warning LAND ROVER DEFENDER 1996 Service Manual

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
1
REPAIR GENERAL BRAKE SERVICE PRACTICE
Brake fluid precautions
WARNING: Do not allow brake fluid to
come into contact with eyes or skin.
CAUTION: Brake fluid can damage
paintwork, if spilled wash off immediately
with plenty of clean water.
CAUTION: Use only correct grade of brake
fluid. If an assembly fluid is required use
ONLY brake fluid. Do NOT use mineral oil,
i.e. engine oil etc.
CAUTION: Thoroughly clean all brake
calipers, pipes and fittings before
commencing work on any part of the brake
system. Failure to do so could cause foreign
matter to enter the system and cause damage to
seals and pistons which will seriously impair the
efficiency of the brake system. To ensure the
brake system efficiency is not impaired the
following warnings must be adhered to :-
·DO NOT use any petroleum based cleaning
fluids or any proprietary fluids containing
petrol.
·DO NOT use brake fluid previously bled from
the system.
·DO NOT flush the brake system with any fluid
other than the recommended brake fluid.
The brake system should be drained and flushed
at the recommended service intervals.
Cover all electrical terminals carefully to make
absolutely certain that no fluid enters the
terminals and plugs.FLUID LEVEL CHECK/TOP UP
WARNING: Clean reservoir body and filler
cap before removing cap. Use only fluid
from a sealed container.
1.Park vehicle on level ground.
2.Check level is between 'MIN' and 'MAX' marks.
3.If level is below 'MIN' mark top up fluid level to
'MAX' mark on reservoir, using correct fluid.
See
LUBRICANTS, FLUIDS AND CAPACITIES,
Information, Recommended lubricants and
fluids
CAUTION: Do not fill reservoir above
maximum line.

70BRAKES
2
REPAIR BRAKE SYSTEM BLEED
Service repair no - 70.25.02
Preparation
WARNING: Before bleeding the brake
system refer to general brake service
practice.
See General Brake Service
Practice
.
·During bleed procedure, brake fluid level must
not be allowed to fall below the MIN level.
·To bleed the hydraulic circuits, four bleed
nipples are provided, one at each caliper.
·There are two methods by which air can be
removed from the braking system:-
1. MANUAL BLEED PROCEDURE.
2. PRESSURE BLEED PROCEDURE.
Pressure bleed procedure
Purpose designed equipment for pressure filling and
bleeding of hydraulic systems may be used on Land
Rover vehicles. The equipment manufacturer's
instructions must be followed and the pressure must
not exceed 4.5 bar, 65 lb/in
2.
Manual bleed procedure
Equipment required
·Clean glass receptacle
·Bleed hose
·Wrench
·Approx 2 litres (3 pints) brake fluid.
See
LUBRICANTS, FLUIDS AND CAPACITIES,
Information, Recommended lubricants and
fluids
Master cylinder bleed
1.Disconnect battery.
2.Depress brake pedal fully and slowly 5 times.
3.Release the pedal and wait for ten seconds.
4.Air bubbles will rise into the reservoir during
these instructions.
5.Repeat instructions until a firm resistance is felt
at the pedal.
Complete circuit bleed
1.Disconnect battery.
2.Bleed front calipers, driver's side first. Fit bleed
hose to bleed screw.
3.Dip free end of bleed hose into brake fluid in
bleed bottle.
4.Open bleed screw of caliper.
5.Depress brake pedal fully several times until fluid
is clear of air bubbles.
6.Keeping pedal fully depressed, tighten bleed
screw, then release pedal.
7.Repeat procedure on other front caliper followed
by rear calipers.
8.Fit all bleed screw protection caps.
9.Check/top-up fluid level when bleeding is
complete
See Fluid Level Check/Top-Up.

70BRAKES
10
REPAIR FRONT BRAKE CALIPERS
Service repair no - 70.55.05
Service repair no - 70.55.16
Before starting repair refer to general brake service
practice
See General Brake Service Practice.
Remove
1.Remove front road wheels.
2.Expose flexible brake hose by moving coiled
protective covering.
3.Using a recognised hose clamp, clamp hose to
prevent loss of brake fluid.
4.Disconnect rigid brake pipe from flexible hose,
seal exposed ends to prevent ingress of dirt.
5.Remove split pin, retaining pins and springs,
withdraw pads. If refitting pads, identify them for
assembly to original locations.
6.Remove 2 bolts and withdraw caliper from swivel
housing.
WARNING: Do not separate caliper halves
7.Clean outer surfaces of caliper using aerosol
brake cleaner.
8.Using special toolLRT-70-500, clamp pistons in
inboard half of caliper. Gently, keeping fingers
clear, and withCAUTION, apply air pressure to
fluid inlet port to expel pistons. It is unlikely that
pistons will expel at same time, regulate rate
with a suitable piece of wood between
appropriate piston and caliper.
9.Finally remove pistons, identifying them with
their respective bores.
10.Remove wiper seal retainer by inserting a blunt
screwdriver between retainer and seal. Pry
retainer carefully from mouth of bore.
11.Taking care not to damage seal grooves, extract
wiper seal and fluid seal.
12.Clean bores, pistons and seal grooves using
clean brake fluid only. If caliper or pistons are
corroded, or their condition is not perfect, new
parts must be fitted.

BRAKES
13
REPAIR REAR BRAKE CALIPERS
Service repair no - 70.55.06
Service repair no - 70.55.17
Before starting repair refer to General brake service
practice
See General Brake Service Practice.
Remove caliper
1.Remove rear road wheels.
2.Using a recognised hose clamp, clamp flexible
brake hose above rear axle.
90 Models
110/130 Models
3.Remove brake pipe from rear brake caliper.4.Seal pipe ends to prevent ingress of dirt.
5.Remove retaining pins and springs and withdraw
pads. If same pads are to be refitted, identify
them for assembly in original positions.
6.Remove 2 bolts and withdraw caliper from rear
axle.
Repair
WARNING: Do not separate caliper halves.
7.Clean outer surfaces of caliper with aerosol
brake cleaner.
8. WITH CAUTIONexpel pistons from their bores
by applying air pressure to fluid inlet port. It is
unlikely both pistons will expel at same time,
regulate rate with a suitable piece of wood
inserted between two pistons.
9.Finally, remove pistons keeping them identified
with their respective bores.
10.Remove wiper seal retainer by inserting a blunt
screwdriver between retainer and seal and pry
retainer carefully from mouth of bore.
11.Taking care not to damage seal grooves, extract
wiper seal and fluid seal.
12.Clean bores, pistons and particularly seal
grooves using clean brake fluid only. If caliper or
pistons are corroded or their condition is not
perfect new parts must be fitted.
13.Apply brake fluid to new seal. Fit seal into
groove in bore. When seal is seated it feels
raised to touch at edge furthest away from
mouth of bore.
14.Coat piston with brake fluid. Insert it squarely
into bore. Do not tilt piston during insertion and
leave 8mm projecting from bore.

WHEELS AND TYRES
1
REPAIR REV: 05/99 GENERAL INFORMATION
WARNING: This is a multi-purpose vehicle
with wheels and tyres designed for both
on and off road usage. Only use wheels
and tyres specified for use on the vehicle.
The vehicle is equipped with tubeless 'S','T' or 'H'
rated radial ply tyres as standard equipment. The
tyres are of European metric size and must not be
confused with the "P" size metric tyres available in
North America.
Vehicle wheel sets, including spare wheel, must be
fitted with the same make and type of tyre to the
correct specification and tread pattern. Under no
circumstances must cross-ply or bias-belted tyres be
used.
For tyre specification and pressures
See GENERAL
SPECIFICATION DATA, Information, Wheels and
Tyres
.
Steel wheels
Tubeless tyres are mounted on 7.0 inch wide by 16
inch diameter steel wheels.
Alloy Wheels
Tubeless tyres are mounted on 7.0 inch wide by 16
inch diameter cast aluminium alloy wheels. The
surface has a paint finish covered with a clear
polyurethane lacquer. Care must be taken when
handling the wheel to avoid scratching or chipping the
finish.
The alloy wheel rim is of the asymmetric hump
type incorporating a safety hump to improve
location of the tyre bead in its seat. If difficulty is
experienced in fitting tyres to this type of rim
See
Tyre Fitting
.
WARNING: DO NOT fit an inner tube to an
alloy wheel.TYRE INSPECTION
Inspect tyres at weekly intervals to obtain maximum
tyre life and performance and to ensure compliance
with legal requirements. Check for signs of incorrect
inflation and uneven wear, which may indicate a need
for balancing or front wheel alignment,
See Fault
diagnosis, Tyre Wear Chart
, if the tyres have
abnormal or uneven wear patterns.
Check tyres at least weekly for cuts, abrasions, bulges
and for objects embedded in the tread. More frequent
inspections are recommended when the vehicle is
regularly used in off road conditions.
To assist tyre inspection, tread wear indicators are
moulded into the bottom of the tread grooves, as
shown in the illustration above.
When the tread has worn to a depth of 1.6 mm the
indicators appear at the surface as bars which
connect the tread pattern across the width of the tread
as shown in the illustration above.

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)

AIR CONDITIONING
1
ADJUSTMENT GENERAL PRECAUTIONS
The refrigerant used in the air conditioning system is
HFC (Hydrofluorocarbon) R134a.
WARNING: R134a is a hazardous liquid
and when handled incorrectly can cause
serious injury. Suitable protective clothing
must be worn when carrying out servicing
operations on the air conditioning system.
WARNING: R134a is odourless and
colourless. Do not handle or discharge in
an enclosed area, or in any area where the
vapour or liquid can come in contact with naked
flame or hot metal. R134a is not flammable, but
can form a highly toxic gas.
WARNING: Do not smoke or weld in areas
where R134a is in use. Inhalation of
concentrations of the vapour can cause
dizziness, disorientation. uncoordination,
narcosis, nausea or vomiting.
WARNING: Do not allow fluids other than
R134a or compressor lubricant to enter the
air conditioning system. Spontaneous
combustion may occur.
WARNING: R134a splashed on any part of
the body will cause immediate freezing of
that area. Also refrigerant cylinders and
replenishment trolleys when discharging will
freeze skin to them if contact is made.
WARNING: The refrigerant used in an air
conditioning system must be reclaimed in
accordance with the recommendations
given with a Refrigerant Recovery Recycling
Recharging Station.
NOTE: Suitable protective clothing
comprises: Wrap around safety glasses or
helmet, heatproof gloves, rubber apron or
waterproof overalls and rubber boots.REMEDIAL ACTIONS
1.If liquid R134a strikes the eye, do not rub it.
Gently run large quantities of eyewash over the
eye to raise the temperature. If eyewash is not
available cool, clean water may be used. Cover
eye with clean pad and seek immediate medical
attention.
2.If liquid R134a is splashed on the skin run large
quantities of water over the area as soon as
possible to raise the temperature. Carry out the
same actions if skin comes into contact with
discharging cylinders. Wrap affected parts in
blankets or similar material and seek immediate
medical attention.
3.If suspected of being overcome by inhalation of
R134a vapour seek fresh air. If unconscious
remove to fresh air. Apply artificial respiration
and/or oxygen and seek immediate medical
attention.
NOTE: Due to its low evaporating
temperature of -30°C, R134a should be
handled with care.
WARNING: Do not allow a refrigerant
container to be heated by a direct flame or
to be placed near any heating appliance. A
refrigerant container must not be heated above
50°C.
WARNING: Do not leave a container of
refrigerant without its cap fitted. Do not
transport a container of refrigerant that is
unrestrained, especially in the boot of a car.

AIR CONDITIONING
3
ADJUSTMENT REFRIGERANT RECOVERY, RECYCLING,
RECHARGING
WARNING: The air conditioning system is
charged with a high pressure, potentially
toxic refrigerant. Repairs or servicing must
only be carried out by an operator familiar with
both the vehicle system and the charging and
testing equipment.
All operations must be carried out in a
well-ventilated area away from open flame and
heat sources.
Always wear safety goggles and gloves when
opening refrigerant connections.
WARNING: Wear eye and hand safety
protection. Open connections slowly in
case liquid or pressure is present. Allow to
bleed off slowly.
CAUTION: Overcharging air conditioning
system will cause excessive head
pressure.
An air conditioning portable Refrigerant Recovery
Recycling Recharging Station for use with R134a
refrigerant incorporates all the features necessary to
recover refrigerant R134a from the air conditioning
system, to filter and remove moisture, to evacuate and
recharge with the reclaimed refrigerant. The unit can
also be used for performance testing and air
conditioning system analysis.
The operator must adhere to the equipment
manufacturers' instructions.
Recovery and recycling
1.Connect a Refrigerant Station to the high and
low pressure servicing connections.
2.Operate the refrigerant recovery system
according to the manufacturers instructions.
3.Measure the amount of oil discharged from the
system. Add an equal amount of new refrigerant
oil to compressor before evacuation sequence.
WARNING: Refrigerant must always be
recycled before reuse, to ensure that the
purity of the refrigerant is high enough for
safe use in the air conditioning system. Recycling
should always be carried out with equipment
which is design certified by Underwriter
Laboratory Inc. for compliance with SAE-J1991.
Other equipment may not recycle refrigerant to
the required level of purity.
A R134a Refrigerant Recovery Recycling
Recharging Station must not be used with any
other type of refrigerant.
Refrigerant R134a from domestic and commercial
sources must not be used in motor vehicle air
conditioning systems.
Evacuation and recharging
1.Add refrigerant oil to compressor if necessary.
2.Renew the receiver/drier.
CAUTION: When a major repair has been
carried out, a leak test should be carried
out using inert gas.
3.Connect a Refrigerant Station to the high and
low pressure servicing connections.
CAUTION: Whenever the refrigerant
system is opened, the receiver/drier must
be renewed immediately before evacuating
and recharging the system.
4.Operate the refrigerant evacuation system
according to the manufactures instructions.
NOTE: If the vacuum reading is below
700mmHg after 15 minutes, suspect a leak
in the system. Partially recharge the
system and check for leaks using an electronic
leak tester. Check suction lines first, then run the
compressor for 5 minutes and then check the high
pressure lines.
CAUTION: The system must be Evacuated
immediately before recharging
commences. Delay between Evacuation
and Recharging is not permitted.

AIR CONDITIONING
5
ADJUSTMENT AIR CONDITIONING SYSTEM - PERFORMANCE
TEST
WARNING: R134a is hazardousSee
Repair, General Precautions
Carry out this test with bonnet and doors or windows
open, air conditioning switched on, temperature
control set to cold and blower at maximum speed. Set
the air supply control to supply fresh air.
1.Close low pressure valve on refrigerant station.
2.Close high pressure valve on refrigerant station.
3.Connect a Refrigerant Station to the high and
low pressure servicing connections.4.Insert dry bulb thermometer into cold air outlet
and position dry and wet bulb thermometer close
to outside air inlet.
Do not spill water from the wet thermometer
(psychrometer).
5.Start engine and run it at 1500 rev/min for 10
minutes with air conditioning switched on.
6.Read both pressure gauges and thermometers.
Check readings against table below with
humidity between 60% and 80%.
7.Switch off air conditioning, stop engine,
disconnect test equipment.
Performance range
Intake temperature Outlet temperature Low pressure High pressure
20 - 24°C4-10°C 18 - 28 lbf/in
2213 - 299 lbf/in2
1.2 - 1.9 bar 14.7 - 20.6 bar
25 - 29°C9-19°C 27 - 37 lbf/in2256 - 341 lbf/in2
1.9 - 2.6 bar 17.6 - 23.5 bar
30 - 35°C20-27°C 33 - 47 lbf/in2299 - 384 lbf/in2
2.3 - 3.2 bar 20.6 - 26.5 bar
Table 1
Ambient Compound Gauge High Pressure
Temperature Readings Gauge Readings
°C°F bar lbf/in
2bar lbf/in2
16 60 1,03-1,4 15-20 6,9-10,3 100-150
26,7 80 1,4-1,72 20-25 9,6-13,1 140-190
38 100 1,72-2,1 25-30 12,4-15,5 180-225
43,5 110 2,1-2,4 30-35 14,8-17,2 215-250