change wheel FORD SIERRA 1990 2.G Braking System Workshop Manual
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Page 3 of 22
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.
Page 5 of 22
the caliper, and the caliper body is modified
accordingly. Also, plastic covers are fitted to
the caliper guide bolts (see illustrations).
22Procedures are unchanged from those
given above.
Rear disc pads
23Slacken the rear roadwheel nuts, chock
the front wheels, then jack up the rear of the
vehicle and support on axle stands. (see
“Jacking and Vehicle Support”). Remove the
roadwheel.
24The disc pads can be inspected through
the top of the caliper after removal of the
blanking spring clip. Check that the friction
material thickness is not less than the
minimum given in the Specifications.
25If any one of the pads has worn below the
specified limit, the rear pads must be renewedas an axle set (4 pads).
26To renew the pads, proceed as follows.
27Release the handbrake, and free the
handbrake cable from the suspension lower
arm by bending back the tangs.
28Where applicable, disconnect the wiring
to the disc pad wear sensor (see illustration).
29Unscrew and remove the bolt from the
forward caliper guide pin, while holding the
pin stationary with a spanner (see
illustration).
30Swing the caliper rearwards and lift out
the disc pads (see illustration). Do not
depress the brake pedal with the caliper
removed.
31Brush all dirt and dust from the caliper,
pads and disc, but do not inhale it as it may
be injurious to health. Scrape any corrosion
from the disc.32As the new pads will be thicker than the
old ones, the piston must be retracted into its
bore to accommodate the new thicker pads.
Retracting the piston will cause the fluid level
in the reservoir to rise, so to avoid spillage,
syphon out some fluid using an old
hydrometer or a teat pipette. Retract the
caliper piston by turning it clockwise. Ford
tool No 12-006 is designed for this purpose,
but a pair of circlip pliers or any similar tool
can be used instead (see illustration).
33Remove the backing paper from the new
pads, and fit them to the caliper.
34Further refitting is a reversal of removal,
bearing in mind the following points.
35If disc pads with wear sensors are fitted,
the pad with the sensor wire should be fitted
inboard.
36Repeat the procedure on the opposite
rear brake.
37On completion, switch on the ignition and
apply the footbrake hard several times to
settle the pads. Switch off the ignition, then
check and if necessary top-up the fluid level in
the reservoir. Check the operation of the
handbrake.
38Avoid heavy braking, if possible, for the
first hundred miles or so after fitting new
pads. This will allow the pads to bed in and
reach full efficiency.
Braking system 10•5
10
4.21a Later type front disc pad retaining
clip
4.32 Retracting the piston using circlip
pliers4.30 Lift out the disc pads
4.28 Rear disc pad wear sensor wiring clip
(arrowed)
4.29 Unscrewing the forward caliper guide
pin bolt
4.21b Removing a caliper guide bolt cover
- later type
4.20b Refitting the caliper retaining clip -
Teves caliper4.20a The clip on the back of the inboard
disc pad fits into the piston recess - Teves
caliper
Page 13 of 22
3Remove the wheel cylinder.
4Remove the driveshaft but do not refit the
securing bolts to the backplate.
5Remove the backplate.
6If required, prise out the handbrake stop
button.
7Refitting is a reversal of removal.
P 100 models
Note: When refitting the backplate, a new rear
hub nut and driveshaft O-ring must be used.
8Proceed as described in paragraphs 1 to 3
inclusive.
9Remove the driveshaft.
10Relieve the staking on the rear hub nut,
and using a 50 mm socket and a suitable
extension bar, unscrew the nut. Note that the
nut is extremely tight.
11Pull off the hub.
12Unscrew the six retaining nuts and
remove the backplate and the oil baffle (see
illustration).
13If required, prise out the handbrake stop
button.
14Refitting is a reversal of removal, bearing
in mind the following points.
15When refitting the backplate and the oil
baffle, coat the area of the oil baffle shown
(see illustration - Chapter 9) with sealant to
Ford spec SPM-4G-9112-F, then refit the
baffle and the backplate to the axle, tightening
the six securing nuts to the specified torque.
16Use a new rear hub nut, and tighten to the
specified torque. Stake the nut into the groove
in the axle tube after tightening.
17Refit the driveshaft, using a new O-ring.
Note: A suitable puller will be required to
remove the drive flange, and a new rear hub
nut must be used on reassembly.
Removal
1Loosen the rear hub nut with the vehicle
resting on its wheels. Note that the left-hand
nut has a left-hand thread, ie it is undone in a
clockwise direction. Before loosening the nut,
ensure that the handbrake is applied, and
chock the relevant rear wheel. A suitable
extension bar will be required, as the nut is
extremely tight.
2Loosen the relevant rear roadwheel nuts,
chock the front wheels, then jack up the rear
of the vehicle and support on axle stands (see
“Jacking and Vehicle Support”).Remove the
roadwheel and release the handbrake.
3Free the handbrake cable from its clip on
the suspension lower arm.
4Unscrew the two caliper carrier
bracket-to-hub carrier bolts, and remove the
caliper, supporting it on an axle stand to avoid
straining the flexible hose.
5Mark the position of the brake disc in
relation to the drive flange, remove the
retaining spire washer(s), and remove the
disc.
6Unscrew and remove the rear hub nut, and
using a suitable puller, pull off the drive flange.
7Unscrew the four bolts securing the hub
carrier and splash shield to the lower arm.
Remove the hub carrier and splash shield,
whilst supporting the driveshaft. Support the
driveshaft by placing axle stands underneath
it, or by securing with string to the underbody.
Avoid bending the driveshaft joints to
excessive angles, and do not allow the shaft
to hang down from one end.
Refitting
8Refitting is a reversal of removal, bearing in
mind the following points.
9When reassembling the drive flange and the
hub carrier, fit the drive flange to the hub
carrier in order to centralise the bearings, then
using a soft-faced mallet, drive the drive
flange/hub carrier assembly onto the end of
the stub axle.10Refit the hub carrier/splash
shield-to-lower arm securing bolts. Note that
there are two types of bolts used to secure
the rear hub carrier to the lower arm. The two
types of bolt must not be mixed on a vehicle
but can be changed in complete sets for the
alternative type. A complete set is eight bolts,
four each side. Note that the two types of bolt
have different torque wrench settings. When
renewing the wheel bearings a suitable puller
will be required to remove the drive flange,
and a new rear hub nut must be used on
reassembly.
11When refitting the brake disc, align the
previously made marks on disc and drive
flange.
12Fit a new rear hub nut of the correct type,
and tighten it with the vehicle resting on its
roadwheels. Apply the handbrake and chock
the relevant rear wheel when finally tightening
the hub nut.
Note: Before commencing overhaul obtain a
repair kit containing new pistons and seals.
Removal
1Depress the brake pedal several times to
dissipate the vacuum in the servo.
2Disconnect the wiring plug from the low
fluid level switch on the fluid reservoir cap
(see illustration).
3Place a suitable container beneath the
master cylinder, then unscrew the union nuts
and disconnect the two fluid pipes. Plug the
ends of the pipes to prevent dirt ingress.
13Master cylinder (conventional
braking system) - removal,
overhaul and refitting
12Rear disc splash shield -
removal and refitting
Braking system 10•13
10
13.2 Disconnect the wiring plug from the low fluid level switch
(arrowed)11.12 Brake backplate and oil baffle retaining nuts
Caution: Refer to the
precautions in Section 1.
Caution: Refer to the
precautions in Section 1.