1973 OPEL GT-R service

46. 141973 OPEL SERVICE MANUAL
2. Install rear pinion bearing outer race (without
shims) using installer J-7818 and driver handle
J-8092. See Figure 4B-12.
3. To determine the correct pinion depth setting use
the following procedures:
a. Assemble gauge plate J-21691-4, rear pinion bear-
ing (lubricated), stud J-21691-7, front pinion bearing
(lubricated), pilot washer J-21691-5 and nut into dif-
ferential carrier. See Figure 4B-13.
‘1GAUGING ARBOR
Figure 48-l 3 Pinion Depth Gauging Tools Installed
b. Alternately tighten and rotate until a torque of
7-12 lb.in. (9 Ibin. desired) new bearings or 5-7 lb.in.
(6 lb.in. desired) with used bearings is required to
rotate the gauge plate assembly.
c. Position gauging arbor J-21691-6 in side bearing
bores of the carrier, install side bearing caps in their
respective positions and torque the bearing cap bolts
to 33
lb.ft. See Figure 4B-13.
d. Position adjustable height block J-21691-3 firmly
against the face of gauge plate J-21691-4. Allow the
movable plunger to bear against
#the machined sur-
face of gauging arbor J-21691-6 and tighten the
plunger set screw. See Figure
4B-14.e. Remove the adjustable height block and use a 1”
to 2” micrometer to measure the distance from the
bottom of the height block to
thetop of the extended
plunger. See Figure
4B- 15.
f. Select the correct pinion depth shim thickness as
follows:
(1) Record the height block dimension as determined
in step
(e).
I4814
/Figure 48.14 Gauging Pinion Depth
HEIGHT BLOCK
MICROMETER
48-15Figure 4B-15 Measuring Adjustable Height Block
(2) The control figure (on face of pinion) is shown in
Figure
4B-16.If the CONTROL FIGURE (underlined) is plus,
convert the figure from millimeters to inches and
subtract from Step (1). If the CONTROL FIGURE
(underlined) is minus, convert the figure from milli-
meters to inches and add to Step (1).
(3) Record the result from Steps (1) and (2).
(4) Subtract from Step (3) the nominal figure 1.468.
(5) The difference between Steps (3) and (4) is thick-
ness of shims required to set the pinion,

48. 16
1973 OPEL SERVICE MANUAL
protruding to install the pinion preload nut. Do
not use Installer J-22938 to adjust pinion preload.
See Figure 4B-20.
Assembly and Installation of Differential Case.
Opel 1900 and Manta1. Install side gears without thrust washers or shims.
BARREL SPLINE2. Lubricate and install pinion gears and thrust
washers between the side gears 180 degrees apart and
rotate the gears as an assembly until the pinion gear
bores are aligned with the pinion shaft bores in the
case.3. Install pinion shaft.
4. Install Special Tool J-24093 and, with the use of
a dial indicator, check end play clearance between
side gear and case as follows:
40-20a. Zero dial indicator on end of Tool J-24093. See
Figure 4B-22.
Figure 48.20 Installing Barrel Spline Sleeve
When the drive pinion end play is eliminated, the
preload specification is being approached. If this
specification is exceeded, replace the collapsible
spacer.10. Remove installer J-22938 and install washer and
pinion preload nut. Using Special Tool J-22932, hold
barrel spline and tighten preload nut until a preload
of 6-13
Ib.in. (9 Ibin. desired) with new bearings or
5-8
Ib.in. (6 lb.in. desired) with used bearings is re-
quired to rotate the drive pinion.
11. Use J-2293 1 to install a new pinion oil seal that
has been soaked in differential lubricant. See Figure4B-2
1.Figure 48.22 Zeroing Dial
lndicatotb. Using both hands, raise side gear until it bottoms
against case and record dial indicator reading. See
Figure 4B-23.
c. Measure the thickness of the concave thrust
washer by using a
0” to 1’ micrometer and subtract
this dimension from the dial indicator reading as
obtained in step b. Record dimension. See Figure
4B-24.
/INSTALLER J-22931d. After obtaining a dimension by subtracting con-48-21cave thrust washer thickness from dial indicator
reading, subtract an additional
,002 to obtain the
Figure 46.21 Installing Pinion Oil Sealcorrect shim thickness to be installed.

48. 181973 OPEL SERVICE MANUAL
Figure 48.26 Checking Torque
to Rotate Gear
in;! surfaces are free of burrs or foreign material.
Tighten bolts to 47 lb.ft.
10. Check lateral runout of installed ring gear. Max-imum permissible runout is
.003”. If runout is
greater than specified, make certain that dirt or burrsare not holding the ring gear in a cocked position on
the case and that the bolts are evenly
torqued.Figure 48-27 Installing Differential Side Bearings
g. Install shim packs with respective side bearing1 I.
In.stall side bearings using installer J-22919 and
drive handle J-8092. Support opposite side of case on
pilot J-2241-1
1 to prevent bearing damage. See Fig-ure
4B-27.12. Determine differential side bearing preload and
backlash as follows:
a. Position differential case assembly less side bear-
ing shims into the side bearing bores of the carrier.
See Figure
4B-28.Figure 48.28 Installing Differential Case Assembly
b. Using two sets of feeler gauges, insert feeler stockof suffcent thickness between each bearing outer
race and the carrier to remove all end play. Make
certain the feeler stock is pushed to the bottom of thebearing bores. See Figure
4B-29.
c. Mount dial indicator J-8001 on carrier so indicator
stem is at right angles to a tooth on the ring gear. SeeFigure
4B-29.d. Adjust feeler gauge thickness from side to side
until ring gear backlash is ,004” to
.OO8” (.005” is
desired).e. With zero end play and correct backlash estab-
lished, remove feeler gauge packs, determine thick-
ness of shims required and add ,002” to each shim
pack to provide side bearing preload.
f. Remove case assembly and both side bearings us-ing J-22588 with adapter leg J-22939 and pilot
J-
2241-l 1.

49- 201973 OPEL SERVICE MANUAL
IN.LB. TORQUE
Figure 48.30 Checking Side Bearing Preload
4. With the use of a feeler gauge, check clearance
between differential side gears and case. See Figure
4B-31. Clearance should be ,003” to X106”. If clear-
ance is not within these limits, remove side gears and
install shims of correct thickness to obtain desired
clearance, reassemble and install pinion shaft lock
pin.
Figure 48.31 Checking Side Gear to Case Clearance
5. Install ring gear on case, making certain their
mating surfaces are free of burrs or foreign material.
Tighten bolts to 47
lb.ft.
6. Check lateral runout of installed ring gear. Max- imum permissible

runout is X03”. If runout is
greater than specified, make certain that dirt or burrs
are not holding the ring gear in a cocked position on
the case and that the bolts are evenly torqued.
7.
Imtall side bearings using Installer J-22919 and
Drive Handle J-8092. Support opposite side of case
on Pilot J-2241-1 1 to prevent bearing damage. See
Figure
4B-32.
DRIVER
HANDLE
J-8092
4B.27
Figure 48-32 Installing Differential Side Bearings
Figure
48.33 Installing Differential Case Assembly

48. 221973 OPEL SERVICE MANUAL
9. Position
case assembly and outer races in the car-
rier. Use a soft-faced hammer to drive the case into
the carrier until the side bearing outer races bottom
in their bores.
10. Install side bearing caps in their original location
and torque the bolts to 33
lb.ft.IN. LB. TORQUL
11. Rotate case assembly several times to seat the
bearings. Check backlash and preload using a torque
wrench on a ring gear attaching bolt. See Figure 4B-
35. Torque required to turn case should be 20 to 30
Ib.in. for new bearings or 10 to 20 lb.in., for used
bearings. If torque is not correct, it will be necessary
to r&him the side bearings.
12. Insta!l torque tube assembly.
13. Install axle shafts.Figure 48.35 Checking Side Bearing
Preload
SPECIFICATIONS
DIFFERENTIAL SPECIFICATIONS
General SpecificationsRear Axle Type
.,,...,,,...,,_...._..,,...,,,...,,,....,,.,...,,.,,...,,..,,,........................ Semi-Floating Hypoid
Rear Axle Oil Capacity
..____,,...,,,...,.,..,............,,..,,..,,................................................. 2 l/2 7’.Ring and Pinion Gear Set Type
. . . . . . . . . . . . . . . . . .._................................................................Hypold
Axle Ratios

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

CONTENTS
SubjectPage No.
DESCRIPTION AND OPERATION:
Power
BrakeBooster. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Master
Cylinder
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .DIAGNOSIS:
Power
Brake
,UnitTroubleDiagnosis. . . . . . . . . . . . . . . . . . . . . . . . . .MAINTENANCE AND ADJUSTMENTS:
Checking Brake Booster Operation
. . . . . . . . . . . . . . . . . . . . . . . . . . . .Brake Booster Filter Service
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..Vacuum Control Valve Service
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .MAJOR REPAIR:
5A-2
5A-2SA-4SA-5
5A-65A-6
Brake Booster Removal and Installation
. . . . . . . . . . . . . . . . . .Master Cylinder Overhaul
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . * . . . . . . . . . . .SPECIFICATIONS:
General
Specifications
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .SA-6
5A-7
5A-95A. 21973 OPEL SERVICE MANUAL
POWER BRAKE BOOSTER AND MASTER CYLINDER
DESCRIPTION AND OPERATION
POWER BRAKE BOOSTERThe vacuum power cylinder contains the power pis-
ton assembly which houses the control valve and
reaction mechanism and the power piston return
spring. The control valve is composed of the air valveand the floating control valve assembly. The reaction
mechanism consists of a hydraulic piston, reaction
plate, and a series of springs. An air filter element is
assembled around the push rod and fills the cavity
inside the hub of the power piston. This keeps dirt
and dust from entering the vacuum booster. The
push rod, which operates the air valve, projects out
of the end of the power cylinder ‘housing through a
boot.MASTER CYLINDER
The master cylinder is composed pf a primary pistonand secondary piston; it is supplied with fluid from
two separate reservoirs. A check valve is mounted onthe primary circuit which supplies fluid to the rear
brakes. This keeps a slight static pressure in the rear
brake system. When the pedal is depressed, the pushrod moves the two pistons forward simultaneously
until the seals of the two pistons cover the compen-
sating ports in the cylinder. The pressure is increasedin the two chambers simultaneously, thus supplying
fluid to both front and rear brake systems.Figure
5A-1 Brake Booster Attachment (Opel 1900
and Manta)
In the GT, the brake fluid container is arranged at
right angles to the tandem brake master cylinder. SeeFigure
5A-3. It is pushed over the feed port of the
rear brake circuit onto the brake master cylinder and

5A- 41973 OPEL SERVICE MANUAL
Figure
5A-4 Brake Pedal and Master Cylinder
Attachment
(GT)
v1I cy
1 THRUST SPRING
2 VALVE SEAT
3 HOUSING
Figure
5A-5 Vacuum Control Valve
DIAGNOSIS
POWER BRAKE UNIT TROUBLE DIAGNOSIS
ConditionPossible Cause
CorrectionHard Pedal
1. Broken or damagedhydraulic
brake lines.
1, Inspect and replace as necessary.
2. Vacuum failure.
2. Check for:a) Faulty vacuum check valve or
grommet
- replace.
b) Collapsed or damaged vacuum
hose
- replace.
c) Plugged or loose vacuum
fitting
- repair.
d) Faulty air valve seal
drsupport plate seal
- replace.
e) Damaged floating control valve.
3. Defective diaphragm.
4. Restricted air filter
element.3. Replace
4. Replace5. Defective apply piston5. Repair and replace master
seals.cylinder.
6. Cracked or broken powerpistons or retainer.6. Replace power unit.