1998 JAGUAR X308 vacuum

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.

Fr
ont Brake Disc Runout Check Vehicles With: Brembo Brakes
Special Service tools
Di
al Test Indicator Gauge and Stand.
1.


WA
RNING:
BRAKE DUST, IF INHALED CAN DAMAGE YOUR HEALTH. ALWAYS REMOVE BRAKE DUST USING A VACUUM BRUSH. DO NOT USE A COMPRESSED-AIR LINE TO DISPERSE BRAKE DUST
INTO THE ATMOSPHERE.
CA
UTION:
Replacement of nuts and bolts: Various thread-locking devices are used on nuts and bolts
throughout the vehicle. These devices restrict the number of times a nut or bolt can be used. See
section <<100-00>> for information.
CA
UTION:
The Brembo caliper is aligned to the brake disc when it is first installed to the vehicle, therefore,
care must be taken not to disturb this alignment. When removing the caliper; remove the bolts
that secure the anchor bracket to the vertical link only. DO NOT loosen any other caliper bolts.
Raise front of vehicle and support on stands. Refer to section <<100-02>>.
2. Remove wheel. Refer to section <<74.20.05>>.

Rear
Brake Disc Runout Check Vehicles With: Brembo Brakes
Special Service tools
Di
al Test Indicator Gauge and Stand.
1.


WA
RNING:
BRAKE DUST, IF INHALED CAN DAMAGE YOUR HEALTH. ALWAYS REMOVE BRAKE DUST USING A VACUUM BRUSH. DO NOT USE A COMPRESSED-AIR LINE TO DISPERSE BRAKE DUST
INTO THE ATMOSPHERE.
CA
UTION:
Replacement of nuts and bolts: Various thread-locking devices are used on nuts and bolts
throughout the vehicle. These devices restrict the number of times a nut or bolt can be used. See
section <<100-00>> for information.
CA
UTION:
The Brembo caliper is aligned to the brake disc when it is first installed to the vehicle, therefore,
care must be taken not to disturb this alignment. When removing the caliper; remove the bolts
that secure the anchor bracket to the hub carrier only. DO NOT loosen any other caliper bolts.
Raise rear of vehicle and support on stands. Refer to section <<100-02>>.
2. Remove wheel. Refer to operation <<74.20.05>>.

Front Disc Brake - Brake CaliperVehicles
With: Standard Brakes
Re
moval and Installation
Remov

al
W
ARNING: BRAKE DUST, IF INHALED CAN DAMAGE YOUR
HEALTH. ALWAYS REMOVE BRAKE DUST USING A VACUUM
BRUSH. DO NOT USE A COMPRESSED-AIR LINE TO DISPERSE BRAKE DUST INTO THE ATMOSPHERE.
• CAUTIONS:
Replacement of nuts and bolts: Various thread-locking de vices are used on nuts and bolts throughout the vehicle.
These devices restrict the number of times a nut or bolt can be used. See section 100-00 for information.
Remove brake fluid spilla ge immediately from paint work, with clean water.
A new brake hose must be installe d when replacing a brake caliper.
The brake pad adhesive backing must not be reused, therefore always install new brake pads, irrespective of the
condition of the original pads when replacing a brake caliper. Always replace brake pads as an axle set.
S
pecial Tool(s)

Brake Pedal

Hold Tool
JDS 9013
1. O
pen engine compartment and fit
paint work protection covers
to fenders.
2. Raise vehicle on a four-post lift.
3. Raise front of vehicle and support on stands. Refer to Section
100-02.
4. Remove front wheels. See Section 204-04.

5. NOTE
: The following three pictorial procedures must be
carried-out to minimize brake fl uid loss when disconnecting the
brake hose.
Open Left-Hand-Front and Left-H and-Rear caliper bleed nipples.
Connect
a bleed tube and co
ntainer to the calipers.
O
pen bleed nipples.
6. Depress and hold down brak e pedal at the specified
measurement using special tool.
1. Position tool between brake pedal and seat frame.
2. Turn the tool wheel unti l the brake pedal is held

Front Disc Brake - Brake CaliperVehicles With: High Performance Brakes
Re
moval and Installation
Remov

al
S
pecial Tool(s)

Brake Pedal

Hold Tool
JDS 9013
1. WARNING: BRAKE DUST, IF INHALED CAN DAMAGE
YOUR HEALTH. ALWAYS REMOVE BRAKE DUST USING A VACUUM
BRUSH. DO NOT USE A COMPRE SSED-AIR LINE TO DISPERSE
BRAKE DUST INTO THE ATMOSPHERE.
• CAUTIONS:
Replacement of nuts and bolts: Various thread-locking
devices are used on nuts and bolts throughout the vehicle. These
devices restrict the number of ti mes a nut or bolt can be used.
See section 100-00 for information.
Remove brake fluid spillage immediately from paint work,
with clean water.
The Brembo caliper is aligned to the brake disc when it is
first installed to the vehicle, therefore, care must be taken not to
disturb this alignment. When removing the caliper; remove the
bolts that secure the anchor bracket to the vertical link only. DO
NOT loosen any other caliper bolts.
Open engine compartment and fit paint work protection covers
to fenders.
2. R
aise vehicle on a four-post lift.
3. Raise front of vehicle and support on stands. Refer to Section
100-02.
4. Remove front wheels. Refe r to operation 74.20.05.

5. NOTE
: The following three pictorial procedures must be
carried-out to minimize brake fl uid loss when disconnecting the
brake hose.
Open Left-Hand-Front and Left-H and-Rear caliper bleed nipples.
Connect
a bleed tube and co
ntainer to the calipers.
O
pen bleed nipples.
6. Depress and hold down brak e pedal at the specified
measurement using the special tool.

Front Dis
c Brake - Brake DiscVe
hicles With: Standard Brakes
Re
moval and Installation
Remov

al
• WAR
NINGS:
BRAKE DISCS MUST ALWAYS BE REPLACED IN PAIRS.
BRAKE DUST, IF INHALED CAN DAMAGE YOUR HEALTH. ALWAYS REMOVE BRAKE DUST USING A VACUUM BRUSH.
DO NOT USE A COMPRESSED-AIR LINE TO DI SPERSE BRAKE DUST INTO THE ATMOSPHERE.
CAUTION: Replacement of nuts and bolts: Various thread-locking devices are used on nuts and bolts throughout the
vehicle. These devices restrict the number of times a nut or bolt can be used. See section 100-00 for information.
1. O
pen engine compartment and in
stall paint work protection
covers to fenders.
2. Raise front of vehicle and suppo rt on stands. See Section 100-
02.
3. Remove front wheels. Re fer to Section 204-04.

4. CAUTI
ON: Remove brake flui
d spillage immediately from
paint work, with clean water.
Loosen brake fluid reservoir-cap.
Position a cloth around the
reservoir to collect any fluid
spillage.

5. CAU
TION: 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.
Re
move and tie caliper housing aside.
6.
CAUTI
ON: Always install new brake pads, irrespective of
the condition of the original pads, when renewing brake discs.
• NOTE: The inner brake pad is fitted with a clip which secures
the pad into the caliper piston.
Remove brake pads from caliper housing.