Opel 1900 1973 Service Manual page 265

1973 OPEL SERVICE MANUAL
ing on dusty and sandy roads - the filter and sound
deadener should occasionally be replaced. To do so,
brake booster has to be removed without detaching
brake master cylinder.
Proceed as follows:
2. On the GT only, pry retainer from housing
using a screwdriver. See Figure SA-6.
Figure 5A-6 Brake Booster Filter (GT)
3. With a pointed tool remove air silencer and filter
out of control housing bore and pull it off thrust rod.
4. Install new filter and air silencer. On the GT, the
smooth side of the filter must face towards the inside.
The radial slots in filter and deadener must be stag-
gered to each other by 180 degrees.
5. Slide retainer over control housing (GT only) and
seal it with light plastic hammer strokes. Slide pro-
tective cap over control housing and slip it onto
brake booster housing.
VACUUM CONTROL VALVE SERVICE
A vacuum control valve is installed into the vacuum
hose between intake manifold and brake booster. It
serves to prevent air from flowing back (vacuum
release), when engine is shut off.
The vacuum control valve cannot be disassembled
and has to be replaced, if defective. On replacement,
note the following:
1. The vacuum control valve should
the intake manifold. Therefore, the short vacuum
hose has to be installed between intake manifold and
vacuum control valve and the long hose between
vacuum control valve and brake booster.
2. The arrows on the vacuum control valve housing
must point towards the intake manifold, otherwise
no air can be drawn out of the brake booster which
renders the brake booster ineffective.
3. The connections of the vacuum hoses to the intake
manifold, vacuum control valve and brake booster
must be airtight. For this reason make sure. that the
hose clamps are properly installed.
MAJOR REPAIR
BRAKE BOOSTER REMOVAL
AND INSTALLATION
Removal
Place a cloth under the master cylinder and brake
pipes
2. Disconnect vacuum hose from brake booster.
3. Remove four nuts and washers attaching brake
booster to brake booster support.
4. On the GT only, remove master cylinder support
to fender skirt bolts.
5. On the GT, loosen thrust rod lock nut and un-
screw the piston push rod while holding the master
cylinder brake booster assembly. On the Opel 1900
and Manta, remove the nut and bolt attaching clevis
on the pedal.
6. Remove assembly from car.
Installation
CAUTION:
portant attaching parts in that they could affect the
/or could result in major repair expense. They must
an equivalent part if replacement becomes necessary.
Do not use a replacement part or lesser quality or
substitute design. Torque values must be used as
specified during reassembly to assure proper reten-
tion of these parts.
be located near
1. Using a new front housing seal, assemble master
absorb any brake fluid drippings.
to
Fasteners in the folkwing steps are im-