2002 LAND ROVER DISCOVERY brake

BRAKES
DESCRIPTION AND OPERATION 70-23
Typical disabled times
Diagnostics
While the ignition is on, the diagnostics function of the SLABS ECU monitors the system for faults. In addition, the
return pump is tested by pulsing it briefly immediately after the engine starts provided vehicle speed exceeded 4.4
mph (7 km/h) during the previous ignition cycle. If a fault exists in a warning lamp circuit, the lamp will not illuminate
during the lamp check at ignition on but, provided there are no other faults, the related function will otherwise be fully
operational. If a fault is detected during the power up, the SLABS ECU stores a related fault code in memory and
illuminates the appropriate fault warning lamps. If a fault is detected later in the drive cycle, the SLABS ECU also
sounds the audible warning three times.
Fault codes and diagnostic routines can be accessed by connecting Testbook to the vehicle's diagnostic connector
in the driver's footwell.
Warning lamp fault operation
After detecting a fault, the SLABS ECU selects an appropriate default strategy which, where possible, retains some
operational capability. A shuttle valve switch fault and throttle position signal fault are classified as permanent faults.
If a permanent fault is detected, the related warning lamp illumination and default strategies are automatically
employed in subsequent ignition cycles, even if the fault is intermittent, until the fault has been rectified and cleared
from memory. If a non permanent fault is detected, the related warning lamp illumination and default strategies will
only be employed in subsequent ignition cycles if the fault is still present.
After rectification of an ABS sensor fault, the ABS and ETC functions are disabled, and the ABS warning lamp remains
illuminated after the lamp check, until vehicle speed exceeds 9.4 mph (15 km/h) (to allow additional checks to be
performed).
Vehicle speed, mph (km/h) Time, minutes
1.3 (2) 40
12.5 (20) 33
15.6 (25) 17
25.0 (40) 9
31.3 (50) 6
Item Check Warning lamp
ABS Brake ETC HDC
fault
ABS sensors Resistance (to check status) On On On On
Brake lamps relay Open/Short circuit Off Off Off On
Engine data Sticking throttle, signal failure, data corruption Off Off On On
Inlet solenoid valves Open/Short circuit On On On On
Outlet solenoid valves Open/Short circuit On On On On
Reference earth Connection to earth On On On On
Return pump monitor Correct pump operation On On On On
Return pump relay Open/Short circuit On On On On
Shuttle valve switches Open/Short circuit On On On On
SLABS ECU Internal failure On On On On
Supply voltages Range (10 to 16 V) On On On On

BRAKES
70-24 DESCRIPTION AND OPERATION
Default strategies
Electrical data
Nominal resistance values for applicable brake control components are as detailed below:
Fault Default strategy
Brake lamps relay ABS: Enabled.
ETC: Enabled.
EBD: Enabled.
HDC: Enabled.
Throttle position signal failure ABS: Enabled.
ETC: Disabled.
EBD: Enabled.
HDC: Immediately disabled if not in active braking mode; faded out then disabled if in active
braking mode.
No reference earth ABS: Disabled.
ETC: Disabled.
EBD: Partly disabled.
HDC: Disabled.
Return pump or relay fault ABS: Disabled.
ETC: Disabled.
EBD: Partly disabled.
HDC: Disabled.
Shuttle valve switch failure ABS: Deceleration threshold increased; return pump activated if sum of output valve
actuation on one axle exceeds 140 milliseconds.
ETC: Disabled.
EBD: Inlet valves of rear axle close at vehicle deceleration rates of 0.3 g and above.
HDC: Disabled.
SLABS ECU internal failure ABS: Disabled.
ETC: Disabled.
EBD: Disabled.
HDC: Disabled.
Supply voltage out of limits ABS: Disabled.
ETC: Disabled.
EBD: Disabled.
HDC: Disabled.
Component Resistance, ohms
Brake lamp relay coil117 - 143
Return pump relay coil82.8 - 101.2
ABS sensor950 - 1100
Shuttle valve switches, both open (brakes off) 2977 - 3067
Shuttle valve switches, both closed (brakes on) 1007 - 1037
Shuttle valve switches, one open, one closed 1992 - 2052
Inlet solenoid valve5.9 - 7.3
Outlet solenoid valve3.0 - 3.6

BRAKES
DESCRIPTION AND OPERATION 70-25
DESCRIPTION AND OPERAT ION
Handbrake component layout
1Warning switch
2Handbrake lever
3Cable
4Protective sleeve
5Drum brake
6'C' clip
7Threaded sleeve
8Adjuster wheel
9Base plate
10Transmission tunnel

BRAKES
70-26 DESCRIPTION AND OPERATION
Description
General
The handbrake consists of a drum brake, installed on the rear of the transfer box, operated by a cable connected to
a handbrake lever between the front seats.
Handbrake lever
The handbrake lever is mounted on a base plate which attaches to the transmission tunnel. A conventional ratchet
and thumb operated release button are incorporated for locking and unlocking the lever. A warning switch on the base
of the lever operates the brake warning lamp in the instrument pack. While the handbrake is applied the warning
switch connects an earth to the instrument pack which, if the ignition is on, illuminates the brake warning lamp. In
some markets, the instrument pack performs a bulb check of the brake warning lamp each time the ignition is switched
on.
Cable
The handbrake cable consists of inner and outer cables installed between the handbrake lever and the drum brake.
A protective sleeve is installed on the cable to protect the cable from heat from the exhaust system. Handbrake
adjustment is provided by a threaded sleeve installed on the outer cable where it locates in the handbrake lever.
Turning an adjuster wheel, which is keyed to the threaded sleeve and secured by a 'C' clip, alters the effective length
of the outer sleeve and consequently changes the handbrake lever movement needed to apply the drum brake.

BRAKES
DESCRIPTION AND OPERATION 70-27
Drum brake
1Drum
2Drum securing bolt
3Backplate
4Cable
5Backplate securing bolt
The drum brake consists of a backplate attached to the transfer box casing and a drum attached to the transfer box
rear output shaft. When the handbrake lever is applied, the movement is transmitted by the inner cable to a lever on
one of the brake shoes on the backplate. The lever pivots against the brake adjuster rod, which forces the shoes apart
and into contact with the drum. Brake shoe to drum clearance is set by an adjusting bolt on the rear of the backplate.

BRAKES
70-28 DESCRIPTION AND OPERATION

BRAKES
ADJUSTMENTS 70-29
ADJUST ME NTS
Handbrake
$% 70.45.09
Check
1.Apply the handbrake lever 3 notches on the
ratchet. The handbrake should be fully
operational.
2.If the handbrake is not fully operational, the
brake shoes and/or the handbrake cable need
adjusting.
Adjust
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.Ensure handbrake lever is fully released.
3.Tighten brake shoe adjusting bolt until brake
drum is locked, then back off adjusting bolt 1.5
turns. Check that the brake drum is free to
rotate.
4.Recheck handbrake operation.If handbrake is
not fully applied with 3 notches on the
ratchet, the handbrake cable requires
adjustment.
5.Remove switch panel from centre console.

+ WINDOWS, REPAIRS, Switch -
console.
6.Release handbrake lever gaiter from centre
console.7.Rotate adjuster anti-clockwise to increase
cable tension (reduce notches) or clockwise to
decrease cable tension (increase notches).
8.Recheck handbrake operation.
9.Secure handbrake lever gaiter to centre
console.
10.Fit switch panel to centre console.

+ WINDOWS, REPAIRS, Switch -
console.
11.Remove stand(s) and lower vehicle.

BRAKES
70-30 ADJUSTMENTS
Brake system bleeding
$% 70.25.02
Bleeding of the brake system can be carried out
using the procedures given on TestBook, or by
following the manual procedure given below.
WARNING: If any components upstream of brake
modulator, including the modulator itself are
replaced, the brake system must be bled using
the procedure on TestBook/T4, to ensure that all
air is expelled from the new component(s).
WARNING: Do not allow brake fluid to come into
contact with eyes or skin.
Bleed
NOTE: This procedure covers bleeding the
complete system, but where only the primary or
secondary circuit have been disturbed in
isolation, it should only be necessary to bleed
that circuit. Partial bleeding of the hydraulic
system is only permissible if a brake pipe or
hose has been disconnected with only minor
loss of fluid.
1.Do not allow fluid level in master cylinder to fall
below 'MIN' mark during bleeding.
2.Do not fill reservoir above 'MAX' level.
3.Raise front and rear of vehicle.
WARNING: Do not work on or under a
vehicle supported only by a jack. Always
support the vehicle on safety stands.
4.Check all pipe and hose connections are tight
and there are no signs of leakage.
5.Top-up fluid level in brake reservoir to 'MAX'
mark.
WARNING: Do not allow dirt or foreign
liquids to enter the reservoir. Use only new
DOT 4 brake fluid from airtight containers.
Do not mix brands of brake fluid as they
may not be compatible.6.Attach bleed tube to the bleed screw on front
brake caliper on the passenger side, submerge
free end in a clear container containing brake
fluid.
7.Apply pressure to brake pedal several times,
then apply steady pressure.
8.Loosen bleed screw to release brake fluid and
air. Allow pedal to return unassisted.
9.Depress brake pedal steadily through its full
stroke and allow to return unassisted. Repeat
procedure until a flow of clean air-free fluid is
purged into container then, whilst holding
pedal at end of downward stroke, tighten brake
caliper bleed screw to 10 Nm (7 lbf.ft).
CAUTION: Ensure the fluid in the reservoir
is maintained between the minimum and
maximum levels throughout the bleed
procedure using new brake fluid.
10.Top-up brake fluid level to 'MAX' mark.