brake JAGUAR X308 1998 2.G Repair Manual

W
heels and Tires - Wheels and Tires
D
iagnosis and Testing
General Not

es
1.
1. Factory in
stalled tires and wheels are designed to provide optimum ride and ha
ndling characteristics when inflated
to the recommended inflation pressures, with vehicle loads not exceeding the full-rated load capacity.
2. 2. Correct tire pressures and driv ing technique have an important influence on tire life. Heavy cornering, excessively
rapid acceleration and unnecessary sharp braking increase tire wear.
3. 3. Replacement tires should follow the recommended:
Size
.
Speed

rating.
Load range. Radial c

onstruction type.
4. 4. The use of any other size or type of wheel / tire may seriously affect:
Safety. Ri
de.
Handlin

g.
Speed

ometer / odometer calibration.
Vehi

cle ground clearance.
Ti

re clearance between
body and chassis.
Wh
eel bearing life.
Brake cooli

ng.
5. 5. Wheels must be renewed when:
Impact damaged. Heavil
y corroded.
Porous W

heel stud holes or se
ats become damaged.
They h
ave excessive radial or lateral runout.
Safety Notes
• WAR

NINGS:
DO NOT MIX DIFFERENT TYPES OF TIRES ON THE SAM E VEHICLE, HANDLING MAY BE SERIOUSLY AFFECTED
RESULTING IN LOSS OF CONTROL.
DO NOT MIX DIFFERENT TYPES OF TIRES ON THE SAM E VEHICLE, HANDLING MAY BE SERIOUSLY AFFECTED
RESULTING IN LOSS OF CONTROL.
A TIRE AND WHEEL MUST ALWAYS BE CORRECTLY MATCHED. WIDER OR NARROWER TIRES THAN RECOMMENDED
COULD CAUSE DANGER THROUGH SUDDEN DEFLATION.
WHEN USING THE TEMPORARY SPARE WHEEL, SPEED MUST NOT EXCEED 80 KM/H (50 MPH). DRIVE WITH CAUTION
AND REPLACE WITH THE SPECIFIED WHEEL / TIRE ASSEMBLY AS SOON AS POSSIBLE.
TRACTION CONTROL (IF AVAILABLE) MUST NOT BE ENGAGED WITH THE TEMPORARY SPARE WHEEL FITTED.

WHE
N CHANGING A WHEEL, ENSURE THAT THE VEHICLE CANNOT MOVE. ALWAYS APPLY THE PARK BRAKE AND
SELECT TRANSMISSION 'P' POSITION.
NEVER RUN THE ENGINE WITH ONE WHEEL OFF THE GROUND, FOR EXAMPLE, WHEN CHANGING THE WHEEL. THE
VEHICLE COULD MOVE.
TIGHTEN THE WHEEL NUTS TO SPECIFICATION. WHEELS MAY COME LOOSE IF OVER OR UNDER TIGHTENED.
USE WHEELS AND WHEEL NUTS DESI GNED FOR XJ SERIES VEHICLES ONLY. AFTERMARKET WHEELS OR WHEEL
NUTS MAY NOT FIT OR FUNCTION PROPERLY AND COULD CAUSE INJURY OR DAMAGE.
In
spection and Verification
To maximize ti
re performance, inspec
t the tires frequently for signs of:
Unev
en wear.
Incorrect
ti
re pressure.
Wh
ee
l imbalance.
Cuts. Abrasi
ons.

B
u
lges (blister).
Ply s
e
paration.
Embedded objects. Impact damage.
Inspe c
tion should be
more frequent when:
Continuo
us high speed op
eration is required.
Ra
pid or extreme temperatures changes occur.
R
o
ad surfaces are rough.
Roads ar
e littered
with debris.
Tread W
e
ar Indicator
•
NO
TE: Tire condition must comply with prevailing local legislation.
New tires must be installed if the wear in dicators are exposed or if there is severe shoulder wear. Shoulder wear is usually
caused by either excessive camber or toe on tires.
T i
re Vibration Diagnosis
A
tir
e vibration diagnostic procedure always
begins with a road test. The road test and the custom er interview (if available)
will provide much of the information need ed to find the source of vibration.
During the road test, drive the vehicle on a road that is smooth and free of undulations. If vibration is apparent, note and
record the following:
The s p
eed at which the vibration occurs.
W
h
at type of vibration occurs in each
speed range - mechanical or audible.
How the vibrati
on is affected
by changes in the following:
- -engine torque
- -vehicle speed
- -engine speed.
Type of v i
bration - sensitivity:
- - torque sensitive,
- - vehicle speed sensitive,
- - or engine speed sensitive.

wheels
and tires.
Infl
atio
n pressure too high or low.
*
Cor r
ect pressure to specification
*
Uneven ti re wear.
*Re fe
r to Diagnosis and Testing in this section.
*
Wh ee
l and tire assembly imbalance.
*
Balance wheel an d tire assembly.
*
Brake disc imbalan c
e.
*
Check brak e disc co
oling fins for mud and foreign
material. Check for damage or disc heavy spot.
Refer to Section 206-00.
*
Damaged or distor
ted wh
eel.
*
Renew wh eel.
*
Excessive radial run-o
ut of wheel or
tire. Excessive lateral run-out of wheel or
tire.
*
*
Renew wh
eel or tire.
*
Incorrectl y
seated tire.

*
R e
mount the tire.

*
Loose wh eel mo
untings: damaged
wheel studs, whee l nuts, worn or
broken wheel hub face or foreign
material on mounting faces.
*
Tigh
te
n or Renew worn or
damaged parts. Clean
mounting surfaces.
*
De
fe
ctive wheel bearings.
*
Renew worn
or damaged bearing sets: Refer to
Section 204-00.
*
W
a
ter in tires.
*
R e
move water.
*
Damaged wh eel stud
thre
ads.
Sli
d
ing wheel across the wheel studs
during installation. Loose wheel nuts.
*
Renew wh
eel studs.
*
Broken wh eel
studs.
Loose or overti
ght
ened wheel nuts.
*
Renew wh eel studs.
*
C o
rrosion / contamination
streaks from wheel stud
holes.
Loose wh eel
nuts.
*
Chec k com
plete assembly. Renew damaged parts.
Apply correct torque setting.
*
Damaged wh
eel nu
ts.
Loose wh
eel
assembly.
Over-tightened wheel nuts.
*
*
Renew wh
eel nu
ts. Apply correct torque setting.
*
Se ize
d wheel nuts.
Cor
rosion

*
CAUTI O
N: Do not permit lubricant to
contaminate wheel hub stud holes or wheel nut seats.
If corrosion is light, wire brush away corrosion. If
corrosion is excessive renew wheel studs and wheel
nuts. Lubricate th e first three threads of wheel
studs with a graphite based lubricant.
*

W
heels and Tires - Wheel and Tire
Re
moval and Installation
Remov

al
CAUTI
ON: Do not use heat to loosen a seized wheel nut: heat will change the metal's properties and damage wheel
bearing and brake caliper seals.
I
nstallation

1.
NOTE
: Certain Jaguar wheels are fitted wi
th a hexagon wheel
nut cover
R
emove the cover with the plastic spanner supplied with
the spare wheel jacking equipment.

2. Loosen
, but do not
remove wheel nuts.
3. Raise vehicle and support on st ands. Refer to Section 100-02.

4. R
emove wheel and tire assembly.
1. Remove wheel nuts.
2. Remove wheel.
1. CAUTION: Do not allow grease to contaminate the wheel
stud threads and wheel nut to wh eel mating surface, as this may
cause the nuts to loosen.
• NOTE: To prevent the wheel corroding on to the hub, smear a
thin layer of grease onto the hub mounting face and spigot; and
wheel mounting face and spigot hole.

R
equire no adjustment and are non-serviceable items.
Accelerometers


The three accelerometers:
Sense veh
icle body movement.
Gen

erate an analogue voltag
e (maximum +5 volts) proportional to body movement.
Pr
ovide inputs to the adapti
ve damping control module.
The two vertical acce lerometers are mounted on the bulkhead and in the trunk.
The lateral accelerometer is mounted in the ECM housing.
Ada
ptive Damping Control Module (ADCM)

The ADCM
:
Is

mounted on the fascia support bracket.
Controls the four adaptiv

e dampers in re
sponse to analogue and digital inputs.
It
em
De
scription
1Battery su

pply
2Ignition su

pply
3Ground
4Input from verti

cal accelerometer, front
5Input from verti

cal accelerometer, rear
6Input from later

al accelerometer
7F

ootbrake operation signal
8Vehi

cle speed input
9D

amper control signals
10Ou

tput to message center
11D

iagnostic connector serial link

Is hard-wi
red to the instrume
nt cluster message center.
Is hard
-wired to the J1962 diagnostic connector.
Op
era
tion
Th
e
system selects the soft or
firm damper setting according to the current ro ad and driving conditions, to optimise vehicle
ride and handling.
With the vehicle stationary, the dampers are in the firm setting, but will normally switch to the soft setting when the vehicle
exceeds 8 km/h (5 mile/h); all dampers are switched simultaneously.
Sudden movement of the vehicle body, in response to road inputs, is detected by the vertical accelerometers, and the ADCM
switches the dampers to the firm setting to give improved damping of the resultant oscillations.
When cornering forces are detected by th e lateral accelerometer, the ADCM switches the dampers to the firm setting to
reduce the roll rate an d improve wheel control.
After the event has passed, the dampers revert to the soft setting.
When the footbrake is applied, the ADCM re ceives a signal and calculates the rate of vehicle deceleration. If the deceleration
rate is greater than a certain threshold, the dampers are switched to the firm setting to reduce the pitch rate and improve
wheel control.
If a system failure occurs, the ADCM grounds the output line to the instrument cluster message center, which displays a
text warning SUSPENSION FAULT and illuminates the amber warning lamp. Under fault conditions the system always fails to
the firm setting, so that the vehicle will be safe to drive un der all road and driving conditions.
Connector Pin Identity Chart for EM068

Pin
Number
Ci
rcui
t
Circuit Functi
on
1System erro
r output to instrument
cluster
2Not
used
3O/
P a
ccelerometer ground
4 to

9
Not
used
10K-
li
ne to diagnostic socket
11Ignition su
pply +12V
12Not
used
13Control signal (+ve) output
to l
eft-hand rear damper
14Control signal (+ve) output
to right-hand front damp
er
15Control signal (+ve) output
to right-hand rear
damper
16
a
nd 17
No
t
used
18Ground
19No
t
used
20Lateral
accelerometer i
nput
21Front vertical ac
celerometer in
put
22Rear vertical
acce
lerometer input
23No
t
used
24R
o
ad speed input from
instrument cluster
25Power output +5V to suppl y accelerometers
26Brake peda
l input

Vehicle Dynamic Suspension - Vehicle Dynamic Suspension
Diagn
osis and Testing
Refer to the PDU User Guide for details of diagnosing and testing the Adaptive Damping System. The PDU interrogates the
ADCM directly via the K and L lines to the J1962 diagnostic socket.
The PDU will give an indication of the integrity of each electron ic and electrical component. It will indicate, for example, that
the accelerometers are not broken, but not that they functionin g correctly when the vehicle is in motion. However, it is
exceptional for an accelero meter to function incorrectly in its dynamic mode if it is proved to be functioning when static.
Basic Checks
The accele
rometers have the following ch
aracteristics. At 0g (no movement of the body) each vertical accelerometer
outputs approximately 2.5V steady voltage; the lateral acce lerometer outputs approximately 1.5V. The voltage output due
to body movement is proportional to acceleration in the acceleration axis, up to approximately 4.5V and down to
approximately 0.5V.
Before changing any component, refer to the circuit diagrams and check the cont inuity of relevant harness circuits; in some
instances, the PDU will not different iate between a faulty component an d a damaged connection or wiring.
Check the following fuses:
En
gine compartment fuse
box, fuse F5 (10A).
Engine m
anagement fuse
box, fuse F1 (20A).
Check the following ADCM input/output lines:
Sy stem erro
r output from the ADCM
to the instrument cluster.
Vehicl
e speed output from the inst
rument cluster to the ADCM.
Foo
tbrake signal to the ADCM.
Check any relevant connections to confirm that the connection is electrically sound and that a terminal pin has not been
pushed back into the connector shell, ie. not ma king a connection to its mating pin or socket.

Driveshaft -
Torques



Comp

onent
Nm
Bol
t
M12 - Jurid flexible coupling to
transmission and final drive flanges
75
-
88
Screw
-
Centre bearing to underbody
19
,5
- 26,5
Screw
-
Parking brake relay mounting bracket to underbody
19
,5
- 26,5_

Driveshaft - Driveshaft
Remo
val and Installation
Remov
a
l
CAUTI
O
N: To preserve 'drive line' refine
ment, individual parts, other than fixings, MUST NOT be renewed. In the event
of any balance or driveshaft component related problem, the complete assembly must be renewed. Under no circumstances
may the flexible (Jurid) coupling be remo ved from the driveshaft (or its fixings be loosened). Do not drop or subject the
driveshaft to damage.
1. Disc
onnect the battery ground
lead and raise the vehicle for
access
2. Remove the front exha ust muffler, 30.10.18

3. Re
move the driveshaft from
the transmission flange.
If required, 'match mark'

the transmissi on flang and
coupling
Unscrew the fi xings (3)

4. Relea s
e the parking brake relay
lever mounting bracket fixings
(4) and allow the assembly to hang down

5. Disc onne
ct the driveshaft fr
om the differential flange
5. CAUTION: Under no circumstances must the
flexible coupling (or its fixings) be loosened or removed
from the drive shaft
1. 'Match mark' the FLEX IBLE COUPLING to the
differential DRIVE FLANGE
2. Remove the fixings (3)
6. Re
move the driveshaft
6. CAUTION: Ensure that the driveshaft front and
rear sections do not become disengaged. Secure the front
and rear sections to preven t sliding joint disengagement
during transport

Re
ar Drive Axle/Differential - Axle Shaft
In-v
ehic
le Repair
Remov
a
l
S
p
ecial Tool(s)

Hub remover

2
04-011

Thread protector
JD
1D
/ 7

1. Disc
onnect the battery ground lead.
2. Support the vehicle at the rear and remove the appropriate
rear road wheel.
3. Remove and discard the hub nut, apply the brakes to prevent
rotation.
4. Remove the brake caliper in acco rdance with 70.55.03, but do
not disconnect the hydraulics.

5. Pr
epare the hub carrier.
1. 'Match mark' the hub carr ier fulcrum bolt head and
the carrier.
6. Prepare the hub carrier.
1. Slacken the hub ca rrier fulcrum nut.
2. Disconnect the ABS sensor multiplug at the hub