Range-Rover-Maunua-Brakes, land rover
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BRAKE SYSTEM - Description
reducing valve.
A brake failure switch incorporated in the master
cylinder will illuminate a panel warning light if a
failure occurs in either the primary or secondary
hydraulic circuits.
The brake fluid reservoir is divided, the front
section (section closest to the servo) feeds the
primary circuit and the rear section feeds the
secondary circuit. Under normal
operating
conditions both the primary and secondary
hydraulic circuits operate simultaneously on brake
pedal application. In the event 01 a failure in the
primary circuit the secondary circuit will still
function and operate front and rear calipers.
Alternatively, if the secondary circuit fails, the
primary circuit will still function and operate the
upper pistons in the front calipers.
If the servo should fail, both hydraulic circuits will
still function but would require greater pedal
pressure.
The hand-operated parking brake is completely
independent of the hydraulic circuits.
Brake pad wear sensors are incorporated into the
front right and rear left hand side, inboard brake
pads. The sensors will illuminate a brake pad wear
warning light in the instrument binnacle, when pad
thickness has been reduced to approximately 3mm
(0.118
in).
:
The brake system fitted to Range Rovers is of the
I.H. split type.
Early 1987 Range Rover vehicles were fitted during
manufacture with an Automotive Products (AP)
master cylinder and servo assembly, together with
associated brake pipes and pedal box assembly.
The brake failure warning system on the AP type
master cylinder is a Pressure Differential Warning
Actuator (P.D.W.A.) switch, which is activated when
the shuttle valve moves along its bore due to
pressure differential in either the primary or
secondary circuits caused by fluid loss or seal
failure. The result of the shuttle valve movement is
to illuminate a brake failure warning light in the
instrument binnacle.
Later 1987 models are fitted with an uprated Lucas
Girting type LSC
115
servo and 25,4mm AS/AS
master cylinder plus associated brake pipes and
pedal box assembly.
The brake failure warning system on the Lucas
Girling type is a Fluid Level Warning Indicator
(F.L.W.I.) which is incorporated into the fluid
reservoir cap and is activated when fluid loss in the
reservoir is sufficient so that the float in the switch
drops and in turn illuminates a brake failure warning
light in the instrument binnacle.
NOTE: It should be noted that the two systems
are not interchangeable on a component by
component basis but must be changed as a
complete package, ie, servo, master cylinder,
brake pipes and pedal box.
.
CAUTION: THOROUGHLY CLEAN ALL BRAKE
CALIPERS,
PIPES AND FD-HNCS BEFORE
COMMENCING WORK ON ANY PART OF THE
BRAKE SYSTEM. FAILURE TO DO SO COULD
CAUSE FOREIGN MATTER TO ENTER THE SYSTEM
AND CAUSE DAMAGE TO SEALS, AND PISTONS
WHICH WILL SERIOUSLY IMPAIR THE BRAKE
SYSTEM EFFICIENCY.
The AP system can be found on pages :
1-19 inclusive.
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The Lucas Girling system can be found on pages :
31-42 inclusive.
To ensure the brake system efficiency is not
impaired the following warnings must be
adhered to:-
BRAKE SYSTEM - (Vehicles fitted with AP servo and
master cylinder)
WARNING:
Description
DO NOT use brake fluid previously bled from
the system.
1
The hydraulic braking system fitted to the Range
Rover is of the dual line type, incorporating primary
and secondary hydraulic circuits.
:
.:
DO NOT use old or stored brake fluid.
‘.
ENSURE that only new fluid is used and that it is
taken from a sealed container:
.:
NOTE: References made to primary and
secondary do not imply main service brakes or
emergency brakes but denote hydraulic line
identification.
‘.
DO NOT flush the brake system with any fluid
other than the recommended brake fluid. (See
Lubricants, Fluids and Capacities Section 09).
.:
.
.:
The brake pedal is connected to a vacuum-assisted
mechanical servo which in turn operates a tandem
master cylinder. The front disc brake calipers each
house four pistons,
the upper pistons are fed by
the primary hydraulic circuit, the lower pistons by
the secondary hydraulic circuit. The rear disc brake
calipers each house two pistons and these are fed
by the secondary hydraulic circuit via a pressure
The brake system should be drained and flushed
at the recommended service intervals. (See
Maintenance Section 10).
:
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.
:
:
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_:. ., ‘:
REVISED: JULY 87
1
1987 RANCE
ROVER
PRIMARY HYDRAULIC CIRCUIT
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SECONDARY HYDRAULIC CIRCUIT
WARNING: Some components on the vehicle,
such as gaskets and friction surfaces (brake
linings, clutch discs or automatic transmission
brake bands), may contain asbestos. Inhaling
asbestos dust is dangerous to your health and
the following essential precautions must be
observed:-
.
Dust found on the vehicle or produced
during work on the vehicle should be
removed by vacuuming and not by blowing.
.
Dust waste should be dampened, placed in
a sealed container and marked to ensure
safe disposal.
.
If any cutting, drilling etc., is attempted on
materials containing asbestos the item
should be dampened and only hands tools
or low speed power tools used.
.
Work out of doors or in a well ventilated
area and wear a protective mask.
. . . .
; .i
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‘, ’
REVISED: JULY 87
BRAKE SYSTEM LAYOUT
‘(.
RRlB45E
HOSES
1.
Front left hand flexible hoses.
2. Front right hand flexible hoses.
3. Intermediate flexible hose.
7. Feed to front right hand caliper.
8. Feed to rear left hand caliper.
9. Feed to rear right hand 5aliper.
10.
Feed to two way connector.
11.
Feed to intermediate hose.
12. Feed to pressure reducing valve.
13. Brake failure warning switch.
PIPES
,..;
4. Feed to front left hand hose connector.
5. Feed to front right hand hose connector.
‘.
‘.’ :.:.::.
6. Feed to front left hand caliper.
..I.:
.:.
3
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‘.
RANGE
“*’ ROVER
._ .’
BRAKES
Bleed
.
The hydraulic system comprises two completely
independent sections. The rear calipers and the
lower pistons in the front calipers form the
secondary section, while the upper pistons in the
front calipers form the primary section. The
following procedure covers bleeding the complete
system, but it is permissible to bleed one section
only if disconnections are limited to that section.
: .:.::::
‘.
Bleeding will be assisted if the engine is run or a
vacuum supply is connected to the servo.
‘.’
WARNING: IF THE ENGINE IS RUNNING DURING
THE BRAKE BLEEDING PROCESS ENSURE THAT
NEUTRAL GEAR IS SELECTED AND THAT THE
PARKING BRAKE IS APPLIED.
NOTE: When bleeding the system
commence with the caliper furthest from
the master cylinder and bleed from the
screw on the same side as the fluid inlet
pipes, then close the screw and bleed from
the screw on the opposite side of the same
caliper. Tighten the bleed screws to the
correct torque. (see section 06.Torque
values).
;’ ‘.
When bleeding any part of the secondary section,
almost full brake pedal travel is available. When
bleeding the primary section only, brake pedal
travel will be restricted to approximately half.
WARNING: Before commencing to bleed the
system it is necessary to loosen off the brake
failure warning switch to prevent the shuttle
valve damaging the switch unit.
Bleeding
,’ ;’
1. Fill the fluid reservoir with the correct fluid,
see IData Section’.
.
1.
Disconnect the leads from the switch.
2. Unscrew the switch and insert the ‘C’ washer
between the switch and master cylinder before
depressing the brake pedal.
3. After completion of bleeding, remove the ‘Cl
washer and screw in the switch and tighten to
the correct torque (see section 06-Torque
values).
‘.
.:’ ,.,
NOTE: The correct fluid level must be
maintained throughout the procedure of
bleeding
2. Connect a bleed hose to the bleed screw on
the rear caliper furthest from the master
cylinder.
.-
‘.
3. Submerge the free end of the bleed hose in a
container of clean brake fluid.
4. Loosen the bleed screw.
5. Operate the brake pedal -fully and allow to
return.
NOTE: Allow at least five seconds to elapse
with the foot right off the pedal to ensure
that the pistons fully return before
operating the pedal again.
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ROVER ls8’
6. Repeat 5 until fluid clear of air bubbles
appears in the container, then keeping the
pedal fully depressed, tighten the bleed screw.
7. Remove the bleed hose and replace the dust
cap on the bleed screw.
13.
Connect a bleed hose to the other screw on
the front caliper furthest from the master
cylinder.
Repeat 3 to 7 for the second secondary screw
on the front caliper.
Refit the front wheel.
Repeat 9 to
15
for the front caliper nearest the
master cylinder.
Remove the ‘C’ washer and tighten the PDWA
switch to the correct torque. (see section
06-Torque values).
14.
15.
16.
17.
BRAKE PRESSURE REDUCING VALVE
Remove and refit
Removing
1. Remove all dust, grime, etc., from the vicinity
of the pressure reducing valve fluid pipe
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RR1646E
unions.
2. Disconnect the outlet fluid pipe from the
pressure reducing valve. Plug the pipe and
reducing valve port to prevent the ingress of
foreign matter.
3. Remove the valve from the three-way
connector and plug both openings.
4. Withdraw the pressure reducing valve from the
engine compartment.
8.
9.
Repeat 1 to 7 for the other rear caliper.
Remove the front wheel on the side furthest
from the master cylinder.
Connect a bleed hose to the primary bleed
screw on the front caliper furthest from the
master cylinder.
Connect a bleed hose to the secondary bleed
screw on the same side of the caliper as the
primary screw.
Repeat 3 to 7 for the front caliper, bleeding
from the two screws simultaneously.
10.
,,..;.
11.
12.
RRlO4TE
Refitting
5.
Reverse the removal instructions.
6.
Bleed the brake systems.
NOTE: The pressure reducing valve is not a
serviceable item, in the event of failure or
damage, a new unit must be fitted.
Continued
REVISED: DEC. 87
5
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