1986 FORD SIERRA ECU

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.

4A flexible hose must never be installed
twisted, but a slight “set” is permissible to
give it clearance from adjacent components.
This can be achieved by turning the hose
slightly before fitting the U-shaped retaining
clip to the mounting bracket.
5Rigid pipelines can be made to pattern by
motor factors supplying brake components.
Removal
1Chock the front wheels, loosen the rear
roadwheel nuts, then jack up the rear of the
vehicle and support on axle stands. Release
the handbrake and remove the roadwheels.
2Slacken the handbrake cable adjuster.
3Extract the securing circlip and pivot pin,
and detach the handbrake equaliser from the
linkage on the underbody (see illustration).4On models with a conventional braking
system, remove the brake shoes and
disconnect the handbrake cables from the
operating levers, then disconnect the cables
from the brake backplates by extracting the
U-clips.
5On models with ABS, unhook the
handbrake cables from the operating levers
on the calipers, then disconnect the cables
from the caliper carrier brackets by removing
the retaining circlips (see illustrations).
6On Saloon, Hatchback and Estate models
bend back the tangs and release the cables
from the lower suspension arms, then feed
the cables through the holes in the
suspension crossmember and release them
from the brackets on the underbody, noting
that the right-hand cable is retained by a
circlip (see illustration). Withdraw the cable
assembly from the vehicle.
7On P100 models, release the cables from
the brackets on the chassis crossmember,
noting that the left-hand cable is retained by a
circlip, then unhook the cable support springsand withdraw the cable assembly from the
vehicle (see illustration).
Refitting
8Refitting is a reversal of removal. On
models with a conventional braking system
refit the brake shoes.
9On completion, adjust the cable.
27Handbrake cable -removal
andrefitting
10•20Braking system
27.3 Handbrake equaliser securing circlip
(arrowed) and pivot pin
27.5b Handbrake cable-to-caliper carrier bracket attachment -
ABS
27.7 Handbrake cable support spring (arrowed)27.6 Handbrake cable-to-lower suspension arm attachment
27.5a Handbrake cable-to-operating lever attachment - ABS

Note: Where fitted, the adjuster locking pin
must be renewed on completion of
adjustment.
Conventional braking system
(except P100 models)
1The handbrake cable is normally
self-adjusting in use, however adjustment
may be required to compensate for cable
stretch over a long period, and is also
necessary after fitting a new cable.
2Chock the front wheels, jack up the rear of
the vehicle and support on axle stands (see
“Jacking and Vehicle Support”).Release the
handbrake.
3Unscrew the locknut from the adjuster
located on the left-hand underbody bracket
(see illustration). On later models, a locking
pin is fitted to the bracket to lock the adjuster
nuts in position. Where applicable, remove the
locking pin before unscrewing the locknut.4Apply the footbrake vigorously several
times to set the self-adjuster mechanism.
5Turn the adjuster until the plastic plungers
located in the brake lockplates are free to
turn, and the total movement of both plungers
added together is between 0.5 and 1.0 mm
(0.02 and 0.04 in) (see illustration).
6Tighten the adjuster locknut against the
adjuster nut by hand (two clicks), then tighten
further by a minimum of two and a maximum
of four clicks, using a suitable spanner or
pliers.
7Where applicable, fit a new adjuster locking
pin. The old pin should not be re-used.
8Check that with the handbrake released,
the rear wheels are free to rotate and no brake
“bind” is evident. The handbrake lever travel
should be between two and four clicks of the
ratchet. If brake “bind” or excessive lever
travel is evident, check the handbrake cable
routing, and check the self-adjuster
mechanism for wear or damage.
ABS
9Proceed as described in paragraphs 1 to 3
inclusive.
10Bend back the tangs and release the
cables from the lower suspension arms.
11Ensure that both handbrake operating
levers are returned to their stops on the
calipers, then make alignment marks between
the levers and the caliper bodies (see
illustration).
12Turn the adjuster until either lever just
starts to move, as indicated by the alignment
marks.
13Apply the handbrake and release it
several times to equalise the cable runs.
14With the handbrake released, proceed as
described in paragraphs 6 and 7.
15Refit the cables to the lower suspension
arms, and secure by bending over the tangs.
16Check that with the handbrake released,
the rear wheels are free to rotate and no brake“bind” is evident. The handbrake lever travel
should be between two and four clicks of the
ratchet. If brake “bind” or excessive lever
travel is evident, check the handbrake cable
routing, and check the caliper mechanism for
wear or damage.
P100 models
17Proceed as described in paragraphs 1 to
4 inclusive, but note that the adjuster is
located on the right-hand side of the chassis
crossmember (see illustration).
18Apply the handbrake, pulling the lever
upwards three clicks.
19Turn the adjuster until both rear wheels
are locked and cannot be turned by hand.
20Proceed as described in paragraphs 6
and 7.
21Check that with the handbrake released,
the rear wheels are free to rotate and no brake
“bind” is evident. The handbrake lever travel
should be between three and five clicks of the
ratchet. If brake “bind” or excessive lever
travel is evident, check the handbrake cable
routing, and check the self-adjuster
mechanism for wear or damage.
28Handbrake cable - adjustment
Braking system 10•21
10
28.5 Plastic plunger (arrowed) in brake backplate
28.17 Handbrake cable adjuster on right-
hand side of chassis crossmember28.11 Make alignment marks between
each handbrake operating lever and
caliper body (arrowed) - ABS
28.3 Handbrake cable adjuster on left-hand underbody bracket
(arrowed)

Removal
1Chock the rear wheels, jack up the front of
the vehicle and support on axle stands.
Release the handbrake. Disconnect the
battery negative lead.
2Slacken the handbrake cable adjuster.
3Extract the securing circlip and pivot pin,
and detach the handbrake equaliser from the
linkage on the underbody (see illustration).
4Working inside the vehicle, remove the
handbrake lever rubber gaiter and/or the
centre console, as necessary.
5Disconnect the wiring connector from the
handbrake “on” warning switch. 6Unscrew the two handbrake lever mounting
bolts, and carefully lift the lever through the
underfloor gaiter.
7If required, the handbrake “on” warning
switch can be removed.Refitting
8Refitting is a reversal of removal, but on
completion, adjust the handbrake cable.
Removal
1Remove the clutch pedal as described in
Chapter 6.
2Extract the inboard circlip from the brake
pedal end of the pivot shaft (see illustration).3The brake pedal can now be removed from
the pedal bracket by sliding out the pivot
shaft, noting the position of any washers and
spacers which may be fitted.
4If desired, the nylon bushes can be prised
from each side of the pedal for renewal, and
the brake lamp switch removed.
Refitting
5Refitting is a reversal of removal, fitting any
washers and spacers in their original
positions. Refit the clutch pedal.
30Brake pedal - removal and
refitting
29Handbrake lever -removal
andrefitting
10•22Braking system
29.3 Handbrake equaliser and linkage on underbody30.2 Extract the inboard circlip (arrowed) to remove the pedal
pivot shaft