options weighing over 5 lbs. (2.3 kg) in excess of those standard
items which they replace, not pre ­
viously considered in curb weight
or accessory weight, including heavy duty brakes , ride levelers ,
roof rack, heavy duty battery, and
special trim .
Radial ply 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 .
Recommended inflation
pressure
see ~ page 286, Cold tire infla­
tion pressure .
Reinforced tire
means a tire designed to operate
at higher loads and at higher in­
flat ion pressures than the corre­
sponding standard tire. Rein ­
forced tires may be iden tified as
.,.
28 7

LL
"' .... N ,-.. N .... g :r st
use a spare tire* that is the same
circumference as the regular
tires.
&_ WARNING
-Only use tire/rim combina­ tions and suitable wheel bolts
that have been approved by
Audi. Otherwise, damage to
the vehicle and an accident
could result.
-For technical reasons, it is not
possible to use tires from oth­
er vehicles
-in some cases,
you cannot even use tires from
the same vehicle model.
-Make sure that the tires you
select have enough clearance
to the vehicle. Replacement
tires should not be chosen
simply based on the nominal
size, because tires with a dif­
ferent construction can differ greatly even if they are the
same size. If there is not
enough clearance, the tires or
the vehicle can be damaged and this can reduce driving
safety and increase the risk of
an accident.
-Only use tires that are more
than six years old when abso-
Wheels
lutely necessary and drive
carefully when doing so .
-Do not use run-flat tires on
your vehicle. Using them when
not permitted can lead to ve­
hicle damage or accidents.
-If you install wheel covers on
the vehicle, make sure they al­ low enough air circulation to
cool the brake system. If they
do not, this could increase the
risk of an accident.
Tire wear/damage
Fig. 265 T ir e profile: treadwear indica­
tor
Tire wear
Check the tires regularly for wear.
-Inflation pressure that is too low
or high can increase tire wear
considerably.
-Driving quickly through curves, rapid acceleration and heavy
braking increase tire wear.
291

Wheels
sure that load limits are not ex­
ceeded. Vehicle load includes ev­
erybody and everything in and on
the vehicle. These load limits are
technically referred to as the vehi­
cle's
Gross Vehicle Weight Rat­
ing
("GVWR").
The "GVWR" includes the weight
of the basic vehicle, all factory in­
stalled accessories, a full tank of
fuel, oil, coolant and other fluids plus maximum load. The maxi­
mum load includes the number of
passengers that the vehicle is in­
tended to carry ("seating capaci­
ty") with an assumed weight of
150 lbs. (68 kg) for each passen­
ger at a designated seating posi­
tion and the total weight of any
l uggage in the vehicle. If you tow
a trailer, the weight of the trailer
hitch and the tongue weight of
the loaded trailer must be includ­
ed as part of the vehicle load.
The
Gross Axle Weight Rating
("GAWR") is the maximum load
that can be applied at each of the
vehicle's two axles.
The fact that there is an upper
limit to your vehicle's Gross Vehi­
cle Weight Rating means that the
total weight of whatever is being
296
carried in the vehicle (including
the weight of a trailer hitch and the tongue weight of the loaded
trailer) is limited. The more pas­
sengers in the vehicle or passen­
gers who are heavier than the
standard weights assumed mean
that less weight can be carried as l uggage .
The Gross Vehicle Weight Rating
and the Gross Axle Weight Rating
are listed on the safety compli­
ance sticker label located on the
driver's side B-pillar
¢ page 293,
fig. 266.
_& WARNING ~
Overloading a vehicle can cause
loss of vehicle control, a crash
or other accident, serious per­
sonal injury, and even death.
-Carrying more weight than
your vehicle was designed to
carry will prevent the vehicle
from handling properly and increase the risk of the loss of
vehicle control.
-The brakes on a vehicle that
has been overloaded may not
be able to stop the vehicle
within a safe distance.

u. co .... N
" N .... 0 0 :c ' & WARNING
-Only wash the vehicle when the ignition is
off and follow the instructions from the car
wash operator to reduce the risk of acci­
dents.
-To reduce the risk of cuts, protect yourself
from sharp metal components when wash­
ing the underbody or the inside of the wheel
housings.
-After washing the vehicle, the braking effect may be delayed due to moisture on the
brake rotors or ice in the winter . This in­
creases the risk of an accident. The brakes
must be dried first with a few careful brake
applications.
@ Note
-If you wash the vehicle in an automatic car
wash, you must fold the exterior mirrors in
to reduce the risk of damage to the mirrors.
Power folding exterior mirrors* must only
be folded in and out using the power folding
function.
-To reduce the risk of paint damage, do not
wash the vehicle in direct sunlight.
-
Care and cleaning
-To reduce the risk of damage, do not wash
the power top with a pressure washer.
-To reduce the risk of damage to the surface,
do not use insect removing sponges, kitchen
sponges or similar items.
-Matte finish painted vehicle components:
-To reduce the risk of damage to the sur-
face, do not use polishing agents or hard
wax.
-Never use protective wax. It can destroy
the matte finish effect .
-Do not place any stickers or magnetic
signs on vehicle parts painted with matte
finish paint. The paint could be damaged
when the stickers or magnets are re­
moved .
@ For the sake of the environment
Only wash the vehicle in facilities specially de­
signed for that purpose . This will reduce the
risk of dirty water contaminated with oil from
entering the sewer system.
Cleaning and care information
When cleaning and caring for individual vehicle
components, refer to the following tables. The
information contained there is simply recom­
mendations. For questions or for components that are
not listed, consult an authorized Audi
dealer or authorized Audi Service Facility. Also
follow the information found
in~.&. -
Exterior cleaning
Component Situation Solution
Windshield wiper
Deposits ~ page 51
blades
Headlights/
Deposits Soft sponge with a
mild soap solutiona)
Tail lights
Sensors/
Deposits Sensors: soft cloth with solvent-free cleaning solution
camera lenses Camera lenses: soft cloth with alcohol-free cleaning solu-
tion
Snow/ice Hand brush/solvent-free de-icing spray
Wheels Road salt Water
Brake dust Acid-free special cleaning solution
307
...

Emergency assistance
Emergency assistance
General information
.,. Park the vehicle as far as possible from moving
traffic in the event of a breakdown. In the event
of a flat tire, park the vehicle on a level surface .
It you are on a steep hill, be especially careful.
.,. Set the parking brake .
.,. Switch the emergency flashers on .
.,. Set up the warning triangle r=;,page 312 .
.,. Have the passengers exit the vehicle . They
should move to a safe place, for example be­
hind a guard rail.
A WARNING
Follow the steps given above. This is for your
protection and the for the safety of other driv­
ers.
Equipment
Warning triangle
Applies to: vehicles with warning triangle
Fig. 270 L uggage co mpartm ent lid : w arnin g triangle
The warning triangle placed in the vehicle at the
factory is located in the luggage compartment.
.,. To remove the warning triangle, press the fas-
tener in the direction of the arrow and fold the
holder down.
The luggage compartment lid is only designed to
hold the warning triangle offered by the Audi
Genuine Accessories program.
312
Vehicle tool kit
Applies to: vehicles with vehicle toot kit
Fig. 271 Lu gg age compartment : cargo floor cove r folded
upward
Fig. 272 Luggage compartment: examp le of vehicle toot
kit and vehicle j ack
The vehicle tools and vehicle jack* are stored in
the luggage compartment under the floor cover .
.,. Lift the cargo floor by the plastic handle .
.,. Hook the handle into the luggage compartment
seal
r:;, fig. 2 71 .
.,. Turn the handwheel counter-clockwise and re ­
move it .
.,. Remove the spare tire* to access the vehicle
tool kit
~ fig. 271 .
Depending on the equipment , the veh icle tool kit
may be located under the spare tire, under an­
other cover or in the tool box.
The position of the vehicle jack* may vary .
A WARNING
Improper use of the veh icle jack can cause se­
rious personal injuries.
-Never use the screw driver hex head to
tighten wheel bolts, since the bolts cannot
attain the necessary tightening torque if you
..,.

u. co .... N
" N .... 0 0 :c ' use the hex head, potentially causing an ac­
c ident.
- The factory-supplied jack is intended on ly
for your vehicle m odel. Under no circum­
stances should it be used to lift heavy
vehicles or other loads; you r isk injuring
yourself .
- Never start the en gine when the vehicle is
ra ised, which could cause an accident .
- Support the veh icle secure ly w ith appropr i­
ate stands if work is to be performed under­
neath the vehicle; otherwise, there is a po ­
tent ial risk for in ju ry .
- Never use the jack supplied with your Audi
on another vehicle, particularly on a heav ier
one . The jack is only suitable for use on the
vehicle it came w it h .
(D Tips
The vehicle jack* in your vehicle is mainte­
na nee -free .
Replacing wheels
Before changing a wheel
Observe the following precautions for your own
and your passenger's safety when changing a
wheel.
.,. After yo u experience a tire fail ure, pull the car
we ll away from moving t raffic and t ry to rea ch
level g round before you s top ¢&, .
.,. All passengers sho uld lea ve the ca r and move
to a saf e location (for instance, be hind t he
guardrai l) ¢ &, .
.,. Engage the parking brake to prevent you r vehi­
cle from rol ling
unintentionally ¢ A_.
.,. Move selector lever to position P ¢ A_.
.,. If you a re towing a trailer, unh itch the trailer
from your ve hicle.
.,. Take the jack and the spare tire ou t of the lug­
gage compa rtment
¢ page 312.
A WARNING
You or your passengers cou ld be inju red wh ile
chang ing a wheel if you do not follow these
safety precautions :
Emergenc y ass is tanc e
-If you have a flat tire, move a safe distance
off the road. Turn off the eng ine, turn the
emergency flashers on and use other warn­ ing dev ices to alert other motorists .
- Make sure that passengers wait in a safe
p lace away from the vehicle and well away
from the road and traff ic .
- To help prevent the veh icle from moving
suddenly and possib ly slipping off the jack ,
always fu lly set the par king brake and block
the front and back of the wheel diagonally
opposite the wheel being changed. W hen
one front w heel is li fted off the gro und,
p lacing the Au tom atic Transmi ssion in P
(Park) will
not p revent the vehicle from
mov ing.
- Before you change a wheel, be sure the
g ro u nd is leve l and firm. If necessary, use a
sturdy board under the jack .
- Always s tore the vehicle tool ki t, the jack
an d the replaced tire in the luggage com­
pa rtment ¢
page 213 .
(D Tips
Befo re c hangin g the wheel, you mus t activ ate
the jacking mode, so that the a utomat ic con ­
tro ls for the Adaptive Air Suspension do not
make it more di fficult to lift the vehicle with
the jack
¢ page 315 .
Changing a wheel
When you change a wheel , follow the sequence
described below step -by-step and in exactly that
order .
1. Activate the vehicle jack mode ¢ page 315 .
2. Remove the de corative wheel cover *. For
more detai ls see
a lso ¢ page 314, Decora­
tive wheel covers
or ¢ page 314, Wheels
with wheel bolt caps .
3. Loosen the wheel bolts ¢ page 315 .
4. Loca te t he p roper mount ing point for the
jac k and alig n the jack be low that po int
¢page 315 or ¢ page 316.
S. Rai se the ca r wi th the jack ¢ page 315 or
¢page 316 .
313

lL t:0 ....
"' ......
"' .... 0 0 :c ' The caps are to protect and keep the wheel bolts
clean.
Loosening and tightening the wheel bolts
Th e whe el bolts must be loos en e d b efor e raising
the vehicle .
Fig. 275 C han gin g a w hee l: l oose ning t he wheel bo lt s
Loo sening
.. Slide the w heel wr enc h onto the wheel bolt as
far as it will go .
.. Take tight hold of the end of the wrench handle
and turn the wheel bolts
c o unter -clock wise
about one single tu rn in the d irection of ar row
¢ fig. 275.
Tightening
.. Slide the wheel wrench onto the wheel bolt as
far as it w ill go.
.. T ake t ight hold of the end of the wrench handle
and tu rn each whee l bolt
cl ockwi se until it is
seated.
& WARNING
- Do not use force or hurry when changing a
wheel
-you can cause the vehicle to slip off
the jack and cause serious personal injuries .
-Do not loosen the wheel bolts more than
one turn
before you raise the vehicle with
the jack. - You risk an injury.
(D Tips
- Never use the hexagonal socket in the han­
dle of the screwdriver to loosen or tighten
the wheel bo lts .
- If a whee l bolt is very tight, you may find it
easier to loosen by carefully push ing down
Em ergen cy as sis tanc e
on the end of the whee l bolt wrench with
one foot only . As you do so, hold on to the
car to keep your balance and take care not
to slip .
AB: Raising the vehicle
The vehicle must b e lifted with the jack first be­
fore the wheel can be removed.
Fi g. 276 Sill panels: ma rk in gs
F ig. 277 S ill: posit ion ing t he veh icle jac k
.. Act iva te the veh icle jack mode in the MMI :
!CARI function button> Car system s control
button >
Servi cing & ch ecks > Air su sp. : jack
mode > On .
.. Engage the parking brake to prevent your vehi­
cl e from rolling unintentiona lly.
.. Move the s elector le ver to p osition P .
.. Find the mark ing (imprint) on the sill that is
nearest the wheel that will be changed
¢ fig . 2 76 . Beh ind the marki ng, there is a lift­
ing point on the sill for the veh icle jack .
.. Turn the ve hicl e ja ck located u nder the lift ing
point on the sill to raise the jack unt il its
a rm @
¢ fig. 277 is located under the design ated plas­
tic mo unt ¢
_A ¢(D .
.. Align the jack so that its arm @¢ fig. 2 77 en­
gages in the designated lifting point in the door
sill and the movable base @ lies flat on the
""
315