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secure. Fit the spring and spring retainer on the primary piston spigot,
compress the spring and secure with
the
"Spirolex" circlip. Smear the
inner end of the push rod with silicon grease, ease the push rod into the
rubber boot and fit the boot to its retaining plate.
Ease the spring clip into the non-return valve body, fit the return spring
over the valve body and insert the assembly, spring first, into the fluid
outlet port. Fit the gasketto the outlet adaptor and screw the adaptor in
the outlet port, tighten it to the specified torque. Repeat for the other
non-return valve.
If removed, refit the cover to the brake fluid reservoir using a new gasket.
MASTER CYUNDER
(WITH
SERVO)
Removal and Installation
When removing and installing the master cylinder, it is not necessary to
remove the vacuum servo unit.
Place rags under the master cylinder to prevent damage to the paintwork.
Unscrew the two hydraulic pipes from the master cylinder unions and fit
blanking plugs to prevent the ingress of dirt and loss of fluid. Unscrew the
two master cylinder retaining bolts and separate
the
master cylinder from
the vacuum servo unit.
Installation is the reverse of the removal procedure. Refill the system with
the recommended brake fluid and bleed the brakes.
Overhaul:
The master cylinder should only be dismantled if an exchange unit is
unobtainable.
Refer to
Fig.
J:23 for an exploded view of the components
referred to in this section.
Depress the spring retainer, extract the "Spirolex" circlip from the groove
on the primary piston and remove the spring retainer, spring, washer and
gasket. Extract the circlip retaining the nylon guide bearing, tap the
cylinder mounting flange lightly on the bench and remove the guide
bearing, the secondary cup and the plain washer. Using long-nosed pliers,
extract the circlip retaining the piston stop ring
(Fig.
J:21}. Both pistons
together with the stop ring can now be withdrawn from the
cylinder.
Depress the spring holder between the two pistons sufficiently to allow the
clip retaining
pin
to be driven
out.
The pistons can now be separated
and
the spring
and
spring holder removed. No attempt should be made to
remove the link clip from the secondary pistqn as the clip
is
permanently
peened in position. Remove the primary and
secondary
cups and piston
washers from the pistons.
Unscrew the
adaptors
from the fluid outlets on the cylinder body
(Fig.
J:25).
Remove the gaskets. Withdraw the non-return valves, comprising the
spring, valve body and spring clip, from the fluid outlets. Take care not to
distort the spring
clip
when removing it from the
valve
body.
If
necessary,
the four retaining bolts
can
be unscrewed and the brake fluid
reservoir cover and gasket detached from the cylinder
body.
Reference should be made to "HYDRAULIC SYSTEM OVERHAUL
PROCEDURES" earlier in this section concerning the inspection and
overhaul of the master cylinder. Use a piece of thin steel wire to probe the
by-pass
ports.
Dip all the components in clean brake fluid before
reassembling.
Using fingers
only,
fit the secondary
cup
on the large end of the secondary
piston so that the flat side of the cup
abuts
the shoulder of the
piston.
Locate the piston washer on the other end of the piston with the
concave
face towards the piston shoulder and fit the primary cup so that the flat
side of the cup also faces the piston shoulder (Fig.
J:
22}.
Fit the primary
cup and piston washer to the primary piston in the same way.
Fit the link clip retaining pin in the hole in the primary piston, but do not
push it fully home. Fit the spring and spring holder to the secondary
piston and compress the spring until the link clip is visible. Locate the end
of the clip in the primary piston and
secure
with the retaining pin. Release
the spring and spring holder and check that the holder is correctly
positioned.
100
Dip the assembly in clean brake fluid and insert it into the cylinder. Slide
the pison stop ring
over
the primary piston
and
using long-nosed pliers, fit
the retaining circlip. Install the plain washer, secondary cup with the lip
inwards, nylon guide bearing and outer retaining clirclip. Fit the gasket,
washer,
spring
and spring retainer on the primary piston spigot,
compress
the spring and secure with the
"Spirolex'
circlip.
Ease the spring clip into the non-return valve body, fit the return spring
over the valve body and insert the assembly, spring first, into the fluid
outlet port. Fit the gasket to the outlet adpator and screw the adaptor
into the outlet port. Tighten it to the specified torque. Repeat for the
other non-return
valve.
If removed, refit the cover to the brake fluid reservoir using a new gasket.
VACUUM SERVO UNIT
A
vacuum servo unit is incorporated in the braking system on models as
from
1969.
The servo unit is mounted on the engine compartment bulk-
head directly
in
front of the driver with the master cylinder mounted
directly on the front
of
the unit.
Removal and Installation
From inside the car, remove the protective cover from the steering wheel
shaft. Remove the cotter pin and washer and disconnect the master
cylinder push rod from the brake pedal. Place rags under the master
cylinder to prevent damage to the paint work. Unscrew the two hydraulic
pipes from the unions on the master cylinder and fit blanking plugs to
prevent the ingress of dirt and loss of fluid. Disconnect the vacuum hose
from the vacuum servo unit. Unscrew the four nuts retaining the servo unit
to the bulkhead. These nuts are accessible from inside the car. Remove the
vacuum servo unit and master cylinder.
Unscrew the two master cylinder retaining bolts and separate the master
cylinder
from
the servo unit.
Installation is the reverse of the removal
procedure.
Refill the system with
recommended brake fluid and bleed the brakes.
Air
Filter Replacement
:
Remove the protective cover
from
the steering wheel shaft. Remove the
cotter pin
and
washer and disconnect the master cylinder push rod from
the brake pedal. Remove the rubber
bellows.
Insert
a
screwdriver behind
the
air
filter retaining washer and pry the washer off. Extract the old air
filter. Insert the new filter and refit the washer by tapping gently with a
hammer around the
edge of
the washer. Refit the rubber bellows and
reconnect the push rod to the brake pedal.
Overhaul
:
The vacuum servo unit is serviced as a complete
assembly and
no attempt
should be made to dismantle
or overhaul it.
BLEEDING THE BRAKES
As the master
cylinder
has tandem pistons, both
rear
wheels and both
front
wheels must be bled simultaneously. The positions
of
the bleed valves
are
shown in
Figs.
J:26 &
J:27.
Top up the brake fluid reservoir. Fit
a
bleeder tube to the bleed valve at
each of
the rear
brakes.
Immerse the
other
end of the tube in
a small
quantity of hydraulic fluid in a clean jar (Fig. J: 28}. Open the bleed valves
1/2- I turn, and de£ress brake pedal, quickly and then allow it to
return slowly to its' OFF" position. Continue depressing the brake pedal,
pausing after each return stroke, until the fluid coming from
the
bleed
tubes is free from air bubbles. When the fluid
above
comes from the bleed
tubes, close the bleed valve with the pedal in the depressed
position.
Check the fluid level in the master cylinder and repeat the bleeding proced-
ure
for the
front
brakes.
Top up the fluid reservoir
and
replace the reservoir
cap after
checking that the vent holes in the cap are clear.lf the brake
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