1996 LAND ROVER DEFENDER ECU

64REAR SUSPENSION
6
REPAIR Refit
10.Ensure ball pin threads are clean and smear
Loctite grade CVX on ball pin threads.
11.Fit upper ball joint to levelling unit and secure
gaiter.
12.Fit top bracket complete with levelling unit to
chassis and secure with 4 nuts and tighten to
47
Nm (35 lbf/ft).
13.Fit levelling unit to lower ball joint and secure
gaiter.
14.Attach webbing strap to chassis cross member.
15.Fit upper links to the pivot bracket and retain
with 2 bolts and nuts but do not tighten at this
stage.
16.Remove jack in support of axle and support from
under chassis.
17.Allow suspension to settle and then tighten 2
bolts and nuts retaining upper links to pivot
bracket to
176 Nm (130 lbf/ft).

BRAKES
1
DESCRIPTION AND OPERATION DESCRIPTION
The mechanical components of the hydraulic braking
system consists of four piston caliper disc brakes at
the front and two piston caliper disc brakes at the rear.
Vented front brake discs are fitted as standard on
110/130 models, while 90 models have solid discs.
However, on 90 models with a heavy duty chassis,
vented front discs may also be fitted.A cable controlled parking brake operates a single
drum brake mounted on the output shaft of the
transfer gearbox and is completely independent of the
main braking system.
The basic hydraulic system involves 2 separate and
independent primary and secondary circuits which
permits a degree of braking should a fault occur in
one of the circuits. The primary circuit operates the
rear brake calipers and the secondary circuit the front
brake calipers.
Master cylinder components
1.Secondary plunger
2.Secondary spring
3.Recuperation seal4.Primary spring
5.Recuperation seal
6.Primary plunger

70BRAKES
2
DESCRIPTION AND OPERATION REV: 05/99 OPERATION
Master cylinder
A tandem master cylinder, which is assisted by a light
weight, short, compact servo, is fed by a divided fluid
reservoir. The rear section supplies fluid for the
primary circuit and the front section the secondary
circuit.
When the brakes are off, the fluid can move
unrestricted between the dual line system and the
separate reservoirs in the fluid supply tank.
When the footbrake is applied, the primary plunger
assembly moves up the cylinder bore and the
pressure created acts in conjunction with the primary
spring to overcome the secondary springs, thus
moving the secondary plunger assembly up the bore.
At the same time initial movement of both plungers
takes the recuperating seals past the cut-off holes in
the cylinder chambers 'A' and 'C',see J6321, and
applies pressure to the fliud in those chambers, which
is directed to the respective circuits.
The fluid in chambers 'B' and 'D'is unaffected by
movement of the plungers and can move unrestricted
between the separate chambers and respective
reservoirs in the fluid supply tank, both before and
during brake application. When the brakes are
released, the plunger assemblies, aided by the return
springs are retracted faster than the fluid; this creates
a depression between the fluid in chambers 'A' and
'C'and the recuperation seals.
The recuperation seals momentarily collapse allowing
fluid in chambers 'B' and 'D'to flow through the holes
in the plungers, over the collapsed seals and into
chambers 'A' and 'C'respectively. The movement of
fluid from one set of chambers to the other, is
compensated for by fluid from the separate reservoirs
in the supply tank moving through the feed holes in
the cylinder. Conversely, the final return movement of
the plunger assemblies causes the extra fluid in
chambers 'A' and 'C'to move through the cut off holes
into the fluid reservoir.The servo unit provides controlled power assistance
to to the brake pedal when pressure is applied. Power
is obtained from a vacuum pump located on the RH
side of the engine cylinder block. The vacuum is
applied to both sides of a flexing diaphragm, and by
admitting atmosheric pressure to the rear diaphragm,
assistance is obtained. The servo unit is mounted
between the brake pedal and master cylinder and is
linked to these by push rods. Should a vacuum failure
occur, the two push rods will act as a single rod
allowing the brakes to function in the normal way,
although more effort will be required to operate the
brake pedal.
Hydraulic system
A brake fluid loss switch is fitted to the master cylinder
reservoir filler cap. The switch is wired to a warning
light on the vehicle fascia and will illuminate as a bulb
check when the ignition is switched on and
extinguishes when the engine is running and the
handbrake is released. A hydraulic failure in the
system will result in fluid loss, causing the warning
light to illuminate.
On 90 models a pressure reducing valve (PRV), fitted
to the RH bulkhead in the engine compartment,
maintains the braking balance, see J6322. Pressure
to the rear calipers is regulated by the PRV, this valve
is of the failure by-pass type, allowing full system
pressure to the rear brake calipers in the event of a
front (secondary) circuit failure.
NOTE: In some countries, a pressure
reducing valve may be fitted to 110 models
to conform to legal requirements.

BRAKES
3
REPAIR MASTER CYLINDER
Service repair no - 70.30.08
Before starting repair refer to general brake service
practice
See General Brake Service Practice.
Remove
1.Disconnect battery.
2.Place a container under the master cylinder to
catch escaping brake fluid.
3.Clean area round master cylinder ports.
4.Disconnect pipes from master cylinder ports.
Cover, not plug, the pipe ends to prevent entry of
dirt.
5.Disconnect electrical leads from reservoir cap.
6.Remove two nuts securing master cylinder to
servo and withdraw cylinder.
7.Remove reservoir cap and drain fluid into
suitable container for disposal.
8.The reservoir is a push fit in the master cylinder
and secured by seals. Carefully ease the
reservoir from the master cylinder by rolling it
from the seals. Note that the two seals are
different sizes.
Refit
9.Insert new reservoir seals in the master cylinder
ports and fit reservoir to master cylinder.
10.Ensuring that water ingress seal is in position, fit
master cylinder to servo. Tighten fixings to
26
Nm (19 lbf/ft).
11.Connect brake pipes to master cylinder ports
and tighten to
15 Nm (11 lbf/ft).
12.Fit electrical leads to reservoir cap
13.Fill reservoir with recommended brake fluid.
See
LUBRICANTS, FLUIDS AND CAPACITIES,
Information, Recommended lubricants and
fluids
14.Bleed the brake systemSee Brake system
bleed
.
15.Reconnect battery and road test vehicle.

70BRAKES
4
REPAIR PRESSURE REDUCING VALVE (PRV)
Service repair no - 70.25.21
Remove
1.Disconnect battery.
2.Clean area around reducing valve ports.
3.Place a container under valve to catch escaping
brake fluid.
4.Disconnect primary circuit pipe unions ñAñ
from valve.
5.Disconnect secondary circuit pipe unions ñBñ
from valve.
6.Cover pipes to prevent ingress of dirt.
7.Remove single retaining nut and bolt securing
valve to engine bulkhead.
8.Remove valve.
Refit
9.Fit valve to engine bulkhead. Tighten bolt to
15
Nm (11 lbf/ft).
10.Connect primary and secondary circuit pipes to
valve. Tighten to
16 Nm (12 lbf/ft).
11.Fill brake reservoir with recommended brake
fluid
See LUBRICANTS, FLUIDS AND
CAPACITIES, Information, Recommended
lubricants and fluids
.
12.Bleed the brake system
See Brake system
bleed
.
13.Reconnect battery and road test vehicle.SERVO NON RETURN VALVE
Service repair no - 70.50.15
Remove
1.Disconnect brake vacuum hose from servo non
return valve.
2.Carefully prise valve out with a screwdriver blade
between valve and grommet. Take care not to
exert too much pressure on the vacuum
chamber.
3.Remove rubber grommet but be careful not to
allow it to fall into the vacuum chamber.
4.Check the valve for correct operation; it should
not be possible to pass air through into the servo
in direction of arrow. Do not use compressed air.
Refit
5.Fit rubber grommet.
6.Smear ribs of the valve with Lucas Girling rubber
grease to assist assembly, and push valve fully
home.
7.Connect vacuum hose to the valve.
8.Road test vehicle.

BRAKES
5
REPAIR SERVO ASSEMBLY
Service repair no - 70.50.01
Remove
Before starting repair refer to general brake service
practice
See General Brake Service Practice.
NOTE: The non-return valve and grommet,
are the only serviceable components. In
event of failure or damage, fit a new unit.
1.Remove master cylinderSee Master cylinder.
2.Disconnect vacuum supply hose from servo unit.
3.At footwell, release 2 brake pedal return springs.
4.Disconnect leads from brake light switch at rear
of pedal box.
5.Remove blanking grommets from each side of
pedal box.
6.Remove split pin and clevis pin securing servo
push rod to brake pedal.
7.Remove 4 nuts and plain washers securing
servo to pedal box.
8.Remove servo assembly and rubber washer
from bulkhead.Refit
9.Locate servo assembly and rubber washer to
engine bulkhead and secure to pedal box.
Tighten fixings to
14 Nm (10 lbf/ft).
10.Fit brake pedal to servo push rod with clevis pin
and new split pin.
11.Fit blanking grommets to each side of pedal box.
12.At footwell, attach pedal return springs.
13.Connect vacuum hose to servo non-return valve.
14.Fit brake master cylinder to servo unit
See
Master cylinder
.

70BRAKES
6
REPAIR BRAKE PEDAL
Service repair no - 70.35.01 - Brake pedal
Service repair no - 70.35.03 - Pedal box
Remove
1.Remove brake servo assembly.
See Servo
assembly
.
2.Remove 6 bolts securing pedal box to engine
bulkhead.
3.Taking care not damage brake fluid pipes,
remove pedal box assembly and gasket.
4.Release return springs from pedal and pedal box
bosses.
5.Using a suitable punch, drift out retaining pin and
withdraw pedal pivot shaft.
6.Remove brake pedal complete with pivot
bushes.
7.Examine components for wear or damage,
renew as necessary.
8.If it is necessary to fit new pivot bushes, they
must be reamed out to 15,87 mm±0,02 mm
(0.625±0.001 in) after fitment.Refit
9.Lubricate pedal pivot shaft and bushes with
general purpose grease.
10.Fit pedal to pedal box, insert pivot shaft and
secure with new split pin.
11.Attach return springs to pedal and pedal box
bosses.
12.Fit pedal box and gasket to engine bulkhead.
Tighten fixings to
25 Nm (18 lbf/ft).
13.Fit brake servo assembly.See Servo
assembly
.

BRAKES
7
REPAIR REV: 05/99 FRONT BRAKE PADS - ALL MODELS
Service repair no - 70.40.02
Remove
1.Remove front road wheels .
2.Clean exterior of calipers.
3.Remove split pin from retaining pins.
4.Remove pad retaining pins and anti-rattle
springs.
5.Remove brake pads.
6.Clean exposed parts of pistons, using new brake
fluid. Wipe away excess with a lint free cloth.
7.Using piston clampLRT-70-500press each
piston back into its bore. Ensure that displaced
brake fluid does not overflow from reservoir.
Refit
8.Fit brake pads.
9.Fit pad retaining pins and anti-rattle springs.
Secure with new split pins.
10.Apply service brake pedal several times to locate
pads.
11.Fit road wheels. Tighten wheel nuts to correct
torque:
Alloy wheels -
130 Nm (96 lbf/ft)
Steel wheels -100 Nm (80 lbf/ft)
Heavy duty wheels -170 Nm (125 lbf/ft)
12.Check fluid reservoir. Top up if necessary, using
correct grade of fluid
See LUBRICANTS,
FLUIDS AND CAPACITIES, Information,
Recommended lubricants and fluids
.