tyre pressure FORD SIERRA 1987 2.G Braking System Workshop Manual

8Open the bleed screw half a turn and have
your assistant depress the brake pedal slowly
to the floor and then, after the bleed screw is
retightened, quickly remove his foot to allow
the pedal to return unimpeded. Repeat the
procedure.
9Observe the submerged end of the tube in
the jar. When air bubbles cease to appear,
tighten the bleed screw when the pedal is
being held fully down by your assistant.
10Top-up the fluid reservoir. It must be kept
topped up throughout the bleeding
operations. If the connecting holes to the
master cylinder are exposed at any time due
to low fluid level, then air will be drawn into
the system and work will have to start all over
again.
11Assuming that the complete system is
being bled, the procedure described in the
preceding paragraphs should be repeated on
the front right-hand caliper followed by the
rear right-hand and left-hand wheel cylinders.
12On completion, remove the bleed tube,
and discard the fluid which has been bled
from the system unless it is required for bleed
jar purposes. Never re-use old fluid.
13On completion of bleeding, top-up the
fluid level in the reservoir. Check the action of
the brake pedal, which should be firm and free
from any “sponginess” which would indicate
that air is still present in the system.
With one-way valve
14There are a number of one-man brake
bleeding kits currently available from motor
accessory shops. It is recommended that one
of these kits should be used whenever
possible, as they greatly simplify the bleeding
operation and also reduce the risk of expelled
air or fluid being drawn back into the system.
15Proceed as described in paragraphs 5
and 6.
16Open the bleed screw half a turn then
depress the brake pedal to the floor and
slowly release it. The one-way valve in the
bleeder device will prevent expelled air from
returning to the system at the completion of
each stroke. Repeat this operation until clear
hydraulic fluid, free from air bubbles, can be
seen coming through the tube. Tighten the
bleed screw.
17Proceed as shown in paragraphs 11 to 13.
With pressure bleeding kit
18These too are available from motor
accessory shops and are usually operated by
air pressure from the spare tyre.
19By connecting a pressurised container to
the master cylinder fluid reservoir, bleeding is
then carried out by simply opening each bleed
screw in turn and allowing the fluid to run out,
rather like turning on a tap, until no air bubbles
are visible in the fluid being expelled.
20Using this system, the large reserve of
fluid provides a safeguard against air being
drawn into the master cylinder during the
bleeding operations.21This method is particularly effective when
bleeding “difficult” systems or when bleeding
the entire system at time of routine fluid
renewal.
22Begin bleeding with reference to
paragraphs 5 and 6 and proceed as described
in paragraphs 11 to 13.
1Keep the fluid reservoir replenished
throughout the bleeding operations.
2Remove the dust cap where fitted, and
clean around the bleed screw on the left-hand
front caliper. Fit a bleed tube to the screw and
immerse the open end in a jar containing
clean hydraulic fluid.
3Open the bleed valve one full turn and have
an assistant depress the brake pedal fully and
hold it down.
4Close the bleed valve and release the brake
pedal. Repeat the procedure until fluid ejected
from the end of the tube is free from air
bubbles.
5Repeat the operations on the right-hand
front caliper.
6Fit the bleed tube to the left-hand rear
caliper and open the bleed valve one full turn.
7Have an assistant depress the brake pedal
fully and hold it down.
8Switch on the ignition to position ll.
9Allow the fluid to bleed from the tube for at
least 15 seconds, when the fluid should be
free from air bubbles.
10Close the bleed valve.
11Release the brake pedal and wait for the
hydraulic pump to stop.
12Fit the bleed tube to the right-hand rear
caliper and open the bleed valve one full turn.
13Have your assistant depress the brake
pedal through half its travel and hold it there.
Allow the fluid to bleed from the tube for at
least 15 seconds, when the fluid should be
free from air bubbles.
14Close the bleed valve.
15Release the brake pedal and wait for the
hydraulic pump to stop then switch off the
ignition.
16Top-up the reservoir with clean fluid.
17When the hydraulic system is being bled
for the purpose of renewing the fluid at the
specified interval, as each caliper is bled,
operate the brake pedal continuously until
clean fluid is seen to enter the jar.
18When the hydraulic pump is running its
note will be heard to change once fluid has
purged through it. Do not allow the pump torun continuously for more than two minutes. If
it does run for a longer period, switch off the
ignition and allow the motor to cool for ten
minutes.
19On completion, discard the fluid which
has been bled from the system unless it is
required for bleed jar purposes. Never re-use
old fluid.
20Check the action of the brake pedal,
which should be firm and free from any
“sponginess”, which would indicate that air is
still present in the system.
Front disc pads
1The disc pad friction material can be
inspected for wear without removing the
roadwheels. Working beneath the vehicle,
insert a mirror between the caliper and the
roadwheel and check that the friction material
thickness is not less than the minimum given
in the Specifications.
2If any one of the pads has worn below the
specified limit, the front pads must be
renewed as an axle set (4 pads).
3To renew the pads, slacken the front
roadwheel nuts, apply the handbrake, then
jack up the front of the vehicle and support on
axle stands (see “Jacking and Vehicle
Support”). Remove the roadwheels. On P100
models, mark the position of the roadwheels
in relation to the wheel studs before removal.
4Proceed as follows according to model:
Girling caliper (1.3 and early 1.6 litre
models)
5Where applicable, disconnect the wiring to
the disc pad wear sensor.
6Unscrew and remove the bolt from the
upper caliper guide pin while holding the pin
stationary with a spanner (see illustration).
7Swing the caliper downwards and lift out
the disc pads. If the outboard pad is stuck to
4Disc pads -inspectionand
renewal
3Brake hydraulic system (ABS)
- bleeding
Braking system 10•3
10
4.6 Unscrewing the bolt from the upper
caliper guide pin - Girling caliper
Caution: Refer to the
precautions in Section 1.
Caution: The rear brake
hydraulic circuit may be under
considerable pressure, take
care not to allow hydraulic fluid
to spray into the face or eyes. Refer to the
precautions in Section 1.

neck with a rubber band, or by refitting the
cap. This will reduce the loss of fluid during
the following procedure.
3Disconnect the flexible fluid hose from the
rigid brake pipe under the wing of the vehicle,
or alternatively unscrew the flexible hose from
the union on the caliper. Take care not to twist
the hose, and plug the open ends to prevent
fluid loss and dirt ingress.
4Remove the disc pads.
5On models fitted with Girling calipers (1.3
and early 1.6 litre models) (see illustration),
unscrew and remove the bolt from the lower
caliper guide pin, while holding the pin
stationary with a spanner, then remove the
caliper.
6On models fitted with Teves calipers (later
1.6, 1.8 and 2.0 litre models) (see
illustration), remove the caliper from the
vehicle.
7If required, the caliper carrier bracket can
be unbolted and removed from the hub
carrier.
Overhaul
8Brush away all external dirt and dust, but
take care not to inhale any dust as it may be
injurious to health.
9Pull the dust-excluding rubber seal from the
end of the piston.
10Apply air pressure to the fluid inlet union,
and eject the piston. Only low air pressure is
required for this, such as is produced by a
foot-operated tyre pump. Position a thin piece
of wood between the piston and caliper body
to prevent damage to the end face of the
piston in the event of its being ejected
suddenly.
11Using a suitable pointed instrument, prise
the piston seal from the groove in the cylinder
bore. Take care not to scratch the surface of
the bore.
12Clean the piston and caliper body with
methylated spirit and allow to dry. Examine
the surfaces of the piston and cylinder bore
for wear, damage and corrosion. If the piston
surface alone is unserviceable, a new piston
must be obtained, along with seals. If the
cylinder bore is unserviceable, the complete
caliper must be renewed. The seals must be
renewed regardless of the condition of the
other components.
13Coat the piston and seals with clean
brake fluid, then manipulate the piston seal
into the groove in the cylinder bore.
14Push the piston squarely into its bore.
15Fit the dust-excluding rubber seal
between the piston and caliper, then depress
the piston fully.
Refitting
16Refit the caliper and where applicable the
carrier bracket by reversing the removal
operations. Tighten the mounting bolts to the
specified torque.17On P100 models, when refitting the
roadwheel align the previously made marks
on the roadwheel and wheel stud.18On completion, bleed the front brake
circuit.
Braking system 10•9
10
6.6 Exploded view of Teves front disc caliper
A Guide bolts
B Caliper carrier bracket
C Caliper retaining clipD Disc pads
E Dust-excluding seal
F Piston sealG Piston
H Caliper
6.5 Exploded view of Girling front disc caliper
A Caliper
B Guide pin and dust
bootC Piston seal
D Piston
E Dust-excluding sealF Disc pads
G Caliper carrier bracket