suspension LAND ROVER DISCOVERY 1999 Workshop Manual

REAR SUSPENSION
REPAIRS 64-35
Sensor - height - SLS
$% 64.36.01
WARNING: Ensure the air suspension system is
made safe before commencing work. Otherwise
the chassis may lower onto the bump stops
during repair.
Remove
1.Raise rear of vehicle.
WARNING: Do not work on or under a
vehicle supported only by a jack. Always
support the vehicle on safety stands.
2.Disconnect height sensor multiplug.
3.Remove bolt securing height sensor link to
radius arm.
4.Remove 2 bolts securing height sensor to
chassis and remove height sensor.
Refit
1.Position height sensor to chassis and tighten
bolts to 6 Nm (4.4 lbf.ft).
2.Position height sensor link to radius arm and
tighten bolt to 25 Nm (18 lbf.ft).
3.Connect height sensor multiplug.
4.Remove stand(s) and lower vehicle.
5.Use TestBook to calibrate height sensor.
Compressor unit - air - SLS
$% 64.50.10
WARNING: Ensure the air suspension system is
made safe before commencing work. Otherwise
the chassis may lower onto the bump stops
during repair.
Remove
1.Using TestBook, depressurise SLS air system.
After depressurisation, approximately 1 bar
(15 lbf.in
2) air pressure remains in the
system.
2.Release 2 fasteners and remove air
compressor unit cover.
3.Remove 2 bolts securing air compressor unit to
chassis. Release unit and lower onto blocks to
support the weight.
4.Noting their fitted position, disconnect pipes
from air valves.
CAUTION: Always fit plugs to open
connections to prevent contamination.

REAR SUSPENSION
64-36 REPAIRS
5.Disconnect inlet and exhaust pipes.
CAUTION: Always fit plugs to open
connections to prevent contamination.
6.Disconnect multiplugs from air valves, exhaust
valve and compressor.
7.Release and disconnect compressor multiplug
from casing.
8.Remove air compressor unit from vehicle.
9.Release supply/exhaust pipe.
CAUTION: Always fit plugs to open
connections to prevent contamination.
10.Remove 3 bolts securing compressor to
casing. Remove compressor and collect
mounting washers. Refit
1.Locate mounting washers and position
compressor in casing.
2.Apply sealant, Part No. STC 50552 to
compressor securing bolts. Fit bolts and tighten
to 7 Nm (5.2 lbf.ft).
3.Connect compressor multiplug to casing.
4.Connect supply/exhaust pipe.
5.Position air compressor unit on support block,
connect inlet and exhaust pipes.
6.Connect multiplugs to air valves, exhaust valve
and compressor.
7.Connect pipes to air valves.
8.Position air compressor unit to chassis and
engage casing in retaining lugs. Fit air
compressor unit securing bolts and tighten to
25 Nm (18 lbf.ft).
9.Ensure pipes are located in cut outs in casing.
10.Position air compressor unit cover and lock
fasteners.
11.Repressurise SLS air system using TestBook.
WARNING: Eye protection must be worn
during the repressurisation procedure.

REAR SUSPENSION
REPAIRS 64-37
Filter - intake - SLS
$% 64.50.12
Remove
1.Remove LH tail lamp.

+ LIGHTING, REPAIRS, Lamp - tail.
2.Disconnect filter from retaining peg.
3.Disconnect quick release connection and
remove filter assembly.
Refit
1.Position filter assembly and connect quick
release connection.
2.Secure filter retaining peg.
3.Fit LH tail lamp.

+ LIGHTING, REPAIRS, Lamp - tail.
Switch - ride height
$% 64.50.45
Remove
1.Carefully remove switch.
2.Disconnect multiplug from switch.
3.Remove switch.
Refit
1.Connect multiplug switch.
2.Position switch and push to secure.

REAR SUSPENSION
64-38 REPAIRS
Air valve - SLS
$% 64.50.47
WARNING: Ensure the air suspension system is
made safe before commencing work. Otherwise
the chassis may lower onto the bump stops
during repair.
Remove
1.Using TestBook, depressurise SLS air system.
After depressurisation, approximately 1 bar
(15 lbf.in
2) air pressure remains in the
system.
2.Release 2 fasteners and remove air
compressor unit cover.
3.Noting their fitted position, disconnect pipes
from air valves and discard 'O' rings.
4.Disconnect air valve multiplugs.
5.Remove 2 bolts securing air valves and
remove air valves. Refit
1.Position air valves and fit and tighten bolts.
2.Connect air valve multiplugs.
3.Connect air valve pipes.
4.Ensure pipes are located in cut outs in casing.
5.Position air compressor unit cover and lock
fasteners.
6.Repressurise SLS air system using TestBook.
WARNING: Eye protection must be worn
during the repressurisation procedure.

REAR SUSPENSION
REPAIRS 64-39
Actuator - rear - ACE
$% 64.60.40
CAUTION: The ACE hydraulic system is
extremely sensitive to the ingress of dirt or
debris. The smallest amount could render the
system unserviceable. It is imperative that the
following precautions are taken.
lACE components are thoroughly cleaned
externally before work commences;
lall opened pipe and module ports are
capped immediately;
lall fluid is stored in and administered
through clean containers.
Models with SLS:
WARNING: Ensure the air suspension system is
made safe before commencing work. Otherwise
the chassis may lower onto the bump stops
during repair.
Remove
1.Raise vehicle on ramp.
2.Remove nuts securing anti-roll bar links to
axle. Release links from axle.
3.Pull torsion bar down for access to actuator. 4.Remove nut securing anti-roll bar link to long
arm and remove link.
5.Position container to collect fluid spillage.
6.Remove cap nuts securing fluid pipes to
actuator. Disconnect pipes and remove and
discard sealing washers.
CAUTION: Always fit plugs to open
connections to prevent contamination.

REAR SUSPENSION
64-40 REPAIRS
7.Use LRT-60-009 to remove nut securing
actuator push rod to long arm.
8.Remove nut and bolt securing actuator to short
arm and remove actuator.
CAUTION: The short arm and torsion bar
are supplied as an assembly and must not
be separated.Refit
1.Position actuator and tighten nut and bolt
securing actuator to short arm to 180 Nm (133
lbf.ft).
2.Using LRT-60-009 , fit and tighten nut securing
actuator push rod to long arm to 48 Nm (35
lbf.ft).
3.Connect pipes to actuator with cap nuts and
new sealing washers. Tighten cap nuts to 29
Nm (21 lbf.ft). Ensure pipes are not under
tension or kinked.
4.Connect anti-roll bar link to long arm and
tighten nut to 50 Nm (37 lbf.ft).
5.Ensure washer is in place on lower ball joint of
each anti-roll bar link and connect lower ball
joints to axle. Tighten nuts to 100 Nm (74 lbf.ft).
6.Renew ACE high pressure filter.

+ FRONT SUSPENSION, REPAIRS,
Filter - high pressure - ACE.
7.Lower vehicle.
8.Bleed ACE hydraulic system.

+ FRONT SUSPENSION,
ADJUSTMENTS, ACE hydraulic system
bleeding.

REAR SUSPENSION
REPAIRS 64-41
Bushes - rear long arm - ACE
$% 64.60.46
CAUTION: The ACE hydraulic system is
extremely sensitive to the ingress of dirt or
debris. The smallest amount could render the
system unserviceable. It is imperative that the
following precautions are taken.
lACE components are thoroughly cleaned
externally before work commences;
lall opened pipe and module ports are
capped immediately;
lall fluid is stored in and administered
through clean containers.
Models with SLS:
WARNING: Ensure the air suspension system is
made safe before commencing work. Otherwise
the chassis may lower onto the bump stops
during repair.
Remove
1.Raise vehicle on ramp.
2.Remove nuts securing anti-roll bar links to axle.
Release links from axle.
3.Pull torsion bar down for access to actuator.4.Remove securing nuts and remove anti-roll bar
links from torsion bar.
5.Position container to collect fluid spillage.
6.Remove cap nuts securing fluid pipes to
actuator. Disconnect pipes and remove and
discard sealing washers.
CAUTION: Always fit plugs to open
connections to prevent contamination.
7.With assistance, remove bolts securing torsion
bar clamps. Remove clamps and remove
torsion bar and actuator.

REAR SUSPENSION
64-42 REPAIRS
8.Use LRT-60-009 to remove nut securing
actuator push rod to long arm.
9.Remove nut and bolt securing actuator to short
arm and remove actuator.
10.Restrain torsion bar and remove long arm
securing bolt and washer. Remove long arm
from torsion bar.
CAUTION: The short arm and torsion bar
are supplied as an assembly and must not
be separated.11.Use a suitable drift to remove both halves of
slipper bush from long arm.
12.Use suitable adaptors to press actuator rod end
bush from long arm.

REAR SUSPENSION
REPAIRS 64-43
Refit
1.Clean bush locations in long arm.
2.Use suitable adaptors to press new actuator
rod end bush into long arm. Ensure bush is
correctly aligned.
3.Align slots in new slipper bush halves with
those in long arm. Carefully press both halves
of slipper bush into long arm. Ensure the
sealing rings on the bush faces are not
damaged.
4.Clean long arm and mating face on torsion bar.
5.Fit long arm to torsion bar. Restrain torsion bar
and tighten bolt to 180 Nm (133 lbf.ft).
6.Ensure actuator and bushes are clean.
7.Fit actuator and tighten nut and bolt securing
actuator to short arm to 180 Nm (133 lbf.ft).
8.Using LRT-60-009 , fit and tighten nut securing
actuator push rod to long arm to 48 Nm (35
lbf.ft).
9.With assistance, position torsion bar and
actuator to vehicle and fit torsion bar clamps.
Tighten torsion bar clamp bolts to 45 Nm (33
lbf.ft).
10.Connect pipes to actuator with cap nuts and
new sealing washers. Tighten cap nuts to 29
Nm (21 lbf.ft). Ensure pipes are not under
tension or kinked.
11.Fit anti-roll bar links to torsion bar and tighten
nuts to 50 Nm (37 lbf.ft).
12.Ensure washer is in place on lower ball joint of
each anti-roll bar link and connect lower ball
joints to axle. Tighten nuts to 100 Nm (74 lbf.ft).
13.Renew ACE high pressure filter.

+ FRONT SUSPENSION, REPAIRS,
Filter - high pressure - ACE.
14.Lower vehicle.
15.Bleed ACE hydraulic system.

+ FRONT SUSPENSION,
ADJUSTMENTS, ACE hydraulic system
bleeding.

BRAKES
70-18 DESCRIPTION AND OPERATION
The SLABS ECU continually calculates vehicle speed using the wheel speed inputs from all four ABS sensors. The
calculated vehicle speed is then used as a reference against which individual wheel speeds are monitored for
unacceptable acceleration or deceleration. The ABS sensor inputs are also used by the SLABS ECU to detect vehicle
deceleration rate, vehicle cornering rate and rough terrain.
The engaged forward gear and (on manual gearbox models) the clutch status are computed from the engine data
input, the engine speed input and vehicle speed. Reverse gear status is provided by an input from the reverse lamp
switch (manual gearbox models) or the BCU (automatic gearbox models). On automatic models, the BCU also
provides the neutral selected input.
In addition to controlling the brake related functions, the SLABS ECU:
lControls the operation of the self levelling suspension (SLS) system (where fitted).

+ REAR SUSPENSION, DESCRIPTION AND OPERATION, Description.
lOn V8 models, outputs a rough road signal to the ECM when traversing rough terrain.
lOutputs a vehicle speed signal.
The vehicle speed signal is output to the following systems (where fitted):
lActive Cornering Enhancement.

+ FRONT SUSPENSION, DESCRIPTION AND OPERATION, Description - ACE.
lAir conditioning.

+ AIR CONDITIONING, DESCRIPTION AND OPERATION, Description.
lCruise control.

+ ENGINE MANAGEMENT SYSTEM - Td5, DESCRIPTION AND OPERATION, Description.

+ ENGINE MANAGEMENT SYSTEM - V8, DESCRIPTION AND OPERATION, Description - engine
management.
lEngine management.

+ ENGINE MANAGEMENT SYSTEM - Td5, DESCRIPTION AND OPERATION, Description.

+ ENGINE MANAGEMENT SYSTEM - V8, DESCRIPTION AND OPERATION, Description - engine
management.
lIn-car entertainment.

+ IN CAR ENTERTAINMENT, DESCRIPTION AND OPERATION, Description.
lInstrument pack.

+ INSTRUMENTS, DESCRIPTION AND OPERATION, Description.
5 Front right inlet solenoid valve Output
6 Shuttle valve switches Input
7 Rear left outlet solenoid valve Output
8 Rear left inlet solenoid valve Output
9 Centre differential lock switch Input
10 Rear right outlet solenoid valve Output
11 Rear right inlet solenoid valve Output
12 Brake lamp relay Output
15 Return pump relay Output
C0655
7 Audible warning Output
10 Engine speed Input
Connector and pins not listed are either not used or used by the self levelling suspension system.

+ REAR SUSPENSION, DESCRIPTION AND OPERATION, Description.
Connector/Pin
No.Description Input/Output