1998 JAGUAR X308 brake

Brake S
ystem - General Information -
Lu
bricants, Fluids, Sealants and Adhesives
Front Brake Dimensions
• NO
TE: When a component reaches its maximum / minimum dimension limit the component must be replaced. Care must be
taken when refinishing brake discs that the dimension limits are not exceeded.
F
ront Brake Dimensions - Brembo Brakes
• NO

TE: When a component reaches its maximum / minimum dimension limit the component must be replaced. Care must be
taken when refinishing brake discs and drums that the dimension limits are not exceeded.
R
ear Brake Dimensions
• NO

TE: When a component reaches its maximum / minimum dimension limit the component must be replaced. Care must be
taken when refinishing brake discs and drums that the dimension limits are not exceeded.
R
ear Brake Dimensions - Brembo Brakes
• NO

TE: When a component reaches its maximum / minimum dimension limit the component must be replaced. Care must be
taken when refinishing brake discs and drums that the dimension limits are not exceeded.


UnitSp
ecification
Bra

ke fluid
IT
T Super Dot 4
Brembo Br

ake Grease
M
olikote Cu 7439
Co

mponent
Dimension - Normall
y Aspirated Vehicle
Dimension
- Super Charged Vehicle
Brake disc

- diameter
305 mm325 mm
Brake disc

- thickness (new)
28
- 28.5 mm
28 -
28.5 mm
B

rake disc - minimum thickness
26 mm26 mm
B

rake disc - minimum wall thickness
6.2 mm6.6 mm
I

nstalled brake disc - maximum run-out
0.1 mm0.1 mm
B

rake pad - minimum thickness
2 mm2 mm
Cal

iper piston diameter
60 mm60 mm
Co

mponent
Dimension
Brake disc

- diameter
355 mm
Brake disc

- thickness (new)
32 mm
B

rake disc - minimum thickness
30 mm
B

rake disc - minimum wall thickness
6.7 mm
I

nstalled brake disc - maximum run-out
0.1 mm
Cal

iper piston diameter
40/44 equiv
alent 60 mm
B

rake pad - minimum thickness
2 mm
Co

mponent
Dimension
Brake disc

- diameter
305 mm
Brake disc

- thickness (new)
19.5
- 20 mm
B

rake disc - minimum thickness
18.5 mm
B

rake disc - minimum wall thickness
4.9 mm
I

nstalled brake disc - maximum run-out
0.15 mm
Cal

iper piston diameter
42 mm
Pa

rking brake drum - maximum diameter
181 mm
B

rake pad - minimum thickness
2 mm
Pa

rking brake shoes - minimum thickness
2 mm
Co

mponent
Dimension
Brake disc

- diameter
330 mm
Brake disc

- thickness (new)
28 mm
B

rake disc - minimum thickness
26 mm
B

rake disc - minimum wall thickness
6.7 mm
I

nstalled brake disc - maximum run-out
0.1 mm
Cal

iper piston diameter
28/30 equiv
alent 41 mm
B

rake pad - minimum thickness
2 mm

Brake System - Gener
al Information - Brake System
Description an
d Operation

Details of the Brake System can be found in sections 206-03, 206-04, 206-05, 206-06, 206-07 and 206-09.

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.
*

P
INPOINT TEST A : BRAKES NOISY
TE
ST
CONDITIONS
D
ETAILS/RESULTS/ACTIONS
A1

: INSPECT BRAKE PADS
Inspect the condi

tion of the front and rear brake
pads. Check for damage to any anti-squeal shims.
1
Are th
e brake pads OK?
Yes GO to A2
.
No

CLEAN the front brake pads or INSTALL new front brak e pads if necessary. For additional information,
refer toSection 206
-03
Front Disc Brake
. CLEA
N the rear brake pads or INSTALL new rear brake pads
if necessary. For additional information, refer toSection 206
-0
4 Rear Disc Brake
.
Test vehicle for
presence of brake squeal.
A2
: INSPECT BRAKE DISCS
Inspe

ct the brake discs for excessive corrosi
on, wear or disc thickness variation.
1
D
oes excessive corrosion, wear or
disc thickness variation exist?
REFER to Specification
- in t
his section.
Yes INSTALL new front brake discs and brake pads. For additional information, refer toSection 206
-03

Fr

ont Disc Brake
. INSTALL n
ew rear brake discs and brake
pads. For additional information, refer
toSection 206
-0
4 Rear Disc Brake
. TEST
the system for normal operation.
No Vehicle is OK.
P
INPOINT TEST B : VIBRATIO
N WHEN BRAKES ARE APPLIED
TE
ST
CONDITIONS
D
ETAILS/RESULTS/ACTIONS
B1

: ROAD TEST VEHICLE
R

oad test the vehicle between 40-80 km/h (25-50 mph) without applying brakes.
1
Is th

e vibration present?
Yes TEST for noise vibration and harshness. REPEAT road test if necessary.
No GO to B2
. .

B2

: CHECK FOR BRAKE VIBRATION
R

oad test the vehicle between 40-80 km/h (25-50
mph) with light and medium application on the
brake pedal.
1
Is a vibration
present?
Yes If the vibration is from the front of the vehicle GO to B3
. If
the vibration is
from the rear of the
vehicle or can not be di agnosed between front or rear of the vehicle GO to B6
.
No

Vehicle is OK.
B3: CHECK
THE SUSPENSION
AND STEERING COMPONENTS
Chec
k the condition of the front susp
ension bushes and ball joints
REFER to Section 204
-01
Front Suspension
.
Chec
k the condition of the steering linkage components
REFER to Section 211
-0
2 Power Steering
/

211
-0
3 Steering Linkage
.
1
D

o any of the front suspension components or steering comp
onents require replacement?
Yes INSTALL new components as necessary
REFER to Section 204
-01
Front Suspension
/

211
-0
2 Power Steering
/

211
-0
3 Steering Linkage
.
R
oad test the vehicle between 40-80 km/h (25-50
mph) with light and medium application on the
brake pedal. If vibr ation still exists GO to B4
.
No

GO to B4
.
B4: CHECK
THE FRONT BRAKE PA
DS AND FRONT BRAKE DISCS
Chec
k the condition of the front br
ake pads and front brake discs.
1
D
oes excessive brake disc runout or br
ake disc thickness variation exist?

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

Do t
he disc brake caliper pistons
and pins bind, leak or stick?
Yes INSTALL new calipers as necessary. TE ST the system for normal operation.
No GO to C4
.
C4: INSPECT BR
AKE DISCS
Check the brake discs fo

r excess
ive damage, thickness variatio n or runout. For additional
information, refer to General Procedures in this section.
1
D
oes excessive damage or runout exist?
Yes INSTALL new brake discs and brak e pads as necessary. TEST the system for normal operation.
No GO to C5
.
C5: INSPECT THE FRONT HU
B AND WHEEL BEARING ASSEMBLY
Check the fr

ont hub and wheel bearing assembly.
For additional information, refer toSection 204
-00

Su

spension System
- General
Information
. 1
Are th

e wheel bearings OK?
Yes GO to C6
.
No

INSTALL new wheel bearings. For additional inform ation, refer toSection 204
-01
Front Suspension
.
TEST the system
for normal operation.
C

6: CHECK SUSPENSION BUSHES AND BALL JOINTS.
Chec

k all suspension bu
shes and ball joints.
1
Are th
e suspension bushes and ball joints OK?
Yes Vehicle is OK.
No INSTALL new front suspension bushes and ball joints as required. For additional information, refer
toSection 204
-01
Front Suspension
. INSTALL n
ew rear suspension bush
es and ball joints as required.
For additional informat ion, refer toSection 204
-0
2 Rear Suspension
.
P

INPOINT TEST D : THE PEDAL FEELS SPONGY
TE
ST
CONDITIONS
D
ETAILS/RESULTS/ACTIONS
D

1: CHECK FOR SPONGY PEDAL (ENGINE OFF)
Check f

or a firm brake pedal.
1
Is th

e brake pedal effort an
d brake pedal travel normal?
Yes Vehicle is OK.
No GO to D2
.
D2:
CHECK BRAKE PEDAL RESERVE (ENGINE OFF)
Pump th

e brake pedal 10 times and
hold on the final application.
1
Does th
e brake pedal feel fi
rm on final application?
Yes GO to D3
.
No

BLEED the brake system. For additional information, re fer to General Procedures in this section. TEST
the system for normal operation.
D3:
CHECK BRAKE PEDAL RESERVE (ENGINE ON)
Engine is

idle.
1
Apply the brake pedal ligh

tl
y three or four times.
2
W
ait 15 seconds for the vacuum to recover.
3
Push down on

the brake pedal until it stops moving
downward or an increased resistance to the brake
pedal travel occurs.
4
Hol
d the brake pedal in the applied position while increasing the engine speed to 2000 revs/min.
5
Re

lease the accelerator pedal.
6
Does th

e brake pedal move downward as
the engine speed returns to idle?
Yes GO to D4
.
No

CHECK the vacuum to brake booster. For additional information, refer toSection 206
-0
7 Power Brake
Actuation.

D4: CHECK
BRAKE FLUID LEVEL
Check the brake master cyli
nd
er reservoir fluid level.
1
Is the fl
ui
d level OK?
Yes BLEED the brake system. For additional information, re fer to General Procedures in this section. TEST
the system for normal operation.
No CHECK brake master cylinder reservoir sealing points. For additional information, refer to Brake
Master Cylinder in this section. ADD fluid and BL EED the brake system. For additional information,
refer to General Procedures in this section. TEST the system for normal operation. REPEAT road test if
necessary.
P I
NPOINT TEST E : THE
PEDAL GOES DOWN FAST
TES
T
CONDITIONS
D E
TAILS/RESULTS/ACTIONS
E1
:
ROAD TEST VEHICLE
Road test and apply th
e brake peda
l.
1
Is th
e brake pedal ef
fort an
d brake pedal travel normal?
Yes Vehicle is OK.
No GO to E2
.
E2: CHECK BRAK
E FLUID LEVEL
Check the brake master cyli
nd
er reservoir fluid level.
1
Is
t
he fluid level within specification?
Yes GO to E3
.
No
CH
ECK the brake master cylinder reservoir sealing po
ints. For additional information, refer to Brake
Master Cylinder Component Test in this section. ADD fluid and BLEED brake system. For additional
information, refer to General Proc edures in this section. TEST the system for normal operation.
REPEAT road test if necessary.
E3 : CHECK BRAK
E PEDAL TRAVEL-PRESSURIZE SYSTEM
Pump th
e brake pedal rapidly (f
ive times).
1
Does th
e brake pedal trav
el build up and then hold?
Yes BLEED the brake system. For additional information, re fer to General Procedures in this section. TEST
the system for normal oper ation. REPEAT road test.
No GO to E4
.
E4: CHECK FOR
BRAKE SYSTEM LEAKS
Chec
k for e
xternal brake system leaks. For additional information, refer to Master Cylinder in this
section.
1
Are le aks foun
d?
Yes REPAIR as necessary, ADD fluid and BLEED brake syst em. For additional information, refer to General
Procedures in this section. TEST the system for normal operation. REPEAT road test.
No System is OK.
PINPOINT TEST
F : THE PEDAL GOES DOWN SLOWLY
TES
T
CONDITIONS
DE
TAILS/RESULTS/ACTIONS
F1
:
ROAD TEST VEHICLE - CHECK BRAKE PEDAL OPERATION
Chec
k
if the condition occurs duri
ng actual stopping application by applying the brake pedal while
the vehicle is moving.
1
Doe s
the condition occur when the vehicle is moving?
Yes GO to F2
.
No
GO to F
3
.
F2:
CHECK
FOR BRAKE SYSTEM LEAKS
Chec
k for e
xternal brake system leaks. For additional information, refer to Master Cylinder in this
section.
1