1998 JAGUAR X308 tire pressure

O
ne locking wheel nut is fitted to each road wheel and can on
ly be removed by using the correctly coded socket. For road
wheels with exposed wheel nuts, each locking wheel nut is provided with a cover, which is removed using the cover removal
tool.
Locking wheel nuts have different coded keyway combinations with corresponding coded sockets. The correct socket, and
cover removal tool are supplied with the vehicle toolkit. Sets of sockets are available to Jaguar dealers.
Temporary Spare Wheel
•
NOTE: When using this type of spare wheel note that:
Speed

must not exceed 80 km/h (50 mph).
The normal ro

ad wheel must be reinstalled as soon as possible.
On

ly one temporary wheel may be installed to the vehicle.
Tracti

on control (where fitted
) must be switched OFF.
In certain markets, the spare wheel supplied with the vehicle is of the temporary-use type, it is narrower than the normal
road wheel and takes up less room in the luggage compartment.
Tire
s
The
radial ply tires shown in the 204-04
Specification Section are recommended by Jaguar to meet the high speed
performance of the vehicle. Only tires of identical specification may be fitted as replacements. Unde r no circumstances must
cross-ply tires be fitted.
Tire Inflation Pressures
Al
l recommended tires, including winter tire
s, must be inflated to the pressures shown in the 204-04 Specification Section.
Inflation pressures must only be checked when the tires are cold.
Tire Replac
ement and Wheel-Interchanging
W
hen renewal of tires is necessary, it is
preferable to fit a complete set. If two replacement tires are fitted (to one axle),
they must be of the same manufacturer and type as those on the other axle.
No attempt must be made to interchange wh eels from the front to the rear or vice-versa, as wear produc es a characteristic
pattern on each tire depending upon its po sition on the vehicle. If this position is changed after wear has occurred, the
performance of the tire w ill be adversely affected.
It should be remembered that new tires must be balanced befo re installing to the vehicle.
Win
ter Tires
•
NOTE: Speed must not exceed 210 km/h (131 mph) when winter tires are installed.
Jaguar recommended winter tires as specified in 204-04 Specification Section must only be fitted in complete four-wheel
sets of the same type and size.
Snow Chains and Spike Spider Traction System

Jagu
ar recommended snow chains, must on
ly be installed when using 16 inch wheels with 255/60 R16 winter tires.
• NOTE: When using snow chains or the spike spider traction system, note that:
Snow ch
ains and the spike spider
traction system must only be fitted to the rear wheels.
O
nly Jaguar recommended snow chains and spik
e spider traction system must be used.
The m
aximum permissible speed with winter tires and snow chains or the spike spider traction system fitted is 48
km/h (30 mph).
Tracti
on control (where fitted) must be
switched OFF when using snow chains or the spike spider traction system.

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.

The
following explanations will help isolate the source of vibration.
Torque Sensitive
This

means that the condition can be impr
oved or made worse by accelerating, dece lerating, coasting, maintaining a steady
vehicle speed, or applying engine torque.
Ve
hicle Speed Sensitive
This means th
at the vibration al
ways occurs at the same vehicle speed and is not affected by engine torque, engine speed
or gear selection.
Engine Speed Sensit
ive
This means th
at the vibration
occurs at varying vehicle spee ds when a different gear is selected. It can sometimes be
isolated by increasing or decreasing engine speed with the tran smission in neutral or by stall testing with the transmission in
gear. If the condition is engine speed sensitive, the cause is probably not related to tires.
If the road test indicates that there is tire wine, but no shake or vibration, the noise originates with the contact between th e
tire and the road surface.
A thumping noise usually means that the tire is flat or has soft spots making a noise as they slap the roadway. Tire whine
can be distinguished from axle no ise, as tire whine remains the same over a range of speeds.
Sym
ptom Chart
Sy
mptom Chart
Sy

mptom
Possib
le Sources
Acti
on
Uneven ti

re wear.
Incorrect ti
re inflation.
*
Cor
rect to specification.
*
Exce
ssive radial an
d lateral runout.
*
Renew tire
or wheel.
*
O
ut of specification steering
geometry.
*
R
ealign steering geometry: Refer to Section 204-
00.
*
W
orn ball joint.
*
Renew
damaged component, realign steering
geometry.
*
W
orn tie-rod end.
*
R
enew component, realign steering geometry.
*
Incorrect
tire / wheel usage.
*
Inst
all correct tire and wheel combination.
*
Loose or leaki
ng shock absorbers.
*
Tigh
ten or Renew as nece
ssary: Refer to Section
204-00.
*
Suspensi
on geometry out of
alignment.
*
Che
ck and adjust: Refer to Section 204-00.
*
Loose, worn or da mage
d suspension
components.
*
In
spect, Repair or Renew as necessary.
*
Wh
eel and tire assembly out of
balance.
*
Balance wheel an
d tire assembly.
*
Excessive later
al or radial runout of
wheel or tire.
*
Check, Repair o
r
Renew as required.
*
Tire
s show excess wear on

edge of treads.
Ti
res under-inflated.
*
Cor
rect pressure to specification.
*
Vehi
cle overloaded.
*
Cor
rect to specification.
*
Tire
s show excess wear on

edge of treads (with tire
pressures correct).
Incorre
ct toe setting.
*
Se
t to specification: Refer to Section 204-00.
*
Tire
s show excess wear in
center of tread.
Tire
s over-inflated.
*
Cor
rect pressure to specification
*
W
heel mounting is
difficult.
Incorrect app
lication or mismatched
parts, including wheel studs and
wheel nuts. Corroded, worn or
damaged parts.
*
Fol
low the manufacturer's specifications. Clean or
Renew.
*
Wobble or sh
immy
affecting wheel runout.
Damaged wh
eel (eventually
damaging wheel bearings and causing
uneven tire wear).
*
Inspect wheel rims for
damage and runout. Renew
as required.
*
Vehicle vibrations from

Tire
s / wheels mismatched.
*
Inst
all correct tire / wheel combination.
*

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.
*

Brake System - General Inform
ation - Brake System
D
iagnosis and Testing
Principles of Operations
The brake system operates by transferring effort applied to th e brake pedal, by the driver to the brakes at each wheel.
The braking effort is distributed to each wheel, using a hydraulic system. The system is assisted using a vacuum brake
booster that reduces pedal effort for a given hydraulic pressure. The parking brake operates on the rear wheels and is
applied using a hand operated control.
I
nspection and Verification
•
NOTE: Prior to carrying out any diagno
sis, make sure that the brake system warning indicator is functional.
Visually examine the front and rear tire and wheel assemblies for damage such as un even wear patterns, tread worn out or
sidewall damage. Verify the tires are th e same size, type and, where possible, same manufacture. Replace the damaged
wheel or excessively worn tire. For a dditional information, refer toSection 204
-0
4 Wheels and Tires
.
W
heels and tires must be cleared of an
y foreign matter and tire pressures ad justed to the correct specification.
If the tires exhibit uneven wear or feathering, the cause must be corrected. Check the steering and suspension components
for damage or wear and, if ne cessary, check and adjust front wheel alignment. For additional information, refer toSection
204
-00 Suspen
sion System
- General Informati
on
.
Road Test


V
isual Inspection Chart
Carr

y out a road test to compare actual vehicle braking performance with the
performance standards expected by the
driver. The ability of the test driver to make valid compar isons and detect performance deficiencies will depend on
experience.
The driver should have a thorough knowledge of brake system operation and accepted general performance guidelines to
make good comparisons and de tect performance concerns.
An experienced brake technician will always establish a route that will be used for all br ake diagnosis road tests. The roads
selected will be reasonably smooth and level. Gravel or bump y roads are not suitable because the surface does not allow the
tires to grip the road equally. Crowned roads should be avoide d because of the large amount of weight shifted to the low set
of wheels on this type of road. Once th e route is established and consistently used, the road surface variable can be
eliminated from the test results.
Before a road test, obtain a complete description of the customer concerns or suspec ted condition. From the description, the
technician's experience will allow the te chnician to match possible causes with symptoms. Certain components will be
tagged as possible suspects while others wi ll be eliminated by the evidence. More importantly, the customer description can
reveal unsafe conditions which should be ch ecked or corrected before the road test. The description will also help form the
basic approach to the road test by narrowing the concern to specific components, vehicle speed or conditions.
Begin the road test with a general brake performance check. Keeping the description of the concern in mind, test the brakes
at different vehicle speeds using both ligh t and heavy pedal pressure. To determine if the concern is in the front or rear
braking system, use the brake pe dal and then use the parking brake control. If the condition (pull, vibration, pulsation)
MechanicalElectrical
Brake m
aster cylinder
Parkin
g brake switch
Brake ca

liper piston(s)
D
amaged or corroded wiring harness
Brake di

scs
B
rake master cylinder fluid level switch
Wh

eel bearin
gs
Brake pads
Power brake booster
Brake ped

al linkage
Boost

er vacuum hose
Tire

s
De

bris

oc
curs only with the parking brake, th
e concern is in the rear brake system.
If the concern becomes evident during this check, verify it fits the description given before the road test. If the concern is
not evident, attempt to duplicate the condition using the information from the description.
If a concern exists, use the Symptom Chart in order to isolate it to a specific sub-system and condition description. From
this description, a list of possible sources can be used to further narrow the cause to a specific component or condition.
Sym
ptom Chart
Sy
m
ptom
Possib
l
e Sources
Acti
o
n
Brakes
n
oisy
Brake pads.
Brake di
scs
.
*
*
GO to Pinpoint
Tes
t A.
*
Vibration wh
en brakes
are applied
Wh eels require bala
ncing.
Wheel hub nuts.
Caliper mounting bolts.
Brake pads.
Foreign material/scr atches/corrosion
on brake disc contact surfaces. Excessive brake disc thickness
variation. Excessive brake disc runout.
Wheel bearing wear or failure.
Suspension bush wear or failure.
Steering bush wear or failure.
*
*
*
*
*
*
*
*
*
*
Go to Pinpoint
Tes
t B.
*
The brakes pull or drif tTire pressures/wear.
Calipers.
Brake pads.
Brake di
scs.
Wheel alignment adjustment.
Wheel bearing.
Suspension bushes and ball joints.
*
*
*
*
*
*
*
GO to Pinpoint
Tes
t C.
*
The pedal feels spongyAir i
n brake system.
Leak in hydraulic system.
Brake booster/master cylinder.
Brake pads.
*
*
*
*
GO to Pinpoint Tes
t D.
*
The pedal goes down
fa s
t
Ai
r i
n brake system.
Leak in hydraulic system.
Brake booster/master cylinder.
Brake pads.
*
*
*
*
GO to Pinpoint
Tes
t E.
*
The pedal goes down
slowl yAir i
n brake system.
Brake booster/master cylinder.
*
*
Go to Pinpoint
Tes
t F.
*
Excessive brake pedal
effor tBrake pads.
Brake booster.
*
*GO to Pinpoint
Tes
t G.
*
Brake lockup du ring ligh
t

brake pedal force
Brake pads.
Calipers.
*
*GO to Pinpoint
Tes
t H.
*
Brakes d r
ag
Parkin
g brake con
trol
applied/malfunction. Seized parking brake cables.
Seized caliper slide pins.
Seized caliper.
Brake booster.
Pedal gear.
*
*
*
*
*
*
GO to Pinpoint
Tes
t I.
*
Exce ssi
ve/Erratic brake
pedal travel
Hydrau li
c system.
Brake pads.
Brake discs.
Hub and bearing assembly.
*
*
*
*
GO to Pinpoint
Tes
t J.
*
The red brak e warning
indi
cator is always on
Fl
ui
d level.
*
F I
LL the system to specification. CHECK for leaks.
*
Brake flu i
d level sensor.
*
I N
STALL a new brake master cylinder fluid
reservoir. For additional in formation, refer toSection
206
-0 6
Hydraulic Brake Actuation
.
*
Parkin
g brake con
trol.
*
REL
E
ASE and ADJUST the parking brake. For
additional information, refer toSection 206
-05
Parkin g Brake an
d Actuation
.
*
E
l
ectrical circuit.
*
F or additional
information, refer to PDU for
analysis/rectification of the concern.
*
Sl
ow or i
ncomplete brake

Brake peda
l binding.
*
GO to Pinpoint Tes
t K.
*

pedal retu rnBr
ake booster/master cylinder.
*

REFE
R to
Specification
- /
F r
ont Brake Disc Runout Check
- V
eh
icles With: Brembo Brakes
/

F
ront Brake Disc Runout Check
- V
e
hicles Without: Brembo Brakes

in this
section.
Yes GO to B5
.
No
GO to B6
.
B5: CHECK VEHICLE
FOR A HISTORY OF BRAKE VIBRATION PROBLEMS
Chec
k to se
e if the vehicle has recently been
repaired for brake vibration problems by the
installation of new front brake discs and pads.
1
Has vehicl
e has recently been repaired for brake vibrat
ion problems by the installation of new front brake
discs and pads.
Yes INSTALL new front wheel hubs
REFER to Section 204
-01 Fron
t Suspension
.
INST ALL new fr
ont brake disc
s and front brake pads
REFER to Section 206
-03 Fr
ont Disc Brake
.
TEST the system for normal
operation.
No INSTALL front brake discs and front brake pads
REFER to Section 206
-03 Fr
ont Disc Brake
.
CHECK for excessiv
e brake disc runout
REFER to Front Brake Disc Runout Check
- Veh
icles With: Brembo Brakes
/

F
ront Brake Disc Runout Check
- V
e
hicles Without: Brembo Brakes

in this
section.
If excessive brake disc runout exis ts INSTALL new front wheel hubs
REFER to Section 204
-01 Fron
t Suspension
.
TEST the system for normal
operation.
B
6:
CHECK THE REAR BRAKE PADS AND REAR BRAKE DISCS
Chec
k
the condition of the rear brake pads and rear brake discs.
1
D
o
es excessive brake disc runout or br
ake disc thickness variation exist?
REFER to Specification
- /
Rear B
rake Disc Runout Check
- Ve
hicles Without: Brembo Brakes
/
Rear
Brake Disc Runout Check
- Veh
icles With: Brembo Brakes
in this
section.
Yes INSTALL rear brake discs and rear brake pads
REFER to Section 206
-04
Rear Disc Brake
.
CHECK for excessiv
e brake disc runout.
REFER to Rear Brake Disc Runout Check
- Veh
icles With: Brembo Brakes
/

Rear
Brake Disc Runout Check
- V
e
hicles Without: Brembo Brakes

in this
section.
If excessive brake disc runout exists INSTALL ne w rear wheel hubs. TEST the system for normal
operation.
No REPEAT road test and re-check for a vi bration concern. If vibration exists GO to B3
.
PINPOINT TEST
C : THE BRAKES PULL OR DRIFT
TE
S
T
CONDITIONS
D E
TAILS/RESULTS/ACTIONS
C1
:
ROAD TEST VEHICLE
Road test th
e veh
icle and apply the brake pedal.
1
D
o
es the vehicle pull or drift?
Yes GO to C2
.
No
Vehicle is OK.

C2:
INS
PECT TIRE PRESSURE
Check f
or ex
cessive tire wear
or incorrect pressures.
1
Are the ti
res at the correct pressure and in good condition?
Yes GO to C3
.
No
AD
JUST the tire pressures or IN
STALL new tires if excessively wo rn. TEST the system for normal
operation.
C3 : CH
ECK CALIPERS
Check the fr
on
t caliper pistons for binding, leakin
g or sticking. For additional information, refer
toSection 206
-03 Fr
ont Disc Brake
. Check the rear cal
i
per pistons for
binding, leaking or sticking. For
additional information, refer toSection 206
-04
Rear Disc Brake
.
1