Land Rover Defender 90 Workshop 2nd Edition Nas Rover Manual

							70BRAKES
4
REPAIR PRESSURE REDUCING VALVE (PRV)
Service repair no - 70.25.21
Remove
1.Disconnect battery.
2.Clean reducing valve parts.
3.Place a container under PRV valve to catch
escaping brake fluid.
4.Disconnect primary circuit pipe unions ñAñ
from PRV.
5.Disconnect secondary circuit pipe unions ñBñ
from PRV.
6.Cover pipes to prevent ingress of dirt.
7.Remove single retaining nut and bolt securing
PRV to engine bulkhead.
8.Remove valve.
Refit
9.Fit valve to engine bulkhead. Tighten bolt to
15
Nm, 11 lbf/ft.
10.Connect primary and secondary circuit pipes to
PRV. Tighten to
16 Nm, 12 lbf/ft.
11.Fill brake reservoir with recommended brake
fluid.
See LUBRICANTS, FLUIDS AND
CAPACITIES, Information, Recommended
lubricants and fluids
12.Bleed the brake system.See Brake system
bleed
13.Reconnect battery and road test vehicle.SERVO NON RETURN VALVE
Service repair no - 70.50.15
Remove
1.Disconnect brake vacuum hose from servo
non-return valve.
2.Carefully prise valve out with a screwdriver blade
between valve and grommet. Take care not to
exert too much pressure on the vacuum
chamber.
3.Remove rubber grommet but be careful not to
allow it to fall into the vacuum chamber.
4.Check the valve for correct operation; it should
not be possible to pass air through into the servo
in direction of arrow.
WARNING: Do not use compressed air.
Refit
5.Fit rubber grommet.
6.Smear ribs of the valve with Lucas Girling
grease to assist assembly, and push valve fully
home.
7.Connect vacuum hose to the valve.
8.Road test vehicle. 
						

							BRAKES
5
REPAIR SERVO ASSEMBLY
Service repair no - 70.50.01
Remove
Before starting repair refer to general brake service
practice.
See General Brake Service Practice
NOTE: The non-return valve and grommet,
are the only serviceable components, in
event of failure or damage, fit a new unit.
1.Remove master cylinder.See Master cylinder
2.Disconnect vacuum supply hose from servo unit.
3.At footwell, release 2 brake pedal return springs.
4.Disconnect leads from brake light switch at rear
of pedal box.
5.Remove blanking grommets from each side of
pedal box.
6.Remove split pin and clevis pin securing servo
push rod to brake pedal.
7.Remove 4 nuts and plain washers securing
servo to pedal box.
8.Remove servo assembly and rubber washer
from bulkhead.Refit
9.Locate servo assembly and rubber washer to
engine bulkhead and secure to pedal box.
Tighten fixings to
14 Nm, 10 lbf/ft.
10.Fit brake pedal to servo push rod with clevis pin
and new split pin.
11.Fit blanking grommets to each side of pedal box.
12.At footwell, attach pedal return springs.
13.Connect vacuum hose to servo non-return valve.
14.Fit brake master cylinder to servo unit.
See
master cylinder 
						

							70BRAKES
6
REPAIR BRAKE PEDAL
Service repair no - 70.35.01 - Brake pedal
Service repair no - 70.35.03 - Pedal box
Remove
1.Remove brake servo assembly.
See Brake
servo assembly
2.Remove 6 bolts securing pedal box to engine
bulkhead.
3.Taking care not damage brake fluid pipes,
remove pedal box assembly and gasket.
4.Release return springs from pedal and pedal box
bosses.
5.Using a suitable punch, drift out retaining pin and
withdraw pedal pivot shaft.
6.Remove brake pedal complete with pivot
bushes.
7.Examine components for wear or damage,
renew as necessary.
8.If it is necessary to fit new pivot bushes, they
must be reamed out to 15,87 mm±0,02 mm,
0.625±0.001 in after fitment.Refit
9.Lubricate pedal pivot shaft and bushes with
general purpose grease.
10.Fit pedal to pedal box, insert pivot shaft and
secure with new split pin.
11.Attach return springs to pedal and pedal box
bosses.
12.Fit pedal box and gasket to engine bulkhead.
Tighten fixings to
25 Nm, 18 lbf/ft.
13.Fit brake servo assembly.See Brake servo
assembly 
						

							BRAKES
7
REPAIR FRONT BRAKE PADS
Service repair no - 70.40.02
Remove
1.Remove front road wheels .
2.Clean exterior of calipers.
3.Remove split [cotter] pin from retaining pins.
4.Remove pad retaining pins and anti-rattle
springs.
5.Remove brake pads.
6.Clean exposed parts of pistons, using new brake
fluid. Wipe away excess with a lint free cloth.
7.Using piston clampLRT-70-500press each
piston back into its bore. Ensure that displaced
brake fluid does not overflow from reservoir.
Refit
8.Fit brake pads.
9.Fit pad retaining pins and anti-rattle springs.
Secure with new split [cotter] pins.
10.Apply service brake pedal several times to locate
pads.
11.Check fluid reservoir. Top-up if necessary, using
correct grade of fluid.
See LUBRICANTS,
FLUIDS AND CAPACITIES, Information,
Recommended lubricants and fluids 
						

							70BRAKES
8
REPAIR REAR BRAKE PADS
Service repair no - 70.40.03
Remove
1.Remove rear road wheels.
2.Clean exterior of calipers.
3.Remove pad retaining pins and anti-rattle
springs.
4.Remove brake pads.
5.Clean exposed parts of pistons, using new brake
fluid. Wipe away excess with a lint free cloth.
6.Using piston clampLRT-70-500press each
piston back into its bore. Ensure that displaced
brake fluid does not overflow from reservoir.
Refit
7.Insert brake pads.
8.Position pad retaining springs, fit new pins and
spread ends.
9.Apply brake pedal several times to locate pads.
10.Fit road wheels.
130 Nm, 95 lbf ft.
11.Check fluid reservoir, top up if necessary, using
correct grade of fluid
See LUBRICANTS,
FLUIDS AND CAPACITIES, Information,
Recommended lubricants and fluids 
						

							BRAKES
9
REPAIR FRONT BRAKE CALIPER ASSEMBLY
Key to caliper
1.Caliper
2.Bleedscrew
3.Anti-rattle springs
4.Pad retaining pins
5.Split [cotter] pin
6.Friction pads7.Piston
8.Wiper seal retainer
9.Wiper seal
10.Fluid seal
11.Brake disc 
						

							70BRAKES
10
REPAIR FRONT BRAKE CALIPERS
Service repair no - 70.55.05
Service repair no - 70.55.16
Before starting repair refer to general brake service
practice.
See General Brake Service Practice
Remove
1.Remove front road wheels.
2.Expose flexible brake hose by moving coiled
protective covering.
3.Using a hose clamp, clamp hose to prevent loss
of brake fluid.
4.Disconnect rigid brake pipe from flexible hose,
seal exposed ends to prevent ingress of dirt.
5.Remove split [cotter] pin, retaining pins and
springs, withdraw pads. If refitting pads, identify
them for assembly to original locations.
6.Remove 2 bolts and withdraw caliper from swivel
housing.Refit
WARNING: Do not separate caliper halves
7.Clean outer surfaces of caliper using aerosol
brake cleaner.
8.Using special toolLRT-70-500, clamp pistons in
inboard half of caliper. Gently, keeping fingers
clear, and withCAUTION,apply air pressure to
fluid inlet port to expel pistons. It is unlikely that
pistons will expel at same time. Regulate rate
with a suitable piece of wood between
appropriate piston and caliper.
9.Finally remove pistons, identifying them with
their respective bores.
10.Remove wiper seal retainer by inserting a blunt
screwdriver between retainer and seal. Pry
retainer carefully from mouth of bore.
11.Taking care not to damage seal grooves, extract
wiper seal and fluid seal.
12.Clean bores, pistons and seal grooves using
clean brake fluid only. If caliper or pistons are
corroded, or their condition is not perfect, new
parts must be fitted. 
						

							BRAKES
11
REPAIR Assemble outboard pistons
13.Coat new fluid seal with brake fluid. Ease seal
into groove in bore using only fingers, ensuring it
is properly seated. Fluid seal and groove are not
same in section, so when seal is seated it feels
raised to touch at edge furthest away from
mouth of bore.
14.Coat appropriate piston with brake fluid. Insert it
squarely into bore by hand only. Do not tilt piston
during insertion, leave approximately 8mm
projecting from bore.
15.Coat new wiper seal with brake fluid and fit to
new seal retainer. Slide assembly, seal first, over
protruding piston and into bore recess. Use
piston clamp to press home seal retainer and
piston.
Mounting inboard pistons
16.Clamp outboard pistons and carry out same
procedure for removing and fitting outboard
pistons and seals, instructions 8 to 15.
Fit calipers and pads
17.Fit caliper, tighten bolts evenly to
82 Nm, 60
lbf/ft.
18.Connect brake flexible hoses to caliper. Tighten
to
15 Nm, 11 lbf/ft.
19.Remove hose clamps.
20.Insert pads. Fit pins and springs, secure using
new split [cotter] pin.
21.Bleed brake system.
See Brake System Bleed
22.Press brake pedal firmly several times to locate
friction pads.
23.Fit road wheels, remove axle stands. Finally
tighten road wheel nuts to
130 Nm, 96 lbf/ft.
24.Road test vehicle. Note that new friction pads
require bedding-in, this may take several
hundred miles before brakes are at maximum
efficiency.FRONT BRAKE DISCS
Service repair no - 70.10.10.
Remove
1.Remove hub assembly.
See FRONT AXLE
AND FINAL DRIVE, Repair, Front hub
assembly
2.Remove 5 hub to disc bolts.
3.Tap disc to separate from hub.
Refit
4.Locate disc to hub.
5.Apply Loctite 270 to disc bolts and tighten to
73
Nm, 54 lbf/ft.
6.Check total disc runout with a dial indicator, this
must not exceed 0,15 mm, 0.006 in. If necessary
reposition disc.
7.Fit hub assembly
See FRONT AXLE AND
FINAL DRIVE, Repair, Front hub assembly
Disc reclamation
8.Check disc thickness. This dimension may be
machined to minimum thickness of 22 mm,
0.875 in - ventilated discs. Machine equal
amount off each face.
NOTE: The disc MUST BE renewed if the
minimum running thickness stamped on
the disc is recorded. 
						

							70BRAKES
12
REPAIR REAR BRAKE CALIPER ASSEMBLY
Key to rear caliper
1.Caliper
2.Bleed screw
3.Pad retaining springs
4.Brake pads
5.Piston6.Wiper seal retainer
7.Wiper seal
8.Fluid seal
9.Retaining pins 
						

							BRAKES
13
REPAIR REAR BRAKE CALIPERS
Service repair no - 70.55.06
Service repair no - 70.55.17
Before starting repair refer to General brake service
practice.
See General Brake Service Practice
Remove
1.Remove rear road wheels.
2.Using a recognised hose clamp, clamp flexible
brake hose above rear axle.
3.Remove brake pipe from rear brake caliper.
4.Seal pipe ends to prevent ingress of dirt.
5.Remove retaining pins and withdraw pads. If
same pads are to be refitted, identify them for
assembly in original positions.
6.Remove 2 bolts and withdraw caliper from rear
axle.Refit
WARNING: Do not separate caliper halves.
7.Clean outer surfaces of caliper with aerosol
brake cleaner.
8. WITH CAUTIONexpel pistons from their bores
by applying air pressure to fluid inlet port. It is
unlikely both pistons will expel at same time,
regulate rate with a suitable piece of wood
inserted between two pistons.
9.Finally, remove pistons keeping them identified
with their respective bores.
10.Remove wiper seal retainer by inserting a blunt
screwdriver between retainer and seal and pry
retainer carefully from mouth of bore.
11.Taking care not to damage seal grooves, extract
wiper seal and fluid seal.
12.Clean bores, pistons and particularly seal
grooves using clean brake fluid only. If caliper or
pistons are corroded or their condition is not
perfect new parts must be fitted.
13.Apply brake fluid to new seal. Fit seal into
groove in bore. When seal is seated it feels
raised to touch at edge furthest away from
mouth of bore.