Discovery 2. Manual — part 8

GENERAL INFORMATION

03-25

Service precautions
Observe the following precautions when handling
components used in the air conditioning system:

l

Air conditioning units must not be lifted by their
hoses, pipes or capillary lines.

l

Hoses and lines must not be subjected to any
twist or stress; the efficiency of the system will
be impaired by kinks or restrictions. Ensure that
hoses are correctly positioned before tightening
couplings, and ensure that all clips and supports
are utilised.

l

Flexible hoses should not be positioned close to
the exhaust manifold (less than 100mm) unless
protected by heat shielding.

l

Completed assemblies must be checked for
refrigeration lines touching metal panels. Any
direct contact of components and panels may
transmit noise and so must be eliminated.

l

The appropriate torque wrench must be used
when tightening refrigerant connections to the
stipulated value. An additional spanner must be
used to hold the union to prevent twisting of the
pipe when tightening connections.

l

Before connecting any hose or pipe, ensure that
refrigerant oil is applied to the seat of the new 'O'
rings, BUT NOT to the threads of the
connection.

l

All protective plugs must remain in place to seal
the component until immediately prior to
connection.

l

Ensure components are at room temperature
before uncapping, to prevent condensation of
moisture from the air that enters it.

l

Components must not remain uncapped for
longer than 15 minutes. In the event of a delay,
the caps must be fitted.

l

When disconnecting, immediately cap all air
conditioning pipes to prevent ingress of dirt and
moisture into the system.

l

The receiver/drier contains desiccant which
absorbs moisture. It must be positively sealed at
all times. A receiver/drier that has been left
uncapped must not be used, fit a new unit.

l

The receiver/drier should be the last component
connected to the system to ensure optimum
dehydration and maximum moisture protection
of the system.

l

Whenever the refrigerant system is opened, the
receiver/drier must be renewed immediately
before evacuating and recharging the system.

l

Use alcohol and a clean lint-free cloth to clean
dirty connections.

l

Ensure that all new parts fitted are marked for
use with R134a.

When a major repair has been completed, a leak test
should be conducted; refer to the Air Conditioning
section of this manual for the correct procedure.

Refrigerant oil
Refrigerant oil easily absorbs water and must not
be stored for long periods. Do not pour unused
refrigerant oil back into the container. Always
use an approved refrigerant oil.

+

CAPACITIES, FLUIDS, LUBRICANTS

AND SEALANTS, Lubrication.

When replacing components in the A/C system,
drain the refrigerant oil from the component being
replaced into a graduated container. On assembly,
add the quantity of refrigerant oil drained to the new
component.

Compressor
A new compressor is sealed and pressurised with
Nitrogen gas. When fitting a new compressor, slowly
release the sealing cap; gas pressure should be
heard to vent as the seal is broken.

CAUTION: A new compressor should always be
sealed and could be pressurised with nitrogen
gas. To avoid possible oil loss, release the
sealing cap(s) slowly. Do not remove the cap(s)
until immediately prior to connecting the air
conditioning pipes to the compressor.

Rapid refrigerant discharge
If the air conditioning system is involved in accident
damage and the system is punctured, the refrigerant
will discharge rapidly. The rapid discharge of
refrigerant will also result in the loss of most of the oil
from the system. The compressor must be removed
and all the remaining oil in the compressor drained
and refilled as instructed in the air conditioning
section of this manual.

GENERAL INFORMATION

03-26

Precautions for refrigerant recovery, recycling
and recharging
When the air conditioning system is recharged, any
existing refrigerant is first recovered from the system
and recycled. The system is then charged with the
required weight of refrigerant and volume of
refrigerant oil.

WARNING: Refrigerant must always be recycled
before re-use 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.

CAUTION: The system must be evacuated
immediately before recharging commences.
Delay between evacuation and recharging is not
permitted.

Air Conditioning Compressor
Replacement

A new compressor is supplied filled with a full charge
(X cm

3

) of refrigerant oil.

+

CAPACITIES, FLUIDS, LUBRICANTS

AND SEALANTS, Capacities.A calculated quantity
of oil must be drained from the new compressor
before fitting. To calculate the quantity of oil to be
drained:

1 Remove the drain plug from the old

compressor.

2 Invert the compressor and gravity drain the oil

into a calibrated measuring cylinder. Rotate the
compressor clutch to ensure the compressor is
completely drained.

3 Note the quantity of oil drained (Y cm

3

).

4 Calculate the quantity of oil to be drained from

the new compressor using the following
formula:

X cm

3

— (Y cm

3

+ 20 cm

3

) = Q cm

3

5 Remove the drain plug from the new

compressor and drain Q cm

3

of oil. Fit and

tighten the compressor drain plug.

GENERAL INFORMATION

03-27

Body Repairs

General
Body shells are of welded construction and bolted to
a chassis frame. Front and rear sections of the shell
are designed as 'energy absorbing' zones. This
means they are designed to deform progressively
when subjected to impact in order to minimise the
likelihood of injury to vehicle occupants.

It is essential that design dimensions and strength
are restored in accident rectification. It is important
that neither structural weakness nor excessive local
stiffness are introduced into the vehicle during body
repair.

Repairs usually involve a combination of operations
ranging from straightening procedures to renewal of
individual panels or panel assemblies. The repairer
will determine the repair method and this decision will
take into account a balance of economics between
labour and material costs and the availability of repair
facilities in both equipment and skills. It may also
involve considerations of the vehicles' downtime,
replacement vehicle availability and repair turn-
around time.

It is expected that a repairer will select the best and
most economic repair method possible, making use
of the facilities available. The instructions given are
intended to assist a skilled body repairer by
expanding approved procedures for panel
replacement. The objective is to restore the vehicle
to a safe running condition by carrying out a repair
which is as close as is feasible to original standard.
The results should not advertise to the experienced
eye that the vehicle has been damaged, although the
repair might not be identical in all respects to the
original factory build. Commercial bodyshop repair
facilities cannot always duplicate methods of
construction used during production.

Operations covered in this Manual do not include
reference to testing the vehicle after repair. It is
essential that work is inspected and suspension
geometry checked after completion. Where
necessary a road test of the vehicle should be carried
out, particularly where safety-related items are
concerned.

Where major units have been disconnected or
removed it is necessary to ensure that fluid levels are
checked and topped up where necessary. It is also
necessary to ensure that the repaired vehicle is in a
roadworthy condition in respect of tyre pressures,
lights, washer fluid etc.

Body repairs often involve the removal of mechanical
and electrical units and associated wiring. Where
necessary, refer to the relevant section of the
Workshop Manual for removal and refitting
instructions.

Taking into consideration the differences in body
styles, suspension systems and engine and
transmission layouts, the location of the following
components as applicable to a particular vehicle is
critical:

l

Front suspension upper damper mountings on
RH and LH chassis longitudinals.

l

Front suspension or sub frame mountings.

l

Engine mountings on RH and LH chassis
longitudinals.

l

Rear suspension upper damper mountings on
RH and LH chassis longitudinals.

l

Rear suspension mountings or lower pivots.

Additional points which can be used to check
alignment and assembly are:

l

Inner holes in cross member - side - main floor.

l

Holes in front bulkhead.

l

Holes in rear longitudinals.

l

Holes in rear lower panels.

Apertures for windscreen, rear screen, bonnet and
doors can be measured and checked using the
dimensional information provided and also by
offering up an undamaged component as a gauge.

Straightening
Whenever possible, structural members should be
cold straightened under tension. Do not attempt to
straighten with a single pull but rework the damaged
area using a series of pulls, releasing tension
between each stage and using the opportunity to
check alignment.

Body jig
Unless damage is limited to cosmetic panels, all
repair work to body members must be carried out on
a body jig, to ensure that impact damage has not
spread into more remote parts of the structure.
Mounting on a jig will also ensure that the
straightening and panel replacement procedures do
not cause further distortion.

If original dimensions cannot be satisfactorily
restored by these methods, damaged structural
members should be replaced. Damaged areas
should be cut away using a high speed saw, NOT an
oxy-acetylene torch.

As a rule, body dimensions are symmetrical about
the centre line. A good initial check for distortion is
therefore to measure diagonally and to investigate
apparent differences in dimensions.

GENERAL INFORMATION

03-28

Inspection
Every accident produces individual variations in
damage. Each repair is influenced by the extent of
the damage and the facilities and equipment
available for its rectification.

Most accident damage can be visually inspected and
the approximate extent of damage assessed.
Sometimes deformation will extend beyond the
directly damaged area, and the severity of this must
be accurately established so that steps can be taken
to restore critical body components to their original
dimensions. An initial check can be carried out by
means of drop checks or, preferably, trammels.
Gauges are available which will accurately check for
body twist.