light JAGUAR XJ6 1997 2.G Repair Manual

28Check the signal voltage from the
potentiometer. Carefully backprobe the
electrical connector on the signal voltage
wire (-) with the ignition key ON (engine not
running) (see illustration). There should be
approximately 0.5 volts.
29Next, rotate the throttle lever manually and
confirm that the reference voltage increases to
approximately 4.8 volts (see illustration).
30If the voltage does not increase, renew
the throttle potentiometer with a new part.
Renewal
31Remove the throttle body from the intake
manifold (see Chapter 4).
32Remove the two mounting bolts and
separate the throttle potentiometer from the
throttle body. Note:The throttle potentiometer
is difficult to reach and adjustment requires
that the home mechanic tighten the bolts after
the final adjustment using a mirror. Be sure to
mark the mounting position of the old throttle
potentiometer before refitting the new part.
33Refitting is the reverse of removal.
Adjustment
34Refit the throttle body with the throttle
potentiometer mounting bolts just looseenough to move the potentiometer. Be sure
the bolts are tight and the potentiometer does
not rotate easily.
35Backprobe the signal wire and the ground
wire (see Step 28) and with the throttle closed
(idle position), rotate the potentiometer until
the voltmeter reads between 0.2 and 0.5 volts.
Note:The throttle potentiometer is difficult to
reach. Be sure to rotate the potentiometer
slowly and do not interfere with the voltmeter
and the electrical connectors to the gauge.
36Rotate the throttle lever and confirm that
the voltage increases to around 4.8 volts.
If the voltage range is correct, the throttle
potentiometer is installed correctly.
37Tighten the throttle potentiometer bolts. If
necessary, use a small mirror to locate the
bolts.
Mass airflow (MAF) sensor
General Information
38The mass airflow sensor (MAF) is located
on the air intake duct. This sensor uses a hot
wire sensing element to measure the amount
of air entering the engine. The air passing over
the hot wire causes it to cool. Consequently,this change in temperature can be converted
into an analogue voltage signal to the ECU
which in turn calculates the required fuel
injector pulse width.
Check
39Check for power to the MAF sensor.
Backprobe the MAF sensor electrical plug.
Working on the harness side with the ignition
ON (engine not running), check for battery
voltage on terminal number 5 (see illustration).
40Remove the pin and backprobe the MAF
sensor electrical connector terminal number 3
with the voltmeter (see illustration). The
voltage should be less than 1.0 volt with the
ignition switch ON (engine not running). Raise
the engine rpm. The signal voltage from the
MAF sensor should increase to about 2.0 volts.
It is impossible to simulate load conditions in
the driveway but it is necessary to observe the
voltmeter for a fluctuation in voltage as the
engine speed is raised. The vehicle will not be
under load conditions but MAF sensor voltage
should vary slightly.
41If the voltage readings are correct, check
the wiring harness for open circuits or a
damaged harness (see Chapter 12).
6•6 Emissions and engine control systems
4.29 . . . then check the SIGNAL voltage
with the throttle wide open. It should be
between 4.5 and 5.0 volts4.39 Check for battery voltage to the MAF
sensor on terminal number 54.40 With the engine idling, raise the engine
rpm and observe the voltage changes on
terminal number 3
3261 Jaguar XJ6 4.27 Backprobe the throttle potentiometer electrical connector
with a pin and with the ignition key ON (engine not running) there
should be 5.0 volts REFERENCE available
4.28 First check the throttle potentiometer SIGNAL voltage with the
throttle closed (idle). It should be 0.2 to 0.5 volts . . .

3261 Jaguar XJ6
9
Chapter 9
Braking system
General
Brake fluid type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . See Chapter 1
Minimum brake pad thickness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . See Chapter 1
Brake disc minimum permissible thickness . . . . . . . . . . . . . . . . . . . . . . Cast into disc
Parallelism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.013 mm (0.0005 inch) maximum
Runout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.102 mm (0.004 inch) maximum
Torque wrench settingsNm lbf ft
Brake servo mounting nuts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 7
Caliper bolts (front and rear) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 to 40 23 to 29
Caliper bracket bolts
Front bracket . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102 to 128 75 to 94
Rear bracket . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 to 62 40 to 45
Master cylinder-to-brake servo nuts . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 to 28 16 to 20
Wheel nuts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . See Chapter 1 Specifications Anti-lock Brake System (ABS) - general information . . . . . . . . . . . . . 2
Brake check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . See Chapter 1
Brake disc - inspection, removal and refitting . . . . . . . . . . . . . . . . . . 5
Brake fluid level check . . . . . . . . . . . . . . . . . . . . . . . . . . See Chapter 1
Brake hoses and lines - inspection and renewal . . . . . . . . . . . . . . . . 8
Brake hydraulic system - bleeding . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Brake light switch - check and renewal . . . . . . . . . . . . . . . . . . . . . . . 13
Brake servo - general information, removal and refitting . . . . . . . . . 7Disc brake caliper - removal, overhaul and refitting . . . . . . . . . . . . . 4
Disc brake pads - renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
General information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Handbrake cable - adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Handbrake cables - renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Handbrake shoes - check and renewal . . . . . . . . . . . . . . . . . . . . . . 12
Master cylinder - removal, overhaul and refitting . . . . . . . . . . . . . . . 6
9•1
Specifications Contents
Easy,suitable for
novice with little
experienceFairly easy,suitable
for beginner with
some experienceFairly difficult,
suitable for competent
DIY mechanic
Difficult,suitable for
experienced DIY
mechanicVery difficult,
suitable for expert DIY
or professional
Degrees of difficulty
54321
1 General information
All models covered by this manual are
equipped with hydraulically operated front
and rear disc brake systems. Both front and
rear brakes are self adjusting.
Hydraulic system
The hydraulic system is divided into
two separate circuits. The master cylinder has
separate reservoirs for the two circuits, and, in
the event of a leak or failure in one hydraulic
circuit, the other circuit will remain operative.
All models are equipped with an Anti-lock
Braking System (ABS).
Brake servo
A hydraulic brake servo system is used on
all models covered by this manual. Thissystem uses hydraulic pressure from an
engine-driven pump on models equipped with
a power hydraulic system, and an electric
pump on models without the power hydraulic
system.
Handbrake
The handbrake lever operates the rear
brakes through cable actuation. It’s activated
by a lever mounted in the centre console. The
handbrake assembly uses a pair of brake
shoes located inside the rear hub/brake disc.
Brake pad wear warning system
The brake pad wear warning system turns
on a red light in the instrument cluster when
the brake pads have worn down to the point
at which they must be replaced. Do NOT
ignore this reminder. If you don’t renew the
pads shortly after the brake pad wear warning
light comes on, the brake discs will be
damaged.The wear sensors are attached to the brake
pads. Once the pads wear down to the point
at which they’re flush with the sensor, the disc
grinds away the side of the sensor facing the
disc, the wire inside the sensor is broken, the
circuit is opened and the red light on the
instrument panel comes on.
Always check the sensor(s) when replacing
the pads. If you change the pads before the
warning light comes on, the sensor(s) may still
be good; once the light has come on, renew
the sensor.
Service
After completing any operation involving
dismantling of any part of the brake system,
always test drive the vehicle to check for
proper braking performance before resuming
normal driving. When testing the brakes,
perform the tests on a clean, dry, flat surface.
Conditions other than these can lead to
inaccurate test results.

Test the brakes at various speeds with both
light and heavy pedal pressure. The vehicle
should stop evenly without pulling to one side
or the other. Avoid locking the brakes,
because this slides the tyres and diminishes
braking efficiency and control of the vehicle.
Tyres, vehicle load and wheel alignment are
factors which also affect braking performance.
2 Anti-lock Brake system
(ABS)- general information
The Anti-lock Brake System is designed to
maintain vehicle steerability, directional stability
and optimum deceleration under severe
braking conditions on most road surfaces. It
does so by monitoring the rotational speed of
each wheel and controlling the brake line
pressure to each wheel during braking. This
prevents the wheels from locking up.
The ABS system has three main units - the
wheel speed sensors, the electronic control unit
and the modulator (hydraulic control unit). The
sensors - one at each wheel - send a variable
voltage signal to the electronic control unit,
which monitors these signals, compares them
to its program and determines whether a wheel
is about to lock up. When a wheel is about to
lock up, the control unit signals the hydraulic
unit to reduce hydraulic pressure (or not
increase it further) at that wheel’s brake caliper.
Pressure modulation is handled by three
electrically-operated solenoid valves - one for
each front wheel and one for the rear wheels -
inside the modulator.
If a problem develops within the system, an
“ABS” warning light will glow on the dashboard.
Sometimes, a visual inspection of the ABS
system can help you locate the problem.
Carefully inspect the ABS wiring harness. Pay
particularly close attention to the harness and
connections near each wheel. Look for signs of
chafing and other damage caused by
incorrectly routed wires. If a wheel sensor
harness is damaged, the sensor should be
replaced (the harness and sensor are integral).
Warning: Do NOT try to repair an
ABS wiring harness. The ABS
system is sensitive to even thesmallest changes in resistance. Repairing
the harness could alter resistance values
and cause the system to malfunction. If the
ABS wiring harness is damaged in any way,
it must be replaced.
Caution: Make sure the ignition is turned
off before unplugging or reattaching any
electrical connections.
Diagnosis and repair
If a dashboard warning light comes on and
stays on while the vehicle is in operation, the
ABS system requires attention. Although
special electronic ABS diagnostic testing tools
are necessary to properly diagnose the system,
you can perform a few preliminary checks
before taking the vehicle to a dealer service
department or other qualified repair workshop.
a) Check the brake fluid level in the master
cylinder reservoir.
b) Verify that all ABS system electrical
connectors in the engine compartment
are plugged in.
c) Check the fuses.
d) Follow the wiring harness to each front
wheel and to the differential sensor and
verify that all connections are secure and
that the wiring is undamaged.
If the above preliminary checks do not
rectify the problem, the vehicle should be
diagnosed by a dealer service department.
Due to the complex nature of this system, all
actual repair work must be done by a dealer
service department or other qualified repair
workshop.
3 Disc brake pads- renewal
2
Warning: Disc brake pads must
be replaced on both front wheels
or both rear wheels at the same
time - never renew the pads on
only one wheel. Also, the dust created by
the brake system may contain asbestos,
which is harmful to your health. Never blow
it out with compressed air and don’t inhale
any of it. An approved filtering mask should
be worn when working on the brakes. Do
not, under any circumstances, use
petroleum-based solvents to clean brake
parts. Use brake system cleaner only!
Note:The following procedure applies to both
the front and rear brake pads.
1Remove the cap from the brake fluid
reservoir and siphon off about two-thirds of
the fluid from the reservoir. Failing to do this
could result in fluid overflowing when the
caliper pistons are pressed into their bores.
2Loosen the wheel nuts, raise the front of the
vehicle and support it securely on axle stands.
3Remove the front wheels. Work on one
brake assembly at a time, using the
assembled brake for reference if necessary.
4Inspect the brake disc (see Section 5).
5Follow the accompanying photos,
beginning with illustration 3.5a, for the pad
removal procedure. Be sure to stay in order
and read the caption under each illustration.
9•2 Braking system
3.5a Before starting, wash down the
caliper and disc with brake cleaner
3.5b Attach a hose to the bleed screw,
open the bleed screw slightly and depress
the piston into the caliper. Tighten the
bleed screw when the piston bottoms
3.5c Remove the caliper mounting bolts
(upper bolt arrowed); use another spanner
to hold the flats of the caliper guide pins
while you back out the caliper bolts3.5d Remove the caliper . . .3.5e . . . and suspend it out of the way
with a piece of wire
3261 Jaguar XJ6

6Be sure to buy new pads with wear
sensors. Pattern pads may not have wear
sensors; refitting pads without wear sensors
will cause the dash warning light to come on.
7To refit the new pads, reverse the removal
procedure. When refitting the caliper, be sure
to tighten the mounting bolts to the torque
listed in this Chapter’s Specifications.
8After the job is completed, depress the
brake pedal a few times to bring the pads into
contact with the discs. The pedal should be at
normal height above the floorpan and firm.
Check the brake fluid level and add enough to
top it up (see Chapter 1). Inspect carefully for
leaks and check the operation of the brakes
before placing the vehicle into normal service.
9Tighten the wheel nuts to the specified
torque.
4 Disc brake caliper- removal,
overhaul and refitting
3
Warning: Dust created by the
brake system may contain
asbestos, which is harmful to
your health. Never blow it out
with compressed air and don’t inhale any
of it. An approved filtering mask should be
worn when working on the brakes. Do not,
under any circumstances, use petroleum-
based solvents to clean brake parts. Use
brake system cleaner only!
Note 1:The following procedure applies to
both front and rear calipers.
Note 2:If an overhaul is indicated, explore all
options before beginning the job. New andfactory rebuilt calipers are available on an
exchange basis, which makes this job quite
easy. If you decide to rebuild the calipers,
make sure a rebuild kit is available before
proceeding. Always rebuild the calipers in
pairs - never rebuild just one of them.
Removal
1Loosen the wheel nuts, raise the front or
rear of the vehicle and place it securely on
axle stands. Remove the wheel.
2If you’re just removing the caliper for
access to other components, it isn’t
Braking system 9•3
9
3.5f Remove the outer brake pad3.5g Remove the inner brake pad
3.5h Pull out the wear sensor, trace the
sensor lead back to its plug, detach the
lead from the suspension, and discard it
3.5i Remove the caliper guide pins and
boots (lower pin and boot shown) . . .
3.5j . . . clean them off, inspect the pin and
boot for damage, renew as necessary,
then lubricate the pins with brake grease
and refit them in the caliper bracket
3.5k Apply anti-squeal compound to the
new brake pads
3261 Jaguar XJ6
3.5l Insert the new wear sensor into the
inner pad as shown . . .
3.5n Refit the outer pad
3.5m . . . then refit the inner pad onto the
caliper bracket
3.5o Refit the caliper, then tighten the
mounting bolts to the specified torque

necessary to detach the brake line. If you’re
removing the caliper for overhaul, detach the
hose from the metal line at the frame bracket
(see Section 8), then disconnect the brake line
from the caliper with a flare-nut spanner to
protect the fitting (see illustration). Plug the
metal line to keep contaminants out of the
brake system and to prevent losing brake
fluid.
3Refer to illustration 3.5c and unbolt the
front or rear caliper.
Overhaul
4Before you remove the piston, place a
wood block between the piston and caliper to
prevent damage as it is removed.
5To remove the piston from the caliper,
apply compressed air to the brake fluid hose
connection on the caliper body (see
illustration). Use only enough pressure to
ease the piston out of its bore. Remove the
dust boot.
Warning: Be careful not to place
your fingers between the piston
and the caliper as the piston
may come out with some force.
Be sure to wear eye protection when using
compressed air.
6Inspect the mating surfaces of the piston
and caliper bore wall. If there is any scoring,
rust, pitting or bright areas, renew the
complete caliper unit with a new one.
7If these components are in good condition,
remove the piston seal from the caliper bore
using a wooden or plastic tool (see
illustration). Metal tools may damage the
cylinder bore.
8Remove the caliper guide pins and the
rubber dust boots from the caliper bracket.
9Wash all the components in brake system
cleaner.
10Using the correct rebuild kit for your
vehicle, reassemble the caliper as follows.11Submerge the new rubber seal in clean
brake fluid and refit it in the lower groove in
the caliper bore, making sure it isn’t twisted.
12Coat the piston with clean brake fluid and
stretch the new dust boot over the bottom of
the piston. Hold the piston over the caliper
bore and insert the rubber flange of the dust
boot into the upper groove in the bore. Start
with the side farthest from you and work your
way around toward the front until it is
completely seated. Push the piston into the
caliper bore until it is bottomed in the bore,
then seat the top of the dust boot in the
groove in the piston.
13Lubricate the sliding surfaces of the guide
pins with silicone-based grease (usually
supplied in the kit), then refit the new dust
boots and pins into the caliper bracket.
Refitting
14Refit the caliper by reversing the removal
procedure (see Section 3).
15If the brake hose was disconnected from
the caliper, bleed the brake system (see
Section 9).
5 Brake disc- inspection,
removal and refitting
2
Note:The following procedure applies to both
the front and rear brake discs.
Inspection
1Loosen the wheel nuts, raise the vehicle
and support it securely on axle stands.
Remove the wheel and refit three nuts to hold
the disc in place. If the rear brake disc is being
worked on, release the handbrake.
2Remove the brake caliper as outlined in
Section 4. It is not necessary to disconnect
the brake hose. After removing the caliper,
suspend it out of the way with a piece of wire.
3Visually inspect the disc surface for scoring
or damage. Light scratches and shallow
grooves are normal after use and may not
always be detrimental to brake operation, but
deep scoring - over 0.015 inch - requires disc
removal and refinishing by an automotive
machine shop. Be sure to check both sides of
the disc (see illustration). If pulsating has
9•4 Braking system
4.7 Remove the piston seal from the
caliper bore using a wooden or plastic tool
(metal tools may damage the
cylinder bore)5.3 The brake pads on this vehicle were
obviously neglected, as they wore down to
the rivets and cut deep grooves into the
disc - this disc must be replaced
3261 Jaguar XJ6 4.2 Use a flare-nut spanner to protect the brake hose fitting when
unscrewing it from the caliper
4.5 With the caliper padded to catch the piston, use compressed
air to force the piston out of its bore - make sure your fingers are
not between the piston and the caliper

Refitting
8Place the disc on the hub and refit the disc
retaining screw. Tighten the screw securely.
9Refit the caliper mounting bracket, using a
new safety wire on the mounting bolts.
10Refit the brake pads and caliper (see
Section 3). Tighten all fasteners to the torque
listed in this Chapter’s Specifications.
11Refit the wheel and wheel nuts, then lower
the vehicle to the ground. Tighten the wheel
nuts to the specified torque (see Chapter 1
Specifications). Depress the brake pedal a
few times to bring the brake pads into contact
with the disc.
12Adjust the handbrake shoes, if necessary.
13Check the operation of the brakes
carefully, if possible before driving the vehicle
on public roads.
6 Master cylinder- removal,
overhaul and refitting
3
Note:Although master cylinder parts and
rebuild kits are available for most models, we
recommend replacing the master cylinder with
a new or remanufactured unit, if possible.
Removal
1The master cylinder is connected to the
brake servo, which is attached to the pedal
box, in front of the bulkhead on the driver’s
side of the engine compartment.
2Remove as much fluid as you can from the
reservoir with a syringe.
3Place rags under the line fittings and
prepare caps or plastic bags to cover the
ends of the lines once they are disconnected.
Caution: Brake fluid will damage paint.
Cover all body parts and be careful not to
spill fluid during this procedure.
4Disconnect the electrical connector for the
low fluid level warning light (see illustration).
5Loosen the brake line fittings at the mastercylinder (see illustration). Use a flare-nut
spanner to prevent rounding off the nuts. Pull
the brake lines away from the master cylinder
slightly and plug the ends to prevent
contamination.
6Remove the nuts attaching the master
cylinder to the servo (see illustration). Pull
the master cylinder off the studs and lift it out
of the engine compartment. Again, be careful
not to spill fluid as this is done.
Overhaul
7Follow the accompanying photo sequence,
beginning with illustration 6.7a. Stay in order,don’t skip steps, read each caption and study
the photo carefully.
8Once you have dismantled the master
cylinder, clean everything thoroughly, blow
the parts dry with compressed air and
carefully inspect the secondary piston and the
bore of the master cylinder with a bright light.
If the secondary piston or the master cylinder
bore is damaged or worn, renew the master
cylinder with a new or rebuilt unit.
Bench bleeding procedure
9Before refitting a new or rebuilt master
cylinder it should be bench bled. Because it
9•6 Braking system
6.7a Knock out the roll pin that secures
the reservoir to the master cylinder
6.7b Carefully pry off the reservoir by
inserting a screwdriver between the
reservoir and each grommet; this takes
firm pressure, so don’t slip and damage
the reservoir or the master cylinder
6.7c Remove the grommets, noting the
position of each one
6.6 Remove the two master cylinder
mounting nuts
3261 Jaguar XJ6 6.4 Trace the electrical lead back from the reservoir cap and
disconnect the low fluid level sensor
6.5 Loosen the hydraulic brake line fittings with a flare-nut
spanner to protect the corners of the nuts

being drawn back into the master cylinder.
Wait several seconds for brake fluid to be
drawn from the reservoir into the piston bore,
then depress the piston again, removing your
finger as brake fluid is expelled. Be sure to put
your finger back over the hole each time
before releasing the piston, and when the
bleeding procedure is complete for that outlet,
renew the plug and snug it up before going on
to the other port.
Refitting
16Refit the master cylinder over the studs on
the brake servo and tighten the mounting nuts
only finger tight at this time.
17Thread the brake line fittings into the
master cylinder. Since the master cylinder is
still a bit loose, it can be moved slightly to
allow the fitting threads to start easily. Do not
strip the threads as the fittings are tightened.
18Tighten the brake fittings securely and the
mounting nuts to the torque listed in this
Chapter’s Specifications.
19Fill the master cylinder reservoir with fluid,
then bleed the master cylinder and the brake
system (see Section 9).
20To bleed the master cylinder on the
vehicle, have an assistant pump the brake
pedal several times and then hold the pedal to
the floor. Loosen the fitting nut to allow air and
fluid to escape, then tighten the nut. Repeat
this procedure on both fittings until the fluid is
clear of air bubbles. Test the operation of the
brake system carefully before placing the
vehicle into service.
7 Brake servo-
general information,
removal and refitting
2
General information
1A hydraulic brake servo system assists
braking when the brake pedal is depressed.
The booster unit, located between the brake
pedal box and the master cylinder, is operated
by hydraulic pressure generated by an engine-
driven pump (on early models) or by an electric
pump (on later models). When the engine isrunning, the pump supplies hydraulic pressure
to an accumulator. The accumulator stores and
regulates the pressure to the hydraulic brake
servo. When you depress the brake pedal, the
pressure in the booster helps actuate the
master cylinder, reducing pedal effort.
2The hydraulic brake servo isn’t rebuildable;
if it fails, it must be replaced. Basic operation
can be checked (see Chapter 1, Section 15),
but in-depth testing of the system requires
special tools, so diagnosis is beyond the
scope of the home mechanic. If the system
fails, take it to a dealer service department or
other qualified repair workshop for repairs.
However, if the unit must be replaced, you
can do it yourself as follows.
Removal and refitting
3With the engine off, discharge the hydraulic
accumulator by depressing the brake pedal
several times until it feels hard to depress.
4Remove the master cylinder (see Section 6).
5Clean the area around the return and
supply tube nuts, then disconnect them with a
flare-nut spanner (see illustration). Plug the
lines to prevent dirt from entering the system.
Caution: Even a particle of dirt can damage
the servo system, so be extremely careful
to prevent dirt from entering the system
while the lines are disconnected.
6To disconnect the brake servo pushrod
from the brake pedal, remove the access
plugs from both sides of the pedal box (see
illustration), remove the clevis pin retaining
clip and drive out the clevis pin.
7Remove the four mounting nuts and
remove the brake servo (see illustration).
8Refitting is the reverse of removal. Tighten
the hydraulic line fittings securely.
9When you’re done, adjust the brake light
switch (see Section 13).
8 Brake hoses and lines-
inspection and renewal
4
Inspection
1About every six months, with the vehicleraised and placed securely on axle stands, the
flexible hoses which connect the steel brake
lines with the front and rear brake assemblies
should be inspected for cracks, chafing of the
outer cover, leaks, blisters and other damage.
These are important and vulnerable parts of
the brake system and inspection should be
complete. A light and mirror will prove helpful
for a thorough check. If a hose exhibits any of
the above conditions, renew it with a new one.
Flexible hose renewal
2Clean all dirt away from the ends of the
hose.
3To disconnect the hose at the frame end,
use a second spanner on the hex-shaped
fitting on the end of the flexible hose and
loosen the nut on the metal brake line (see
illustrations). If the nut is stuck, soak it with
penetrating oil. After the hose is disconnected
from the metal line, remove the nut right
above the bracket and detach the hose from
the bracket.
4To detach the flexible hose from the caliper,
simply unscrew it.
5Refitting is the reverse of the removal
procedure. Make sure the brackets are in
good condition and the locknuts are tightened
securely.
Braking system 9•9
9
7.5 Use a flare-nut spanner to loosen the
fittings, then pull the lines back from the
brake servo and plug them to prevent
contamination7.6 Pry off the two rubber caps from the
pedal box7.7 To detach the brake servo from the
pedal box, remove these four nuts
(arrowed) (lower right nut not visible
in this photo)
8.3a To remove a front flexible brake hose
from a metal brake line, use one spanner
to hold the hose fitting just below the
bracket (lower spanner), then break loose
the nut on the metal line (upper spanner);
to disconnect the flex hose from the
bracket, remove the centre nut (arrowed)
just above the bracket
3261 Jaguar XJ6

6Carefully check to make sure the
suspension and steering components do not
make contact with the hoses. Have an
assistant push on the vehicle and also turn the
steering wheel from lock-to-lock during
inspection.
7Bleed the brake system (see Section 9).
Metal brake line renewal
8When replacing brake lines, use the proper
parts only. Do not use copper line for any
brake system connections. Purchase steel
brake lines from a dealer or motor factors..
9Unless you’re using factory renewal brake
lines, you may need a tubing bender to bend
the lines to the proper shape.
10First, remove the line you intend to renew,
lay it on a clean workbench and measure it
carefully. Obtain a new line of the same length
and bend it to match the pattern of the old
line.
Warning: Do not crimp or
damage the line. No bend should
have a smaller radius than
9/16-inch. Make sure the
protective coating on the new line is
undamaged at the bends.
11When refitting the new line, make sure it’s
well supported by the brackets, the routing
matches the original and there’s plenty of
clearance between moving or hot
components.
12After refitting, check the master cylinder
fluid level and add fluid as necessary. Bleed
the brake system as outlined in Section 9 and
test the brakes carefully before driving the
vehicle. Be sure there are no leaks.
9 Brake hydraulic system-
bleeding
2
Warning: Wear eye protection
when bleeding the brake
system. If the fluid comes in
contact with your eyes,
immediately rinse them with water and
seek medical attention.Note:Bleeding the hydraulic system is
necessary to remove any air which has entered
the system during removal and refitting of a
hose, line, caliper or master cylinder.
1It will probably be necessary to bleed the
system at all four brakes if air has entered the
system due to low fluid level or if the brake
lines have been disconnected at the master
cylinder.
2If a brake line was disconnected at only one
wheel, then only that caliper or wheel cylinder
must be bled.
3If a brake line is disconnected at a fitting
located between the master cylinder and any
of the brakes, that part of the system served
by the disconnected line must be bled.
4Bleed the right rear, the left rear, the right
front and the left front caliper, in that order,
when the entire system is involved.
5Remove any residual vacuum from the
servo and pressure in the anti-lock braking
system (if equipped) by applying the brake
about 30 times with the engine off.
6Remove the master cylinder reservoir cover
and fill the reservoir with brake fluid. Refit the
cover. Note:Check the fluid level often during
the bleeding operation and add fluid as
necessary to prevent the fluid level from falling
low enough to allow air into the master
cylinder.
7Have an assistant on hand, as well as a
supply of new brake fluid, an empty clear
plastic container, a length of 3/16-inch clear
tubing to fit over the bleed screws and a
spanner to open and close the bleed screws.
8Beginning at the right rear wheel, loosen the
bleed screw slightly, then tighten it to a point
where it is snug but can still be loosened
quickly and easily.
9Place one end of the tubing over the bleed
valve and submerge the other end in brake
fluid in the container (see illustration).
10Have the assistant pump the brakes a few
times to build pressure in the system, then
hold the pedal firmly depressed.
11While the pedal is held depressed, open
the bleed screw just enough to allow fluid to
flow from the caliper. Watch for air bubbles toexit the submerged end of the tube. When the
fluid flow slows after a couple of seconds,
close the screw and have your assistant
release the pedal.
12Repeat Steps 10 and 11 until no more air
is seen leaving the tube, then tighten the
bleed screw and proceed to the left rear
wheel, the right front wheel and the left
front wheel, in that order, and perform the
same procedure. Be sure to check the fluid in
the master cylinder reservoir frequently.
13Never reuse old brake fluid. It contains
contaminates and moisture which could
damage the braking system.
14Refill the master cylinder with fluid at the
end of the operation.
15Check the operation of the brakes. The
pedal should feel solid when depressed, with
no sponginess. If necessary, repeat the entire
process.
Warning: Do not drive the car if
in doubt about the effectiveness
of the brake system.
10 Handbrake cable-
adjustment
1
1Slowly apply the handbrake and count the
number of clicks at the lever. It should be fully
applied within three to five clicks. If the lever is
still not fully applied by the fifth click, adjust
the handbrake cable as follows:
2Raise the vehicle and place it securely on
axle stands.
3Loosen the locknut (see illustration)and
tighten the cable adjuster until all slack has
been removed. Tighten the locknut. Make
sure the wheels turn freely with the handbrake
lever released
4Lower the vehicle and recheck the
handbrake lever. It should now be properly
adjusted. If it’s now fully applied within three
to five clicks, raise the vehicle again and
readjust the cable at the adjuster.
5Make sure the handbrake holds the vehicle
on an incline.
9•10 Braking system
8.3b The connection (arrowed) for the rear
hose and line is located right above the
mounting bracket for the front corner of
the differential crossmember; remove the
hose as described in the previous
illustration9.9 When bleeding the brakes, a hose is
connected to the bleed screw at the caliper
or wheel cylinder and then submerged in
brake fluid - air will be seen as bubbles in
the tube and container (all air must be
expelled before moving to the next brake)
10.3 To adjust the handbrake cable,
loosen the locknut, then turn the adjuster
to remove any slack in the cable; be sure
to tighten the locknut when the cable is
properly adjusted
3261 Jaguar XJ6

at a time, so you can use the other side as a
reference during reassembly.
6Refitting is the reverse of removal.
7After refitting the brake disc, adjust the
handbrake shoes. Temporarily refit two nuts,
turn the adjuster (see illustration 5.7c)and
expand the shoes until the disc locks, then
back off the adjuster until you can spin the
disc without the shoes dragging.
8Adjust the handbrake cable (Section 10).
9Remove the axle stands and lower the
vehicle. Tighten the wheel nuts to the specified
torque (see Chapter 1 Specifications).
13 Brake light switch-
check and renewal
1
1The brake light switch activates the brake
lights when the brake pedal is depressed. It‘s
located at the top of the brake pedal, inside
the pedal box.
2If the brake lights don’t come on when the
brake pedal is depressed, check the fuses
(the fuse for the left brake light is in the left
fuse panel and the fuse for the right brake
light is in the right panel).
3If the fuses are okay, check the brake light
bulbs (see Chapter 12).
4If the fuses and bulbs are okay, either the
switch isn’t getting voltage (there’s an open-
circuit between the voltage source and the
switch), voltage isn’t reaching the brake light
Braking system 9•13
9
12.5j Place the front shoe in position,
insert the pin through the backing plate
and the shoe . . .12.5k . . . and refit the hold-down spring
and washers12.5i Lubricate the six friction points
(two arrowed) on the backing plate with
high-temperature brake grease
3261 Jaguar XJ6 12.5l Hook the lower return spring into its
hole in the front shoe . . .
12.5m . . . hook the other end of the
lower spring into the rear shoe . . .12.5n . . . stretch the spring over the top of
the handbrake lever box . . .
12.5o . . . place the rear shoe in position,
insert the pin through the backing plate
and the shoe and refit the rear washers
and hold-down spring12.5p Hook the upper return spring into
the front shoe . . .
12.5q . . . and into the rear shoe12.5r Pull the shoes apart and refit the
adjuster mechanism

bulbs (open-circuit between the switch and
the bulbs), or the switch is defective.
5To remove the switch, reach up under the
dash and unplug the two electrical connectors
- one for the brake lights and one for the
cruise control system. Locate the two pairs of
leads coming down the pedal box and trace
them to their connectors on or near the
steering column.
6Remove the three switch-plate retaining
bolts and remove the switch assembly (see
illustrations). Inspect the switch-plate rubber
gasket for cracks or deterioration and renew it
if it’s damaged or worn.
7Place the switch assembly on a workbench
and connect an ohmmeter to the brake lightswitch terminals. With the switch plunger in its
normal, extended position (brake pedal not
applied), there should be no continuity (infinite
resistance) (see illustration); when the
plunger is depressed (brake pedal applied),
there should be continuity (zero resistance)
(see illustration). If the switch doesn’t
perform as described, renew it. If the switch
works in an opposite fashion, i.e. continuity
when the plunger is free, no continuity when
the plunger is depressed, you’ve tested the
cruise control switch! Switch the ohmmeter
leads to the other connector and recheck.
8To remove the switch from the plate,
remove the two small nuts on the back of the
plate (see illustration).9Refit the switch assembly and the switch
plate bolts but don’t tighten the bolts yet.
10Plug in the brake light and cruise control
connectors.
11The holes in the switch plate are slotted
for adjustment. While an assistant presses the
brake pedal, verify that the brake lights come
on; with the pedal released, make sure the
brake lights are off. If the lights don’t come on
when the pedal is depressed, or stay on when
the pedal is released, adjust the switch by
moving the plate until proper operation is
achieved. Tighten the switch-plate bolts.
12After tightening the switch-plate bolts,
check the switch again to make sure it
performs properly.
9•14 Braking system
13.6a To remove the brake light switch,
remove the three mounting plate screws
(arrowed) . . .13.6b . . . and carefully pry the switch plate
away from the pedal box - be careful not to
damage the gasket13.7a To check the brake light switch,
connect an ohmmeter to the switch
terminals; with the switch plunger
released, there should be no continuity
(infinite resistance)
13.7b With the switch plunger depressed,
there should be continuity
(zero resistance)13.8 If you’re replacing the switch, remove
these two nuts (arrowed) and transfer the
retaining plate to the new switch
3261 Jaguar XJ6