belt LAND ROVER DISCOVERY 1995 Owners Manual

CHASSIS AND BODY
69
REPAIR FRONT SEAT BELTS - 5 DOOR (96 MODELS)
Service repair no - 76.73.10
Remove
1.Move the seat to gain access to the seat belt
mountings.
2.Remove the cover and securing bolt to release
the upper mounting and spacer from the 'B' post
adjustable mounting.
3. Electric seats only:Release fixings securing
the seat side valance.
4.Remove the side valance.
5.Remove the Torx bolt securing the lower
mounting to the seat.
6.Detach the door seals from the 'B' post
sufficiently to allow removal of the lower trim
panel from the post.
7.Release the seat belt from the split section at the
top of the trim panel and withdraw the panel.

76CHASSIS AND BODY
70
REPAIR
8.Remove the securing bolt and detach the inertia
reel from the bottom of the 'B' post.9.Release the seat belt sensor connector (if fitted).
10.Release Torx bolt to allow removal of the seat
belt stalk assembly.
Refit
11.Reverse removal procedure.
NOTE: Ensure the seat belt is not twisted.
12.Re-connect the seat belt sensor connector (if
fitted).
13.Finally, tighten the seat belt fixings to
32 Nm (24
lbf ft)
.

AIR CONDITIONING
3
DESCRIPTION AND OPERATION AIR CONDITIONING SYSTEM OPERATION
The air conditioning system provides the means of
supplying cooled and dehumidified, fresh or
recirculated air to the interior of the vehicle. The
cooling effect is obtained by blowing air through the
matrix of an evaporator unit and when required,
mixing that air with heated air by means of the heater
distribution and blend unit, to provide the conditions
required inside the vehicle. The volume of conditioned
air being supplied is controlled by a variable speed
blower.
A sealed system, charged with Refrigerant R134a,
together with a blower unit, blend unit and control
system combine to achieve the cooled air condition.
For air conditioning air distribution system.
See
HEATING AND VENTILATION, Description and
operation, Heating and ventilation unit
The air conditioning system comprises five major
units:
1.An engine-mounted compressor.
2.A condenser mounted in front of the radiator.
3.A receiver/drier unit located in front of the
condenser.
4.Thermostatic expansion valve mounted above
the evaporator.
5.An evaporator unit mounted in front of the heater
matrix.
NOTE: Vehicles fitted with rear air
conditioning have an additional
evaporator/blower motor assembly located
behind the LH rear compartment lower trim panel.
These units are interconnected by hoses and pipes
carrying Refrigerant R134a, the evaporator is linked
into the vehicle ventilation system.
Refrigeration cycle
1. Compressor
The compressor (1), belt driven from the crankshaft
pulley, pressurises and circulates the refrigerant
through the system. Mounted on the compressor, an
electro-mechanical clutch maintains the correct
temperature and pressure by engaging or disengaging
to support the system's requirements. The clutch
action is normally controlled by a thermostat located
at the evaporator (5). The compressor is of the
swashplate type having fixed displacement.Should the temperature at the evaporator (5) fall low
enough for ice to begin to form on the fins, the
thermostat disengages the clutch and also isolates the
cooling fans relays. When the temperature at the
evaporator (5) rises to the control temperature, the
clutch is re-engaged.
Should the system pressure become excessive or
drop sufficiently to cause damage to the compressor
(1) a dual pressure switch (7), located in the high
pressure line, signals the relay unit to disengage the
clutch. The compressor also has an emergency high
pressure relief valve (9) fitted.
The cooling fans are controlled by engine temperature
when the air conditioning is not switched on.
2. Condenser
From the compressor, hot high pressure vaporised
refrigerant (F1) passes to the condenser (2), which is
mounted in front of the engine coolant radiator. Ram
air(A1) passing through the condenser (2),
supplemented by 2 cooling fans (8) mounted in front
of the condenser, cools the refrigerant vapour
sufficiently to form a high pressure slightly subcooled
liquid (F2).
3. Receiver/drier
This liquid then passes to a receiver/drier (3) which
fulfils two functions. It acts as a reservoir and moisture
extractor (11).
A sight glass (10), in the high pressure line, provides a
method of determining the state of the refrigerant
without breaking into the system.
4. Expansion valve
From the receiver/drier (3) the moisture free high
pressure liquid refrigerant (F3) passes through a
thermostatic expansion valve (4). A severe pressure
drop occurs across the valve and as the refrigerant
enters the evaporator space at a temperature of
approximately -5°C it boils and vaporises.

AIR CONDITIONING
1
FAULT DIAGNOSIS AIR CONDITIONING FAULTS
FAULT CAUSE REMEDY
1. Incorrect voltage. 1. Check voltage.
A.2. Open or defective fuse or relay. 2. Check and replace as necessary.
BLOWER3. Loose wire connection including 3. Check system wires; tighten
MOTORground. all connections.
INOPERATIVE4. Switch open or defective. 4. Replace switch.
OR SLOW5. Tight, worn, or burnt motor 5. Replace motor.
RUNNINGbearings.
6. Open rotor windings. 6. Replace motor.
7. Worn motor brushes. 7. Replace motor.
8. Shaft binding-blade misaligned. 8. Check alignment. Repair or replace
as necessary.
9. Defective resistors 9. Rectify or replace.
1. Incorrect voltage. 1. Check voltage.
2. Open or defective fuse or relay. 2. Check and replace as necessary.
B.3. Defective thermostat control or 3. Replace thermostat or
COMPRESSORpressure switch. pressure switch.
CLUTCH4. Shorted or open field coil. 4. Replace coil.
INOPERATIVE5. Bearing seized (clutch will not 5. Replace clutch pulley assembly.
disengage).
6. Refrigeration circuit problem causing
heavy load and excessive drive
torque.6. Check and rectify.
1. Incorrect alignment. 1. Check alignment; repair as
necessary.
2. Loose belt. 2. Adjust to proper tension.
C.3. Compressor not mounted securely. 3. Repair as necessary.
COMPRESSOR4. Bearing in clutch-pulley 4. Remove clutch and replace
CLUTCHassembly not pressed in. clutch pulley assembly.
NOISY5. Low voltage to clutch. 5. Check connections and voltage.
6. Clutch will not spin freely. 6. Refer to B5 above.
7. Oil on clutch face. 7. Check compressor seals for leaks.
8. Slipping clutch. 8. Refer to C5 above. Then check air
gap.
9. Overloaded or locked compressor. 9. Repair or replace compressor.
10. Icing. 10. Check for suction line frosting.
Replace expansion valve if
necessary.
Replace receiver/drier if necessary.
D.1. Motor and/or blades improperly 1. Check mountings, adjust as
CONDENSERmounted. necessary.
VIBRATION2. Foreign matter build-up on 2. Clean blades with a suitable
blades. non-inflammable cleaner.
3. Excessive wear of motor bearings. 3. Replace motor.

82AIR CONDITIONING
2
FAULT DIAGNOSIS REFRIGERATION SYSTEM FAULTS
For any refrigeration system to function properly all
components must be in good working order. The unit
cooling cycle and the relationship between air
discharge temperature and ambient temperature and
the pressures at the compressor can help to
determine proper operation of the system.
The length of any cooling cycle is determined by such
factors as ambient temperature and humidity,
thermostat setting, compressor speed and air leakage
into the cooled area, etc. With these factors constant,
any sudden increase in the length of the cooling cycle
would be indicative of abnormal operation of the air
conditioner.
The low and high side pressures at the compressor
will vary with changing ambient temperature, humidity,
in-car temperature and altitude.
The following items should be checked before
operating the system:
1.Compressor drive belt tension.
2.Compressor magnetic clutch operation.
3.Condenser fan operation.
4.Condenser fins, dirt will cause poor cooling and
higher operating temperatures.The following conditions should be checked after
operating the system for several minutes:
1.All high pressure lines and components should
be hot to the touch.
2.All low pressure lines should be cool to the
touch.
3.Inlet and outlet temperatures at the receiver/drier
should be at the same temperature (warm). Any
very noticeable temperature difference indicates
a blocked receiver/drier.
4.Heavy frost on the inlet to the expansion valve
may indicate a defective valve or moisture in the
system.
5.Evaporation air temperature will vary with
ambient temperature and humidity. As humidity
increases the outlet temperature will be higher.

AIR CONDITIONING
3
FAULT DIAGNOSIS FAULT CAUSE REMEDY
1. Overcharge of refrigerant. 1. Discharge, evacuate and charge
system.
A.
HIGH HEAD2. Air in system. 2. Discharge system, fit new drier,
PRESSUREevacuate and charge system.
3. Condenser air passage clogged 3. Clean condenser of debris.
with dirt or other foreign matter.
4. Condenser fan motor defective. 4. Replace motor.
5. Incorrect voltage to fan motor. 5. Check voltage.
1. Undercharge of refrigerant; 1. Evacuate and charge system.
B.evident by bubbles in sight Check for leakage.
LOW HEADglass while system is operating
PRESSURE2. Split compressor gasket or 2. Replace gasket and/or reed
leaking valves. valve. Fit new drier, evacuate and
charge system.
3. Defective compressor. 3. Repair or replace compressor.
1. Loose drive belt 1. Check belt tension.
2. Refrigerant flooding through
evaporator into suction line; evident
by ice on suction line and suction
service valve.2. Check thermobulb. Bulb should be
securely clamped to clean horizontal
section of copper suction pipe.
C.3. Expansion valve stuck open. 3. Replace expansion valve.
HIGH4. Leaking compressor valves, 4. Replace valves and/or
SUCTIONvalve gaskets and/or service gaskets. Fit new drier
PRESSUREvalves. evacuate and charge system.
5. Receiver/drier blocked; evident 5. Fit new drier, evacuate
by temperature difference and charge system.
between input and output lines.
1. Expansion valve thermobulb not 1. Warm thermobulb with hand.
operating. Suction should rise rapidly to 1.4 bar
20 lb/in
2or more. If not replace
expansion valve.
2. Expansion valve sticking closed. 2. Check inlet side screen.
D.Clean if clogged. Refer
LOWto C-2 and C-3.
SUCTION3. Moisture freezing in expansion valve
orifice. Valve outlet tube will frost
while inlet hose tube will have little or
no frost. System operates
periodically.3. Fit new drier, evacuate and charge
system.
4. Dust, paper scraps, or other debris
restricting evaporator blower grille4. Clean grilles as required.
5. Defective evaporator blower motor,
wiring, or blower switch.5. Refer to Fault Diagnosis Chart for
blower motor.

82AIR CONDITIONING
4
FAULT DIAGNOSISFAULT CAUSE REMEDY
E.
NOISY
EXPANSION
VALVE
(steady hissing)1. Low refrigerant charge; evident by
bubbles in sight glass.1. Leak test. Repair or replace
components as required.
F.1. Expansion valve not operating 1. Refer to C-2, C-3, D-1
INSUFFICIENTproperly. and E.
COOLING2. Low refrigerant charge-evident 2. Refer to B-1 and E.
by bubbles in sight glass.
3. Compressor not pumping. 3. Refer to B-2 and B-3
G.1. Belt tension. 1. Adjust belt tension.
COMPRESSOR2. Excessive head pressure. 2. Refer to A-1 through
BELTA-4 and C-6.
SLIPPING3. Incorrect alignment of pulleys 3. Repair as needed.
or worn belt not riding properly.
4. Nicked or broken pulley. 4. Replace as needed.
5. Seized compressor. 5. Replace compressor.
1. Loose or missing mounting bolts. 1. Repair as necessary.
2. Broken mounting bracket. 2. Replace bracket.
3. Loose flywheel or clutch 3. Repair as necessary.
retaining bolt.
H.4. Rough idler pulley bearing. 4. Replace bearing.
ENGINE5. Bent, loose, or improperly 5. Repair as necessary.
NOISEmounted engine drive pulley.
AND/OR6. Defective compressor bearing. 6. Replace bearing.
VIBRATION7. Insecure mountings of 7. Repair as necessary.
accessories; generator, power
steering, air filter, etc.
8. Excessive head pressure. 8. Refer to A-1, A-2, A-3
A-4 and C-6.
9. Incorrect compressor oil level. 9. Refer to compressor Oil
Level Check.
HEATER AND AIR CONDITIONING - CIRCUIT
DIAGRAMS
1.For details of heating and air conditioning
electrics
See Electrical Trouble Shooting
Manual.

82AIR CONDITIONING
6
ADJUSTMENT SYSTEM TEST
1.Place the vehicle in a ventilated, shaded area
free from excessive draught, with the doors and
windows open.
2.Check that the surface of the condenser is not
restricted with dirt, leaves, flies, etc. Do not
neglect to check the surface between the
condenser and the radiator. Clean as necessary.
3.Switch on the ignition and the air conditioner air
flow control. Check that the blower is operating
efficiently at low, medium and high speeds.
Switch off the blower and the ignition.
4.Check that the evaporator condensate drain
tubes are open and clear.
5.Check the tension of the compressor driving belt,
and adjust if necessary.
6.Inspect all connections for the presence of
refrigerant oil. If oil is evident, check for leaks,
and repair as necessary.
NOTE: The compressor oil is soluble in
Refrigerant R134a and is deposited when
the refrigerant evaporates from a leak.
7.Start the engine.
8.Set the temperature controls to cold and switch
the air conditioner blower control on and off
several times, checking that the magnetic clutch
on the compressor engages and releases each
time.9.With the temperature control at maximum
cooling and the blower control at high speed,
warm up the engine and fast idle at 1000
rev/min. Check the sight glass for bubbles or
foam. The sight glass should be generally clear
after five minutes running, occasional bubbles
being acceptable. Continuous bubbles may
appear in a serviceable system on a cool day, or
if there is insufficient air flow over the condenser
at a high ambient temperature.
10.Repeat at 1800 rev/min.
11.Gradually increase the engine speed to the high
range, and check the sight glass at intervals.
12.Check for frosting on the service valves.
13.Check the high pressure hoses and connections
by hand for varying temperature. Low
temperature indicates a restriction or blockage at
that point.
14.Switch off the air conditioning blower and stop
the engine.
15.If the air conditioning equipment is still not
satisfactory, carry out a pressure test as
previously described in this section.
COMPRESSOR DRIVE BELT
Service repair no - 82.10.01.
Tdi -
See ENGINE, Repair, Compressor drive belt
V8i and MpiSee ENGINE, Repair, Drive belt

82AIR CONDITIONING
2
REPAIR 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 and Receiver/Drier
Examine the sight glass for bubbles with the system
operating. Check connections for leakage.
Evaporator
Examine the refrigeration connections at the unit. If
the system should develop a fault, or if erratic
operation is noticed,
See Fault diagnosis,
Refrigeration System Faults
RECEIVER DRIER
Service repair no - 82.17.01
Remove
CAUTION: If receiver/drier is to be refitted,
the ports must be blanked off immediately
on disconnection. Exposed life of unit is
only 15 minutes.
1.Disconnect battery negative lead.
2.Recover refrigerant from system.
See
Adjustment, Refrigerant Recovery Recycling
Recharging
WARNING: Wear eye and hand protection
when disconnecting components
containing refrigerant. Plug all exposed
connections immediately.
3.Remove 3 screws from bonnet locking platform
and remove radiator grille.
Automatic gearbox
4.Remove 4 bolts securing transmission oil cooler
to body.

AIR CONDITIONING
5
REPAIR COMPRESSOR
Service repair no - 82.10.20
Remove
1.Disconnect battery negative lead.
2.Recover refrigerant from air conditioning system.
See Adjustment, Refrigerant Recovery
Recycling Recharging
3.Remove screws retaining centre panel to fan
cowl
4.Remove centre panel.
V8i engine illustrated
5.Remove 2 bolts securing hose flanges to
compressor.
WARNING: Wear eye and hand protection
when disconnecting components
containing refrigerant. Plug all exposed
connections immediately.6.Disconnect high pressure hose from
compressor.
7.Disconnect low pressure hose from compressor.
8.Remove 'O' ring from each flange.
9.Disconnect electrical lead from compressor
clutch.
10.Release drive belt from compressor pulley.
See
ENGINE, Repair, Drive Belt
11.Remove 4 bolts securing compressor to
mounting bracket.
12.Remove compressor from mounting bracket.
Refit
13.New compressor to be fitted: Drain oil from new
compressor outlet port. Drain and measure oil
from old compressor. Measure new oil equal to
amount drained from old compressor, add 30 ml
extra to this amount and refill new compressor
through outlet port.
14.Locate compressor in mounting bracket, fit bolts.
Tighten to
25 Nm.
15.Connect electrical lead to compressor clutch.
16.Fit new 'O' rings to high and low pressure hose
flanges, lubricate with refrigerant oil.
17.Engage hose flanges, fit bolts. Tighten to
10
Nm.
18.Fit compressor drive belt.See ENGINE, Repair,
Drive Belt
19.Fit centre panel to fan cowl.
20.Evacuate and recharge air conditioning system.
See Adjustment, Refrigerant Recovery
Recycling Recharging
21.Perform a leak test on disturbed joints.
22.Carry out a functional check.