Volkswagen Self Study Program 448 – Wheel Alignment – Basics SSP-448-Wheel-alignment-basics

Service Training

Self-study Programme 448

Wheel Alignment – Basics

Today’s modern vehicles have increasingly complex and advanced suspension systems that need to fulfil the
requirements of comfort, sporty usage and especially road safety.

We now have very good means for measuring the suspension geometry and for correcting misaligned settings
to ensure that the high requirements set for the suspension system can also be met over the entire vehicle life
and after accidents.

In this self-study programme, you will learn about the background of wheel alignment,
for example:

● Suspension-related terms

● Preparation of the wheel alignment system

● Checking the wheel alignment system

● Why the alignment is carried out

● The tools used for wheel alignment

● How the alignment principle works

For current testing, adjustment and repair
instructions, refer to the relevant service literature.

S448_002

Important

Note

2

Contents

Basics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Design configuration – vehicle position X-Y-Z axis system . . . . . . . . . . . . . . . . 5

Suspension-related terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Wheel Alignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Why do the wheels need to be aligned? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Workshop equipment for wheel alignment . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Carrying out the wheel alignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Using Wheel Alignment Stands For Other Systems . . . . . . . . . . . . . . . . . . . 38

Driver assistance systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

Axles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Types of axle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Flowchart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

Flowchart for wheel alignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

3

Basics

Introduction

The suspension system is the connecting link between
the vehicle and the road. Wheel contact forces, drive
forces and the lateral forces in corners are all
transferred through the suspension onto the road via
the wheels.

The suspension system is therefore subjected to a
number of forces and moments.

Increasing vehicle performance figures and also
greater expectations for vehicle comfort and vehicle
safety have led to a constant increase in requirements
for the suspension.

The structural design in the suspension kinematics has
resulted in increasingly complex alignment processes
and smaller tolerances in the adjustments.

To measure and, if necessary, re-align the suspension
kinematics, the suspension needs to be checked and
adjusted on a special wheel alignment stand.

It should be noted that the suspension should only be
adjusted after repairs or problems with the
suspension.

This self-study programme will provide you with an overview of wheel alignment – starting with the terms and
going onto the actual alignment.

Suspension design

The suspension consists of

● Wheel mountings

● Wheels

● Springs

● Shock absorbers

● Front and rear axles

● Steering

● Brakes including controls

● Subframes

4

Design configuration – vehicle position in an X-Y-Z axis system

The design configuration is first defined during the
development of a vehicle. It is described by an X-Y-Z
axis system.

The Z- and the X-axes run through the centre of the
front axle, and the Y-axis normally runs exactly
through the centre of the front wheels. The design
configuration corresponds with the vehicle position at
the nominal ride height.

All nominal data specified by the vehicle
manufacturer relate to the design configuration.

If data is collected and compared during the wheel
alignment, the design configuration is always taken as
a reference – this concerns the suspension terms
described below.

S448_035

Ride height

The ride height has a decisive influence on the results of the wheel alignment. It is influenced by the load carried in
the vehicle, by the contents of the fuel tank or other liquid containers and also by temperature differences that can
cause the suspension measurements, for example, toe, camber and caster, to change.

5

Basics

Suspension-related terms

Wheel centre plane

The wheel centre plane intersects the wheel rotational
axis vertically in the centre of the tyre.

Wheel contact point

The wheel contact point is the point where a vertical
line passing through the wheel centre plane intersects
the rotational axis and the road surface.

S448_020

S448_023

6

Track width

The track width is the measurement from tyre centre to
tyre centre on each axle.

On vehicles with independent wheel suspension using
traverse or semi-trailing links, the track width varies
during compression and extension cycles.

S448_011

Wheelbase

The wheelbase is the distance between the centres of
the wheels on the front axle and the rear axle.

S448_012

7

Basics

Vehicle longitudinal median plane

The longitudinal median plane of the vehicle is a fixed
vehicle-related plane that is vertical to the road and
passes through the centre of the track width of the
front and rear axle (X/Z plane).

Thrust axis

The thrust axis bisects the total toe angle of the rear
axle.

The rear axle defines the tracking of the vehicle. For
this reason, all measurements for the front wheels and
for some assist systems are related to the thrust axis.
Ideally, the thrust axis should be along the vehicle
longitudinal median plane.

S448_014

Possible situation

S448_013

8

Thrust axis deviation

The thrust axis deviation is the angle between the
vehicle longitudinal median plane (2) and the thrust
axis (1).

It results from the thrust axis, the lateral offset and the
angle of the rear axle.

If the thrust axis deviation is oriented to the front left, it
is called positive. If it is oriented to the front right, it is
called negative.

Optimum thrust axis deviation

S448_015

Straight-ahead driving

This wheel position is a reference position in which the
two front wheels have the same toe angles to the
vehicle longitudinal median plane.

The rear axle is aligned in this position.

S448_016

9

Basics

Toe angle of rear wheels

The toe angle of the rear wheels is the angle between
the vehicle longitudinal median plane and a line
intersecting the wheel centre plane.

Vehicle longitudinal
median plane

S448_112

It is positive (toe-in) when the front part of the wheel
points towards the vehicle longitudinal median plane.

It is negative (toe-out) when the front part of the wheel
points away from the vehicle longitudinal median
plane.

Toe -i n

S448_065

Toe -o ut

10

S448_018

Individual toe angle of front
wheels

The individual toe angle of the front wheels is the
angle between the thrust axis and a line running
along the wheel centre plane.

Thrust axis

S448_113

It is positive (toe-in) when the front part of the wheel
points towards the thrust axis.

It is negative (toe-out) when the front part of the wheel
points away from the thrust axis.

Toe-in

S448_064

Toe-out

S448_017

Total toe

The total toe is the sum of the angles of the left and right wheels on an axle. The negative or positive sign in front of
the individual toe angles is important.

11

Basics

Camber

Camber is the angle between the wheel centre plane
and a vertical line passing through the wheel contact
point with the road surface.

Camber can be positive and negative.

● Positive (+) is when the upper part of the wheel is

inclined away from the wheel centre plane to the
outside.

● Negative (+) is when the upper part of the wheel

is inclined away from the wheel centre plane to the
inside.

Positive

S448_019

Negative

Steering axis inclination (SAI)

The steering axis inclination (also called king pin
inclination) is the angle of inclination of the steering
axis (b) from the true vertical (a) (parallel to the
vehicle longitudinal median plane).

The steering axis inclination causes the vehicle to lift
when steered thus generating steering return forces.

S448_071

12

S448_063

Scrub radius

The scrub radius is the distance from the wheel
contact point to the point where the extended steering
axis meets the road surface.

Positive

scrub radius

scrub radius

Negative

The scrub radius can be positive (+), negative (–) or
zero.

The scrub radius results from the camber, steering axis
inclination and wheel offset.

Neutral

scrub radius

Scrub radius – tracking stability

If the scrub radius is negative, the wheel with the
greater frictional value is turned more to the inside –
autonomous countersteer results – the driver just has
to hold onto the steering wheel.

When the scrub radius is zero, the transfer of
interfering forces to the steering will be prevented if
the brakes pull to one side or there is a faulty tyre.

S448_021

S448_022

13

Basics

Caster

Caster is the inclination of the steering axis along the
vehicle longitudinal axis from a vertical line to the
road surface.

Caster can be positive and negative.

● Positive: The “wheel contact point is behind the

point at which the steering axis intersects the road
surface” – the wheels are pulled => tracking
stability

● Negative: The “wheel contact point is in front of

the point at which the steering axis intersects the
road surface” – the wheels are pushed.

Positive
caster

S448_066

Negative
caster

Toe-out on turns

Toe-out on turns is the difference between the angles
of the inside and outside wheels when the vehicle is
cornering.

Toe-out on turns is determined by the Ackermann
steering geometry. It thus provides information on the
way the Ackermann steering geometry works for the
respective steering angle – to the left of right.

S448_067

14

S448_024

Ackermann steering geometry

The front axle, the steering arms and the steering rack
with the track rods form the Ackermann steering
geometry.
The Ackermann steering geometry creates the
different steering angles that are required when the
vehicle is cornering.

The steering knuckle and steering arms are not
positioned at a 90° angle to each other. This results in
unequal travel at the ends of the two steering arms
when the steering wheel is turned. Consequently the
wheels are turned at different angles.

Straight-ahead

Steering knuckle

Steering arm

S448_025

Cornering

Maximum steering angle

The maximum steering angle is the angle of the centre

plane of the inside wheel (B) and of the outside wheel
(A) relative to the vehicle longitudinal median plane
when the steering wheel is at full left or right lock.

The maximum steering angle should be the same on
both sides. The turning circles will then be the same.

S448_068

Vehicle longitudinal
median plane

S448_026

15

Basics

Slip angle

The slip angle is the angle between the wheel plane
and the direction of travel (direction that the wheel
moves).

A slip angle is formed when a rolling vehicle is
subjected to interfering lateral forces, for example,
wind and centrifugal forces. The wheels change their
direction of travel and run at a specific angle
diagonally to the original direction of travel.

If the slip angle is the same at the front and rear, the
handling will be neutral. If the slip angle is greater at
the front, the vehicle will understeer. If the slip angle is
greater at the rear, the vehicle will oversteer.

Lateral
interfering
forces

The slip angle depends on the wheel load,
interference force, tyre type, tyre tread, tyre inflation
pressure and static friction.

Wheel set-back

The wheel set-back is the angle between a line
connecting the wheel contact point and a line that
runs at 90° to the thrust axis.

The wheel set-back can be positive and negative.

● Positive – right wheel is set to the front

● Negative – right wheel is set to the rear

S448_027

Thrust axis

16

S448_028

Wheelbase difference

The wheelbase difference is the angle between a line
connecting the front wheel contact points and a line
connecting the rear wheel contact points.

The wheelbase difference can be positive and
negative.

● Positive – the wheelbase is longer on the right-

hand side than on the left-hand side

● Negative – the wheelbase is shorter on the right-

hand side than on the left-hand side

Lateral offset

The lateral offset is the angle between a line
connecting the wheel contact points of the right-hand
or left-hand front and rear wheels and the thrust axis.

The lateral offset can be used to diagnose possible
body damage.

S448_029

Thrust axis

S448_030

17

Basics

Track width difference

The track width difference is the angle between a line
connecting the wheel contact points of the left-hand
front and rear wheels and a line connecting the wheel
contact points of the right-hand front and rear wheels.

The track width is positive if the rear track width is
larger than the front track width.

Axle offset

The axle offset is considered to be positive if the rear
axle is offset to the right of the front axle in relation to
the thrust axis.

The axle offset can be used to diagnose possible body
damage.

S448_031

Thrust axis

18

S448_032

Wheel offset

The wheel offset is the measurement from the
centreline of the wheel to the hub mounting surface
of the wheel (“x”).

The wheel offset influences the track width and the
scrub radius.

S448_033

One must distinguish between three variants of wheel offset

● Zero – If the hub mounting surface is precisely on the centreline of the wheel

● Positive – If the hub mounting surface, relative to the centreline of the wheel, is offset to the outside of the wheel

– reduction in track width

● Negative – If the hub mounting surface, relative to the centreline of the wheel, is offset to the inside of the wheel

– increase in track width

Positive Zero Negative

S448_034

19

Wheel Alignment

Why do the wheels need to be aligned?

Correct wheel alignment is necessary to run a vehicle
with optimum handling and minimum tyre wear.

Incorrect adjustment, for example, of the toe or
camber, caused by wear or accidents will affect the
road safety of the vehicle.

Impermissible deviations in the wheel alignment can
also occur following repairs, for example, when
suspension parts are replaced.

Incorrect alignment can lead to incorrect wheel
positions, which can consequently cause damage
to the tyres.

If handling problems or noticeable wear occur, wheel
alignment can be used to diagnose the causes and
determine what action needs to be taken to restore
the correct suspension set-up.

Wheel alignment should only be
performed by properly trained personnel.

Suspension parameters – Effects of faults – Adjustment possibilities

The suspension parameters are distinguished by non-adjustable original and reference design parameters and
adjustable parameters. These will be explained separately in the following table.

Suspension parameter
(basic terms)

Track width Original and reference design parameter – therefore faults have no effect

Wheelbase Original and reference design parameter – therefore faults have no effect

Effect of fault – Adjustment possibility

● Non-adjustable suspension parameter

● Non-adjustable suspension parameter

20

Suspension parameter
(basic terms)

Effect of fault – Adjustment possibility

Wheel centre

Original and reference design parameter – therefore no fault effects

plane

● Non-adjustable suspension parameter

Wheel contact

Original and reference design parameter – therefore no fault effects

point

● Non-adjustable suspension parameter

Thrust axis If this straight line deviates from the vehicle longitudinal median plane, a thrust

axis deviation results and the vehicle will run to one side – this is known as
“crabbing”.

● Adjustable suspension parameter

Veh ic le

Original and reference design parameter – therefore no fault effects
longitudinal
median plane

● Non-adjustable suspension parameter

Thrust axis
deviation

Straight ahead In this wheel position, the front wheels are set at the same individual toe angle to

Toe Too much negative toe (toe-out): Wear on inside of tyre and poor

If the thrust axis deviation is an angle other than zero, the vehicle will run to one

side – this is known as “crabbing”.

● Adjustable suspension parameter

the vehicle longitudinal median plane.

The rear axle is aligned in this position.

straight running

Too much positive toe (toe-in): Wear on outside of tyre and poor

straight running

● Adjustable suspension parameter

21

Wheel Alignment

Suspension parameter

Effect of fault – Adjustment possibility

(basic terms)

Camber Too much negative camber: Better directional stability in corners, but one-sided

overloading and consequently greater wear on inside of tyre

Too much positive camber: Poorer directional stability, increased wear on the
outside of the tyre

● Vehicle-dependent adjustable suspension parameter

Steering axis
inclination
(SAI)

Steering axis inclination too large: High steering and holding forces
Steering axis inclination too small: Poor steering wheel return, sensitive to tyre
faults, vehicle may pull to one side
Right/left steering axis inclination different: Vehicle tends to pull to side

● Non-adjustable suspension parameter

Scrub radius The scrub radius is influenced by the camber, steering axis inclination and wheel

offset and can therefore only be changed by adjusting these parameters.

● Non-adjustable suspension parameter

Caster Too much positive caster: High steering and holding forces

Toe-out on
turns

Ackermann
steering
geometry

Max. steering
angle

Too much negative caster: Poor steering wheel return, sensitive to tyre faults
Right/left caster different: Vehicle tends to pull to side
The caster changes, for example, depending on the load in the luggage
compartment.

● Vehicle-dependent adjustable suspension parameter

Original and reference design parameter – therefore no fault effects

● Non-adjustable suspension parameter

The front axle, the steering arms and the steering rack with the track rods form the
Ackermann steering geometry.
The Ackermann steering geometry creates the different steering angles that are
required when the vehicle is cornering.

● Non-adjustable suspension parameter

If the maximum steering angle differs for left/right full lock, the turning circle
will be different on the left and right.
This is a design specification.

22

● Adjustable suspension parameter

Suspension parameter

Effect of fault – Adjustment possibility
(basic terms)

Slip angle The slip angle results from the parameters wheel load, lateral force, tyre design,

tyre tread, tyre inflation pressure and static friction coefficient.

● Non-adjustable suspension parameter

Wheel set-

The wheel set-back is a measure of the angle of an axle.
back

● Non-adjustable suspension parameter

Wheelbase

The wheelbase difference is a measure of the angle of the axles.
difference

● Non-adjustable suspension parameter

Lateral offset Lateral offset can result from body damage.

● Non-adjustable suspension parameter

Track wid t h
difference

A track width difference can result from body damage.

● Non-adjustable suspension parameter

Axle offset Axle offset can result from body damage.

● Non-adjustable suspension parameter

Wheel offset Original and reference design parameter

23

Wheel Alignment

Workshop equipment for wheel alignment

Special components are used for wheel alignment. They will be described over the following pages.

Wheel alignment platform

A special wheel alignment platform is used for wheel alignment.

Turntable Turntable

In order to perform a precise wheel alignment and also to ensure reproducible measuring results, this alignment
set-up must meet certain requirements.

● The wheel alignment platform must be clean and

the turntables and sliding plates must move
smoothly.

● The turntables and sliding plates should be locked

in place with pins or similar locking devices so that
they cannot move while the vehicle is driven onto
or off the platform.

Sliding plate Sliding plate

S448_037

● All wheel contact points must be at the same

height.
The maximum permitted height differences should
be maintained both in the lowered position for the
initial and final measurements and in the raised
position for the adjustment work.

24

Wheel alignment system

For precise wheel alignment, a corresponding
alignment system that is approved by Volkswagen
like, for example, the V.A.G 1813 F system from
Beissbarth, should be used.

However, we cannot look at all systems approved by
Volkswagen in this book. The following discussion
therefore describes wheel alignment using only a
computer-supported wheel alignment system as an
example.

Wheel alignment system/
wheel alignment computer

The system comprises the following main components

● Computer with monitor and corresponding alignment software

● Input devices like keyboard and remote control

● Output unit, for example, printer

● Sensors

● Clamps for sensors

Wheel alignment
platform

S448_044

Tur nt ab le

25

Wheel Alignment

Sensors

The sensors work with rechargeable batteries or can be connected with power leads, if necessary. Each of the four
sensors is equipped with two CCD cameras that allow infrared measurements.

The measurement is made with an infrared light beam that is projected through a lens to a light mark. All
measurements on the horizontal plane are carried out with two transceiver CCD cameras that communicate with
each other.

The measurement data is transferred to the measuring box wirelessly.

Sensor

Spirit level

CCD camera

26

S448_050

The sensors form a closed measuring rectangle around the vehicle (see page 30).

Aerial

CCD camera

Measuring unit bracket

The measuring unit bracket is universally suitable for
wheels from 10 inches to 23 inches. The brackets on
the clamp simply fit onto the tyre tread.

The corresponding accessories, for example, plastic
sleeves, prevent damage to painted wheels or alloy
wheels.

Measuring unit bracket

S448_048

Brake pedal actuator

The brake pedal actuator prevents wheels rolling on
the turntables when the steering wheel is turned. This
is absolutely necessary to obtain precise caster,
steering axis inclination and track difference angle
measurements.

Brake pedal actuator

S448_114

27

Wheel Alignment

Bases for wheels

Turntable

The turntable can be ordered as an accessory for the
wheel alignment computer.

It allows the steering to be turned.

Sliding plate

Tur nt ab le

S448_038

Sliding plate

The sliding plate can be ordered as an accessory
for the wheel alignment computer.

The sliding plate allows wheel alignment to be
performed on vehicles with different wheelbases
without having to reposition the sliding plate.

The turntables and the sliding plates should be
unlocked after wheel rim run-out compensation.

Wheel alignment
platform

S448_039

28

Wheel alignment software

Once the preparations have been completed and the alignment system has been set up, you can start the wheel
alignment process.

The measurements are made in single steps with the aid of a dialog box on the computer screen.

The software has been specially developed for VW. It provides vehicle-specific measuring procedures and
information. It provides information on the adjustment procedures and contains alignment data for vehicles
throughout the Group.

The screenshot is only an example.

S448_054

29

Wheel Alignment

Wheel alignment system set-up

The illustration shows the communication paths of the wheel alignment system.

Monitor Computer

Keyboard

Measuring box

Printer

Sensor

Sensor Sensor

Tur nt ab le

Sliding plate

Sensor

30

Infrared light beam

S448_047

The infrared light beams emitted by the measuring
system may not be broken during the measurement.

Carrying out the wheel alignment

The wheel alignment process allows the existing adjustment values (current state) to be compared with the
parameters specified by the vehicle manufacturer for the suspension.

Corrective adjustments can be made if there are impermissible deviations.

Procedure for wheel alignment

Preparation for wheel alignment

● Select vehicle type

● Create job order data

● Measure ride height

● Perform wheel rim run-out compensation

Wheel alignment process

● Initial measurement

● Corrective adjustments, if necessary

● Final measurement

● Alignment report

In the following descriptions, wheel alignment will be
explained using electronic alignment with a wheel
alignment computer.

S448_111

31

Wheel Alignment

Preparations for wheel alignment

The following table provides an overview of the basic work steps to prepare for the wheel alignment.

Preparations for wheel alignment

Line up the turntables and sliding plates and adjust the lifting platform width for the track width and wheelbase of
the vehicle.

Drive the vehicle onto the turntables and sliding plates; the wheels must be in the centre of the turntables and plates.

Secure vehicle against rolling.

Test prerequisites:

Please observe the vehicle-specific information in the wheel alignment software.

● Check the general condition of the suspension and shock absorbers.

● Check that the wheel rims and tyres are the same size.

● Check the suspension, wheel bearings, steering and steering linkage checked for impermissible play and damage.

● The tread depth of the tyres on one axle may differ by a maximum of 2 mm.

● The inflation pressure of the tyres must comply with the specifications.

● The kerb weight of the vehicle must be observed.

● The fuel tank must be full. Fill it up if necessary.

● The spare wheel and vehicle tool set must be in the prescribed location in the vehicle.

● The water reservoir for the windscreen and headlight washer system must be full.

● Make sure that none of the sliding plates or turntables are at their end position during the alignment process.

● Alternatively, compensating weights can be used for missing liquids.

● The vehicle should be cool (e.g. Touareg/Phaeton with air suspension).

Attach the measuring unit brackets to the wheels.
The following criteria should be observed in particular:

● Sleeves should be used if necessary.

● Secure attachment of the measuring unit bracket

● Same attaching surface of measuring unit bracket

● Good form fit and positive engagement

32

Settings for wheel alignment

Ride height

The ride height has a decisive influence on the results of the wheel alignment because the toe and camber readings
will be different if the ride height differs due to the suspension geometry.

The ride height is determined by measuring vertically
from the centre of the wheel to the lower edge of the
wheel arch.

It is, however, also possible to measure the distance
from the lower edge of the wheel arch to the rim
flange and then add half of the wheel rim diameter
(the wheel rim diameter must be measured).

This method is recommended as the centre of the
wheel could be obscured by parts of the measuring
equipment, for example, the quick clamp units.

The ride height can be varied by changing the load,
which also changes the readings for the suspension.
The vehicle should therefore have the correct kerb
weight before the wheel alignment is started.

Lower edge of wheel arch

Measuring tool
fitted on centre of wheel

You must make sure that the ride height is within the tolerance
range specified by the manufacturer.
If the tank is not completely filled with fuel, changes to the toe,
camber and caster readings will result.

S448_051

33

Wheel Alignment

Wheel rim run-out compensation

Wheel rim run-out compensation must be carried out.
This measures the lateral run-out of the wheel and the
clamping errors of the measuring unit bracket in one
revolution of the wheel and compensates the toe and
camber readings.

The wheels must be lifted off the ground to perform
the wheel rim run-out compensation. Loosen the
securing screw on the sensor so that the rotational
angle sender flanged onto the pin can measure the
wheel position.

S448_052

After the wheel rim run-out compensation has been
started, the wheel should be turned one quarter of a
revolution three times in the direction of travel in
accordance with the user guide on the screen.

The following work is also necessary after the
wheel rim run-out compensation and before the initial
measurement

● Pull out the locking pins from the turntables under

the wheels to prevent tension in the suspension

● Lower the vehicle

● Rock the vehicle at the front and rear axle so that

the suspension settles in a stable central position

● Lock the brakes by fitting the brake pedal actuator

S448_053

The vehicle should be lowered onto the
centres of the turntables and sliding
plates.

34

The screens shown over the following
pages are purely examples.

Initial measurement

The initial measurement should basically be carried out with the following steps:

● Set wheels to straight-ahead

● Align spirit level on sensors

● Measure the rear axle values

● Perform steering routine by turning wheels to 20°

on both sides in order to determine caster, steering
axis inclination and toe-out on turns.
Return steering wheel to straight ahead position.

● Measure toe and camber of front axle

● Perform steering routine for measuring maximum

left/right steering angle

● Overview of readings with specified/current value

comparison. If all readings are within the
permitted tolerances, an alignment report can be
printed out immediately and the wheel alignment
can be ended on this vehicle.

● If the current readings are outside the tolerance

range, adjustments are required. All values that
can be adjusted on the vehicle are indicated by
a tool icon during the adjustment work.
Corresponding adjustment diagrams and
information can be displayed on the screen for
these readings at the touch of a button.

Due to possible changes and updates, the instructions in ELSA
(electronic service information system) should be observed
during the preparation and performance of the wheel
alignment.

S448_073

35

Wheel Alignment

Adjustment work – camber and caster
setting on front axle

The following can be set:

● Left camber

● Left caster

● Left toe

● Right camber

● Right caster

● Right toe

● Camber difference

● Caster difference

Adjustment work – rear axle settings

The following can be set:

● Left camber

● Right camber

● Left toe

● Right toe

● Tota l toe

● Camber difference

On torsion beam axles like, for example, on the Polo,
individual adjustments cannot be made. The readings
can be averaged out by shifting the axle.

Adjustment work – front axle settings

The following can be set:

S448_056

S448_057

36

● Left camber

● Right camber

● Left toe

● Right toe

● Tota l toe

S448_059

Final measurement

The final measurement should be carried out in the
same way as the initial measurement.

The alignment report is displayed at the end of the
final measurement.

If all readings from the final measurement are within
the permitted tolerances, an alignment report can
then be printed and the wheel alignment can be
ended on this vehicle.

Before the final measurement, all loosened screw connections
on the axles should be tightened to the specified torques.

S448_061

Alignment report

The customer and vehicle data is shown at the top of
the alignment report.

In the lower section, you will see the specified data
related to the readings from the initial and final
measurement.

S448_072

37

Using Wheel Alignment Stands for Other Systems

Driver assistance systems

Driver assistance systems provide physical and psychological support for the driver.
As ever, the driver is solely responsible for his vehicle and its performance.

Lane departure warning system

If a vehicle is equipped with the lane departure
warning system, the system’s camera may need to be
re-calibrated after wheel alignment.

This is absolutely necessary if the toe or camber of the
rear axle has been adjusted.
Adjusting the settings on the rear axle also changes
the thrust axis of the vehicle.

The setting device VAS 6430 is used to calibrate the
warning system camera. It is positioned in front of the
vehicle at a right angle to the thrust axis with the help
of the wheel alignment system.
The setting device comprises different components
and is also used to calibrate the ACC system, for
example.

Calibration board for warning system – VAS 6430/4

S448_105

Setting device VAS 6430/1

38

The steps for the calibration process are listed in the wheel alignment
computer software.

You will find detailed information on the warning system in self-study
programme no. 418 “The Lane Departure Warning System”.

Adaptive Cruise Control – ACC

If the vehicle is equipped with the adaptive cruise
control system (ACC), the radar sensors used by the
system may need to be re-calibrated after wheel
alignment.

This is absolutely necessary if the rear axle toe has
been adjusted during the wheel alignment. You will
need the setting device VAS 6430 to calibrate the
radar sensor.

You will find detailed information on the adaptive
cruise control system in self-study programme no. 470
“The Touareg 2011 Electrical/Electronics System”.

S448_115

Setting device VAS 6430

Rear view camera –
reversing camera system

If a vehicle is equipped with the rear view system, the
system’s camera will need to be re-calibrated if the
toe or camber settings of the rear axle have been
adjusted during wheel alignment.

The calibration unit VAS 6350 is used to calibrate the
rear view camera.

Adjusting the settings on the rear axle also changes
the thrust axis of the vehicle. The optimum scanning
area of the rear view camera depends on the thrust
axis.

You will find detailed information on the reversing camera system
in self-study programme. 407 “Reversing Camera System”.

S448_116

Calibration unit VAS 6350

39

Axles

Types of axle

The following are some examples of the types of axle used by Volkswagen.

McPherson strut front suspension on Golf 2004

● Toe adjustable

● Camber not adjustable, can be influenced by centring the axle

Four-link rear axle on Golf 2004

● Toe and camber separately adjustable

S448_006

S448_007

40

Torsion-beam rear axle on Polo 2010

● Cannot be adjusted

● Can only be centred

Four-link 4motion rear axle on Passat and Tiguan

● Toe and camber separately adjustable

S448_070

S448_069

41

Axles

Steel-spring suspension or air suspension on Touareg

The Touareg can be equipped either with a steel-spring suspension system or an air suspension system.
The illustrations show the version with air suspension.

Front axle

● Toe, camber and caster separately adjustable

Rear axle

● Toe and camber separately adjustable

S448_008

S448_106

42

Steel-spring suspension or air suspension on Phaeton

The Phaeton can be equipped either with a steel-spring suspension system or an air suspension system.
The illustrations show the version with air suspension.

Front axle

● Toe, camber and caster separately adjustable

Rear axle

● Toe and camber separately adjustable

S448_009

S448_107

43

Flowchart

Flowchart for wheel alignment

(using example of Golf 2009)

Start

Preparation of
wheel alignment

Measuring procedure

Comparison of specified
and current values

Correction/adjustment

Select vehicle

Create job order data

Initial measurement

Check camber of

Measure

ride height

front axle

Check toe of

front axle

IMPORTANT

End

Check camber of

rear axle

Check toe of

rear axle

Check toe of

front axle

Final measurement

44

Perform wheel rim run-out

compensation

Rock

vehicle

Fit brake pedal

actuator

Current reading

within tolerance?

Ye s

Current reading

within tolerance?

Ye s

Current reading

within tolerance?

Ye s

Current reading

within tolerance?

Ye s

No

No

No

No

Adjust

camber

Adjust

toe

Adjust

camber

Adjust

toe

Current reading

within tolerance?

Tighten screw connections

to specified torque

Ye s

No

Adjust

toe

S448_110

45

Notes

46

47

448

© VOLKSWAGEN AG, Wolfsburg
All rights and rights to make technical alterations reserved.

000.2812.28.20 Technical status 02.2011

Vol ksw agen AG
Service Training VSQ-1
Brieffach 1995
38436 Wolfsburg

❀ This paper was manufactured from pulp that was bleached without the use of chlorine.