Peugeot 405 Haynes (petrol). Manual - part 20

AC voltage is created. The amplifier unit uses
this voltage to switch the transistors in the
unit and complete the ignition system primary
(LT) circuit.

As the reluctor teeth move out of alignment

with the stator projections the AC voltage
changes and the transistors in the amplifier
unit are switched again to interrupt the
primary (LT) circuit. This causes a high voltage
to be induced in the coil secondary (HT)
windings which then travels down the HT lead
to the distributor and onto the relevant spark
plug.

A TDC sensor is fitted to the rear of the

flywheel but the sensor is not part of the
ignition system. It is there to be used for
diagnostic purposes only.

Integral ignition/
fuel injection system

On fuel-injected models except the L3.1

and LU2 systems, the ignition system is
integrated with the fuel injection system to
form a combined engine management system
under the control of one ECU (See the
relevant Part of Chapter 4 for further
information).

The Bosch Motronic ML4.1 and Fenix 1B

systems retain the distributor cap and rotor
arm assembly in order to distribute the spark
to the cylinders, together with a conventional
ignition coil.

All other models use a static (distribu-

torless) ignition system, consisting only of a
four output ignition coil. The ignition coil
actually consists of two separate HT coils
which supply two cylinders each (one coil
supplies cylinders 1 and 4, and the other
cylinders 2 and 3). Under the control of the
ECU, the ignition coil operates on the “wasted
spark” principle, ie. each spark plug sparks
twice for every cycle of the engine, once on
the compression stroke and once on the
exhaust stroke - the spark on the exhaust
stroke has no effect on the running of the
engine, and is therefore “wasted”. The ECU
uses its inputs from the various sensors to
calculate the required ignition advance setting
and coil charging time.

On some models a knock sensor is

incorporated into the ignition system. The
sensor is mounted onto the cylinder head and
prevents the engine “pinking” under load. The
sensor is sensitive to vibration and detects the
knocking which occurs when the engine starts
to “pink” (pre-ignite). The knock sensor sends
an electrical signal to the ECU which in turn
retards the ignition advance setting until the
“pinking” ceases.

Direct ignition system

The ignition system on 1998 cc XU10J4

(16-valve) models is of the “direct” type. The
system components consist of two amplifier
modules, four ignition HT coils, and a knock
sensor. The ignition system is integrated with
the fuel injection system, to form a combined
engine management system under the control

of one ECU via the ignition amplifier modules.

Each ignition amplifier module operates two

HT coils; the ignition HT coils are integral with
the plug caps, and are pushed directly onto
the spark plugs, one for each plug. This
removes the need for any HT leads
connecting the coils to the plugs. The ECU
uses the inputs from the various sensors to
calculate the required ignition advance setting
and coil charging time.

The knock sensor is mounted onto the

cylinder head, and prevents the engine
“pinking” under load. The sensor detects
abnormal vibration, and is thus able to detect
the knocking which occurs when the engine
starts to “pink” (pre-ignite). The knock sensor
sends an electrical signal to the ECU, which in
turn retards the ignition advance setting until
the “pinking” ceases.

Ignition system - testing

Breakerless
Electronic ignition system

Note: Refer to the precautions given in
Section 1 of Part A of this Chapter before
starting work. Always switch off the ignition
before disconnecting or connecting any
component and when using a multi-meter to
check resistances.

General

1 The components of electronic ignition
systems are normally very reliable; most faults
are far more likely to be due to loose or dirty
connections or to “tracking” of HT voltage
due to dirt, dampness or damaged insulation
than to the failure of any of the system’s
components. Always

check all wiring

thoroughly before condemning an electrical
component and work methodically to
eliminate all other possibilities before deciding
that a particular component is faulty.
2 The old practice of checking for a spark by
holding the live end of an HT lead a short
distance away from the engine is not
recommended; not only is there a high risk of
a powerful electric shock, but the HT coil or
amplifier unit will be damaged. Similarly,
never try to “diagnose” misfires by pulling off
one HT lead at a time.

Engine will not start

3 If the engine either will not turn over at all,
or only turns very slowly, check the battery
and starter motor. Connect a voltmeter across
the battery terminals (meter positive probe to
battery positive terminal), disconnect the
ignition coil HT lead from the distributor cap
and earth it, then note the voltage reading
obtained while turning over the engine on the
starter for (no more than) ten seconds. If the
reading obtained is less than approximately
9.5 volts, first check the battery, starter motor
and charging system as described in the
relevant Sections of this Chapter.
4 If the engine turns over at normal speed but
will not start, check the HT circuit by
connecting a timing light (following the
manufacturer’s instructions) and turning the
engine over on the starter motor; if the light
flashes, voltage is reaching the spark plugs,
so these should be checked first. If the light
does not flash, check the HT leads
themselves followed by the distributor cap,
carbon brush and rotor arm using the
information given in Chapter 1.
5 If there is a spark, check the fuel system for
faults referring to the relevant part of Chapter
4 for further information.
6 If there is still no spark, check the voltage at
the ignition HT coil “+” terminal; it should be
the same as the battery voltage (ie, at least
11.7 volts). If the voltage at the coil is more
than 1 volt less than that at the battery, check
the feed back through the fusebox and
ignition switch to the battery and its earth until
the fault is found.
7 If the feed to the HT coil is sound, check the
coil’s primary and secondary winding
resistance as described later in this Section;
renew the coil if faulty, but be careful to check
carefully the condition of the LT connections
themselves before doing so, to ensure that
the fault is not due to dirty or poorly-fastened
connectors.
8 If the HT coil is in good condition, the fault
is probably within the amplifier unit or
distributor stator assembly. Testing of these
components should be entrusted to a
Peugeot dealer.

Engine misfires

9 An irregular misfire suggests either a loose
connection or intermittent fault on the primary
circuit, or an HT fault on the coil side of the
rotor arm.
10 With the ignition switched off, check
carefully through the system ensuring that all
connections are clean and securely fastened.
If the equipment is available, check the LT
circuit as described above.
11 Check that the HT coil, the distributor cap
and the HT leads are clean and dry. Check the
leads themselves and the spark plugs (by
substitution, if necessary), then check the
distributor cap, carbon brush and rotor arm as
described in Chapter 1.
12 Regular misfiring is almost certainly due to
a fault in the distributor cap, HT leads or spark

5B•2 Ignition system

Warning: Voltages produced by
an electronic ignition system
are considerably higher than
those produced by conventional

ignition systems. Extreme care must be
taken when working on the system with
the ignition switched on. Persons with
surgically-implanted cardiac pacemaker
devices should keep well clear of the
ignition circuits, components and test
equipment.

plugs. Use a timing light (paragraph 4 above)
to check whether HT voltage is present at all
leads.
13 If HT voltage is not present on any
particular lead, the fault will be in that lead or
in the distributor cap. If HT voltage is present
on all leads, the fault will be in the spark
plugs; check and renew them if there is any
doubt about their condition.
14 If no HT voltage is present, check the HT
coil; its secondary windings may be breaking
down under load.

Integral and
Direct ignition systems

15 If a fault appears in the engine
management (fuel injection/ignition) system
first ensure that the fault is not due to a poor
electrical connection or poor maintenance; ie,
check that the air cleaner filter element is
clean, the spark plugs are in good condition
and correctly gapped, that the engine
breather hoses are clear and undamaged,
referring to Chapter 1 for further information.
Also check that the accelerator cable is
correctly adjusted as described in the relevant
part of Chapter 4. If the engine is running very
roughly, check the compression pressures
and the valve clearances as described in
Chapter 2A.
16 On systems with a distributor cap and
rotor arm, check these items as described in
the previous sub-section.
17 If these checks fail to reveal the cause of
the problem the vehicle should be taken to a
suitably equipped Peugeot dealer for testing.
A wiring block connector is incorporated in

the engine management circuit into which a
special electronic diagnostic tester can be
plugged. The tester will locate the fault quickly
and simply alleviating the need to test all the
system components individually which is a
time consuming operation that carries a high
risk of damaging the ECU.
18 The only other ignition system checks
which can be carried out by the home
mechanic are those described in Chapter 1,
relating to the spark plugs, and the ignition
coil test described in this Chapter. If
necessary, the system wiring and wiring
connectors can be checked as described in
Chapter 12 ensuring that the ECU wiring
connector(s) have first been disconnected.

Ignition HT coil(s) -
removal, testing and refitting

Removal

Breakerless Electronic ignition system

1 On early models the coil is mounted either
on the cylinder block above the starter motor
or on the inlet manifold. On later models it is
mounted on the left-hand end of the cylinder
head. First disconnect the battery negative
terminal.
2 Where necessary, disconnect the hot air
inlet hose from the exhaust manifold shroud
and air temperature control valve and remove
it from the engine. Release the inlet duct
fastener and position the duct clear of the coil.

3 Disconnect the wiring connector from the
capacitor mounted on the coil mounting
bracket and where necessary release the TDC
sensor wiring connector from the front of the
bracket (see illustration).
4 Disconnect the HT lead from the coil then
depress the retaining clip and disconnect the
coil wiring connector (see illustrations).
5 Slacken and remove the two retaining bolts
and remove the coil and mounting bracket.
Where necessary, slacken and remove the
four screws and nuts and separate the HT coil
and mounting bracket (see illustrations).

Integral ignition models

6 Disconnect the battery negative terminal.
The ignition HT coil is mounted on the left-
hand end of the cylinder head.
7 Depress the retaining clip and disconnect
the wiring connector from the HT coil.

Ignition system 5B•3

3.4b . . . and wiring connector (arrowed)

from the ignition HT coil

3.5c Coil mounting bolts (arrowed) on

Bosch L3.1 system

3.5b . . . and remove the coil and mounting

bracket from the cylinder head

3.5a Undo the two retaining bolts

(arrowed) . . .

3.4a . . . then disconnect the HT lead . . .

3.3 On breakerless ignition models,

disconnect the capacitor wiring connector,

and release the TDC sensor connector . . .

3.5d Removing the ignition coil and

bracket on the Motronic ignition system

8 Make a note of the correct fitted positions
of the HT leads then disconnect them from
the coil terminals.
9 Undo the four retaining screws securing the
coil to its mounting bracket and remove it
from the engine compartment.

Direct ignition models

10 Disconnect the battery negative terminal.
There are four separate ignition HT coils, one
on the top of each spark plug.
11 To gain access to the coils, undo the eight
bolts, noting the correct fitted position of the
wiring clip, and remove the access cover from
the centre of the cylinder head cover.
12 To remove an HT coil, depress the
retaining clip and disconnect the wiring
connector, then pull the coil off the spark plug
and remove it along with its rubber seal.

Testing

13 Testing of the coil consists of using a
multimeter set to its resistance function, to
check the primary (LT “+’“to “-” terminals) and
secondary (LT “+” to HT lead terminal)
windings for continuity, bearing in mind that
on the four output, static type HT coil there
are two sets of each windings. Compare the
results obtained to those given in the Specifi-
cations at the start of this Chapter. Note the
resistance of the coil windings will vary slightly
according to the coil temperature, the results
in the Specifications are approximate values
for when the coil is at 20°C.
14 Check that there is no continuity between
the HT lead terminal and the coil body/
mounting bracket.

15 If the coil is thought to be faulty, have your
findings confirmed by a Peugeot dealer before
renewing the coil.

Refitting

16 Refitting is a reversal of the relevant removal
procedure, ensuring the wiring connectors are
securely reconnected and, where necessary, the
HT leads are correctly connected.

Distributor -
removal and refitting

Removal

Breakerless ignition system

1 Disconnect the battery negative terminal.
Where necessary, to improve access to the
distributor, remove the ignition HT coil as

described in Section 3 and the inlet duct as
described in the relevant Part of Chapter 4.
2 Peel back the waterproof cover then
slacken and remove the distributor cap
retaining screws. Remove the cap and
position it clear of the distributor body (see
illustrations). Recover the seal from the cap.
If necessary disconnect the HT leads from the
spark plugs after noting their positions.
3 Depress the retaining clip and disconnect
the wiring connector from the distributor.
Disconnect the hose from the vacuum
diaphragm unit (see illustrations).
4 Check the cylinder head and distributor
flange for signs of alignment marks. If no
marks are visible, using a scriber or suitable
marker pen, mark the relationship of the
distributor body to the cylinder head. Slacken
and remove the two mounting nuts and
withdraw the distributor from the cylinder
head (see illustrations). Remove the O-ring

4.2a Peel back the

waterproof cover . . .

4.2b . . . then undo the

retaining screws . . .

5B•4 Ignition system

4.2c . . . and remove the cap from the end

of the distributor

4.3b . . . and the vacuum diaphragm hose

4.4c . . . and withdraw the distributor from

the cylinder head

4.4b Unscrew the retaining nuts . . .

4.4a Alignment marks across the

distributor and cylinder head housing

4.3a Disconnect the distributor

wiring connector . . .

from the end of the distributor body and
discard it; a new one must be used on
refitting.

Integral ignition system with
distributor

5 Disconnect the battery negative terminal. If
necessary, to improve access to the
distributor, remove the airflow meter as
described in Chapter 4.
6 Peel back the waterproof cover, slacken
and remove the distributor cap retaining
screws, then remove the cap and position it
clear of the distributor body. Recover the seal
from the cap. If necessary, disconnect the HT
leads from the spark plugs after noting their
positions - on 16-valve engines it will be
necessary to remove the cover plate over the
spark plugs.
7 On 8-valve engines slacken and remove the
two mounting bolts and washers, and
withdraw the distributor from the cylinder
head. Remove the O-ring from the end of the
distributor body, and discard it; a new one
must be used on refitting.
8 On XU9J4 16-valve engines undo the three
Torx-headed screws securing the rotor to the
rotor drive flange and lift off the rotor, then
unscrew the screw from the centre of the
drive flange and withdraw the flange. Remove
the plastic base plate from the end of the
cylinder head (see illustrations).

Refitting

Breakerless ignition system

9 Lubricate the new O-ring with a smear of
engine oil and fit it to the groove in the

distributor body. Examine the distributor cap
seal for wear or damage and renew if
necessary.
10 Align the distributor rotor shaft drive
coupling key with the slots in the camshaft
end noting that the slots are offset to ensure
that the distributor can only be fitted in one
position (see illustration). Carefully insert the
distributor into the cylinder head whilst
rotating the rotor arm slightly to ensure that
the coupling is correctly engaged. Refit the
distributor retaining nuts, tightening them
lightly only.
11 Ensure that the seal is correctly located in
its groove then refit the cap assembly to the
distributor and tighten its retaining screws
securely. Fold the waterproof cover back over
the distributor cap ensuring it is correctly
located. Where necessary reconnect the HT
leads to the spark plugs.
12 Reconnect the vacuum hose to the
diaphragm unit and the distributor wiring
connector. Where necessary, refit the ignition
HT coil as described in Section 3, and the inlet
duct as described in Chapter 4.
13 Reconnect the battery negative terminal,
then check and if necessary adjust the ignition
timing as described in Section 6. Tighten the
distributor mounting nuts to the specified
torque.

Integral ignition system
with distributor

14 On XU9J4 16-valve engines refit the
plastic base plate to the end of the cylinder
head, then refit the drive flange using locking
fluid on the threads of the drive flange screw.

Tighten the centre screw. Refit the rotor and
tighten the Torx-headed screws.
15 On 8-valve engines lubricate the new O-
ring with a smear of engine oil and fit it to the
groove in the distributor body. Examine the
distributor cap seal for wear or damage and
renew if necessary. Align the distributor rotor
shaft drive coupling key with the slots in the
camshaft end noting that the slots are offset
to ensure that the distributor can only be fitted
in one position. Carefully insert the distributor
into the cylinder head whilst rotating the rotor
arm slightly to ensure that the coupling is
correctly engaged. Refit the distributor
retaining nuts, tightening them securely.
16 Ensure that the seal is correctly located in
its groove then refit the cap assembly to the
distributor and tighten its retaining screws
securely. Fold the waterproof cover back over
the distributor cap ensuring it is correctly
located.
17 Where necessary reconnect the HT leads
to the spark plugs (see illustration) and
on 16-valve engines refit the cover plate.

Ignition system amplifier
unit(s) - removal and refitting

Removal

1 Disconnect the battery negative terminal.

Breakerless ignition system

2 The amplifier unit is mounted onto the side
of the distributor body (see illustration). To
improve access to the unit, disengage the hot
air inlet hose from the control valve and
manifold shroud and remove it from the
vehicle.
3 Disconnect the wiring connector then undo
the two retaining screws and remove the
amplifier unit.

Integral ignition system

4 The amplifier unit is located in the right-
hand rear corner of the engine compartment.
5 To remove the unit, disconnect the wiring
connector, undo the two retaining screws and
remove the amplifier from its mounting
bracket.

Ignition system 5B•5

4.10 Off-set drive slots on the camshaft

5.2 On breakerless ignition systems the

amplifier unit is mounted on the side

of the distributor body

4.17 Distributor cap and HT leads on the

XU9J4 16-valve model

4.8b Rotor drive flange

4.8a On XU9J4 16-valve engines undo the

rotor screws and remove the rotor

Direct ignition system

6 Both amplifier units are located on a
bracket situated in the left-hand rear corner of
the engine compartment, to the rear of the
battery.
7 To remove either unit, disconnect the wiring
connector, undo the two retaining screws and
remove the amplifier unit from its mounting
bracket.

Refitting

8 Refitting is a reversal of the removal
procedure.

Ignition timing -
checking and adjustment

Breakerless
Electronic ignition system

1 To check the ignition timing, a stroboscopic
timing light will be required. It is also
recommended that the flywheel timing mark is
highlighted as follows.
2 Remove the plastic cover from the aperture
on the front of the transmission clutch
housing. Using a socket and suitable
extension bar on the crankshaft pulley bolt,
slowly turn the engine over until the timing
mark (a straight line) scribed on the edge of
the flywheel appears in the aperture. Highlight
the line with quick-drying white paint - typist’s
correction fluid is ideal (see illustrations).
3 Start the engine, allow it to warm up to
operating temperature, and then stop it.
4 Disconnect the vacuum hose from the
distributor diaphragm, and plug the hose end.
5 Connect the timing light to No 1 cylinder
spark plug lead (No 1 cylinder is at the
transmission end of the engine) as described
in the timing light manufacturer’s instructions.
6 Start the engine, allowing it to idle at the
specified speed, and point the timing light at

the transmission housing aperture. The
flywheel timing mark should be aligned with
the appropriate notch on the timing plate
(refer to the Specifications for the correct
setting). The numbers on the plate indicate
degrees Before Top Dead Centre (BTDC).
7 If adjustment is necessary, slacken the two
distributor mounting nuts, then slowly rotate
the distributor body as required until the
flywheel mark and the timing plate notch are
brought into alignment. Once the marks are
correctly aligned, hold the distributor
stationary and tighten its mounting nuts.
Recheck that the timing marks are still
correctly aligned and, if necessary, repeat the
adjustment procedure.
8 When the timing is correctly set, increase
the engine speed, and check that the pulley
mark advances to beyond the beginning of
the timing plate reference marks, returning to
the specified mark when the engine is allowed
to idle. This shows that the centrifugal
advance mechanism is functioning; if a
detailed check is thought necessary, this must
be left to a Peugeot dealer having the
necessary equipment. Reconnect the vacuum
hose to the distributor, and repeat the check.
The rate of advance should significantly
increase if the vacuum diaphragm is
functioning correctly, but again a detailed

check must be left to a Peugeot dealer.
9 When the ignition timing is correct, stop the
engine and disconnect the timing light.

Integral and
Direct ignition systems

10 On these systems, there are no timing
marks on the flywheel or crankshaft pulley.
The timing is constantly being monitored and
adjusted by the engine management ECU,
and nominal values cannot be given.
Therefore, it is not possible for the home
mechanic to check the ignition timing.
11 The only way in which the ignition timing
can be checked is using special electronic
test equipment, connected to the engine
management system diagnostic connector
(refer to the relevant Part of Chapter 4 for
further information).
12 On models with Magneti Marelli engine
management systems, adjustment of the
ignition timing is possible. However,
adjustments can be made only by re-
programming the ECU using the special test
equipment (see relevant Part of Chapter 4).
13 On all other models, with Bosch engine
management systems, no adjustment of the
ignition timing is possible. Should the ignition
timing be incorrect, then a fault must be
present in the engine management system.

5B•6 Ignition system

6.2a Removing the plastic cover from the

timing aperture

6.2b Timing marks on the flywheel and

timing plate

Front brakes

Disc diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

266.0 mm

Disc thickness:

New:

Solid disc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

10.0 mm

Ventilated disc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

20.4 mm

Minimum thickness:

Solid disc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

9.0 mm

Ventilated disc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

18.0 mm

Maximum disc run-out . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

0.07 mm

Brake pad minimum thickness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.0 mm

Rear drum brakes

Drum internal diameter:

New

228.6 mm

Maximum diameter after machining . . . . . . . . . . . . . . . . . . . . . . . . . .

229.6 mm

Brake shoe lining minimum thickness . . . . . . . . . . . . . . . . . . . . . . . . . .

1.0 mm

Rear disc brakes

Disc diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

247.0 mm

Disc thickness:

New

8.0 mm

Minimum thickness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6.0 mm

Maximum disc run-out . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

0.07 mm

Brake pad minimum thickness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.0 mm

Chapter 9
Braking system

Anti-lock Braking System (ABS) - general information . . . . . . . . . . . .23
Anti-lock Braking System (ABS) components -

removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24

Brake pedal - removal and refitting  . . . . . . . . . . . . . . . . . . . . . . . . . .14
Front brake caliper - removal, overhaul and refitting  . . . . . . . . . . . . .10
Front brake disc - inspection, removal and refitting . . . . . . . . . . . . . . .7
Front brake pad wear check  . . . . . . . . . . . . . . . . . . . . . .See Chapter 1
Front brake pads - renewal  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
General information  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
Handbrake - checking and adjustment  . . . . . . . . . . . . . . . . . . . . . . .17
Handbrake cables - removal and refitting  . . . . . . . . . . . . . . . . . . . . .19
Handbrake lever - removal and refitting  . . . . . . . . . . . . . . . . . . . . . . .18
Handbrake “on” warning light switch - removal and refitting . . . . . . .20
Hydraulic fluid level check  . . . . . . . . . . . . . . . . . .See “Weekly Checks”
Hydraulic fluid renewal  . . . . . . . . . . . . . . . . . . . . . . . . . .See Chapter 1
Hydraulic pipes and hoses - renewal  . . . . . . . . . . . . . . . . . . . . . . . . . .3

Hydraulic system - bleeding  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
Master cylinder - removal, overhaul and refitting  . . . . . . . . . . . . . . . .13
Rear brake caliper - removal, overhaul and refitting  . . . . . . . . . . . . .11
Rear brake disc - inspection, removal and refitting  . . . . . . . . . . . . . . .8
Rear brake drum - removal, inspection and refitting  . . . . . . . . . . . . . .9
Rear brake pad wear check . . . . . . . . . . . . . . . . . . . . . . .See Chapter 1
Rear brake pads - renewal  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
Rear brake pressure-regulating valve (underbody-mounted) -

removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21

Rear brake shoe wear check  . . . . . . . . . . . . . . . . . . . . . .See Chapter 1
Rear brake shoes - renewal  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Rear wheel cylinder - removal, overhaul and refitting  . . . . . . . . . . . .12
Stop-light switch - removal, refitting and adjustment  . . . . . . . . . . . .22
Vacuum servo unit - testing, removal and refitting . . . . . . . . . . . . . . .15
Vacuum servo unit check valve - removal, testing and refitting  . . . . .16

9•1

Specifications

Contents

Easy, suitable for
novice with little
experience

Fairly easy, suitable
for beginner with
some experience

Fairly difficult,
suitable for competent
DIY mechanic

Difficult, suitable for
experienced DIY
mechanic

Very difficult,
suitable for expert DIY
or professional

Degrees of difficulty

General information

The braking system is of the servo-

assisted, dual-circuit hydraulic type. The
arrangement of the hydraulic system is such
that each circuit operates one front and one
rear brake from a tandem master cylinder.
Under normal circumstances, both circuits
operate in unison. However, in the event of
hydraulic failure in one circuit, full braking
force will still be available at two wheels.

Some large-capacity engine models have

disc brakes all round as standard; other
models are fitted with front disc brakes and
rear drum brakes. ABS is fitted as standard to
certain models, and is offered as an option on
most other models (refer to Section 23 for
further information on ABS operation).

The front disc brakes are actuated by

single-piston sliding type calipers, which
ensure that equal pressure is applied to each
disc pad.

On models with rear drum brakes, the rear

brakes incorporate leading and trailing shoes,
which are actuated by twin-piston wheel
cylinders. On models not equipped with an
underbody-mounted rear brake pressure
regulating valve, the wheel cylinders
incorporate integral pressure-regulating
valves, which control the hydraulic pressure
applied to the rear brakes. The regulating
valves help to prevent rear wheel lock-up
during emergency braking. On some models,
an underbody-mounted load-sensitive rear
pressure-regulating valve is fitted. A self-
adjust mechanism is incorporated, to
automatically compensate for brake shoe
wear. As the brake shoe linings wear, the
footbrake operation automatically operates
the adjuster mechanism, which effectively

lengthens the shoe strut and repositions the
brake shoes, to remove the lining-to-drum
clearance.

On models with rear disc brakes, the

brakes are actuated by single-piston sliding
calipers which incorporate mechanical
handbrake mechanisms. A load-sensitive
pressure-regulating valve is fitted to regulate
the hydraulic pressure applied to the rear
brakes. The regulating valve is similar to that
fitted to drum brake models with ABS, and
helps to prevent rear wheel lock-up during
emergency braking.

On all models, the handbrake provides an

independent mechanical means of rear brake
application.

Note: When servicing any part of the

system, work carefully and methodically; also
observe scrupulous cleanliness when
overhauling any part of the hydraulic system.
Always renew components (in axle sets, where
applicable) if in doubt about their condition,
and use only genuine Peugeot replacement
parts, or at least those of known good quality.
Note the warnings given in “Safety first” and at
relevant points in this Chapter concerning the
dangers of asbestos dust and hydraulic fluid.

Hydraulic system - bleeding

General

1 The correct operation of any hydraulic
system is only possible after removing all air
from the components and circuit; this is
achieved by bleeding the system.
2 During the bleeding procedure, add only
clean, unused hydraulic fluid of the
recommended type; never re-use fluid that
has already been bled from the system.
Ensure that sufficient fluid is available before
starting work.
3 If there is any possibility of incorrect fluid
being already in the system, the brake
components and circuit must be flushed
completely with uncontaminated, correct
fluid, and new seals should be fitted to the
various components.
4 If hydraulic fluid has been lost from the
system, or air has entered because of a leak,
ensure that the fault is cured before
proceeding further.

Torque wrench settings

lbf ft

Hydraulic pipe unions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Front brake caliper:

Guide pin bolts (Girling caliper)** . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Caliper mounting bolts (Bendix caliper):*^:

Early (solid) type hub carrier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

120

Later (hollow) type hub carrier . . . . . . . . . . . . . . . . . . . . . . . . . . . .

105

Caliper mounting bracket bolts (Girling caliper):*^

Early (solid) type hub carrier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

120

Later (hollow) type hub carrier . . . . . . . . . . . . . . . . . . . . . . . . . . . .

105

Rear brake caliper:

Guide pin bolts* . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Caliper mounting bracket bolts* . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Master cylinder-to-servo unit nuts . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Brake pedal pivot bolt nut . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Vacuum servo unit securing nuts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

ABS wheel sensor securing bolts* . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

ABS wheel sensor adjuster bolt (Bendix “integral” ABS) . . . . . . . . . . . .

ABS hydraulic modulator mounting nuts . . . . . . . . . . . . . . . . . . . . . . . .

Roadwheel bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

*Use thread-locking compound.
**Use new bolts coated with thread-locking compound
^Refer to note in Chapter 10, Section 2.

9•2 Braking system

Warning: Hydraulic fluid is
poisonous; wash off
immediately and thoroughly in
the case of skin contact, and

seek immediate medical advice if any fluid
is swallowed or gets into the eyes. Certain
types of hydraulic fluid are inflammable,
and may ignite when allowed into contact
with hot components; when servicing any
hydraulic system, it is safest to assume

that the fluid is inflammable, and to take
precautions against the risk of fire as
though it is petrol that is being handled.
Hydraulic fluid is also an effective paint
stripper, and will attack plastics; if any is
spilt, it should be washed off immediately,
using copious quantities of fresh water.
Finally, it is hygroscopic (it absorbs
moisture from the air) - old fluid may be
contaminated and unfit for further use.
When topping-up or renewing the fluid,
always use the recommended type, and
ensure that it comes from a freshly-
opened sealed container.

Warning: Do not attempt to
bleed any part of the hydraulic
system on models equipped
with the Bendix “integral” ABS.

Special equipment is required, and the
task must be referred to a Peugeot dealer.

5 Park the vehicle on level ground, switch off
the engine and select first or reverse gear, then
chock the wheels and release the handbrake.
6 Check that all pipes and hoses are secure,
unions tight and bleed screws closed. Clean
any dirt from around the bleed screws.
7 Unscrew the master cylinder reservoir cap,
and top the master cylinder reservoir up to the
“MAX” level line; refit the cap loosely, and
remember to maintain the fluid level at least
above the “MIN” level line throughout the
procedure, or there is a risk of further air
entering the system.
8 There are a number of one-man, do-it-yourself
brake bleeding kits currently available from
motor accessory shops. It is recommended that
one of these kits is used whenever possible,
as they greatly simplify the bleeding operation,
and also reduce the risk of expelled air and
fluid being drawn back into the system. If such
a kit is not available, the basic (two-man)
method must be used, which is described in
detail below.
9 If a kit is to be used, prepare the vehicle as
described previously, and follow the kit
manufacturer’s instructions, as the procedure
may vary slightly according to the type being
used; generally, they are as outlined below in
the relevant sub-section.
10 Whichever method is used, the same
sequence must be followed to ensure the
removal of all air from the system.

Bleeding sequence

Conventional braking system

a) Right-hand rear wheel.
b) Left-hand front wheel.
c) Left-hand rear wheel.
d) Right-hand front wheel.

Bendix “additional” ABS

Note: Before carrying out any bleeding,
switch off the ignition, and disconnect the 3-
pin brown wiring connector from the hydraulic
modulator assembly (see illustration).

a) Rear brake furthest from master cylinder.
b) Rear brake nearest master cylinder.
c) Front brake furthest from master cylinder.

d) Front brake nearest master cylinder.
e) Hydraulic modulator (see illustration).

Bosch “additional” ABS

Note: Before carrying out any bleeding,
switch off the ignition, and disconnect the 4-
pin black wiring connector from the hydraulic
modulator assembly.

a) Left-hand front wheel.
b) Right-hand front wheel.
c) Left-hand rear wheel.
d) Right-hand rear wheel.

Note: If difficulty is experienced in bleeding
the hydraulic circuit on models with Bosch
“additional” ABS, using the above sequence,
try bleeding the complete system working in
the following order:

a) Right-hand rear brake.
b) Left-hand rear brake.
c) Left-hand front brake.
d) Right-hand front brake.

Bleeding -
basic (two-man) method

11 Collect a clean glass jar, a suitable length
of plastic or rubber tubing which is a tight fit
over the bleed screw, and a ring spanner to fit
the screw. The help of an assistant will also be
required.
12 Remove the dust cap from the first screw
in the sequence (see illustrations). Fit the
spanner and tube to the screw, place the

other end of the tube in the jar, and pour in
sufficient fluid to cover the end of the tube.
13 Ensure that the master cylinder reservoir
fluid level is maintained at least above the
“MIN” level line throughout the procedure.
14 Have the assistant fully depress the brake
pedal several times to build up pressure, then
maintain it on the final downstroke.
15 While pedal pressure is maintained,
unscrew the bleed screw (approximately one
turn) and allow the compressed fluid and air to
flow into the jar. The assistant should maintain
pedal pressure, following it down to the floor if
necessary, and should not release it until
instructed to do so. When the flow stops,
tighten the bleed screw again, have the
assistant release the pedal slowly, and
recheck the reservoir fluid level.
16 Repeat the steps given in paragraphs 14
and 15 until the fluid emerging from the bleed
screw is free from air bubbles. If the master
cylinder has been drained and refilled, and air
is being bled from the first screw in the
sequence, allow approximately five seconds
between cycles for the master cylinder
passages to refill.
17 When no more air bubbles appear, tighten
the bleed screw securely, remove the tube
and spanner, and refit the dust cap. Do not
overtighten the bleed screw.
18 Repeat the procedure on the remaining
screws in the sequence, until all air is
removed from the system and the brake pedal
feels firm again.

Bleeding -
using a one-way valve kit

19 As their name implies, these kits consist
of a length of tubing with a one-way valve
fitted, to prevent expelled air and fluid being
drawn back into the system; some kits include
a translucent container, which can be
positioned so that the air bubbles can be
more easily seen flowing from the end of the
tube.
20 The kit is connected to the bleed screw,
which is then opened. The user returns to the
driver’s seat, depresses the brake pedal with
a smooth, steady stroke, and slowly releases
it; this is repeated until the expelled fluid is
clear of air bubbles (see illustration).
21

Note that these kits simplify work so

Braking system 9•3

2.12a Bleed nipple (arrowed) on

front disc caliper

2.12b Bleed nipple (arrowed) on rear

wheel cylinder

2.10b Bleed the hydraulic modulator using

the bleed screws (1) first, and (2) second -

Bendix “additional” ABS

2.10a Disconnect the 3-pin brown wiring

connector before bleeding the Bendix

“additional” ABS

Content .. 18 19 20 21 ..