brake AUDI A4 2008 B8 / 4.G Repair Manual

Checking and topping up fluids263
Controls
Safety
Driving tips
General maintenance
Self-help
Technical data
Changing brake fluid
When required, the brake fluid should be changed by a
competent mechanic with the proper equipment.Brake fluid gradually absorbs moisture from the atmosphere. If the
water content in the brake fluid is too high, this may cause corrosion
in the brake system over time. In addition, the boiling point of the
brake fluid will be considerably reduced. This could adversely affect
the braking ability in certain circumstances.
For this reason the brake fluid must be changed periodically.
Your vehicle's Service Schedule will tell you when the brake fluid has
to be changed.
It is advisable to have the brake fluid changed as part of a regular
Inspection Service at your Audi workshop. They are familiar with the
procedure and have the necessary special tools and spare parts as
well as the proper facilities for disposing of the old fluid.
Use only the genuine brake fluid specified by the factory Qualified
workshops know that the brake fluid “DOT 4” is approved by Audi.
The brake fluid must be fresh and unused.
WARNING
•
Brake fluid is poisonous; store it in the sealed original container
in a safe place out of reach of children.
•
Heavy use of the brakes may cause a vapour lock if the brake
fluid is left in the system for too long. This would seriously affect
the efficiency of the brakes and the safety of the car – risk of acci-
dent.Caution
Please note that brake fluid will attack the paintwork on contact.
For the sake of the environment
If the fluid has to be drained out of the brake system, use an appro-
priate container to catch the used brake fluid and dispose of it in the
proper manner.BatteryGeneral notes
All work on batteries requires specialist knowledge.The battery is virtually maintenance-free. It is checked as part of the
Inspection Service.
We recommend that you replace a battery once it is older than 5
years.
When an airbag is triggered, the battery will, under certain circum-
stances, be disconnected from the on-board power supply for
safety reasons ⇒ in “General notes on airbag system” on
page 201.
Disconnecting the battery
If the battery is disconnected, some of the vehicle's functions will
become inoperative (e.g. electric windows). These functions will
require resetting after the battery is reconnected. For this reason,
the battery should only be disconnected from the vehicle's electrical
system when absolutely necessary.
If the vehicle is not used for long periods
If you do not drive your vehicle for a period of several days or weeks,
the power management will gradually shut off the on-board
systems one by one, or reduce the amount of current they are using.
This limits the amount of power consumed and helps to ensure reli-
able starting even after a long period ⇒page 226.
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Wheels and tyres271
Controls
Safety
Driving tips
General maintenance
Self-help
Technical data
– Never use tyres whose actual size exceeds the dimen-
sions of the factory-approved makes of tyre.
– If you wish to fit the vehicle with non-standard rims or
tyres, it is advisable to consult an Audi dealer before
purchasing them.The tyres and wheel rims are an essential part of the vehicle's
design. The tyres and rims approved by Audi are specially matched
to the characteristics of the vehicle and make a major contribution
to good roadholding and safe handling ⇒.
The sizes of the rims and tyres approved for your vehicle are listed
in the vehicle's documents (e.g. EC Certificate of Conformity or COC
document
3)). The vehicle documents vary depending on the
country of residence.
Understanding the tyre designations makes it easier to choose the
correct tyres. For example, radial ply tyres have the following tyre
designations marked on the sidewall:
225 / 50 R 17 94 Y
This contains the following information:
The manufacturing date is also indicated on the tyre sidewall
(possibly only on the inner side of the wheel):
DOT ... 1006...means, for example, that the tyre was produced in the 10th week of
2006.
Please note that with some types of tyres, the actual tyre size can
differ from the nominal size marked on the tyre (for instance 225/50
R 17 94 Y), and there may be significant differences in the contours
of the tyres, even though the tyres are marked with the same
nominal size designation. When replacing the tyres, it is therefore
important to make sure that the actual size of the new tyres does
not exceed the dimensions of the factory-approved makes of tyre.
Failure to observe this requirement can affect the clearance needed
for the tyres. This could result in contact between the tyres and
suspension components or bodywork. The brake lines could also be
damaged and the vehicle's safety could be severely impaired ⇒.
When using tyres with the maximum permitted nominal dimen-
sions, this can also void the vehicle's registration.
If you use tyres that are approved by Audi you can be sure that the
actual tyre dimensions will be correct for your vehicle. If you decide
to fit a different type of tyre, you must obtain the appropriate manu-
facturer's certificate from the tyre retailer to confirm that the tyres
are suitable for your vehicle. Keep this certificate in a safe place.
Your local Audi dealer will be able to advise you on which tyres may
be fitted to your vehicle.
On vehicles with four-wheel drive, all four tyres must always be
fitted with tyres of the same type, make and tread pattern, as other-
wise the driveline can be damaged by continuous variations in the
wheel speeds. For the same reason, only use a spare wheel* with
the same tyre dimensions as the normal road wheels.
It the spare tyre* is not the same type as the tyres fitted on the car
(for example if the car has winter tyres or wide-section tyres) you
should only use the spare tyre if a puncture occurs, and then only
for a short period of time. In this case, please drive with extra care.
Refit the normal road wheel as soon as possible.
It is best to have all servicing of wheels and tyres performed by a
qualified workshop. They have the necessary special tools and
3)COC = certificate of conformity
225
Tyre width in mm
50
Height/width ratio in %
R
Tyre construction: Radial
17
Rim diameter in inches
94
Load rating code
Y
Speed rating code letter
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Wheels and tyres 272replacement parts, trained personnel and facilities for disposing of
the old tyres.
WARNING
•
It is very important to ensure that the tyres you have chosen
have adequate clearance. When selecting replacement tyres, do
not rely entirely on the nominal tyre size marked on the tyre; with
some makes of tyre the effective tyre size can differ significantly
from the nominal dimensions, even though the tyres have the
same size designation. Inadequate tyre clearance can result in
damage to the tyres or the vehicle, causing a serious safety risk. It
may also invalidate the vehicle's type approval for use on public
roads.
•
Please ask your Audi dealer or qualified workshop whether run
flat tyres can be used on your vehicle. Unauthorised use of these
tyres can invalidate the vehicle's type approval for use on public
roads. Furthermore, this could cause damage to your vehicle and
possibly also result in an accident.
•
Avoid running the car on tyres that are more than 6 years old.
If you have no alternative, you should drive slowly and with extra
care at all times.For the sake of the environment
Old tyres must be disposed of according to the laws in the country
concerned.
Note
•
Never mount used tyres if you are not sure of their previous
history.
•
For technical reasons it is not normally possible to use wheel
rims from other vehicles. In some cases this also applies to rims
from other vehicles of the same model.
Wheel bolts
The wheel bolts are designed to suit the rims on your car.The wheel bolts are matched to the rims. When installing different
wheels (for instance wheels with winter tyres) it is important to use
the correct wheel bolts with the right length and correctly shaped
bolt heads. This is essential for the secure fit of the wheels and for
the proper function of the brake system.
Audi dealers have full information on the technical requirements
when installing or changing tyres, rims or wheel trims.
The wheel bolts should be clean and turn easily.
A special adapter is required to turn the anti-theft wheel bolts*
⇒page 292.Winter tyres
Winter tyres will significantly improve the car's handling
in winter road conditions.–Use only radial ply winter tyres.
– Winter tyres must be fitted on all four wheels.
– Only use winter tyres of the correct type approved for
your vehicle.
– Please note that the maximum permissible speed for
winter tyres may be lower than for summer tyres.
– Also note that winter tyres are no longer effective when
the tread is worn down.
– After fitting the wheels you must always check the tyre
pressures. The correct tyre pressures are listed on the
sticker on the end face of the driver's door.
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Wheels and tyres 274For technical reasons snow chains may only be used on tyres with
certain wheel rim/tyre combinations.
Only use snow chains with fine-pitch links. The links must not
protrude more than 13.5 mm from the tyres (including tensioner).
Remove the chains when roads are free of snow. Otherwise they will
impair handling, damage the tyres and wear out very quickly.
Four-wheel drive: where snow chains are compulsory on certain
roads, this normally also applies to cars with four-wheel drive. Snow
chains may only be fitted to the front wheels (also on vehicles with
four-wheel drive).Run flat tyresApplies to vehicles: with run flat tyresIntroduction
Run flat tyres allow you to continue your journey in the
event of a loss of tyre pressure.Run flat tyres have reinforced sidewalls which support the tyre in
the event of a loss of pressure.
Run flat tyres must only be used on vehicles which were already
factory-fitted with these tyres and which also have a tyre pressure
monitoring system*.
Run flat tyres can be identified by the marking “RSC” (Runflat
System Component) on the sidewall.If you change the tyres on your vehicle from regular tyres to run flat
tyres or vice-versa, the control unit must be reprogrammed by an
Audi dealer or other qualified workshop.
What are the benefits of run flat tyres?
Run flat tyres ensure that you remain mobile, even in the event of a
loss of tyre pressure. In favourable conditions these tyres have an
operating range of at least 30 km, however the vehicle must not be
driven faster than 80 km/h ⇒ in “Driving with run flat tyres” on
page 275.
The tyre pressures are constantly checked by the tyre pressure
monitoring system. When the run flat system becomes active
(centre display), it is still the driver's responsibility to check the
tyre(s) affected and to decide whether it is possible to continue
driving. Also refer to ⇒page 275, “Driving with run flat tyres”.
When is it no longer possible to continue driving with
the help of the run flat tyres?
•
If the Electronic Stabilisation Program (ESP) is out of operation
or is triggered continuously.
•
If the tyre pressure monitoring system is out of operation.
•
If one of the tyres has been severely damaged in an accident, etc.
If a tyre has been badly damaged there is a risk that parts of the
tread can be thrown off and cause damage to the fuel lines, brake
pipes or fuel filler.
•
You must stop driving if severe vibrations occur, or if the wheel
starts overheating and gives off smoke.
•
You must also stop driving if damage to the tyres (e.g. tears in
the sidewalls) becomes apparent.
WARNING
Please ask your Audi dealer or qualified workshop whether run flat
tyres can be used on your vehicle. Unauthorised use of these tyres
can invalidate the vehicle's type approval for use on public roads.
Rim size
Rim offset
Tyre size
7Jx16
39 mm
205/60
7Jx16
46 mm
225/55
7Jx17
46 mm
225/50
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Self-help 286The TMS can be used at outside temperatures down to – 20 °C.
WARNING
After repairing a tyre please note the following points:•
Do not drive faster than 80 km/h.
•
Avoid heavy acceleration, hard braking and fast cornering.
•
Vehicle handling could be impaired.
•
Tyres which have been sealed using the TMS are only suitable
for temporary use. Damaged tyres must be renewed.
•
The TMS must NOT be used,
−on cuts and punctures larger than 4 mm
−if the wheel rim has been damaged
−if you have been driving with very low pressure or a
completely flat tyre
•
Seek professional assistance if the repair of a tyre puncture is
not possible with the sealing compound.
•
Do not allow the sealant to come into contact with your eyes,
skin or clothing.
•
If you do come into contact with the sealant immediately rinse
the eyes or skin affected with clean water.
•
Change clothing immediately if it becomes soiled with the tyre
sealant.
•
Make sure you do not breathe in the fumes!
•
If any of the tyre sealant is accidentally ingested, immediately
rinse the mouth thoroughly and drink lots of water.
•
Do not induce vomiting. Immediately contact a doctor!
•
If any allergic reactions should occur get medical help immedi-
ately.
•
Keep the sealant away from children.
For the sake of the environment
Used bottles of sealing compound can be returned to an Audi dealer
for disposal.
Note
•
If sealant should leak out, leave it to dry. When it has dried, you
can pull it off like a piece of foil.
•
Observe the expiry date stated on the sealing compound can.
Have the sealing compound exchanged by a qualified workshop.
Repairing a tyrePreparations
– If you have a flat tyre, stop the car well away from moving
traffic.
– Apply the parking brake to stop the vehicle moving acci-
dentally.
–Engage first gear (manual gearbox) or move selector
lever to position P (automatic gearbox).
Fig. 270 Repairing a
tyre
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Self-help 288•
Seek professional assistance if the repair of a tyre puncture is
not possible with the sealing compound.
•
If tyre pressure is less than 1.3 bar after driving about 10
minutes, the tyre is too badly damaged. Do not drive on. You
should obtain professional assistance.Caution
Take special care if you have to repair a tyre on a gradient.
Note
•
Do not use the compressor for longer than 6 minutes at a time,
as it could overheat. When the compressor has cooled down, you
can use it again.
•
If tyre sealant should leak out, leave it to dry and then pull it off
like foil.
•
After carrying out a tyre repair remember to buy a new tyre
sealant can at a qualified workshop. This will ensure that the Tyre
Mobility System is operative again.
•
Please observe the relevant regulations.
Changing a wheelPreparations
Some preparations are necessary before changing a
wheel.– If you have a flat tyre, stop the car well away from moving
traffic. Choose a location that is as level as possible.– All passengers should leave the car. They should wait in
a safe place (for instance behind the roadside crash
barrier).
– Apply the parking brake to stop the vehicle moving acci-
dentally.
–Engage first gear (manual gearbox) or move selector
lever to position P (automatic gearbox).
– When towing a trailer: unhitch the trailer from your
vehicle.
– Take the tools ⇒page 283 and the spare wheel*
⇒page 284 out of the luggage compartment.
WARNING
If you have a puncture in moving traffic, switch on the hazard
warning lights and place the warning triangle in a visible location.
This is for your own safety and also warns other road users.
Caution
If you have to change the tyre on a gradient, block the wheel oppo-
site the wheel being changed by placing a stone or similar object
under it to prevent the vehicle from rolling away.
Note
Please observe the relevant regulations.How to change a wheel
Change the wheel as described below.–Pull off the hub cap. Also refer to ⇒page 289, “Hub
caps”.
WARNING (continued)
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Self-help295
Controls
Safety
Driving tips
General maintenance
Self-help
Technical data terminal must not touch metal parts of the vehicle: this can cause
short circuiting.
•
Do not bend over the batteries – risk of acid burns.
•
The screw plugs on the battery cells must be screwed in firmly.
•
Keep sparks, flame and lighted cigarettes away from batteries:
the gases given off can cause an explosion.
•
If jump-starting another vehicle, position the jump leads in
such a way that they cannot come into contact with any moving
parts in the engine compartment of the other vehicle.Caution
Please note that the above method of connecting the leads is meant
for jump-starting your vehicle. If jump-starting another vehicle, you
should not connect the negative lead (–) to the negative terminal of
the discharged battery, but directly to the engine block or a solid
metal part bolted to the engine block. If the battery of the other
vehicle does not have a gas vent, there is a risk that a mixture of
oxygen and hydrogen gas can accumulate and cause an
explosion.Tow-starting and towing awayGeneral notes
Points to observe when tow-starting or towing awayIf you use a towrope:
Notes for the driver of the towing vehicle
– The towrope must be taut before driving off.– Engage the clutch very gently when starting to move; on
vehicles with automatic gearbox press the accelerator
slowly.
Notes for the driver of the towed vehicle
– The ignition should be switched on so that the turn
signals, horn, windscreen wipers and washers can be
used. Please ensure that the steering wheel is unlocked
when you switch on the ignition, and that it moves freely.
–Put gear lever in neutral (manual gearbox) or move
selector lever to position N (automatic gearbox).
– The brake servo and power steering only work when the
engine is running. Considerably more effort is required
on the brake pedal and steering wheel when the engine
is switched off.
– Ensure that the towrope remains taut at all times when
towing.
Towrope or towbar
It is easier and safer to tow a vehicle with a towbar. You should only
use a towrope if you do not have a towbar.
A towrope should be slightly elastic to reduce the loading on both
vehicles. It is advisable to use a towrope made of synthetic fibre or
similar material.
Attach the tow-rope or tow-bar only to the towing anchorages
intended for this purpose ⇒page 296 or ⇒page 297.
Driving technique
Towing requires some experience – especially when using a
towrope. Both drivers should be familiar with the technique required
for towing. Inexperienced drivers should not attempt to tow-start or
tow away another vehicle.
WARNING (continued)
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Self-help 298
WARNING
There is a high risk of accidents when tow-starting, as the towed
vehicle can easily be driven into the towing vehicle.
Caution
When tow-starting the vehicle, do not tow it further than 50 metres:
otherwise the catalytic converter could be damaged.Towing a vehicle with manual gearbox and front-wheel drive
Towing is relatively straightforward.Please observe the notes ⇒page 295.
The vehicle can be towed using a towbar or towrope in the normal
way, with all four wheels on the road; it can also be towed with
either the front or rear wheels lifted off the road. The vehicle must
not be towed faster than 50 km/h.Towing a vehicle with automatic gearbox and front-wheel drive
Certain restrictions must be observed when towing your
vehicle.Please observe the notes ⇒page 295.
The vehicle can be towed with a towbar or towrope in the normal
way, with all four wheels on the ground. When doing so, please note
the following points:•
Release the parking brake ⇒page 121.
•
Make sure the selector lever is in the N position.
•
The vehicle must not be towed faster than 50 km/h.
•
The vehicle must not be towed further than 50 km. The reason
for this is: when the engine is not running, the gearbox oil pump
does not work and the gearbox is not adequately lubricated for
higher speeds or longer distances.
If the vehicle has to be towed with a breakdown truck, it must only
be suspended at the front wheels. The reason for this is: the drive
shafts are located on the front wheels. If the car is towed with the
rear wheels lifted off the road (i.e. travelling backwards), the drive
shafts also turn backwards. The planetary gears in the automatic
gearbox then turn at such high speeds that the gearbox will be
severely damaged in a short time.Note
If it is not possible to tow the vehicle as described above, or if it has
to be towed further than 50 km, it must be transported on a special
car transporter or trailer.Towing a vehicle with manual gearbox and four-wheel drive
Certain restrictions must be observed when towing your
vehicle.Please observe the notes ⇒page 295.
The vehicle can be towed with a towbar or towrope in the normal
way, with all four wheels on the ground. It can also be towed by a
breakdown truck, with the wheels lifted at either the front or rear.
When doing so, please note the following points:•
The vehicle must not be towed faster than 50 km/h.
•
The vehicle must not be towed further than 50 km.
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Self-help299
Controls
Safety
Driving tips
General maintenance
Self-help
Technical data
Note
If it is not possible to tow the vehicle as described above, or if it has
to be towed further than 50 km, it must be transported on a special
car transporter or trailer.Towing a vehicle with automatic gearbox and four-wheel drive
Certain restrictions must be observed when towing your
vehicle.Please observe the notes ⇒page 295.
The vehicle can be towed with a towbar or towrope in the normal
way, with all four wheels on the ground. When doing so, please note
the following points:•
Release the parking brake ⇒page 121.
•
Make sure the selector lever is in the N position.
•
The vehicle must not be towed faster than 50 km/h.
•
The vehicle must not be towed further than 50 km. The reason
for this is: when the engine is not running, the gearbox oil pump
does not work and the gearbox is not adequately lubricated for
higher speeds or longer distances.
The vehicle must not be towed with the wheels lifted at either the
front or rear.Note
If it is not possible to tow the vehicle as described above, or if it has
to be towed further than 50 km, it must be transported on a special
car transporter or trailer.
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Fuses and bulbs303
Controls
Safety
Driving tips
General maintenance
Self-help
Technical data
Fuse list for luggage compartment– Remove the trim.
– Open the fuse cover.Fuse listFuse list
Fuse listNo.
Electrical equipment
amps
Fuse carrier (black)
1
Vacant
2
Control unit for trailer
15
3
Control unit for trailer
20
4
Control unit for trailer
20
5
Electronic parking brake
5
6
Electronic suspension control
15
7
Electro-mechanical parking brake
30
8
Control unit 2 for vehicle's electrical system
30
9
Vacant
Fig. 286 Diagram of
fuse panel
10
Control unit 2 for vehicle's electrical system
30
11
Control unit 2 for vehicle's electrical system
20
12
Vacant
No.
Electrical equipment
amps
Fuse carrier (brown)
1
Electrical socket
15
2
Vacant
3
Radio/navigation
7.5
4
Control unit for digital sound system
30
5
MMI
5
6
Door control unit (driver's side)
30
7
Electro-mechanical parking brake
30
8
Seat heating, rear
30
9
Door control unit (passenger side)
30
10
Remote control receiver for auxiliary heating
5
11
Door control unit (passenger side)
15
12
Control unit for reversing camera
5
No.
Electrical equipment
amps
Fuse carrier (red)
1
Socket, centre console, rear
15
2
Socket, centre console, front
15
3
Socket, luggage compartment
15
No.
Electrical equipment
amps
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