1973 OPEL GT-R torque

REAR AXLE49.23
Adjusting end Fitting SpecificationsPinionBearingPreloadWith
NewBearings. . . . . . . . . . . . . . . . . . . . . . . . . .7-13Lb.In.
Preload With Reused Bearings
__.._..I...................,.................,,...................,,............ 5-8 Lb.In.
Pinion Depth Setting
.002” to -.OOl’ from pinion marking using following selective shims:
Number of Notches
Thickness In.in Circumference.0097Flattened on One Side
.00980
.01081
.01182
.01283
.01384
.01485Clearance Between Differential Side Gears and Case Max.
,000” on the Opel 1900 andManta and
,006” on the GT using the following selective shims:
Thickness In.
1900
,039.04
1,043,045,047,049.05
1,053,055
GT
.0394
.0433
.0473Number of Notches
in Circumference
0
1
2
.05123Max. Permissible Axle Shaft Bearing Seat Radial Runout
.._......................................... ,002”Max. Permissible Rear Axle Shaft Flanze Lateral Runout . .
,004” at Lareest Flange Dia.
Max.Permissible Lateral Ring Gear R&out
._.._,,.........._.....,........................... T . . . . . . . . . . . ...” ,003”RingGearandDrivePinionBacklash
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .,004”-.008”
Differential Side Bearing Preload New, Bearings
- 20-30 Lb.In.; Used Bearings - lo-20Lb.In., using following selective shims:
Thickness In..0059.0069
.0079
.0089
.0098
.0108
.0197
.0433Number of Notches
in Circumference
0
1
;
4
5
8
7
Torque SpecificationsUse a reliable torque wrench. Specifications are for clean and lightly-oiled
threads.

49- 241973 OPEL SERVICE MANUAL
Torque
Lb.Ft.
1.9Nut and BoltPropshaft to Drive Pinion Shaft Extension Flange
......11
NutFlange
toDriveShaftExtension........................................87
BoltRing Gear to Case................................................................
BoltSideBearingCaptoCarrier.............................................i;
BoltDifferentialHousingCover.................................................22
NutTrackRodAttaching(GT)....................................................40
Nut and BoltStabilizer
RodtoRearAxleShackle................................25
BoltStabilizer Rod to Body........................................................15
NutTrack Rod to Rear Axle (Opal1900 & Manta)..............76
NutTrack Rod to Side Member (Opel 1900 & Manta)......22
10 MM Bolt Nut
....................................................................................................................368 MM Bolt Nut
......................................................................................................................156 MM Bolt Nut
........................................................................................................................5

DIFFERENTIAL COVER AND
SIDE BEARING CAPCOVER GASKET
DRIVE PINIONSlDE,BEARlNG /; GEAR REAR PINION BEARINGx
\PRELOAD NUT, DIFFERENTIAL CASE
SIDE GEAR
PINION GEAR
THRUST WASHER
AXLE SHAFT
BEARING RETAINER
FLAT WASHER
TORQUE TUBE40.37PRdPELLER SHAFT
Figure 48-37 Exploded View Rear Axle Assembly

5A- 61973 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:
1. Remove protective cap (boot).
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 be located near
the intake manifold. Therefore, the short vacuumhose 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 REMOVALAND INSTALLATION
Removal
1. Disconnect brake pipes from master cylinder.
Place a cloth under the master cylinder and brake
pipes to absorb any brake fluid drippings.
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
1900and Manta, remove the nut and bolt attaching clevis
on the pedal.
6. Remove assembly from car.
7. Disconnect master cylinder from brake booster.
Installation
CAUTION: Fasteners in the folkwing steps are im-
portant attaching parts in that they could affect the
performance of vital components and systems, and-
/or could result in major repair expense. They must
berep/aced, with one of the same part number or with
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.1. Using a new front housing seal, assemble master

POWER BRAKE BOOSTER AND MASTER CYLINDER5A- 7cylinder to brake booster and torque nuts to 14
Ib.ft.on the GT and 12
lb.ft. on the Opel 1900 and Manta.
2. Position assembly into brake booster bracket and,
on the GT only, thread piston push rod onto the
thrust rod.
3. Install brake booster to support attaching washers
and nuts and tighten to 11
lb.ft. of torque.
4. On the GT install master cylinder support to inner
fender skirt bolts.
5. Connect vacuum hose to brake booster.
6. By turning the piston push rod on the thrust rod,
(GT only) adjust until the brake pedal free travel is
l/4 inch and tighten the lock nut.
7. Connect brake pipes to master cylinder and bleed
brakes.
MASTER CYLINDER OVERHAUL. GT
Removal of Master Cylinder1. Disconnect the two brake pipes from the master
cylinder.
2. Remove the front support to skirt attaching bolts,
the cylinder to booster retaining nuts and lift out
master cylinder.
Disassembly1. Prior to brake master cylinder disassembly, pour
brake fluid out of brake fluid reservoir, remove reser-
voir from master cylinder and take sealing plugs out
of housing.
2. Screw static pressure valve(s) out of housing.
3. To facilitate disassembly, push piston somewhat
into cylinder and insert a rounded off piece of weld-
ing rod approx.
.12 in. thick into feed port to retain
piston in this position.
4. Remove stop screw and snap ring out of housing
and take out both pistons together with springs.
5. Remove stop screw from piston for rear brake
circuit and remove all component parts. Remove
also all component parts from intermediate piston of
front brake circuit.
Cleaning and Checking1. Clean parts with genuine brake fluid, Delco Su-
preme No. 11, or equivalent. Do not use any other
cleaning solvents. Dry with compressed air. Free up
compensating and feed ports.2. Polish cylinder bore of housing with crocus cloth.
If lapping scores and rust spots are still noticeable,
replace brake master cylinder assembly.
3. Check inner components for damage and replace,
if required. The rubber seals and static pressure valve
always have to be replaced.
Assembly1. Assemble front and rear brake circuit pistons.
Prior to assembly coat rubber seals with brake fluid.
2. Coat cylinder bore, piston sliding surfaces and
seals with brake fluid.
3. Insert preassembled intermediate piston for front
brake circuit together with thrust spring and spring
seat into clyinder bore. The smaller diameter of the
tapered thrust spring must face piston.
4. With a drift, push piston (against spring pres-
sure) into housing and insert a piece of welding rod
into feed port of front brake circuit to retain piston.
5. Install stop screw with new seal ring into housing
and tighten.
6. Insert preassembled piston for rear brake circuit
into cylinder bore and install snap ring into groove
in housing.
7. Check piston fof free movement by moving it to
and fro. If required, place washers under the head of
the stop screw.
8. Lightly push piston into housing and remove
piece of welding rod out of feed port of front brake
circuit.
9. With a rounded off piece of welding rod
(.020 -
,024 in.) check whether compensating ports are free.
10. Screw in new static pressure valve(s).
11. Coat new sealing plugs with brake fluid and in-
sert them into housing. Push twin brake fluid con-
tainer into sealing plugs and install screen and cover
with seal ring.
Installation1. Install master cylinder onto brake booster with
washers and nuts. Torque to 14
lb.ft.2. Attach the front mounting bracket.
3. Install brake lines on master cylinder, and bleed
brakes.

POWER BRAKE BOOSTER AND MASTER CYLINDER5A- 9NOTE: Snap ring should not be reused.5. Remove primary and secondary pistons from cyl-
inder.
6. Remove check valve by unscrewing check valve
connection.
Cleaning and Checking
1. Clean parts with genuine brake fluid, Delco Su-
preme No. 11, or equivalent. Do not use any other
cleaning solvents. Dry with compressed air. Free up
compensating and feed parts.
2. Inspect cylinder bore for pits, scoring, cracks,
nicks or other defects.
NOTE: Whenever the master cylinder is overhauled,
a new repair kit must be used.
Assembly
NOTE:
Before reassembly double check that there
is no foreign particles in the master
cyIinder bore
or on any parts that are to be assembled into it.1. Coat master cylinder bore with clean brake fluid
and install secondary and primary pistons.
2. Install new snap ring while holding primary piston
in a forward position.
3. Install check valve spring, check valve and check
valve connector and torque to 26
Ib.ft.4. Install stop screw.
5. Lubricate reservoir seals and remount on master
cylinder body.
6. Install reservoir clips into reservoir and mount
reservoir onto master cylinder without distorting
seals. Do not force reservoir onto master cylinder.
7. Position reservoir cover onto reservoir.
Installation
1. Mount master cylinder to brake booster, using a
new front housing seal if old one is damaged or dis-
torted. Torque nuts to 12
lb.ft.2. Install brake pipes to master cylinder and bleed
brakes.
SPECIFICATIONS
GENERAL SPECIFICATIONSBrake Booster Size
..............................................................................................................7 in.
BrakeBoostRatio
-(GT)..........................................................................................2.06to1Brake Boost Ratio
- (Opel 1900 and Manta)............................................................2.64 to 1
NameTorque
Nut
Nut
Lb.Ft.Master Cylinder to Brake Booster
(GT) .__......._.._...._.........
Master Cylinder to Brake Booster (Opel 1900 and
Manta)14
12Brake ‘Booster to Support
.._...._..........................................11

DISC BRAKES5B- 13
Condition
Possible CauseCorrection
2. Front end out of line.2. Check and align to manufac-
turer’s specifications.
3. Unmatched tires on sameaxle.3. Tires with approximately the
same amount of tread should be used
on the same axle.
4. Restricted brake tubes
or hoses.4. Check for soft hoses and damaged
lines. Replace with new hoses and
new double-walled steel brake
tubing.
5. Malfunctioning caliper
assembly.5. Frozen caliper
- check for
stuck or sluggish pistons, proper
lubrication.
6. Defective or damaged
shoe and lining (grease or
brake fluid on lining or
bent shoe).6. Install new shoe and lining in
complete axle sets.
7. Malfunctioning rear
brakes.7. Check for brake adjustment,
defective lining (grease or brake
fluid on lining) or defective wheel
cylinders. Repair as necessary.
8. Loose suspension parts.
9. Loose calipers.8. Check all suspension mountings.
9. Check and torque bolts to
specifications.
Brake Roughness or Chatter
(Pedal Pulsates)
1. Excessive lateralrunout.1. Check per instructions and
replace or machine the rotor, if not
within specifications.
2. Parallelism not within
specifications.2. Check per instructions and replace
or machine the rotor, if not within
specifications.
3. Wheel bearings not
adjusted.3. Adjust wheel bearings to correct
specifications.
4. Rear drums out of round.4. Check runout and, if not within
specifications, turn the drums within
specifications.
5. Shoe reversed (steel
against iron).5. Replace shoe and lining and
machine rotor within specifications.
ExcesGve Pedal Effort1. Malfunctioning power
brake.1. Check power brake and repair,
if necessary.

5B- 19i973 OPEL SERVICE MANUAL
Figure
56-24 Removing Dowel Pins
Figure 56-25 Removing Friction Pads
4. Check rubber seals for wear. If rubber seals are
hardened, brittle or cracked, they must be replaced
as follows:
(a) Remove brake caliper from steering knuckle and
brake disc. Leave hose attached to brake caliper.
(b) Remove seal clamp rings with screwdriver and
remove seal rings from calipers. See Figure
5B-26.(c) Install new rubber seals and clamp rings. Make
sure rubber seal is properly seated. Make sure clamp
ring is correctly positioned on rubber seal,Figure 56-26 Removing or Installing Rubber Seal
Clamp Ring
(d) Attach brake caliper to steering knuckle and
torque bolts to 72
Ib.ft. Prior to installation of
caliper, make sure contacting surfaces of both caliper
and steering knuckle are perfectly clean and free of
any burrs.
CAUTION: This disc brake caliper attachments fas-
tener is an important attaching part in that it could
affect the performance of vital components and sys-
tems, and/or could
result in major repair expense. It
must be replaced with one of the same part number
or with an equivalent part, if replacement
becomes
necessary. Do not use a replacement part of lesser
quality or substitute design. Torque values must be
used as specified during reassembly to assure proper
retention of this part.5. Before installing new friction pads, press both pis-
tons of each caliper to bottom of their bores, using
Return Clamp J-22430.
While pressing piston into
bores, open caliper bleeder valve to prevent excess
brake fluid from overflowing master cylinder con-tainer As soon as pistons are bottomed, tighten
bleeder valve.
6. Check brake disc for lateral runout.
7. Install new friction pads into brake caliper. Fric-
tion pads must be free enough to be easily moved in
their caliper recesses. See
Figure X3-25.If new friction pads are not free, it will be necessary
to remove pads and clean recesses and recess corners
with a wooden spatula and then with denatured al-
cohol and a brush. After cleaning, blow out recesses
with compressed air. Remove any high spots on
edges of friction pads contacting caliper recesses with