1996 LAND ROVER DEFENDER light

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
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
4
OVERHAUL Assembling master cylinder
CAUTION: It is important that the following
instructions are carried out precisely,
otherwise damage could be caused to new
seals when inserting plungers into cylinder bore.
Generous amounts of new brake fluid should be
used to lubricate parts during assembly.
NOTE: Thoroughly check that no debris is
lodged in fluid passageways and drillings.
If debris is found, carefully remove,
re-clean cylinder and re-check.
16.Fit new swirl tube to bottom of cylinder bore.
17.Lubricate secondary plunger and cylinder bore.
Offer plunger assembly to cylinder until
recuperation seal is resting centrally in mouth of
bore. Gently introduce plunger with a circular
rocking motion, as illustrated. Ensuring that seal
does not become trapped, ease seal into bore
and slowly push plunger down bore in one
continuous movement.
18.Fit primary plunger assembly using same
method as for secondary plunger, push plunger
down bore.
19.Fit original guide ring to support primary plunger.
20.Coat a new 'O' ring with brake fluid and fit to its
respective groove on outer location surface of
master cylinder.
CAUTION: 'O' ring should not be rolled
down outer location surface of master
cylinder but should be slightly stretched
and eased down cylinder and into its groove. Do
not over stretch seal.21.Fit a new retaining ring on outer surface of
master cylinder ensuring that serrations of ring
are facing mounting flange.
22.Fit two new reservoir seals in their respective
ports.
23.Fit a new vacuum seal to either primary plunger
or to bottom of transfer housing bore, open face
of seal towards primary plunger guide ring.
24.Lubricate vacuum seal with brake fluid, fit
transfer housing to master cylinder, push
housing fully up to cylinder mounting flange. Do
not adjust transfer housing after fitting.
25.Lubricate a new water ingress seal with brake
fluid, slightly stretch seal and ease it down
housing until seal is in correct position between
housing and flange.
26.Roll reservoir into top of master cylinder,
reversing procedure described in instruction 3.
27.Fit master cylinder to servo
See Repair,
Master cylinder
.
28.Reconnect battery, and road test vehicle.

74WHEELS AND TYRES
6
REPAIRREV: 05/99 WHEELS
Remove
WARNING: The parking brake acts on
transmission, not rear wheels, and may
not hold vehicle when jacking unless
following procedure is used. If one front wheel
and one rear wheel is raised no vehicle holding or
braking effect is possible. Wheels MUST be
chocked in all circumstances.
Apply parking brake, select a gear in main
gearbox and engage low gear in transfer box.
1.Loosen 5 wheel nuts.
2.Using a suitable trolley jack, raise vehicle and
place on axle stands
See INTRODUCTION,
Information, Jacking
.
3.Remove wheel nuts and carefully withdraw
wheel over studs.
Refit
4.Ensure that retaining studs and nuts are clean.
5.Alloy wheels: Lightly coat wheel mounting spigot
face with a suitable anti-seize compound to
minimise possibility of adhesion between wheel
and spigot face.
6.Refit wheel taking care not to damage stud
threads. (Do not apply oil).
7.Fit wheel nuts and turn by hand for at least three
full threads before using any form of wheel
wrench.
8.Tighten nuts as much as possible using a
suitable wrench.
9.Lower vehicle and finally tighten nuts to correct
torque sequence shown.
Alloy wheels -
130 Nm (96 lbf/ft)
Steel wheels -100 Nm (80 lbf/ft)
Heavy duty wheels -170 Nm (125 lbf/ft)

76CHASSIS AND BODY
16
REPAIR 7.To remove barrel from plastic retaining sleeve,
depess spring loaded button and withdraw
sleeve.
Refit
NOTE: If a new barrel is being fitted, check
that number on barrel coincides with
number on accompanying key.
8.Push plastic retaining sleeve over barrel until
spring loaded peg locks it into position.
9.Fit barrel and plastic sleeve assembly to locking
sleeve and insert into exterior handle reversing
instruction 6.
10.Assemble lock lever components as illustrated
and from inside of door panel, fit them to barrel
assembly with single screw.
11.Connect operating rod to lock lever and secure
with spring clip, reversing instruction 4.
12.Fit mounting panel
See Mounting panel - front
door
.DOOR STRIKER - ADJUST
Service repair no - 76.37.23 - front door
Service repair no - 76.37.24 - rear door, 110/130
Adjust
1.Loosen 2 Torq bolts securing striker to body.
2.Adjust alignment of striker vertically and
horizontally, lightly tighten bolts.
3.Close door, check for correct latching with door
lock and for centering on striker.
4.Add or remove packing shims as necessary
behind striker and fully tighten bolts.
5.Carry out further adjustment as necessary. If full
adjustment is not achieved carry out the
following:
6.Remove striker and nut plate.
7.Elongate striker bolt holes in 'B' or 'C' post in
direction required.
8.Refit striker and adjust as necessary.

AIR CONDITIONING
7
ADJUSTMENT 11.All precautions must be taken to prevent
damage to fittings and connections. Slight
damage could cause a leak with the high
pressures used in the system.
12.Always use two wrenches of the correct size,
one on each fitting when releasing and
tightening refrigeration unions.
13.Joints and 'O' rings should be coated with
refrigeration oil to aid correct seating. Fittings
which are not lubricated with refrigerant oil are
almost certain to leak.
14.All lines must be free of kinks. The efficiency of
the system is reduced by a single kink or
restriction.
15.Flexible hoses should not be bent to a radius
less than 90mm radius.
16.Flexible hoses should not be within 100mm of
the exhaust manifold.
17.Completed assemblies must be checked for
refrigeration lines touching metal panels. Any
direct contact of lines and panels transmits noise
and must be eliminated.PERIODIC MAINTENANCE
Routine servicing, apart from visual checks, is not
necessary. The visual inspections are as follows:
Condenser
With a water hose or air line, clean the fins of the
condenser to remove flies, leaves, etc. Check the pipe
connections for signs of oil leakage.
Compressor
Check pipe connections for signs of oil leakage.
Check flexible hoses for swelling. Examine the
compressor belt for tightness and condition.
Sight glass
Examine the sight glass for bubbles with the system
operating. Check connections for leakage.
Evaporator
Examine the refrigeration connections at the unit.

ELECTRICAL
1
DESCRIPTION AND OPERATION ELECTRICAL EQUIPMENT
Description
The electrical system is Negative ground, and it is
most important to ensure correct polarity of electrical
connections at all times. Any incorrect connections
made when reconnecting cables may cause
irreparable damage to semi-conductor devices used in
generator and regulator. Incorrect polarity would also
seriously damage any transistorized equipment such
as a radio.
WARNING: During battery removal or
before carrying out any repairs or
maintenance to electrical components
always disconnect battery negative lead first. If
positive lead is disconnected with negative lead in
place, accidental contact of wrench to any
grounded metal part could cause a severe spark,
possibly resulting in personal injury. Upon
installation of battery positive lead should be
connected first.
GENERATOR
The generator is a three phase, field sensed unit. The
rotor and stator windings produce three phase
alternating current, AC, which is rectified to direct
current, DC. The electronic voltage regulator unit
controls generator output voltage by high frequency
switching of the rotor field circuit. Use only correct
replacement drive belt. Occasionally check that
engine and generator pulleys are accurately aligned.
It is essential that good electrical connections are
maintained at all times. Of particular importance are
those in the charging circuit (including those at
battery) which should be occasionally inspected to
see that they are clean and tight. In this way any
significant increase in circuit resistance can be
prevented.Do not disconnect battery cables while engine is
running or damage to semi-conductor devices may
occur. It is also inadvisable to break or make any
connections in the generator charging and control
circuits while engine is running.
The electronic voltage regulator employs micro-circuit
techniques resulting in improved performance under
difficult service conditions. The whole assembly is
encapsulated in silicone rubber and housed in an
aluminium heat sink, ensuring complete protection
against adverse effects of temperature, dust, and
moisture etc.
The regulating voltage is set during manufacture to
give required regulating voltage range of 14.2±0.2
volts, and no adjustment is necessary. The only
maintenance needed is occasional check on terminal
connections and wiping with a clean dry cloth.
The generator system provides for direct connection
of a charge (ignition) indicator warning lamp, and
eliminates the need for a field switching relay or
warning light control unit. In the event of bulb failure,
an 'exciter' voltage is supplied through a resistor,
wired in parallel to the bulbs, ensuring that generator
output is maintained. The lamp should be checked
regularly.
When using rapid charge equipment to re-charge
battery, the battery must be disconnected from the
vehicle.

ELECTRICAL
3
DESCRIPTION AND OPERATION Door and bonnet switches
Perimetric protection for the vehicle is provided by
ECU inputs connected to the starter switch, bonnet
switch and door switches.
Ultrasonic sensor
The ultrasonic sensor operates by emitting an air
pressure carrier wave which is subsequently received
by the sensor as it bounces back from objects inside
the vehicle. Once armed, the alarm will sound if wave
is disturbed by a door opening, or if movement is
detected inside the vehicle.
When the volumetric sensor is activated it monitors
movement within the vehicle for 15 seconds before
detecting and responding to intrusions. If the sensor
detects movement it delays arming until a quiet period
has lapsed; if continuous movement is detected, the
alarm will not arm volumetrically.
NOTE: Interior protection will not operate
until 15 seconds after alarm is set.
The ultrasonic sensor is positioned in a different
location, according to vehicle type, as follows:
·90/110 Station Wagon - RH cantrail trim
·90/110 Pick-up - On headlining, between interior
lamp and rear view mirror
·130 Crewcab - On headlining above RH door
Alarm sounder
Two types of alarm sounder can be fitted, one with a
battery back-up facility and or without battery back-up,
both providing an audible warning whenever the alarm
is triggered. The vehicle horn will also operate if the
alarm sounds.
The alarm sounder is fitted to LH inner front wing in
the engine compartment.
NOTE: Disconnecting the battery on
vehicles fitted with the battery backed-up
facility will result in the alarm sounding, if
correct procedure has not been followed.Engine immobilisation warning light
The engine immobilisation warning light is located on
the instrument panel, and provides a visual indication
that the engine is immobilised.
Anti-theft alarm indicator light
The anti-theft alarm indicator light is located on the
instrument panel, between the fuel and coolant
temperature indicators, and provides a visual
indication of the alarm/ immobiliser status.