brake JAGUAR X308 1998 2.G Manual Online

Are th
ere any external brake system leaks?
Yes REPAIR as necessary. ADD fluid and BLEED the brak e system. For additional information, refer to
General Procedures in this section. TEST the system for normal operation.
No GO to F3
.
F
3: CARRY OUT A BRAKE MASTER CYLINDER BYPASS TEST
Te

st for brake master cylinder bypass condition. Re
fer to Brake Master Cylinder Component Test in
this section.
1
A
re any concerns found?
Yes INSTALL a new brake master cylinder, ADD flui d and BLEED the brake system. For additional
information, refer to General Proc edures in this section. TEST the system for normal operation.
No System is OK.
PINPO
INT TEST G : EXCESSIVE BRAKE PEDAL EFFORT
TE
ST
CONDITIONS
D
ETAILS/RESULTS/ACTIONS
G1

: CHECK BRAKE PADS
Check the brake pads for wear, contamin

atio
n, correct installation, damage and type.
1
A
re any concerns found?
Yes INSTALL the front brake pads correctly or INSTALL ne w front brake pads if necessary. For additional
information, refer toSection 206
-03
Front Disc Brake
. INSTALL the
rear brake pads correctly or
INSTALL new rear brake pads if necessary. For additional information, refer toSection 206
-04
Rear
Di

sc Brake
. REPEAT road test.
No

GO to G2
.
G2:
CHECK VACUUM
Di

sconnect the vacuum booster hose from the booster.
1
Conne

ct a vacuum/pressure tester to the vacuum hose.
2
Ru

n the engine at normal operating temperature.
3
Re

cord the vacuum reading.
4
Is

the reading 40.5kPa (1
2 in-Hg) or greater?
Yes GO to G3
.
No

LOCATE and REPAIR the source of low vacuum . TEST the system for normal operation.
G3
: INSPECT SYSTEM
Swi

tch the engine off.
1
Re

connect the vacuum hose.
2
Inspect th

e brake booster, rubber grommet, and al
l vacuum plumbing for cracks, holes, damaged
connections, or missing clamps.
3
Pump th
e brake pedal several time
s to exhaust the vacuum. Push down on the brake pedal and hold.
4
Does th
e brake pedal move down
when the engine is started?
Yes Vacuum system is OK.
No GO to G4
.
G4
: CHECK POWER BRAKE BOOSTER VALVE
Check the brake booster valve. For
add
itional information, refer to
Brake Booster in this section.
1
Is th
e power brake booster valve OK?
Yes CHECK the brake booster. Fo r additional information, refer to Brak e Booster in this section. INSTALL a
new brake booster if necessary. TEST the system for normal operation.
No INSTALL a new brake booster valve. TEST the system for normal operation.
P
INPOINT TEST H : BRAKE LOCKUP
DURING LIGHT BRAKE PEDAL FORCE
TE
ST
CONDITIONS
D
ETAILS/RESULTS/ACTIONS
H1

: TEST BRAKE LOCKUP

Road test the veh
icle and a
pply the brake pe dal lightly.
1
Do th
e brakes lockup?
Yes GO to H2
.
No
Vehicle is OK.
H2: INSPECT BRAKE PADS
Inspect brake pads for con
t
amination,
correct installation , damage and type.
1
Ar
e any concerns found?
Yes CHECK the front brake pads. For additi onal information, refer toSection 206
-03 Fr
ont Disc Brake
.
CHECK
the rear brake pads. For additi
onal information, refer toSection 206
-04
Rear Disc Brake
.
INST ALL new brake pads as ne ce
ssary. REPEAT
road test.
No GO to H3
.
H3: INSPECT BRAKE CALI
PERS
Inspect brake cali
pers for bindi
ng, leaking or sticking.
1
A
r
e any concerns found?
Yes CHECK the front brake calipers. For addi tional information, refer toSection 206
-03 Fr
ont Disc Brake
.
CHECK
the rear brake calipers. For addi
tional information, refer toSection 206
-04
Rear Disc Brake
.
IN ST
ALL the brake calipers correctly or INSTALL new
brake calipers as necessary. TEST the system for
normal operation. REPEAT road test if necessary.
No Vehicle is OK.
PI
NPOINT TEST I : BRAKES DRAG
TE
S
T
CONDITIONS
D E
TAILS/RESULTS/ACTIONS
I1
:
ROAD TEST VEHICLE
Ro
ad t
est the vehicle
and apply the brakes.
1
Are the brakes
functioning correctly?
Yes Vehicle is OK.
No GO to I2
.
I2
: CHECK 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
h
e disc brake caliper pistons
and pins bind, leak or stick?
Yes INSPECT the brake calipers and pa rking brake cables. INSTALL new co mponents as necessary. Road
test vehicle.
No GO to I3
.
I3
: CHECK BRAKE BOOSTER
Check the brake booster con
n
ecting rod alignment
and travel. For additional information, refer
toSection 206
-0 7
Power Brake Actuation
. 1
Is the co
nnecti
ng rod OK?
Yes Vehicle is OK.
No INSTALL a new brake booster. For addi tional information, refer toSection 206
-07
Power Brake
Actuation. TEST
the system for
normal operation.
PINPO
I
NT TEST J : EXCESSIVE/ERRATIC BRAKE PEDAL TRAVEL
TE
S
T
CONDITIONS
D E
TAILS/RESULTS/ACTIONS
J
1
: TEST ON ROUGH ROAD
R
oad test the vehi
cle on rough road conditions.
1
Apply the brakes slowly. 2
Is th
e brake pedal ef
fort an
d brake pedal travel normal?

Yes

Vehicle is OK.
No GO to J2
.
J
2: CHECK BRAKE FLUID LEVEL
Check the brake master cyli

nder reservoir fluid level.
1
Is the fl

uid level OK?
Yes GO to J3
.
No

CHECK brake master cylinder reservoir sealing points. For additional information, refer to Brake
Master Cylinder in this section. ADD brake fl uid and BLEED the brake system. For additional
information, refer to General Proc edures in this section. TEST the system for normal operation.
REPEAT road test if necessary.
J
3: CHECK BRAKE PEDAL RESERVE
Engine is

idle.
1
Apply the brake pedal ligh

tl
y three or four times.
2
W
ait 15 seconds for the vacuum to replenish.
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 J4
.
No

CHECK the vacuum to the brake booster. Fo r additional information, refer toSection 206
-0
7 Power
Brake Ac

tuation
.
J

4: CHECK THE FRONT HUB AND BEARING ASSEMBLY
Check the fr

ont hub and bearing assembly. Fo
r additional information, refer toSection 204
-01
Front
Suspe

nsion
. 1
Are th

e front wheel bearings loose?
Yes INSTALL a new front wheel bearin g if damaged. For additional information, refer toSection 204
-01

F

ront Suspension
. TEST
the system for normal operation.
No CHECK the front brake discs for thickness variances. For additional information, refer to General
Procedures in this section.
PINPO
INT TEST K : SLOW OR INCOMPLETE BRAKE PEDAL RETURN
TE
ST
CONDITIONS
D
ETAILS/RESULTS/ACTIONS
K1: C

HECK FOR BRAKE PEDAL RETURN
Ru

n the engine at fast idle while
making several brake applications.
1
Pull the
brake pedal rearward with approximately 44.5 N (10lb) force.
2
Relea

se the brake pedal and measure
the distance to the toe board.
3
Make a hard brake
application.
4
Relea

se the brake pedal and measure the brake
pedal to toe board distance. The brake pedal
should return to its original position.
5
Does th
e brake pedal return
to its original position?
Yes Vehicle is OK.
No GO to K2
.
K
2: CHECK FOR BRAKE PEDAL BINDING
Check the brake pedal to make
s
ure it is operating freely.
1
Is th

e brake pedal operating freely?
Yes INSTALL a new brake booster. For addi tional information, refer toSection 206
-0
7 Power Brake
Actuation. TEST

the system for normal operation.
No REPAIR or INSTALL new brake pedal. TE ST the system for normal operation.

Comp
onent Tests
Bra
k
e Booster
1.
1. Chec k all
hoses and connections. All unused vacuum connectors should be capped. Hoses and their connections
should be correctly secured and in good condition with no holes and no collapsed areas. Inspect the valve on the
brake booster for damage.
2. 2. Check the hydraulic brake system for leaks or low fluid.
3. 3. With the transmission in PARK, stop the engine and apply the parking brake. Pump the brake pedal several times
to exhaust all vacuum in the system.
4. 4. With the engine switched off and all vacuum in the system exhausted, appl y the brake pedal and hold it down.
Start the engine. If the vacuum system is operating, the brake pedal will tend to move downward under constant
foot pressure. If no motion is felt, the vacuum booster system is not functioning.
5. 5. Remove the vacuum hose from the brake booster. Manifold vacuum should be available at the brake booster end
of the hose with the engine at idle speed and the transm ission in PARK or NEUTRAL. Make sure that all unused
vacuum outlets are correctly capped, hose connectors are correctly secured and vacuum hoses are in good
condition. When it is established that manifold vacuum is available to the brake booster, connect the vacuum hose
to the brake booster and repeat Step 3. If no downward movement of the brake pedal is felt, install a new brake
booster.
6. 6. Operate the engine for a minimum of 10 seconds at a fast idle. Stop the engine and allow the vehicle to stand for
10 minutes. Then, apply th e brake pedal with approximately 89 N ( 20lb) of force. The pedal feel (brake
application) should be the same as that noted with the engine running. If the brake pedal feels hard (no power
assist), install a new valve and then re peat the test. If the brake pedal still feels hard, in stall a new brake booster.
If the brake pedal movement feels spongy, bleed the brak e system. For additional information, refer to General
Procedures in this section.
Bra k
e Master Cylinder
Usual
l
y, the first and strongest
indicator of anything wrong in the brake syst em is a feeling through the brake pedal. In
diagnosing the condition of the brake master cylinder, check pedal feel as evidence of a brake concern. Check for brake
warning lamp illumination and the brake fluid le vel in the brake master cylinder reservoir.
Normal Conditio
ns
The fo
llowing conditions are considered norm
al and are not indications that the brake master cylinder is in need of repair.
New bra
ke systems are designed to produc
e a pedal effort that is not as hard as in the past. Complaints of light
pedal efforts should be compared to the pedal effort s of another vehicle of the same model and year.
The fl
uid level will fall with brake pad wear.
Abnormal Conditions
•

NOTE: Prior to carrying out any diag
nosis, make sure the brake system warning indicator is functional.
Changes in the brake pedal feel or brake pedal travel are in dicators that something could be wrong in the brake system. The
diagnostic procedure and techniques use brake pedal feel, warning indicator illu mination and low brake fluid level as
indicators to diagnosing brake system co ncerns. The following conditions are cons idered abnormal and indicate that the
brake master cylinder is in need of repair:
Brake ped a
l goes down fast. Th
is could be caused by an ex ternal or internal leak.
Brake pedal goes down slowly
. This could be
caused by an internal or external leak.
Brak
e pedal is low or feels spongy. This condition may be ca
used by no fluid in the brake master cylinder, reservoir

cap ven
t holes clogged or air in the hydraulic system.
Brake ped

al effort is excessive. This ma
y be caused by a bind or obstruction in the pedal/linkage, a faulty non return
valve, booster or insuffi cient booster vacuum.
R
ear brakes lock up during light pedal force. This may
be caused by damaged brake pads, an incorrectly adjusted
parking brake, a partially applied parking brake, a damaged ABS sensor or bearing failure.
Brake ped
al effort erratic. This condition could be caused by the brake booste
r or incorrectly installed brake pads.
Brake warning indicator i
s on. This may be caused
by low fluid level or float assembly damaged.
No
n Pressure Leaks
Any reduced fluid v
olume in the brake ma
ster cylinder reservoir condition may be caused by two types of none pressure
external leaks.
Type 1: An external leak may be occur at the master cylinder reservoir cap because of incorre ct positioning of gasket and
cap. Reposition cap and gasket.
Type 2: An external leak may occur at th e reservoir mounting seals. Repair such a leak by installing new seals and make
sure that the reservoir retainin g bolt is correctly installed.

Brake Sys
tem - General Informatio
n - Brake System BleedingVehicles
With: Standard Brakes
Gen e
ral Procedures
WARNING: WASH HANDS AFTER HANDLING BRAKE FLUID. IF BRAKE FLUID COMES INTO CONTACT WITH THE EYES,
FLUSH EYES WITH COLD RUNNING WATER. IF IRRITATION PERSISTS SEEK MEDICAL ATTENTION. IF BRAKE FLUID IS
TAKEN INTERNALLY, DRINK WATER AND INDUCE VO MITING. GET MEDICAL ATTENTION IMMEDIATELY.
CAUTION: Remove brake fluid spillage imme diately from paint work with clean water.
1. Position vehi cl
e on a four-post lift.
2. Open engine compartment and fit paint work protection covers
to fenders.

3. NO
TE: Make sure the
brake-fluid level does not fall below the
fluid reservoir 'MIN' (minimum) mark when bleeding the brake
system.
Fill fluid reservoir to the 'MAX' (maximum) mark.

4. Prepare l e
ft-hand front, br
ake-caliper for bleeding.
Remove du
st cap.
Connect b
l
eed pipe
and fluid container to bleed nipple.
5. Bleed the brake.
1. Apply pressure to brake pedal
2. Open bleed nipple.
3. Fully depres s brake pedal.
4. Close bleed nipple.
5. Release brake pedal.
6. Wait two seconds to allow system to prime.
7. Repeat procedure until air- free brake fluid is expelled
from the caliper.
6. Tighten bleed nipple, see torque settings below.

Front caliper bleed
nipple: 4-6
Nm.
Rear caliper

bleed
nipple: 8-11 Nm.

7. F
ollowing the procedure below,
bleed the brakes in the order
shown:
1. Left-Hand Front,
2. Right-Hand Front,
3. Left- Hand Rear,
4. Right-Hand Rear.

8. CAUTI
ON: Remove brake flui
d spillage immediately from
paint work with clean water.
Fill fluid reservoir.
F
ill reservoir to the 'MAX' mark.
F

it filler cap.
9.
Start e
ngine.
10. Check for correct brake-pedal travel and pressure.
11. Apply brake pedal and check around vehicle for brake fluid
leaks.
12. Make sure brake fluid level is at the 'MAX' mark.

Brake Sys
tem - General Informatio
n - Brake System BleedingVehicles
With: High Performance Brakes
Gen e
ral Procedures
1. WARNINGS:
IF BRAKE FLUID IS TAKEN INTERNALLY, DRINK WATER
AND INDUCE VOMITING. GET MEDICAL ATTENTION
IMMEDIATELY.
WASH HANDS AFTER HANDLING BRAKE FLUID. IF BRAKE
FLUID COMES INTO CONTACT WITH THE EYES, FLUSH EYES
WITH COLD RUNNING WATER. IF IRRITATION PERSISTS SEEK
MEDICAL ATTENTION.
CAUTION: Remove brake flui d spillage immediately from
paint work with clean water.
Position vehicle on a four-post lift.
2. Op
en engine compartment and fit
paint work protection covers
to fenders.

3. NO
TE: Make sure the
brake-fluid level does not fall below the
fluid reservoir 'MIN' (minimum) mark when bleeding the brake
system.
Fill fluid reservoir to the 'MAX' (maximum) mark.

4. Pr
epare the left-hand front,
brake-caliper for bleeding.
Connect b
leed pipes an
d fluid containers to bleed nipples.
5. Bleed the brake.
1. Apply pressure to brake pedal.
2. Open caliper's outer bleed nipple.
3. Fully depres s brake pedal.

4
. Close bleed nipple.
5. Release brake pedal.
6. Wait two seconds to allow system to prime.
7. Repeat procedure until air- free brake fluid is expelled
from the bleed nipple.
8. Repeat procedure to ca liper's inner bleed nipple.

6. Tigh
ten bleed nipples to 12-16 Nm.

7. F
ollowing the procedure above,
bleed the brakes in the order
shown:
1. Left-Hand Front,
2. Right-Hand Front,
3. Left- Hand Rear,
4. Right-Hand Rear.

8. CAUTI
ON: Remove brake flui
d spillage immediately from
paint work with clean water.
Fill fluid reservoir.
F
ill reservoir to the 'MAX' mark.
F

it filler cap.
9.
Start e
ngine.
10. Check for correct brake-pedal travel and pressure.
11. Apply brake pedal and check around vehicle for brake fluid
leaks.
12. Make sure brake fluid level is at the 'MAX' mark.

Brake System - Gener
al Information - Front Brake Disc Runout
CheckVehicles With: Standard Brakes
Gen e
ral Procedures
S
p
ecial Tool(s)

Dial Test Indicator
G
auge and Stand.
1. Raise front of vehicle and support on stands. Refer to section
100-02.
2. Remove wheel.

3. CAUT
ION: Tie caliper housing aside. Do not allow the
caliper housing to hang on the hydraulic hose, as this will damage
the hose.
Remove caliper housing from caliper carrier.
1. Remove anti-rattle spring.
2. Remove dust covers.
3. Remove guide pins.
Remove an
d tie caliper housing aside.
4.
Make sure that wheel
bearing en
d-float is correct. Refer to
specification section 204-01.

5. Measure brake d
isc run-out.
Inst
al
l brake disc to hub and secure with all wheel nuts,
tighten wheel nuts to 20 Nm in a diagonal sequence.
Posi
tion the gauge so that the pointer contacts the disc,
10 mm from its outer edge.
Slo w
ly rotate the disc one revolution, the disc run-out
must not exceed the specification. Refer to Specification
Section 206-03.
6. If the brake disc run-out exceeds specification, reposition the
brake disc on the hub and re peat the above procedure.
Continue repositioning the brake di sc until the run-out is within
specification.
7. If the brake disc run-out still exceeds specification, check the
hub face run-out.
8. Remove brake disc. Refer to procedure 70.10.12.
9. Measure hub face run-out.
Posi
tion the gauge so that the pointer contacts the hub
face.
Slo w
ly rotate the hub one revolution, the hub run-out