1998 JAGUAR X308 Amp

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.

Re
ar Drive Axle/Differential -
Lubric
ants, Fluids, Sealants and Adhesives
Capacities
Torques


UnitSp
ecification
F
i
nal Drive
Shell Sp
irax Supe
r TS 90
Hub s
p
line to Axle shaft
Loct
it
e 270 Studlock or equivalent
UnitLi
t
ers
F
i
nal Drive
1,
90
Com p
onent
Nm
B
ol
t - Final drive nose plate
39
- 51
Bol t
- 'A' frame to final drive
9
0 -
110
Nu
t 'A' f
rame to rear mounting bracket
8
5 -
115
Nu
t -
Axle shaft to final drive flange
81
-
99
Nu
t -
Axle shaft to hub
3
04 -
336
N
u
t - Damper lower fixing
8
0 -
100
Bol
t
M12 - Jurid flexible coupling to
transmission and final drive flanges
75 -
88
N
u
t - Lower fulcrum
9
0 -
110
Nu
t -
Pendulum to final drive
1
60 -
200
N
u
t - Stabilizer to wishbone
30
-
40
N
u
t - Tie rod to final drive
8
5 -
105
Nu
t -
Tie rod to wide mounting bracket
8
5 -
115
Nu
t -
Wishbone pivot
8
0 -
100
N
u
t - Wishbone tie to final drive
8
5 -
105
N
u
t 'A' frame to wide mounting bracket
8
5 -
105

Rea
r Drive Axle/Differential - Axle Assembly
Re
mo
val and Installation
Remov
a
l
•

NOTE: The pinion flange shown in this procedure is NOT intended to be a true representation
S
p
ecial Tool(s)

Suspensi
on
Spring Compressor Tool
204-179

1. Disc
onnect the battery ground lead
2. Raise the vehicle for access and remove both rear roadwheels
3. Remove the rear suspensi on assembly, 51.25.13
4. CAUTION: Do not lift the assembly by the axle shafts,
this may cause damage
Using a suitable hoist, place the assembly onto a workbench

5. Locat e
the spring compressor 204
- 179 to the RH road spring
6. Tighten the spring compressor evenly to release the spring
load on the damper

7. Re
move the damper assembly
1. Mark the tool position on the spring with adhesive
tape
2. Remove the damper lower fixing
3. Remove the damper assembly
8. Repeat for the opposite hand spring / damper unit

9. Relea
se the parking brake cable
1. Disconnect the cable in-line connector
2. Remove the outer cable to frame clips (2)
3. Clear the cable through the frame

10
.
Remove the LH hub and axle shaft assembly
1. Remove the lower fulcrum shaft nut (1)
2. Remove and discard the axle shaft to drive flange nuts (4)
3. Turn the axle-shaft for ac cess to access the fixings for
step 2
4. Support the axle shaft a ssembly and remove the hub
fulcrum
5. Remove the hub and axle shaft assembly
6. Note the position of and remove the camber adjustment spacer
11. Repeat for the opposite hand

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

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

Front Disc Brake - Front Disc Brake
Description and Operation


The brake disc is mounted on the wheel studs and is clamped between the wheel and hub. Cooling ducts run through the
center of the brake disc to provide the required ventilation to keep the disc cool under operating conditions.
The caliper carrier, which is se cured to the vertical link by two bolts, carries the single-pis ton caliper housing. The caliper
housing is secured to the caliper carrier by two guide-pins and an anti-rattle spring. When the brakes are applied the
caliper-housing piston pushes th e brake pad in front of it, towards the brake di sc. This movement forces the caliper housing
to move along the guide-pins, in the oppo site direction of the piston, to apply the second brake pad. The brake disc is
therefore gripped between the two pads. As brake pressure is increased the grip on the brake disc is increased to slow-down
the rotation of the road wheel.
The disc brakes requ ire no adjustment.
It
e
m
Par
t
Number
De
scr
iption
1—B
r
ake Disc
2—Caliper Housin
g
3—Caliper Carrier
4—Brake Pads
5—Guide P i
ns
6—Du
st
Covers
7—An
ti
-rattle Spring
8—Du
st
Shield
9—Brake Hos
e

10—Bleed Nipp
le

• C
AUTIONS:
The Brembo caliper is aligned to the brak e disc when it is first installed to the vehicle, therefore, care must be taken
not to disturb this alignment. When removi ng the caliper; remove the bolts that secure the anchor bracket to the vertical
link only. DO NOT loosen any other caliper bolts.
Do not loosen bolts securing brake disc to disc mounting.
Brembo calipers and discs provide higher -performance braking using the existing hydraulic braking system. The brakes are
installed to the vehicle using unique vertical links, hubs, hydraulic hoses and disc shields.
The front brake disc consists of a ventilated, cross-drilled disc, bolted to a disc carrier. The disc assemb ly is mounted on the
wheel studs and clamped be tween the wheel and hub.
A unique feature of the front disc is th e slanted (non radial) ventilation webs which lean the opposite-way to the disc's
direction of rotation. This design enables he at generated by the disc to be dispersed by air entering at the disc's center and
being forced outwards through the cooling ducts.
Due to the use of fixed calipers in place of the standard floating caliper, certain lateral dimensions on the vertical link and
It
em
Par
t Number
De
scription
1—B

rake Disc
2—Caliper


3—Anch

or Bracket
4—Anchor Pl

ate to Vertical Link - Bolts
5—Brake Pad

s
6—Guide P

ins
7—Anti-r

attle Spring
8—Di

sc Shield
9—Brake Hos

e
10—Bleed Nipp

les


Front Disc Brake—
Brembo