Hydraulic Pipes And Hoses; Bleeding Sequence; Bleeding; Basic (Two-Man} Method - Opel Zafira B MPV 2006 Owners Workshop Manual

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 should be followed (paragraphs 11
and 12) to ensure the removal of all air from
the system.
Bleeding sequence
11 If the system has been only partially
disconnected, and suitable precautions were
taken to minimise fluid loss, it should only be
necessary to bleed that part of the system
(ie, the primary or secondary circuit). If the
master cylinder or main brake lines have been
disconnected, then the complete system must
be bled.
12 If the complete system is to be bled, then
it should be done in the following sequence:
Right-hand drive models
a) Left-hand rear brake.
b) Right-hand rear brake.
c) Left-hand front brake.
d) Right-hand front brake.
Left-hand drive models
a) Right-hand rear brake.
b) Left-hand rear brake.
c) Right-hand front brake.
d) Left-hand front brake.
Bleeding
Basic (two-man} method
13 Collect together 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.
14 Remove the dust cap from the first bleed
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.
15 Ensure that the master cylinder reservoir
fluid level is maintained at least above the MIN
level line throughout the procedure.
16 Have the assistant fully depress the brake
pedal several times to build-up pressure, then
maintain it on the final downstroke.
17 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.
18 Repeat the steps given in paragraphs 16
and 17 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
2.14a Remove the dust caps from the
front •••
sequence, allow approximately five seconds
between cycles for the master cylinder
passages to refill.
19 When no more air bubbles appear,
securely tighten the bleed screw, remove the
tube and spanner, and refit the dust cap. Do
not overtighten the bleed screw.
20 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.
Using a one-way valve kit
21 As the 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.
22 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.
23 Note that these kits simplify work so
much that it is easy to forget the master
cylinder reservoir fluid level; ensure that this is
maintained at least above the MIN level line at
all times.
Using a pressure-bleeding kit
24 These kits are usually operated by a
reservoir of pressurised air contained in the
spare tyre. However, note that it will probably
be necessary to reduce the pressure to a lower
level than normal; refer to the instructions
supplied with the kit.
25 By connecting a pressurised, fluid-filled
container to the master cylinder reservoir,
bleeding can be carried out simply by opening
each screw in turn (in the specified sequence),
and allowing the fluid to flow out until no more
air bubbles can be seen in the expelled fluid.
26 This method has the advantage that the
large reservoir of fluid provides an additional
safeguard against air being drawn into the
system during bleeding.
27 Pressure-bleeding is particularly effective
when bleeding 'difficult' systems, or when
bleeding the complete system at the time of
routine fluid renewal.
Braking system 9•3
2.14b ••• and rear bleed screws
All methods
28 When bleeding is complete, and firm
pedal feel is restored, wash off any spilt fluid,
securely tighten the bleed screws, and refit
the dust caps.
29 Check the hydraulic fluid level in the
master cylinder reservoir, and top-up if
necessary (see Weekly checks).
30 Discard any hydraulic fluid that has been
bled from the system; it will not be fit for
re-use.
31 Check the feel of the brake pedal. If it
feels at all spongy, air must still be present in
the system, and further bleeding is required.
Failure to bleed satisfactorily after a reasonable
repetition of the bleeding procedure may be
due to worn master cylinder seals.
Note: Before starting work, refer to the note
at the beginning of Section 2 concerning the
dangers of hydraulic fluid.
1 If any pipe or hose is to be renewed,
minimise fluid loss by first removing the
master cylinder reservoir cap and screwing it
down onto a piece of polythene. Alternatively,
flexible hoses can be sealed, if required, using
a proprietary brake hose clamp. Metal brake
pipe unions can be plugged (if care is taken
not to allow dirt into the system) or capped
immediately they are disconnected. Place
a wad of rag under any union that is to be
disconnected, to catch any spilt fluid.
2 If a flexible hose is to be disconnected,
unscrew the brake pipe union nut before
removing the spring clip which secures
the hose to its mounting bracket. Where
applicable, unscrew the banjo union bolt
securing the hose to the caliper and recover
the copper washers. When removing the
front flexible hose, pull out the spring
clip and disconnect it from the strut (see
illustrations).
3 To unscrew union nuts, it is preferable to
obtain a brake pipe spanner of the correct
size; these are available from most motor
accessory shops. Failing this, a close-fitting
open-ended spanner will be required, though
if the nuts are tight or corroded, their flats may