brake fluid FORD SIERRA 1993 2.G Braking System User Guide

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.

4Unscrew the two mounting nuts and spring
washers, and withdraw the master cylinder
from the servo. Cover the master cylinder with
rag or a plastic bag to prevent spillage of
hydraulic fluid on the vehicle paintwork. If fluid
is accidentally spilt on the paintwork, wash off
immediately with cold water.
Overhaul
5Drain the remaining fluid from the master
cylinder, and clean the exterior surfaces with
methylated spirit.
6Pull the fluid reservoir from the top of the
master cylinder and prise out the sealing
rubbers (see illustration).
7Mount the master cylinder in a vice, then
depress the primary piston slightly and extract
the circlip and washer. Withdraw the primary
piston assembly.
8Depress the secondary piston and remove
the stop pin from the fluid aperture.
9Remove the master cylinder from the vice
and tap it on the bench to remove the
secondary piston assembly.
10Prise the seals from the secondary piston.
Do not attempt to dismantle the primary
piston.
11Clean all the components in methylated
spirit and examine them for wear and
damage. In particular check the surfaces of
the pistons and cylinder bore for scoring and
corrosion. If the cylinder bore is worn, renew
the complete master cylinder, otherwise
obtain a repair kit including pistons and seals.
12Check that the fluid inlet and outlet ports
are free and unobstructed. Dip the new
pistons and seals in clean brake fluid.
13Fit the seals to the secondary piston using
the fingers only to manipulate them into the
grooves. Note that the sealing lips must face
away from each other.
14Insert the secondary piston and spring
into the cylinder. Turn the piston slowly as the
first seal enters to avoid trapping the sealing
lip. Similarly insert the primary piston and
spring, then fit the washer and circlip.
15Depress the primary and secondary
pistons and refit the secondary piston stop
pin.
16Fit the fluid reservoir sealing rubbers andpress the reservoir into them. If the rubbers
are worn or perished, or if leakage has been
evident, fit the new rubbers.
Refitting
17Refitting is a reversal of removal but
tighten the mounting nuts and pipe union nuts
to the specified torque and finally bleed the
hydraulic system.
Removal
1To remove the servo, first remove the
master cylinder.
2Disconnect the vacuum hose from the
servo (see illustration).
3Working inside the vehicle, remove the
lower facia panel from the driver’s side.
4Remove the clip from the servo pushrod on
the brake pedal (see illustration).
5Unscrew the two mounting nuts and
washers securing the servo to the bulkhead,
and lift the servo from the bulkhead. Note that
the two mounting nuts also secure the pedal
bracket to the bulkhead.6If required, the vacuum hose can be
disconnected from the inlet manifold, and the
non-return valve can be checked for correct
operation by ensuring that it is only possible
to blow through it in one direction.
7No overhaul of the servo is possible, and if
faulty, it must be renewed as a complete unit.
Refitting
8Refitting is a reversal of removal, but when
refitting the servo to the bulkhead, ensure that
the pushrod is correctly located in the pedal
and that the clip is secure.
Vacuum hose - modification
9From mid-1989, a new type of brake servo
vacuum hose-to-inlet manifold connector has
been used in production. The connector
comprises three parts; a collet which locks
the hose in position, an O-ring, and a brass
insert which is pressed into the inlet manifold.
10To disconnect the hose from the inlet
manifold, apply light even pressure, push and
hold the flange of the collet against the
manifold. While holding the collet forward,
gently pull the hose from the collet (see
illustration). Take care not to pull at an angle
or use excessive force, as this can cause the
collet to snatch and lock the hose.
11To reconnect the hose, push the hose into
the collet until the swage on the hose is hard
against the collet flange. Pull gently on the
hose to check that it is locked by the collet.
14Vacuum servo (conventional
braking system) - removal and
refitting
10•14Braking system
14.10 Disconnecting a later-type brake
servo vacuum hose14.4 Remove the clip (arrowed) from the
servo pushrod14.2 Servo vacuum hose non-return valve
(A) and servo connection (B) - conventional
braking system
13.6 Exploded view of master cylinder -
conventional braking system
A Fluid reservoir
B Sealing rubber
C Spring
D Secondary piston
E Primary piston
F Stop pin
Caution: Refer to the
precautions in Section 1.

Note: New seals must be used between the
reservoir and the hydraulic unit on reassembly.
Removal
1Disconnect the battery negative lead.
2Depressurise the hydraulic system by
pumping the brake pedal at least 20 times, or
until it becomes hard.
3Disconnect the wiring multi-plugs from the
reservoir cap and remove the cap.
4Unscrew the reservoir securing screw, and
remove the securing clip, noting that the clip
also supports the clutch cable (see illustration).5Prepare a suitable container to collect the
fluid as the hydraulic unit is drained, then
remove the securing spring clip and
disconnect the low pressure fluid hose from
the pump (see illustrations). Allow the fluid to
drain out of the hose into the container. If fluid
is accidentally spilt on the paintwork, wash off
immediately with cold water.
6Pull the reservoir out of the seals on the
hydraulic unit and remove it (see illustration).
7Note the spigot locating bush on the rear
hydraulic unit inlet, which may stay in the
hydraulic unit or may come out with the
reservoir (see illustration).
Refitting
8Refitting is a reversal of removal, but use
new seals between the reservoir and the
hydraulic unit.
9On completion, bleed the complete
hydraulic system and check for leaks around
all disturbed components.Note: A new gasket must be used between
the hydraulic unit and the bulkhead on
refitting.
Removal
1Disconnect the battery negative lead.
2Depressurise the hydraulic system by
pumping the brake pedal at least 20 times, or
until it becomes hard.
3Disconnect the six multi-plugs from the
hydraulic unit. They are all different, so there
is no need to label them. When a plug has a
spring clip retainer, lift the clip before pulling
out the plug. To release the pump plug, pull
back the rubber boot and the plug sleeve (see
illustrations).
4Unbolt the earth strap from the unit.
5Prepare a suitable container to catch spilt
fluid. Mark the hydraulic pipes so that they
can be refitted in their original positions, then
disconnect them from the base of the unit.
Plug the open ends of the pipes and hydraulic
unit to prevent fluid leakage and dirt ingress. If
fluid is accidentally spilt on the paintwork,
wash off immediately with cold water.
6Working inside the vehicle, remove the
lower facia panel from the driver’s side.
16Hydraulic unit (ABS)
- removal and refitting
15Fluid reservoir (ABS)
- removal and refitting
Braking system 10•15
10
15.5b . . . and disconnect the low pressure
fluid hose - ABS
16.3c . . . and the pressure switch
multi-plug - ABS16.3b . . . the main valve multi-plug . . .16.3a Disconnecting the low fluid level
switch multi-plug . . .
15.7 Removing the spigot locating bush
from the rear hydraulic unit inlet - ABS15.6 Removing the fluid reservoir from the
hydraulic unit - ABS
15.5a Remove the securing spring clip . . .15.4 Reservoir securing clip (arrowed) also
supports clutch cable - ABS
Caution: Refer to the
precautions in Section 1.
Caution: Refer to the
precautions in Section 1.

7Remove the clip from the hydraulic unit
pushrod on the brake pedal.
8With an assistant supporting the hydraulic
unit, unscrew the four nuts which secure the
unit to the bulkhead (see illustration).
Withdraw the unit from under the bonnet.
9Recover the gasket fitted between the unit
and the bulkhead.
10Drain the fluid from the reservoir. Do not
actuate the pushrod with the unit removed.
11Dismantling of the hydraulic unit should
be limited to the operations described in the
following Sections (see illustration).
Refitting
12Refitting is a reversal of removal, bearing
in mind the following points.13Do not refill the fluid reservoir until
reassembly and refitting is complete.
14Use a new gasket between the hydraulic
unit and the bulkhead.
15Ensure that the hydraulic pipes are
reconnected to the correct unions.
16On completion, bleed the complete
hydraulic system and check for leaks around
all disturbed components.
Note: A new O-ring must be used between
the accumulator and the hydraulic unit on
refitting.
Removal
1Disconnect the battery negative lead.
2Depressurise the hydraulic system by
pumping the brake pedal at least 20 times, or
until it becomes hard.
3Wrap a clean rag round the base of the
accumulator to catch any spilt fluid.
4Unscrew the accumulator using a hexagon
key. Remove the accumulator, noting the
sealing ring and being prepared for fluid
spillage (see illustration). If fluid isaccidentally spilt on the paintwork, wash off
immediately with cold water.
Refitting
5Fit a new O-ring to the base of the
accumulator, fit the accumulator and tighten
it.
6Reconnect the battery. Switch on the
ignition and check that the hydraulic unit
pump stops within 60 seconds; if not, the
accumulator is likely to be faulty.
7On completion, bleed the complete
hydraulic system and check for leaks around
all disturbed components.
Note: New sealing washers must be used on
the high pressure fluid hose banjo union, and
a new O-ring must be used between the
accumulator and the hydraulic unit on refitting.
Removal
1Remove the accumulator.
2Prepare a suitable container to catch spilt
fluid, and disconnect the high pressure fluid
hose from the pump.
3Remove the securing spring clip and
disconnect the low pressure fluid hose from
the pump. Allow the fluid to drain out of the
hose into the container. If fluid is accidentally
spilt on the paintwork, wash off immediately
with cold water.
4Disconnect the multi-plugs from the
pressure switch and the pump motor.
5Remove the pump mounting bolt (see
illustration).
6Pull the pump and motor assembly off the
mounting spigot and remove it.
7Recover the mounting bushes and renew
them if necessary.
8If a new pump is to be fitted, transfer the
pressure switch to it, using a new O-ring.
18Hydraulic unit pump and motor
(ABS) - removal and refitting
17Hydraulic unit accumulator
(ABS) - removal and refitting
10•16Braking system
16.8 Hydraulic unit-to-bulkhead securing
nuts (arrowed) - ABS
17.4 Unscrew the accumulator and remove
it, noting the O-ring (arrowed)
16.11 Hydraulic unit components - ABS
A Fluid reservoir
B Accumulator
C Main valveD Master cylinder
E Pushrod
F Pump and motorG Booster
H Pressure switch
J Valve block
Caution: Refer to the
precautions in Section 1.
Caution: Refer to the
precautions in Section 1.

Refitting
9Commence refitting by offering the pump to
the mounting spigot, then reconnecting the
low pressure fluid hose.
10Refit and tighten the pump mounting bolt.
11Reconnect the high pressure fluid hose,
using new sealing washers on the banjo
union.
12Refit the accumulator, using a new O-ring.
13Reconnect the multi-plugs and the
battery.
14Refill the fluid reservoir, then switch on the
ignition and allow the pump to prime itself.
Allow the pump to run for a maximum of two
minutes at a time then leave it for ten minutes
to cool down.
15On completion, bleed the complete
hydraulic system and check for leaks around
all disturbed components.
Note: To remove the pressure switch from the
hydraulic unit in situ, Ford tool No 12-008 or a
locally made equivalent will be required. The
switch may be removed without special tools
after removing the hydraulic unit complete or
the pump above. A new O-ring must be used
when refitting the switch.
Removal
1Disconnect the battery negative lead.
2Depressurise the hydraulic system by
pumping the brake pedal at least 20 times, or
until it becomes hard.
3Disconnect the multi-plug from the switch,
then unscrew and remove the switch.
Refitting
4Refit the switch using a new O-ring.
Position the plastic sleeve so that the drain
hole faces the pump motor, then tighten the
switch (see illustration).
5Reconnect the multi-plug and the battery.
6On completion, bleed the complete
hydraulic system and check for leaks around
all disturbed components.
Removal
1Disconnect the battery negative lead.
2Depressurise the hydraulic system by
pumping the brake pedal at least 20 times, or
until it becomes hard.
3Apply the handbrake, and slacken the
left-hand front wheel nuts. Jack up the front of
the vehicle and support on axle stands (see
“Jacking and Vehicle Support”).Remove the
left-hand front wheel.
4Remove the plastic liner from under the
wheel arch.
5Prepare a suitable container to catch spilt
fluid, clean around the unions on the valve
block, then unscrew and disconnect the fluid
pipes (see illustration). Plug the open ends of
the pipes and valve block to prevent fluid
leakage and dirt ingress. If fluid is accidentally
spilt on the paintwork, wash off immediately
with cold water.
6Disconnect the multi-plug and the earth
strap from the valve block.
7Working through the wheel arch, unscrew
the three nuts which secure the valve block
mounting bracket (see illustration).8Remove the valve block and mounting
bracket, taking care not to spill brake fluid on
the paintwork.
9No further dismantling of the valve block is
possible, but the pressure regulating valve in
the rear brake pipe union can be renewed if
desired.
Refitting
10Refitting is a reversal of removal.
11On completion, bleed the complete
hydraulic system and check for leaks around
all disturbed components.
Removal
1Disconnect the battery.
2Working inside the vehicle, prise out the
facia trim panel from the passenger’s side.
Remove the insulation.
3To remove the now exposed module, push
it as necessary to release the retaining catch.
21Computer module (ABS)
- removal and refitting
20Valve block (ABS) -removal
andrefitting
19Hydraulic unit pressure switch
(ABS) - removal and refitting
Braking system 10•17
10
20.5 Valve block and associated
components - ABS
A Bracket screws
B Adapter plate
C valve blockD Multi-plug
E Earth strap
anchor point
19.4 Refit the pressure switch with the
drain hole (arrowed) in the plastic sleeve
facing the pump motor - ABS18.5 Hydraulic unit pump mounting bolt -
ABS
20.7 Unscrewing the valve block mounting
bracket nuts (arrowed) - ABS
Caution: Refer to the
precautions in Section 1.
Caution: Refer to the
precautions in Section 1.

4Withdraw the module, and disconnect the
multi-plug (see illustration).
Refitting
5Refitting is a reversal of removal but on
completion check the operation of the ABS
warning lamp as described in the
manufacturer’s handbook.
Note: A new O-ring must be used when
refitting a sensor.
Front wheel sensor
1Apply the handbrake, loosen the relevant
front roadwheel nuts, then jack up the front of
the vehicle and support on axle stands (see
“Jacking and Vehicle Support”). Remove the
roadwheel.
2Working under the bonnet, unclip the ABS
wiring loom from the chassis side member,
and disconnect the wheel sensor wiring plug.
3Unscrew the mounting bolt and withdraw
the sensor (see illustration).
4Refitting is a reversal of removal, bearing in
mind the following points.
5Clean the bore in the hub carrier, and smear
the bore and the sensor with lithium based
grease.
6Use a new O-ring seal when refitting the
sensor.
Rear wheel sensor
7Chock the front wheels, loosen the relevant
rear roadwheel nuts, then jack up the rear of
the vehicle and support on axle stands.
Release the handbrake and remove the
roadwheel.
8Working inside the vehicle, lift up the rear
seat cushion, then remove the side kick panel
and fold the carpet forwards to gain access to
the wheel sensor wiring plug (see
illustrations).
9Remove the wiring plug from its clip, and
disconnect it.
10Prise out the floor panel grommet, then
feed the sensor wiring through the floor panel.
11Free the handbrake cable from its clip on
the suspension lower arm.12Where applicable, disconnect the wiring
to the disc pad wear sensor.
13Unscrew and remove the bolt from the
forward caliper guide pin, while holding the
pin stationary with a spanner.
14Swing the caliper rearwards to gain
access to the wheel sensor.
15Unscrew the bolt securing the sensor to
its mounting bracket.
16Refitting is a reversal of removal, bearing
in mind the following points.
17Clean the bore in the sensor mounting
bracket, and smear the bore and the sensor
with lithium based grease.
18Use a new O-ring seal when refitting the
sensor.
Removal
1The deceleration sensitive valve is located
on the left-hand side of the engine
compartment (see illustrations).
2Place a suitable container beneath the
valve to catch spilt fluid, then unscrew the
union nuts and disconnect the fluid pipes.Plug the open ends of the pipes and valve to
prevent fluid leakage and dirt ingress. If fluid is
accidentally spilt on the paintwork, wash off
immediately with cold water.
3On early models, the valve is secured to the
mounting bracket on the inner wing by a
single bolt. Unscrew the bolt and remove the
valve.
4On later models, the valve is secured to the
mounting bracket by a clip. Remove the clip
and slide out the valve.
Refitting
5Refitting is a reversal of removal, but note
that the early type of valve must be fitted with
the cover bolts facing forwards, and the later
type of valve must be fitted with the smaller
diameter stepped end facing forwards.
6On completion, bleed the rear hydraulic
circuit.
23Deceleration sensitive valve
(all models with conventional
braking system)
- removal and refitting
22Wheel sensor (ABS)
- removal and refitting
10•18Braking system
21.4 Withdraw the module and disconnect
the multi-plug - ABS22.8a Remove the side kick panel
(securing screws arrowed) for access to
the rear wheel sensor wiring plug - ABS
23.1b Later type deceleration sensitive
valve23.1a Early type deceleration sensitive
valve
22.8b Rear wheel sensor wiring plug
(arrowed) - ABS
22.3 Unscrew the mounting bolt and
withdraw the front wheel sensor - ABS
Caution: Refer to the
precautions in Section 1.

Removal
1Chock the front wheels, jack up the rear of
the vehicle and support on axle stands (see
“Jacking and Vehicle Support”).
2The load apportioning valve is located on
the right-hand side of the vehicle underbody
above the axle.
3Remove the spring clip and clevis pin, and
detach the spring from the valve operating
lever (see illustration).
4Place a suitable container beneath the
valve to catch spilt fluid, then unscrew the
union nuts and disconnect the fluid pipes.
Plug the open ends of the pipes and valve to
prevent fluid leakage and dirt ingress.
5Unscrew the three securing nuts and bolts
from the valve mounting bracket, and remove
the valve assembly (see illustration).
Refitting
6Refitting is a reversal of removal, but note
that the fluid inlet pipe from the master cylindermust be connected to the lower valve port, and
the fluid outlet pipe to the rear brakes must be
connected to the upper valve port.
7On completion, bleed the rear hydraulic
circuit and check the valve adjustment.
Models before mid-April 1989
1The vehicle must be unladen, at normal
kerb weight (a full tank of petrol, but no driver
or load).
2With the vehicle standing on its roadwheels,
remove the spring clip and clevis pin, and
detach the spring from the valve operating
lever.
3Loosen the locknut on the abutment block
at the bottom of the spring (see illustration).
4Slide the spring through the grommet in the
bracket on the axle, until the correct “X”
dimension is obtained between the centre of
the spring eye and the centre of the valve
operating lever eye (see illustration).
5Hold the spring in position, slide the
abutment block against the underside of the
grommet, and tighten the locknut.
6Attach the free end of the spring to the
valve operating lever, and refit the clevis pin
and spring clip.
Models from mid-April 1989
7The procedure is as described above, but
note that the dimension “X” has been revised
to 92.0 mm (3.6 in) with the vehicle unladen at
normal kerb weight.
Removal
1To remove a flexible hose, always free it
from any mounting bracket(s) first by prising
out the U-shaped retaining clip, and then
using two close-fitting spanners to disconnect
the hose-to-rigid pipe union (see illustration).
2Once disconnected from the rigid pipe, the
flexible hose may be unscrewed from the
caliper or wheel cylinder union, as applicable.
Refitting
3When reconnecting pipe or hose fittings,
note that the seal is made at the swaged end
of the pipe, so do not continue to tighten a
union if it is tight, yet still stands proud of the
surface into which it is screwed.
26Brake fluid pipes and hoses
- removal and refitting25Load apportioning valve
(P100 models) - adjustment
24Load apportioning valve
(P100 models) - removal and
refitting
Braking system 10•19
10
25.3 Loosen the locknut (arrowed) on the
abutment block
26.1 Flexible hose-to-rigid pipe union. U-shaped retaining clip
arrowed25.4 Load apportioning valve adjustment
X = 77.0 mm (3.0 in) with vehicle unladen at normal kerb weight
24.5 Load apportioning valve securing
bolts (arrowed)24.3 Remove the spring clip (arrowed) and
clevis pin from the valve operating lever
Caution: Refer to the
precautions in Section 1.
Caution: Refer to the
precautions in Section 1.