1997 JAGUAR XJ6 Workshop Manual

Braking system 9•7
9
6.7d Pry off the end cap6.7e Locate the stopper pin (arrowed)
inside the forward grommet hole . . .6.7f . . . insert a punch into the pocket of
the primary piston, place the master
cylinder vertically as shown, push down
on the master cylinder to depress the
pistons and pull out the stopper pin
with a magnet
6.7g Remove the primary piston6.7h Remove the secondary piston6.7i If the secondary piston is stuck, rap
the master cylinder on a wood block to
dislodge it
3261 Jaguar XJ6
6.7j Remove the seals and cups from the
pistons - be very careful not to scratch the
piston surface - then wash the secondary
piston with clean brake fluid and inspect it;
if the secondary piston is damaged, you
must renew the master cylinder with a new
or rebuilt unit (a new primary piston is
included with the rebuild kit)6.7l The master cylinder assembly
1 Roll pin
2 Reservoir
3 Grommets
4 End plate
5 Primary piston
6 Secondary piston stopper pin
7 Secondary piston6.7k Refit the new O-ring seals and cups
as shown; make sure the cups on the
primary piston (the one on the left) face
forward as shown (toward the spring), and
the cups on the secondary piston (the one
on the right) face out, away from the piston
(the one on the left faces toward the
primary piston, the one on the right faces
toward the spring)

will be necessary to apply pressure to the
master cylinder piston and, at the same time,
control flow from the brake line outlets, it is
recommended that the master cylinder be
mounted in a vice. Use caution not to clamp
the vice too tightly, or the master cylinder
body might crack.
10Insert threaded plugs into the brake line
outlet holes and snug them down so that
there will be no air leakage past them, but not
so tight that they cannot be easily loosened.
11Fill the reservoir with brake fluid of the
recommended type (see Recommended
lubricants and fluidsin Chapter 1).
12Remove one plug and push the piston
assembly into the master cylinder bore to
expel the air from the master cylinder. A large
Phillips screwdriver can be used to push on
the piston assembly.
13To prevent air from being drawn back into
the master cylinder, the plug must be
replaced and tightened before releasing the
pressure on the piston assembly.
14Repeat the procedure until only brake
fluid is expelled from the brake line outlet
hole. When only brake fluid is expelled, repeat
the procedure with the other outlet hole and
plug. Be sure to keep the master cylinder
reservoir filled with brake fluid to prevent the
introduction of air into the system.
15Since high pressure is not involved in the
bench bleeding procedure, an alternative to
the removal and renewal of the plugs witheach stroke of the piston assembly is
available. Before pushing in on the piston
assembly, remove the plug as described inStep 12. Before releasing the piston, however,
instead of replacing the plug, simply put your
finger tightly over the hole to keep air from
9•8 Braking system
6.7m Apply some clean brake fluid to the
secondary piston and refit it with the slot
oriented with the stopper pin hole, so that
the stopper pin will go through the slot6.7n Apply a coat of clean brake fluid to
the primary piston and refit it into the bore6.7o Using the same technique as in
illustration 6.7f, depress the pistons and
refit the stopper pin
6.7p Refit the end plate as shown, with the
bend in the plate flange aligned with the
groove in the master cylinder flange6.7q Using a hammer and punch, stake
the end plate as shown (there’s a dimple in
the side of the plate for this purpose)6.7r Refit the grommets
3261 Jaguar XJ6
6.7s Align the reservoir pipes with the
grommets as shown . . .
6.7u Refit the reservoir roll pin . . .6.7v . . . and tap it into place
6.7t . . . and squeeze the reservoir and
master cylinder together; make sure the
reservoir is fully seated

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

11 Handbrake cable(s)- renewal
2
1Raise the vehicle and place it securely on
axle stands.
Front cable
2Remove the cotter pin, washer and clevis
pin from the forward end of the front cable
(see illustration). Disconnect the forward end
of the front cable from the handbrake lever.
3Follow the cable back to the adjuster lever
and remove the cotter, washer and clevis pin
(see illustration). Remove the front cable.
4Refitting is the reverse of removal.
Intermediate cable
5Remove the cotter pins, washers and clevis
pin from both ends of the intermediate cable
(see illustration). Remove the cable.
6Refitting is the reverse of removal.
Rear cables
7Remove the cotter pin, washer and clevis
pin from the intermediate cable-to-rear cable
yoke (see illustration).
8Disconnect the rear end of each cable from
the handbrake assembly (see illustration).,
then pry the cable out of the carrier.
9Refitting is the reverse of removal.
All cables
10Be sure to adjust the handbrake cable
when you’re done (see Section 10). The rear
wheels should turn freely with the handbrake
lever released.
11Remove the axle stands and lower the
vehicle. Apply the handbrake lever, make sure
it’s fully applied within three to five clicks and
that it holds the vehicle on an incline. If it
doesn’t, readjust it (see Section 10).
12 Handbrake shoes-
check and renewal
2
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!
Check
1The handbrake system should be checked
regularly. With the car parked on a hill, apply
the brake, place the transmission in Neutral
and check that the handbrake alone will hold
the car (be sure to stay in the car during this
check). However, every 24 months (or
Braking system 9•11
9
3261 Jaguar XJ6 11.2 To disconnect the forward end of the
front cable from the handbrake lever,
remove this cotter pin, washer
and clevis pin
11.3 To disconnect the rear end of the
front cable from the adjuster lever, remove
this cotter pin, washer and clevis pin
(arrowed)11.5 To disconnect the intermediate cable,
remove the cotter pins, washers and clevis
pins (arrowed) from the adjuster lever
and the yoke
11.7 To disconnect the rear cables and yoke from the
intermediate cable, remove this cotter pin, washer
and clevis pin (arrowed)11.8 The rear handbrake cable-to-handbrake shoe connection is
hidden behind the lower part of the brake backing plate, on the
underside of the carrier (this view is looking straight up from
underneath the carrier). To disconnect either rear handbrake
cable, swing this clip (arrowed) to the side and remove it - the
rear cable is now disconnected

whenever a fault is suspected), the assembly
itself should be visually inspected.
2Loosen the wheel nuts, raise the rear of the
vehicle and place it securely on axle stands.
Remove the rear wheels.
3Remove the rear brake calipers and discs
(see Sections 3, 4 and 5). Support the caliper
assemblies with a coat hanger or heavy wire
and do not disconnect the brake line from the
caliper.4With the disc removed, the handbrake
components are visible and can be inspected
for wear and damage. The linings should last
the life of the vehicle. However, they can wear
down if the handbrake system has been
improperly adjusted. There is no minimum
thickness specification for the handbrake
shoes, but as a rule of thumb, if the shoe
material is less 1/32-inch thick, you should
renew them. Also check the springs andadjuster mechanism and inspect the drum for
deep scratches and other damage.
Renewal
5Loosen the wheel nuts, raise the rear of the
vehicle and place it securely on axle stands.
Remove the rear wheels. Remove the brake
discs (see Section 5). Follow the
accompanying photo sequence beginning
with illustration 12.5a. Work on only one side 1 Adjuster
2 Hold down springs and
washers3 Upper return spring
4 Lower return spring
5 Handbrake shoes
9•12 Braking system
12.5a Wash down the handbrake
assembly with brake cleaner before
dismantling12.5b Back off the star wheel on the
adjuster, then disengage the adjuster
mechanism from the handbrake shoes12.5c Remove the front hold-down spring,
washers and pin; note that one washer
goes below the spring and one above it
12.5d Remove the rear hold-down spring,
washers and pin; put the parts in a plastic
bag so you don’t lose them12.5e Push the shoes together and
disengage the upper return spring
from the rear shoe . . .12.5f . . . and from the front shoe
3261 Jaguar XJ6 12.5g Pull the shoes apart and remove them with the lower spring
attached as shown, then disengage the lower return spring
from both shoes
12.5h The handbrake shoe assembly

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