1999 LAND ROVER DISCOVERY engine

STEERING
57-32 REPAIRS
17.Remove securing nut and bolt and release
Panhard rod.
18.Remove nut securing drag link to drop arm.
Using LRT-57-036, break taper joint and
release drag link. 19. Models with ACE: Remove nut securing anti-
roll bar link lower ball joint and release joint.
20.With assistance, remove 2 nuts and bolts
securing LH engine mounting to chassis.

STEERING
REPAIRS 57-33
21.With assistance remove 2 nuts and bolts
securing RH engine mounting to chassis.
22.Support the engine weight on a jack.
CAUTION: To prevent damage to
components, cushion the jack pad with a
block of wood or hard rubber.
23.Raise the engine sufficiently to allow the
steering box to clear the sump.
24. Models with ACE: Position ACE control arms
to access steering box bolts. 25.With assistance remove 4 bolts securing
steering box and remove steering box.
26.Remove centralising bolt from steering box.
Refit
1.Fit centralising bolt to steering box.
2.With assistance, position steering box, fit bolts
and tighten to 90 Nm (66 lbf.ft).
3.Lower the engine onto its mountings. Fit engine
mounting bolts and tighten to 85 Nm (63 lbf.ft).
4. Models with ACE: Ensure washer is in place
on lower ball joint of anti-roll bar link, then
connect lower ball joint to axle. Tighten nut to
100 Nm (74 lbf.ft).
5.Position drag link, fit nut and tighten to 80 Nm
(59 lbf.ft).
6.Position Panhard rod, fit bolt and nut and
tighten to 230 Nm (170 lbf.ft).
7.Position coolant rail and secure with clips and
bolt.
8.Fit coolant hoses and secure with clips.
9. Models with ACE: Fit and tighten bolt
securing ACE pipes to chassis.
10.Clean PAS pipe ends and 'O' ring recess.
11.Lubricate new 'O' rings for PAS pipes with clean
PAS fluid.
12.Fit 'O' rings to PAS pipes and position pipes in
steering box. Fit PAS pipe bracket and tighten
bolt to 22 Nm (16 lbf.ft).
13.Ensure steering wheel is centralised. Fit
universal joint between steering box and
intermediate shaft and tighten bolts to 25 Nm
(18 lbf.ft).
14.Remove centralising bolt from steering box.
15.Fit intercooler to turbo hose and secure with
clips.
16.Fit road wheel(s) and tighten nuts to 140 Nm
(103 lbf.ft).
17.Remove stand(s) and lower vehicle.
18.Connect battery earth lead.
19.Fit battery cover.
20.Refill cooling system.

+ COOLING SYSTEM - Td5,
ADJUSTMENTS, Drain and refill.
21.Bleed PAS system.

+ STEERING, ADJUSTMENTS,
Hydraulic system - bleed.
22.Centralise steering linkage

+ STEERING, ADJUSTMENTS,
Steering linkage - centralise.

STEERING
REPAIRS 57-41
Refit
1.Position PAS pump to auxiliary housing and
locate housing to engine. Fit and tighten
auxiliary housing bolts to 40 Nm (30 lbf.ft).
2.Tighten auxiliary housing nut to 10 Nm (7 lbf.ft).
3.Fit bolts securing PAS pump and tighten to 22
Nm (16 lbf.ft).
4.Position PAS pump pipe bracket, fit and tighten
bolt to 22 Nm (16 lbf.ft).
5.Fit and tighten PAS pump pressure pipe.
6.Fit PAS pump inlet hose and secure with clip.
7.Position jockey pulley and tighten bolt to 50 Nm
(37 lbf.ft).
8.Clean PAS pump pulley mating faces.
9.Position PAS pump pulley, fit bolts and tighten
to 22 Nm (16 lbf.ft).
10. Models with ACE: Clean ACE pump dowels
and dowel holes. Position ACE pump, fit bolts
and tighten to 25 Nm (18 lbf.ft).
11. Models with A/C: Clean A/C compressor
dowels and dowel holes. Position A/C
compressor, fit bolts and tighten to 22 Nm (16
lbf.ft).
12.Position air intake hose and secure with clips.
13.Secure harness to air intake hose with new
cable tie.
14.Fit auxiliary drive belt.

+ CHARGING AND STARTING,
REPAIRS, Belt - auxiliary drive..
15.Bleed PAS system.

+ STEERING, ADJUSTMENTS,
Hydraulic system - bleed.

FRONT SUSPENSION
DESCRIPTION AND OPERATION 60-5
Coil springs
Coil springs are fitted to the front axle of the vehicle. The front springs differ between petrol and Diesel variants. Each
spring is retained at its base by the lower spring seat. The top of each spring is located in the upper spring seat
isolator. The upper spring seat is manufactured from natural rubber , with a bonded metal plate and four bonded studs
which provide for the attachment of the damper turret. The rubber isolator reduces noise transmitted to the chassis
and body from the suspension.
The coil springs must be installed correctly. The bottom coil of the spring locates in a recess in the lower spring seat.
The top coil of the spring is ground flat to locate the upper spring seat isolator.
Coil Spring Specifications – Models up to 03 Model Year
The front springs on petrol variants are manufactured from carbon chrome 13.9 mm (0.55 in) diameter bar. The spring
has 7.6 coils and a free length of 377 mm (14.8 in). The petrol front spring is identified by a pink and orange stripe
painted on a number of coils.
The front springs on Diesel variants are manufactured from carbon chrome 13.9 mm (0.55 in) diameter bar. The spring
has 7.6 coils and a free length of 383 mm (15.0 in). The Diesel front spring is identified by a white and purple stripe
painted on a number of coils.
Coil Spring Specifications – Models from 03 Model Year
The introduction of the 03MY vehicle introduced a range of additional spring fitments. These were introduced to cover
the introduction of the 4.6l V8 engine, the fitment of a front mounted winch and to optimise the vehicle trim heights.
The coil springs are manufactured from silicon manganese 13.8 mm or 13.9 mm (0.54 in or 0.55 in) diameter bar. The
following spring data table shows the colour codes, number of coils and spring free length.
Spring Data
The following table shows spring fitment applicablity.
Spring Fitment Applicability
The following table shows standard springs and uprated springs required when a front winch is fitted.
Winch Fitment Spring Applicability
Colour Code Total No. of Coils Free Length
Red/Purple 7.4 371 mm (14.6 in)
Yellow/Purple 7.4 378.4 mm (14.9 in)
Blue/Purple 7.4 365 mm (14.4 in)
Grey/Purple 7.4 387 mm (15.2 in)
Purple/Purple 7.4 373.8 mm (14.7 in)
Yellow/Orange 7.4 394.6 mm (15.5 in)
Green/Orange 7.4 382.6 mm (15 in)
Pink/Brown 7.6 405.6 mm (15.9 in)
Left Hand Drive Right Hand Drive
RH side LH side RH side LH side
Red/Purple Red/Purple Yellow/Purple Blue/Purple
Yellow/Purple Yellow/Purple Grey/Purple Purple/Purple
Grey/Purple Grey/Purple Yellow/Orange Green/Orange
Standard Spring Winch Fitted Spring
RH Side LH Side Both Sides
Red/Purple Red/Purple Grey/Purple
Yellow/Purple Blue/Purple Yellow/Orange
Yellow/Purple Yellow/Purple Yellow/Orange
Grey/Purple Purple/Purple Green/Orange
Grey/Purple Grey/Purple Green/Orange
Yellow/Orange Green/Orange Pink/Brown

FRONT SUSPENSION
60-8 DESCRIPTION AND OPERATION
ACE system control diagram
1Upper accelerometer
2Lower accelerometer
3Pressure transducer
4Directional control valve
5Directional control valve
6Pressure control valve
7Instrument pack warning lamp
8Diagnostic socket9Reverse lamp switch
10SLABS ECU
11Engine Control Module (ECM)
12Ignition feed
13ACE relay
14Battery supply
15ACE ECU
M60 0589B
12
5
4
3
6
7
8
9
10
11
12
13
14
15

FRONT SUSPENSION
60-10 DESCRIPTION AND OPERATION
ACE system
aDirection of travel - Right hand bend
bBody roll
cAxle roll
dTyre squash
eTorsion/Anti-roll barfDirection of torsion/anti-roll bar twist
gCoil springs
hBody roll angle
iAxle roll angle
jReduced body roll angle with ACE system
The system is electrically and hydraulically operated with all operations controlled by an ACE ECU located behind the
glovebox in the passenger side footwell. The ACE system comprises front and rear torsion bars and actuators, two
accelerometers, ECU, hydraulic pump, valve block and a fluid reservoir.
The ACE system gives improved vehicle handling and suspension characteristics and is active for both on and off-
road driving. This is achieved by hydraulic actuators applying torque to the front and rear torsion bars in response to
lateral forces sensed by accelerometers. The ACE system prevents body roll with cornering forces of up to 0.4 g. From
0.4 g there is a progressive increase in body roll but significantly lower than a passive system. A passive system will
have a progressive increase in roll angle as soon as cornering forces are applied and will have a higher roll angle than
the ACE system for the same cornering force.
The ACE system can also detect if the vehicle is driven off-road. If off-road conditions are detected the ACE system
operation will be reduced or completely disabled at a speed of 25 mph (40 km/h) or less.
Lateral acceleration of the body is sensed by two accelerometers and signals are transmitted to the ECU. The engine
driven hydraulic pump supplies a constant hydraulic flow to the valve block. Two directional control valves are
solenoid operated by the ECU and these supply fluid to the applicable side of each actuator to apply an equal and
opposite force to the torsion bar. In operation the ACE system maintains the attitude of the vehicle body when
cornering.

FRONT SUSPENSION
DESCRIPTION AND OPERATION 60-11
The ACE system uses a semi-synthetic hydraulic fluid which is the same as the fluid used for the PAS system. The
total capacity of the ACE system is 1.62 litres (0.42 US Gallons).
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.
In the event of an ECU or hydraulic failure the system will fail safe to a 'locked bars' condition. The 'locked bars'
condition will allow the torsion bars to operate in a similar manner as conventional 'passive' anti-roll bars. Prolonged
cornering forces will allow a progressive increase in roll angle due to hydraulic leakage through the actuators and
valve block. Failures will be relayed to the driver by the illumination of the ACE warning lamp in the instrument pack.
Faults are recorded by the ECU and can be retrieved using TestBook.
When the ignition switch is moved to position II, the warning lamp will illuminate for two seconds to check functionality.
The warning lamp functionality can also be checked using TestBook.
TestBook must also be used to perform a bleeding procedure after maintenance operations have been performed to
ensure that complete system bleeding is performed. Trapped air in the system can seriously reduce the system
performance.
Fluid reservoir
The moulded plastic fluid reservoir is mounted on the left hand side of the engine compartment on a bracket which is
attached to the inner wing. The reservoir is dual purpose, being divided into two separate chambers; one for the ACE
system and one for the PAS system. Each chamber has its own filler neck and cap and is identified by moulded
lettering on the reservoir adjacent to each filler.
A non-serviceable filter assembly is fitted in the base of each chamber. The filter is made from fine stainless steel
mesh which is moulded into the body of the reservoir. The filter removes particulate matter from the fluid before it is
drawn into the hydraulic pump.
Upper and lower fluid level marks are moulded onto the reservoir body. The capacity of the ACE reservoir chamber
to the upper level mark is 0.5 litre (0.13 US Gallon).

FRONT SUSPENSION
60-12 DESCRIPTION AND OPERATION
Hydraulic pump
1Outlet port
2Cap
3Piston spring
4Piston
5Inlet port
6Cylinder housing
7Shaft8Cam
9Inlet housing
10Spring
11Discharge valve
12Housing
13Pulley attachment flange
The hydraulic pump is attached to a bracket on the left hand side of the engine and is driven at crankshaft speed by
the auxiliary drive belt. The pump is of the radial piston type which delivers fluid at high pressure.
The radial piston pump has six pistons located in bores in a cylinder housing. A central shaft, which is driven by a
pulley and the auxiliary drive belt, has a cam which operates the pistons as it rotates.
As the cam lobe reaches each piston, the piston is pushed outward, moving the fluid above the piston. The pressure
created by the fluid flow from the bore opens a spring loaded discharge valve and allows the fluid to flow to the pump
outlet port. When the piston reaches its full stroke, the flow reduces and the discharge valve closes under spring
pressure.
As the cam lobe moves away from the piston, a spring pushes the piston down the bore creating a vacuum above the
piston. As the piston moves down the bore, ports in the piston are exposed and connect with the fluid inlet. The
vacuum draws fluid into the piston filling the piston and the chamber above it. As the piston is again pushed upwards,
the ports are closed off by the bore and the fluid opens the discharge valve and flows to the outlet port.