1999 LAND ROVER DEFENDER oil

COOLING SYSTEM
13
DESCRIPTION AND OPERATION When the coolant temperature is low, the heat emitted from the radiator does not affect the bi-metallic coil. The
valve remains closed, preventing fluid escaping from the reservoir into the fluid chamber. In this condition the fan
will’freewheel’at a slow speed.
As the coolant temperature increases, the heat emitted from the radiator causes the bi-metallic coil to tighten. This
movement of the coil moves the valve to which it is attached. The rotation of the valve exposes ports in the valve
plate which allow the silicone fluid to spill into the fluid chamber. As the fluid flows into the clearance between the
annular grooves in the drive plate and body, drag is created between the two components. The drag is due to the
viscosity and shear qualities of the silicone fluid and causes the drive plate to rotate the body and fan blades.
As the coolant temperature decreases, the bi-metallic coil expands, rotating the valve and closing off the ports in
the valve plate. When the valve is closed, centrifugal force pushes the silicone fluid through the return port,
emptying the fluid chamber. As the fluid chamber empties, the drag between the drive plate and the body is
reduced and the body slips on the drive plate, slowing the rotational speed of the fan.
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33CLUTCH
6
DESCRIPTION AND OPERATION DESCRIPTION
General
The clutch system is a diaphragm type clutch operated by a hydraulic cylinder. The drive plate is of the rigid centre
type with no integral damping springs. The flywheel is of the dual mass type with damping springs integral with the
flywheel. The clutch requires no adjustment to compensate for wear.
Hydraulic Clutch
The hydraulic clutch comprises a master cylinder, slave cylinder and a hydraulic reservoir. The master and slave
cylinders are connected to each other hydraulically by plastic and metal pipes. The plastic section of the pipe
allows ease of pipe routing and also absorbs engine movements and vibrations.
The master cylinder comprises a body with a central bore. Two ports in the body connect the bore to the hydraulic
feed pipe to the slave cylinder and the fluid reservoir. The bore is also connected to a damper which prevents
engine pulses being transferred hydraulically to the clutch pedal. A piston is fitted in the bore and has an external
rod which is attached to the clutch pedal with a pin. Two coil springs on the clutch pedal reduce the effort required
to depress the pedal.
The master cylinder is mounted on the bulkhead and secured with two bolts. The cylinder is connected to the
shared brake/clutch reservoir on the brake servo by a braided connecting hose.
The slave cylinder is located on the left hand side of the gearbox housing and secured with two bolts. A heat
shield is fitted to protect the underside of the slave cylinder from heat generated from the exhaust system. The
slave cylinder comprises a cylinder with a piston and a rod. A port in the cylinder body provides the attachment for
the hydraulic feed pipe from the master cylinder. A second port is fitted witha bleed nipple used for removing air
from the hydraulic system after servicing. The piston rod locates on a clutch release lever located in the gearbox
housing. The rod is positively retained on the release lever with a clip.
Clutch Mechanism
The clutch mechanism comprises a flywheel, drive plate, pressure plate, release lever and a release bearing. The
clutch mechanism is fully enclosed at the rear of the engine by the gearbox housing.
A clutch release bearing sleeve is attached in the gearbox housing with two bolts and located on two dowels. A
spigot with a ball end is formed on the release bearing sleeve and provides a mounting and pivot point for the
clutch release lever. A dished pivot washer is located on the ball of the spigot. When the release lever is located
on the ball, the pivot washer seats against the rear face of the release lever. A spring clip is located on the lever
and the pivot washer and secures the lever on the spigot. A small bolt retains the spring clip in position.
The release lever is forked at its inner end and locates on the clutch release bearing carrier. The outer end of the
release lever has a nylon seat which locates the slave cylinder piston rod. A second nylon seat, positioned
centrally on the release lever, locates on the ball spigot of the release bearing sleeve and allows the release lever
to pivot freely around the ball.
The clutch release bearing locates on the clutch release lever and release bearing sleeve. The bearing is retained
on a carrier which has two flats to prevent the carrier rotating on the release lever. A clip retains the release lever
on the carrier. The bearing and carrier are not serviceable individually.
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33CLUTCH
8
DESCRIPTION AND OPERATION The dual mass flywheel is bolted on the rear of the crankshaft with eight bolts. A dowel on the crankshaft flange
ensures that the flywheel is correctly located. A ring gear is fitted on the outer diameter of the flywheel. The ring
gear is not serviceable. Thirty blind holes are drilled in the outer diameter of the flywheel adjacent to the ring gear.
The holes are positioned at 10°intervals with four 20°spaces. The holes are used by the crankshaft position
sensor for engine management.
The dual mass flywheel is used to insulate the gearbox from torsional and transient vibrations produced by the
engine. The flywheel comprises primary and secondary flywheels with the drive between the two transferred by a
torsional damper which comprises four coil springs. The springs are located in the inside diameter of the primary
flywheel. Two of the springs are of smaller diameter and fit inside the larger diameter springs.
The primary flywheel locates the ring gear and is attached to the crankshaft flange with eight bolts. The two pairs
of coil springs are located in a recess in the flywheel between two riveted retainers. A roller bearing is pressed
onto the central boss of the primary flywheel and retained with a riveted plate. The bearing provides the mounting
for the secondary flywheel.
The secondary flywheel comprises two parts; an outer flywheel which provides the friction surface for the clutch
drive plate and an inner drive plate which transfers the drive from the primary flywheel, via the coil springs, to the
outer flywheel. The two components of the secondary flywheel are secured to each other with rivets. The inner
drive plate is located between the two pairs of coil springs and can rotate on the ball bearing in either direction
against the combined compression force of the four coil springs. Under high torque loading conditions the
secondary flywheel can rotate in either direction up to 70°in relation to the primary flywheel.
The operating face of the secondary flywheel is machined to provide a smooth surface for the drive plate to
engage on. Three dowels and six studs and nuts provide for the location and attachment of the pressure plate.
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37 - MANUAL GEARBOX
CONTENTS
Page
ADJUSTMENT
SPRINGS - GEAR LEVER BIAS 1..........................................................................
GEARBOX OIL - DRAIN AND REFILL 2.................................................................
REPAIR
COVER - FRONT - RESEAL AND FIT NEW INPUT SHAFT OIL SEAL 1..............
LEVER - GEAR CHANGE 3....................................................................................
MECHANISM AND HOUSING - GEAR SELECTOR 4...........................................
MECHANISM AND HOUSING - GEAR SELECTOR - RESEAL 6..........................
GEARBOX 7...........................................................................................................
SWITCH - REVERSE LIGHT 12.............................................................................
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37MANUAL GEARBOX
2
ADJUSTMENT GEARBOX OIL - DRAIN AND REFILL
Service repair no - 37.24.01
Drain
1.The oil should be drained when the gearbox is
warm and the vehicle is standing on a level
surface.
WARNING: Observe due care when
draining gearbox as oil can be very hot.
2.Raise vehicle on ramp.
3.Position container to collect oil.
4.Clean area around filler/level plug.
5.Remove filler/level plug.
NOTE: Later gearboxes: Use No. 55 Torx
bit to remove filler/level plug.
6.Remove gearbox drain plug and discard sealing
washer.Refill
1.Clean gearbox drain plug and fit new sealing
washer.
2.Fit gearbox drain plug and tighten to50 Nm (36
lbf.ft).
3.Fill gearbox with correct grade of oil.See
LUBRICANTS, FLUIDS AND CAPACITIES,
Information.
4.Apply Loctite 290 to the filler/level plug and
tighten to30 Nm (22 lbf.ft).
5.Remove fluid container.
6.Lower vehicle on ramp.
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MANUAL GEARBOX
1
REPAIR COVER - FRONT - RESEAL AND FIT NEW INPUT
SHAFT OIL SEAL
Service repair no - 37.12.33.01
Remove
1.Remove gearbox.See this Section.
2.Remove retaining peg and remove release
bearing.
3.Remove bolt securing clutch release fork,
remove retaining clip and remove clutch release
fork.
4.Remove 2 bolts securing release bearing sleeve,
remove bearing sleeve.
5.Remove 6 bolts securing clutch housing, remove
housing.
6.Remove and discard 6 bolts securing front
cover, remove cover.
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37MANUAL GEARBOX
2
REPAIR
7.Using a soft metal drift, carefully remove input
shaft front bearing track from front cover.
CAUTION: Take care not to damage
bearing track, if track is damaged, it will be
necessary to fit a new input shaft front
bearing.
8.Remove input shaft oil seal from front cover;
discard oil seal.
Refit
9.Using a suitable solvent clean seal recess, front
cover and gearbox mating faces; clean threads
of bolts and bolt holes.
10.Clean bearings and bearing races.
11.Lubricate a new oil seal with gearbox oil.
12.Fit oil seal using a suitable mandrel.
13.Fit input shaft front bearing track using a press
and suitable mandrel.
14.Apply sealant, Part No. STC 4404 to front cover.
15.Position front cover, apply Loctite 290 to threads
of bolts; fit new bolts and tighten by diagonal
selection to25 Nm (18 lbf.ft).
16.Clean clutch housing mating faces, dowels and
dowel holes.
17.Position clutch housing, fit bolts and tighten by
diagonal selection to75 Nm (55 lbf.ft).
18.Clean bearing sleeve mating faces, dowel and
dowel holes.
19.Position bearing sleeve, fit bolts and tighten to
25 Nm (18 lbf.ft).
20.Examine clutch release fork pivot points for wear
and replace as required.
21.Apply a smear of Molybdenum disulphide grease
to pivot points and position release fork.
22.Fit retaining clip ensuring it locates over pivot
point washer, fit bolt and tighten to10 Nm (7
lbf.ft).23.Clean release bearing and bearing sleeve
mating faces.
24.Apply smear of Molybdenum disulphide grease
to release bearing sleeve.
25.Fit release bearing and secure with retaining
peg.
26.Fit gearbox.See this Section.
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37MANUAL GEARBOX
8
REPAIR
12.Remove 13 screws securing tunnel cover.
13.Release and remove tunnel cover.
14.Remove cooling fan.See COOLING SYSTEM,
Repair.
15.Remove air filter.See FUEL SYSTEM, Repair.
16.Remove 2 upper bolts securing clutch housing to
engine.
17.Remove bolt securing shim to clutch housing.
18.Release gearbox breather pipes from clips on
heater hose.
19.Remove starter motor.See ELECTRICAL,
Repair.
20.Remove exhaust front pipe.See MANIFOLD
AND EXHAUST SYSTEM, Repair.
21.Drain gearbox oil.See Adjustment.
22.Drain transfer gearbox oil.See
MAINTENANCE ,
23.Remove 3 nuts securing intermediate silencer to
tail pipe.
24.Release silencer from mounting rubbers, remove
silencer and discard gasket.
25.Mark front and rear propeller shaft to transfer
gearbox flanges for reassembly purposes.
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