air filter LAND ROVER DISCOVERY 1999 Repair Manual

STEERING
DESCRIPTION AND OPERATION 57-5
Description
General
The major steering components comprise an impact absorbing telescopic steering column, a Power Assisted Steering
(PAS) box, a PAS pump, and fluid reservoir. Hydraulic fluid from the fluid reservoir is filtered and then supplied
through the suction line to the inlet on the PAS pump. The PAS pump supplies fluid to the steering box through a
pressure line routed above the front cross member. Fluid returns to the reservoir along the same route through a
return line. On LH drive vehicles the pipe route above the front cross member is still used, the length of pipe acting
as an oil cooler.
To minimise driver's injury in the event of an accident the steering system has a number of safety features including
a collapsible steering column. An additional safety feature is an air bag located in the steering wheel.

+ RESTRAINT SYSTEMS, DESCRIPTION AND OPERATION, Description - SRS.
Steering column assembly and intermediate shaft
The steering column central shaft comprises of two shafts, the upper shaft is splined to accept the steering wheel and
located in bearings in the column tube. A universal joint is located on the bottom of the upper shaft, the joint allows
for angular movement between the upper and lower shafts. The lower shaft is made in two parts, the top section of
the lower shaft is located outside of the lower section. The two sections of the lower shaft are connected by two nylon
injection moulded shear pins. The lower shaft goes through a lower bearing attached to the bulkhead, the lower shaft
is connected by a universal joint to the intermediate shaft in the engine compartment.
Steering column
An upper column tube provides for the location of the steering lock and ignition switch and also the steering switch
gear and a rotary coupler. The rotary coupler provides the electrical connection for the steering wheel mounted airbag,
switches and horn. The upper mounting bracket has two slots, a slotted metal bracket is held in each slot by four resin
shear pins.
The column is mounted on four captive studs which are located on a column mounting bracket. The captive studs
pass through the metal brackets, locknuts secure the steering column to the bulkhead. The two lower mountings are
fixed and cannot move when loads are applied to them. The upper mounting is designed to disengage or deform when
a load is applied, allowing the column to collapse in the event of an accident. The steering column must be replaced
as a complete assembly if necessary.
When an axial load is applied to the upper column tube, energy absorption is achieved by the following mechanism:
lthe mounting bracket deforms,
lthe resin shear pins holding the slotted metal brackets shear,
lthe top mounting bracket slides out of the slotted metal brackets.
The slotted metal brackets remain on the captive studs on the bulkhead. If the column mounting moves, injection
moulded shear pins retaining the two sections of the lower column shaft will shear. This allows the two sections of the
lower shaft to 'telescope' together.
In the event of a collision where the steering box itself moves, two universal joints in the column allow the intermediate
shaft to articulate, minimising movement of the column towards the driver. If movement continues energy absorption
is achieved by the following mechanism:
lthe decouple joint in the intermediate shaft will disengage,
lthe lower section of the steering column shaft will move through the lower bearing,
lthe injection moulded shear pins retaining the two sections of the lower column shaft will shear.
This allows the two sections of the lower shaft to 'telescope' together reducing further column intrusion. Protection to
the drivers face and upper torso is provided by an SRS airbag module located in the centre of the steering wheel.

+ RESTRAINT SYSTEMS, DESCRIPTION AND OPERATION, Description - SRS.

STEERING
DESCRIPTION AND OPERATION 57-7
Reservoir
1Filler cap
2Reservoir body (dual PAS/ACE shown )
3Filter4Supply connection
5Return connection
The fluid reservoir is made of moulded plastic and is located on LH side of the engine compartment, on a bracket
which is attached to the inner wing. Dependent on the vehicles specification the reservoir may be a dual PAS/ACE,
or PAS only reservoir. Both types of reservoir are similar to each other the dual PAS/ACE reservoir has two chambers,
the PAS only reservoir has one chamber of a larger capacity. On both types of reservoir the PAS chamber has its own
filler cap and is identified by lettering on the reservoir body.
A filter of fine polyester mesh is moulded into the base of the chamber. The filter removes particulate matter from the
fluid before it is drawn into the supply connection and is non-serviceable. Upper and lower level marks are moulded
into the reservoir body, the reservoir is fitted with filler cap, a seal in the cap prevents leakage. The filler cap is pushed
onto a latch and turned through 90° to lock. A breather hole is incorporated in the cap to allow venting of air due to
fluid level changes during operation. The breather hole also allows air that may be in the fluid to separate out and vent
to atmosphere.
The reservoir holds hydraulic fluid and allows for expansion and contraction of the fluid due to temperature variations.
With the reservoir correctly filled the inlet to the PAS pump will be kept covered at normal operational attitudes. The
fluid flowing to the reservoir is cooled by convection from the pipe surfaces, the fluid held in the reservoir also allows
convection from the sides of the reservoir to take place. The total capacity of the reservoir with PAS only is 1000 cc
(0.264 US gallons), for vehicles fitted with PAS and ACE the total capacity of the reservoir is 500 cc (0.132 US
gallons).

STEERING
57-28 REPAIRS
7. RH drive models:Remove 4 bolts securing oil
filter housing, remove housing and discard 'O'
ring.
CAUTION: Always fit plugs to open
connections to prevent contamination.
8.Remove bolt securing PAS pipe bracket to
steering box, release pipes and discard 'O'
rings.
CAUTION: Always fit plugs to open
connections to prevent contamination.9.Remove securing nut and bolt and release
Panhard rod.
10.Remove nut securing drag link to drop arm.
Using LRT-57-036, break taper joint and
release drag link.
11. RH drive models with ACE: Remove nut
securing anti-roll bar link lower ball joint and
release joint.

STEERING
REPAIRS 57-29
12. RH drive models with ACE: Position ACE
control arms to access steering box bolts.
13.With assistance remove 4 securing bolts and
remove steering box.
14.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. RH drive 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).
4.Position drag link, fit nut and tighten to 80 Nm
(59 lbf.ft).
5.Position Panhard rod, fit bolt and nut and
tighten to 230 Nm (170 lbf.ft).
6.Clean PAS pipe ends and 'O' ring recess.
7.Lubricate new 'O' rings for PAS pipes with clean
PAS fluid.
8.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).
9. RHD models: Fit oil filter and housing:
lClean oil filter housing and engine mating
faces.
lLubricate new 'O' ring with clean engine oil
and fit to housing.
lPosition oil filter housing and tighten bolts to
9 Nm (7 lbf.ft).
10.Ensure steering wheel is centralised. Fit
universal joint between steering box and
intermediate shaft and tighten bolts to 25 Nm
(18 lbf.ft).
11.Remove centralising bolt from steering box.
12.Fit road wheel(s) and tighten nuts to 140 Nm
(103 lbf.ft)..
13.Remove stand(s) and lower vehicle.
14.Check and top up engine oil.
15.Bleed PAS system.

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

+ STEERING, ADJUSTMENTS,
Steering linkage - centralise.

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
60-42 REPAIRS
Refit
1.Clean mating faces of pulley and ACE pump.
2.Position pulley to ACE pump and fit bolts.
Restrain pulley and tighten bolts to 25 Nm (18
lbf.ft).
3.Clean mating faces of ACE pump and
mounting.
4.Connect suction hose to ACE pump and secure
with clip.
5.Ensure there is sufficient fluid in ACE/PAS
reservoir to prime ACE pump.
6.Position ACE pump below level of ACE/PAS
reservoir, with suction hose uppermost, and
allow fluid from ACE/PAS reservoir to
completely fill ACE pump.
7.Position ACE pump to mounting, fit bolts and
tighten to 25 Nm (18 lbf.ft).
8.Rotate ACE pump clockwise (viewed from
pulley end) until a steady flow of fluid runs from
outlet port.
9.Connect pressure pipe to ACE pump with banjo
bolt and new sealing washers. Tighten banjo
bolt to 28 Nm (21 lbf.ft).
10.Position air intake hose and secure clips.
11.Fit auxiliary drive belt.

+ CHARGING AND STARTING,
REPAIRS, Belt - auxiliary drive.
12.Renew ACE high pressure filter.

+ FRONT SUSPENSION, REPAIRS,
Filter - high pressure - ACE.
Pump - ACE - diesel
$% 60.60.10
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.
Remove
1.Remove auxiliary drive belt.

+ CHARGING AND STARTING,
REPAIRS, Belt - auxiliary drive.
2.Disconnect multiplugs from mass air flow
sensor and ambient air pressure sensor.
3.Release clips and disconnect mass air flow
sensor from air cleaner.
4.Loosen hose clip, disconnect inlet air hose
from turbo charger and move hose aside.

FRONT SUSPENSION
60-44 REPAIRS
Refit
1.Clean mating faces of pulley and ACE pump.
2.Position pulley to ACE pump and fit bolts.
Restrain pulley and tighten bolts to 25 Nm (18
lbf.ft).
3.Clean mating faces of ACE pump and
mounting.
4.Connect suction hose to ACE pump and secure
with clip.
5.Ensure there is sufficient fluid in ACE/PAS
reservoir to prime ACE pump.
6.Position ACE pump below level of ACE/PAS
reservoir, with suction hose uppermost, and
allow fluid from ACE/PAS reservoir to
completely fill ACE pump.
7.Position ACE pump to mounting, fit bolts and
tighten to 25 Nm (18 lbf.ft).
8.Rotate ACE pump clockwise (viewed from
pulley end) until a steady flow of fluid runs from
outlet port.
9.Connect pressure pipe to ACE pump with banjo
bolt and new sealing washers. Tighten banjo
bolt to 28 Nm (21 lbf.ft).
10.Connect hose to intercooler and secure with
clip.
11.Fit ACE/PAS reservoir into mounting bracket.
12.Connect air hose to turbo charger and secure
with clip.
13.Fit mass air flow sensor to air filter and secure
with clips.
14.Connect multiplugs to mass air flow sensor and
ambient air pressure sensor.
15.Fit auxiliary drive belt.

+ CHARGING AND STARTING,
REPAIRS, Belt - auxiliary drive.
16.Renew ACE high pressure filter.

+ FRONT SUSPENSION, REPAIRS,
Filter - high pressure - ACE.
Valve block - ACE
$% 60.60.20
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.
Remove
1.Raise vehicle on a ramp.
2.Disconnect 4 multiplugs from valve block.
3.Position container underneath valve block to
collect fluid spillage.

FRONT SUSPENSION
60-46 REPAIRS
7.Remove 3 bolts securing valve block to
chassis.
8.Release front pipes and clamping plate from
valve block and remove valve block.
CAUTION: Always fit plugs to open
connections to prevent contamination.
NOTE: Keep pipes assembled to clamping
plate to maintain correct pipe positions for
refitting.
9.Remove 6 bushes from valve block. Refit
1.Fit 6 bushes to valve block.
2.Ensure valve block and pipe connections are
clean.
3.It is important that the pipe ends are in good
condition to achieve a seal.
4.Position valve block and connect front pipes
and clamping plate. To avoid damage to
seals, keep pipes square to valve block. Fit
and tighten bolts securing valve block to
chassis to 18 Nm (13 lbf.ft).
CAUTION: Ensure pipes are installed in
their correct ports or serious system
damage will occur.
5.Fit and tighten nuts securing front clamping
plate to valve block to 21 Nm (15 lbf.ft).
6.Fit bolt securing front pipe clip to chassis and
tighten to 6 Nm (4.4 lbf.ft).
7.Connect rear pipes and clamping plate to valve
block. To avoid damage to seals, keep pipes
square to valve block. Fit and tighten nuts
securing clamping plate to valve block to 21 Nm
(15 lbf.ft).
CAUTION: Ensure pipes are installed in
their correct ports or serious system
damage will occur.
8.Fit bolts securing rear pipe clips to chassis and
tighten to 6 Nm (4.4 lbf.ft) .
9.Connect 4 multiplugs to valve block.
10.If the same valve block has been refitted, renew
ACE high pressure filter.

+ FRONT SUSPENSION, REPAIRS,
Filter - high pressure - ACE.
11.Bleed ACE hydraulic system.

+ FRONT SUSPENSION,
ADJUSTMENTS, ACE hydraulic system
bleeding.
12.Lower vehicle.

FRONT SUSPENSION
REPAIRS 60-47
Filter - high pressure - ACE
$% 60.60.21
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.
Remove
1.Raise vehicle on a ramp.
2.Position container to collect fluid spillage.
3.Remove filter cap and discard 'O' ring.
4.Fit M6 bolt into base of filter and pull on bolt to
remove filter from valve block. Do not turn
filter in valve block.
CAUTION: Always fit plugs to open
connections to prevent contamination.Refit
1.Ensure new filter has 'O' ring fitted, then fit filter
to valve block.
2.Fit new 'O' ring to filter cap. Fit cap and tighten
to 35 Nm (26 lbf.ft).
3.Lower vehicle.
4.Check fluid level in ACE/PAS reservoir.

+ FRONT SUSPENSION,
ADJUSTMENTS, Fluid level check - ACE
system.
5.Start and run engine for 2 minutes, then re-
check fluid level in ACE/PAS reservoir.

+ FRONT SUSPENSION,
ADJUSTMENTS, Fluid level check - ACE
system.

FRONT SUSPENSION
60-48 REPAIRS
Pressure transducer - ACE
$% 60.60.22
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.
Remove
1.Raise vehicle on a ramp.
2.Disconnect multiplug from transducer.
3.Position container to collect fluid spillage.
4.Remove pressure transducer and discard 'O'
ring.
CAUTION: Always fit plugs to open
connections to prevent contamination.Refit
1.Ensure pressure transducer and port in valve
block is clean.
2.Fit new 'O' ring to pressure transducer. Fit and
tighten pressure transducer to 20 Nm (15
lbf.ft).
3.Connect multiplug to pressure transducer.
4.Renew ACE high pressure filter.

+ FRONT SUSPENSION, REPAIRS,
Filter - high pressure - ACE.
5.Lower vehicle.