service LAND ROVER DISCOVERY 1999 Repair Manual

RESTRAINT SYSTEMS
75-8 DESCRIPTION AND OPERATION
Diagnostic and Control Unit (DCU)
The SRS DCU is an electronic single point crash sensor. It is capable of sensing if a crash has taken place. If all the
relevant parameters are met, then the DCU deploys the airbag(s) and seat belt pretensioners.
The DCU is bolted to the transmission tunnel beneath the centre console in the area of the handbrake.
The DCU performs the following functions:
lInternal self test, system monitoring and fault detection.
lSRS warning lamp operation.
lSystem deployment.
Self test, system monitoring and fault detection
The DCU performs a self-test during start-up and then continually during operation of the system. The following
components are tested:
lThe decelerometer.
lThe electromechanical safing sensor.
lThe microprocessor.
lThe continuity of squib ignition circuits.
lThe SRS warning lamp.
If the DCU detects a fault, it stores the fault code in memory. Diagnose the DCU with TestBook. The DCU cannot
be serviced. It must be replaced if it is faulty.
SRS warning lamp operation
The DCU controls the SRS warning lamp contained in the instrument cluster.
System deployment
The DCU determines when the system deploys based on inputs from both the decelerometer and the
electromechanical safing sensor. Both are located within the DCU. Neither are serviceable.
The electromechanical safing sensor uses a magnet and ball bearing system to provide a mechanical confirmation of
vehicle deceleration. The ball bearing is held in place by the magnet. The strength of the magnet is calibrated such
that the force required for the ball bearing to move away from the magnet will only occur if the vehicle decelerates
suddenly, as in an accident.
The SRS deploys only if both the decelerometer reading and the safing sensor operation occur at the same time.

RESTRAINT SYSTEMS
75-24 REPAIRS
DCU
$% 76.74.06
WARNING: It is imperative that before any work
is undertaken on the SRS system the appropriate
information is read thoroughly.
WARNING: Always disconnect both battery leads
before beginning work on the SRS system.
Disconnect the negative battery lead first. Never
reverse connect the battery.
Remove
1.Remove the key from the starter switch.
Disconnect both battery leads, negative lead
first. Wait ten minutes before starting work.
2.Remove centre console.
lOn manual gearbox models:

+ INTERIOR TRIM COMPONENTS,
REPAIRS, Console - centre - manual
models.
lOn automatic gearbox models:

+ INTERIOR TRIM COMPONENTS,
REPAIRS, Console - centre - automatic
models.
3.Disconnect multiplug from DCU.
4.Remove 3 Torx bolts securing DCU to body and
remove DCU.
CAUTION: The SRS diagnostic control unit
is a non-serviceable component and no
attempt should be made to repair or modify
the unit.Refit
CAUTION: The SRS diagnostic control unit
is a shock sensitive device and must be
handled with extreme care.
1.Position DCU to body and connect multiplug.
2.Fit and tighten DCU Torx bolts to 10 Nm (7
lbf.ft).
3.Fit centre console.
lOn manual gearbox models:

+ INTERIOR TRIM COMPONENTS,
REPAIRS, Console - centre - manual
models.
lOn automatic gearbox models:

+ INTERIOR TRIM COMPONENTS,
REPAIRS, Console - centre - automatic
models.
4.Connect battery leads, earth lead last.

SCREENS
76-4-4 REPAIRS
15.Apply a continuous bead of sealant to sealant
face on screen as shown.
16.With assistance, lift screen into place and align
to screen supports and tape. Ensure top
finisher is located into correct position. Lightly
press glass to fully seat sealer.
CAUTION: Do not apply heavy pressure to
the sides of the windscreen. Lightly press
windscreen from centre outwards until
edges are to required gap. Pushing sides
into position can bend windscreen and lead
to cracking in service.
17.Remove protective covers and tape.
18.Test sealer for leaks, apply additional sealer if
necessary. If water is used, allow sealer to dry
before testing. Spray water around glass and
check for leaks. Mark any area that leaks. Dry
glass and sealer then apply additional sealer.
19.Fit interior mirror to slug.
20.If applicable, connect screen heater multiplugs.
21.Fit air intake plenum.

+ HEATING AND VENTILATION,
REPAIRS, Plenum Air Intake.
CAUTION: A curing time of 6 hours is
desirable. During this time leave a window
open to ventilate the vehicle interior. If the
vehicle must be used before the curing time
has elapsed, do not drive at speed or slam
the doors with the windows closed.
CAUTION: Vehicles fitted with a passenger
airbag should not be driven for 24 hours.
Glass - body side - rear
$% 76.81.18
Introduction
The following equipment is required:
lCutting wire and handles.
lKent cutting knife.
lGlazing knife.
lWindscreen repair kit.
lSealant applicator gun.
lSuction cups.
lA felt covered table or stand to support glass.
WARNING: Wear protective gloves when
handling glass, solvents and primers.
WARNING: Wear suitable eye protection when
removing and refitting glass.
Remove
1.If fitted, disconnect coaxial cable from terminal
on glass.
2.Fit protection to exterior body work adjacent to
glass.
3.Cover body panels adjacent to glass.
4.Fit protection to internal trim adjacent to glass.
5.Cover interior of vehicle with protective sheet.

SEATS
DESCRIPTION AND OPERATION 76-5-7
Lumbar pump
The lumbar pump inflates a bladder in the squab which provides extra support for the seat occupant. With no load on
the seat it takes approximately 10 seconds to completely inflate the bladder. With a load of 25 kg (55 lb) it takes
approximately 15 seconds to inflate the bladder. A pressure cut off switch in the system will operate at 0.12 to 1.93
bar (1.8 to 28 lbf.in
2). If a problem occurs with the lumbar bladder, e.g. a rupture, the whole lumbar system must be
replaced. The components are not serviceable.
Power comes from the seat switch pack through a 3A fuse in the satellite fuse box. The lumbar pump and the lumbar
deflate solenoid share an earth.
Lumbar deflate solenoid
The lumbar deflate solenoid vents the lumbar bladder to atmosphere to allow air to evacuate the bladder. The average
time to evacuate the bladder with a load of 25 kg (55 lb) is 9 seconds.
Power comes from the seat switch pack through a 3A fuse in the satellite fuse box. The lumbar deflate solenoid and
the lumbar pump share an earth.

PANEL REPAIRS
77-2-12 REPLACEMENT PANELS
Replacement panels
The previous illustrations show some of the service panels which feature in the Body Repairs procedures. Additional
panels and full body shells are also available. See Parts Fiche for details.

BODY SEALING MATERIALS
MATERIALS AND APPLICATIONS 77-3-5
Cooper Pegler Falcon Junior Pneumatic Gun (Airless)
Intended primarily for applying transit wax, this pneumatic sprayer has a 5-litre container with integral hand pump and
provides an effective means of wax spraying without the need for compressed air or additional services.
A selection of nozzles, lances, hose lengths and a trigger valve assembly with integral filter allows flexibility in use.
Additional applications include general maintenance, wax injection and paint application. Heavy-bodied materials
may also be applied. All parts are fully replaceable and a wide range of nozzle configurations is available.
SATA Schutz Gun Model UBE
The SATA Schutz Gun is approved for the retreatment of vehicle underbody areas with protective coatings as
supplied in 1 litre, purpose-designed 'one-way' containers. The screw thread fitting (female on the gun) is standard
to most Schutz-type packs.
SATA HKD1 Wax Injection Injection Equipment
This equipment is approved for carrying out cavity wax re-treatment. The SATA HKD1 set comprises a high quality
forged gun with 1-litre pressure feed container, a flexible nylon lance, a straight 1100 mm (43.307 in) steel lance and
hooked- wand lance. A quick-change coupling is provided as a standard fitting to allow lances to be easily
interchanged. Each lance has an integral, machined nozzle with specialised spray characteristics to suit the type of
box section to be treated.
NOTE: Always clean gun after use with appropriate solvent to maintain efficiency.
Specifications of Model UBE:
Air consumption 7 ft
3/min (200 litres/min) @ 45 lbf.in2
Weight: 23.3oz (220 grams)

CORROSION PREVENTION AND SEALING
77-4-6 CORROSION PREVENTION
Corrosion prevention
Factory treatments
During production, vehicle bodies are treated with the following anti-corrosion materials:
lA PVC-based underbody sealer which is sprayed onto the underside of the main floor, rear floor, front and rear
wheelarches and the front valance assembly;
lAn application of cavity wax which is sprayed into the sill panels, 'A' post, 'B-C' post, fuel filler aperture, body rear
panel and the lower areas of the door panels;
lA coating of underbody wax which is applied to the entire underbody inboard of the sill vertical flanges, and
covers all moving and flexible components EXCEPT for wheels, tyres, brakes and exhaust;
lA coat of protective wax applied to the engine bay area.
Whenever body repairs are carried out, ensure the anti-corrosion materials in the affected area are repaired or
renewed as necessary using the approved materials.

+ BODY SEALING MATERIALS, MATERIALS AND APPLICATIONS, Approved materials.
Precautions during body repairs and handling
Take care when handling the vehicle in the workshop. Underbody sealers, seam sealers, underbody wax and body
panels may be damaged if the vehicle is carelessly lifted.

+ LIFTING AND TOWING, LIFTING.
Proprietary anti-corrosion treatments
The application of proprietary anti-corrosion treatments, in addition to the factory-applied treatment, could invalidate
the Corrosion Warranty and should be discouraged. This does not apply to Rover approved, compatible, preservative
waxes which may be applied on top of existing coatings.
Fitting approved accessories
When fitting accessories ensure that the vehicle's corrosion protection is not affected, either by breaking the protective
coating or by introducing a moisture trap.
Do not screw self-tapping screws directly into body panels. Fit suitable plastic inserts to the panel beforehand. Always
ensure that the edges of holes drilled into panels, chassis members and other body parts are protected with a suitable
zinc rich or acid etch primer, and follow with a protective wax coating brushed onto the surrounding area.
Do not attach painted metal surfaces of any accessory directly to the vehicle's bodywork unless suitably protected.
Where metal faces are bolted together always interpose a suitable interface material such as weldable zinc rich
primer, extruded strip, or zinc tape.
Steam cleaning and dewaxing
Due to the high temperatures generated by steam cleaning equipment, there is a risk that certain trim components
could be damaged and some adhesives and corrosion prevention materials softened or liquified.
Adjust the equipment so that the nozzle temperature does not exceed 90° C (194° F). Take care not to allow the steam
jet to dwell on one area, and keep the nozzle at least 300 mm (11.811 in) from panel surfaces.
DO NOT remove wax or lacquer from underbody or underbonnet areas during repairs. Should it be necessary to
steam clean these areas, apply a new coating of wax or underbody protection as soon as possible.
Inspections during maintenance servicing
It is a requirement of the Corrosion Warranty that the vehicle body is checked for corrosion by an authorised Land
Rover Dealer at least once a year, to ensure that the factory-applied protection remains effective.
Service Job Sheets include the following operations to check bodywork for corrosion:
lWith the vehicle on a lift, carry out visual check of underbody sealer for damage;
lWith the vehicle lowered, inspect exterior paintwork for damage and body panels for corrosion.
It will be necessary for the vehicle to be washed by the Dealer prior to inspection of bodywork if the customer has
offered the vehicle in a dirty condition.

CORROSION PREVENTION AND SEALING
CORROSION PREVENTION 77-4-7
The checks described above are intended to be visual only. It is not intended that the operator should remove trim
panels, finishers, rubbing strips or sound-deadening materials when checking the vehicle for corrosion and paint
damage.
With the vehicle on a lift, and using an inspection or spot lamp, visually check for the following:
lCorrosion damage and damaged paintwork, condition of underbody sealer on front and rear lower panels, sills
and wheel arches;
lDamage to underbody sealer. Corrosion in areas adjacent to suspension mountings and fuel tank fixings.
NOTE: The presence of small blisters in the underbody sealer is acceptable, providing they do not expose bare metal.
Pay special attention to signs of damage caused to panels or corrosion protection material by incorrect jack
positioning.
WARNING: It is essential to follow the correct jacking and lifting procedures.
With the vehicle lowered, visually check for evidence of damage and corrosion on all visible painted areas, in
particular the following:
lFront edge of bonnet;
lVisible flanges in engine compartment;
lLower body and door panels.
Rectify any bodywork damage or evidence of corrosion found during inspection as soon as is practicable, both to
minimise the extent of the damage and to ensure the long term effectiveness of the factory-applied corrosion
prevention treatment. Where the cost of rectification work is the owner's responsibility, the Dealer must advise the
owner and endorse the relevant documentation accordingly.
Where corrosion has become evident and is emanating from beneath a removable component (e.g. trim panel,
window glass, seat etc.), remove the component as required to permit effective rectification.
Underbody protection repairs
Whenever body repairs are carried out, ensure that full sealing and corrosion protection treatments are reinstated.
This applies both to the damaged areas and also to areas where protection has been indirectly impaired, as a result
either of accident damage or repair operations.
Remove corrosion protection from the damaged area before straightening or panel beating. This applies in particular
to panels coated with wax, PVC underbody sealer, sound deadening pads etc.
WARNING: DO NOT use oxy-acetylene gas equipment to remove corrosion prevention materials. Large
volumes of fumes and gases are liberated by these materials when they burn.
NOTE: Equipment for the removal of tough anti-corrosion sealers offers varying degrees of speed and effectiveness.
The compressed air-operated scraper (NOT an air chisel) offers a relatively quiet mechanical method using an
extremely rapid reciprocating action. Move the operating end of the tool along the work surface to remove the material.
The most common method of removal is by means of a hot air blower with integral scraper.
Another tool, and one of the most efficient methods, is the rapid-cutting 'hot knife'. This tool uses a wide blade and is
quick and versatile, able to be used easily in profiled sections where access is otherwise difficult.
Use the following procedure when repairing underbody coatings:
1Remove existing underbody coatings
2After panel repair, clean the affected area with a solvent wipe, and treat bare metal with an etch phosphate
material
3Re-prime the affected area
CAUTION: DO NOT, under any circumstances, apply underbody sealer directly to bare metal surfaces.
4Replace all heat-fusible plugs which have been disturbed. Where such plugs are not available use rubber
grommets of equivalent size, ensuring that they are embedded in sealer
5Mask off all mounting faces from which mechanical components, hoses and pipe clips, have been removed.
Underbody sealer must be applied before such components are refitted
6Brush sealer into all exposed seams
7Spray the affected area with an approved service underbody sealer
8Remove masking from component mounting faces, and touch-in where necessary. Allow adequate drying time
before applying underbody wax

CORROSION PREVENTION AND SEALING
77-4-14 SEALING
Seam sealer - doors. Seams symmetrically opposite to those shown are also treated. Ensure drain holes in doors are
not blocked by sealant.
A heat cured, PVC based sealant is applied to specific joint seams during factory assembly. This material is not
suitable for service use and, during repair, should be substituted by an approved Seam Sealer.

+ BODY SEALING MATERIALS, MATERIALS AND APPLICATIONS, Approved materials.
Seams to which seam sealer is applied during factory assembly are detailed in the previous illustrations.
Apply seam sealers after the application of primer and before the application of surfacer and top coat. The seam
sealer must form a continuous bead, with the profile of the bead dependant on the type of seam. If seam sealer is
applied with a brush, take particular care to maintain the required coverage of the seam. Where shaping of the seam
sealer is required, use a cloth soaked with solvent such as white spirit or Shell SBP3 to achieve the required finish.
Ensure that ALL accessible repair seams are sealed following a repair. Damage to a vehicle often flexes areas of the
body remote from the impact. As a result, the seam sealer in these areas may be disturbed by subsequent
straightening and repair operations. Check all seams in the vicinity of the area undergoing repair for evidence of
cracked seam sealer, then clean out as required and apply fresh seam sealer using the following procedure:
lClean the affected seam and re-treat any exposed metal areas with a suitable etch phosphate primer;
lApply appropriate seam sealer as necessary;
lTreat affected area with an acid-etch prime (and underbody sealer as applicable);
lApply appropriate colour coat.
Where seams are inaccessible following the reassembly or fitting of components, ensure that a paste-type seam
sealer is applied to such seams. Certain seams also become inaccessible after the completion of panel repairs. In
such instances apply seam sealer and paint before final assembly.
Provided access is adequate, apply seam sealer to both sides of a repair joint. Where access is limited to one side
only (e.g. box sections), treat the affected box member with cavity wax.
M77 1666A

CORROSION PREVENTION AND SEALING
77-4-18 SEALING
Structural adhesive
Adhesive on rear wheel arch outer assembly.
Joints symmetrically opposite to those shown are also treated. Apply 3 mm diameter beads to all joints shown.
Metal-to-metal adhesive is applied to critical joint areas during factory assembly. The material used is a high-
temperature, heat cured, nitrile phenolic which serves to bond two metal surfaces and also to seal the joint against
ingress of dust, moisture and fumes. This material is not suitable for service use and, during repair, should be
substituted by an approved Structural Adhesive.

+ BODY SEALING MATERIALS, MATERIALS AND APPLICATIONS, Approved materials.
Those joints which require the application of structural adhesive are detailed in the following figures. Only joints
applicable to service panels are included. Apply structural adhesive where indicated or to the mating panel surface.
CAUTION: When separating a joint treated with metal-to-metal adhesive, it is important to avoid distortion.
Heat the joint gradually until the bond weakens sufficiently to permit panel separation.
NOTE: When spot welding through metal-to-metal adhesive, take particular care to adjust the transformer setting to
ensure a reliable weld.
M77 1684A