1973 OPEL GT-R seats

REAR AXLE
CONTENTS
SubjectPage No.
DESCRIPTION AND OPERATION:
Rear Axle Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4B- 7
DIAGNOSIS:
RearAxleTroubleDiagnosis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4B- 8
MAINTENANCE AND ADJUSTMENTS: (Not Applicale)
MAJOR REPAIR:
Removal and Installation of Rear Axle Assembly
Removal and Installation of Axle Shaft Assembly
Disassembly and Assembly of Differential
.* . . . . . . . . . . . .SPECIFICATIONS:
DifferentialSpecifications
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4B- 94B-10
48-l 1
4B-22
DESCRIPTION AND OPERATION
REAR AXLE DESCRIPTIONThe Opel rear axle is a semi-floating type that carries
car weight through the axle shafts by way of ball
bearings which are located on the outer ends of each
axle shaft. The rear axle assembly is attached to the
under body by way of the shock absorbers, track rod,
central joint support, and lower control arms. A sta-
bilizer rod is used on all Wagons, as well as Fast
Backs and Sedans. The GT is not equipped with a
stabilizer rod. The rear springs have a progressive
spring rate which is attained by a gradual reduction
of coil thickness. The springs are arranged between
the spring seats welded onto the rear axle tubes and
the under body side members. The upper and lower
ends are seated in profiled rubber dampening rings.
The differential housing is a malleable iron casting
with tubular axle housings pressed into the sides to
form a complete assembly. An oil feed passage to the
pinion bearings and an oil return hole are provided
to allow lubricant to circulate. A removable steel
cover is bolted on the rear of the differential housing
to permit service of the differential without removing
the rear axle assembly from the vehicle. A breather
fitting is located on top of the right axle tube.Within the differential carrier, the differential case is
supported by two tapered roller side bearings. These
side bearings are preloaded by shims located between
the bearing inner races and differential case. During
installation, varying the shim thickness from side to
side also determines the ring gear to pinion backlash.
The differential case houses two side gears meshed
with two pinions. The pinions and side gears are
backed by thrust washers. The pinion gears are held
in place by a pinion shaft which is anchored in the
differential case by a lock pin.
The inner end of the axle shafts engage and extend
through the splines of the side gears with a floating
tit.
The axle shafts have an enlarged diameter from mid-
shaft to the flange end.
A ball bearing and oil seal are used on all models, and
are pressed onto the outer end of the axle shaft as an
assembly.The drive pinion is mounted in two roller bearings in
the rear axle housing. Pinion setting is established by
shims located between the differential carrier and therear’pinion bearing outer race.

4B- 101973 OPEL SERVICE MANUAL
Figure 48-Z Removing Rear Axle Assemblyan equiva/entpart ifreplacement 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 reten-
tion of these parts.1. Roll rear axle assembly under car on floor jack and
loosely attach lower control arms to rear axle hous-
ing.
2. Attach central joint support, to underbody with
bolts only finger tight.
3. Lower rear axle assembly, install lower damper
rings in spring seats, coil springs and upper damper
rings on springs. Make certain the damper rings and
springs are properly positioned.
4. Install track rod on axle housing.
5. On Opel 1900 and Manta, place a load of approxi-
mately 350
Ibs. in luggage conipartment or on the
GT, place a load of approximately 150 lbs. on drivers
seat and raise rear axle far enough for underbody to
clear jack stands.
6. Torque central joint support t$ underbody bolts to
36 lb.ft.
7. Torque lower control arm to
Axle housing bolts to
18
Ib.ft. on the GT and 22 lb.ft. dn the Opel 1900 and
Manta.
8. Torque track rod to rear axle attaching nut to
40lb.ft. on the GT and to 76
lb.ft. on the Opel 1900 and
Manta and remove added weight.
9. Install shock abosrbers and tighten nuts to 15
Ib.ft.on the GT and to 47
Ib.ft. on the Opel 1900 and
Manta.10. If car is equipped with stabilizer rod, connect
shackles to axle housing. Tighten to 25 lb. ft.
11. Connect brake hose to brake pipe and install
retaining clip.
12. Thread parking brake cable over exhaust system
and connect to lower control arm brackets, parking
brake actuating lever and brake backing plate. Install
brake drum.
13. Align mating marks and connect propeller shaft
to pinion flange. Tighten universal joint attaching
bolts to 11
Ib.ft. Bend respective lock plate tabs to
secure nuts or bolts.
14. Connect parking brake cable equalizer and return
spring to brake rod and adjust to specifications.
15. Bleed rear brake system and fill master cylinder.
16. Install wheel assemblies and tighten lug nuts to
65
lb.ft.17. Remove jack stands and lower car to the floor.
REMOVAL AND INSTALLATION OF AXLE SHAFT
ASSEMBLY
Removal1. Raise and support rear of car at jack brackets.
2. Remove wheel and brake drum as necessary.
3. Unscrew rear axle shaft retaining plate and with
axle shaft puller J-8805 coupled with slide hammer
J- 2619 on axle shaft flange, remove axle shaft.
4. For replacement of the bearing parts, first remove
retaining ring by cutting off with a chisel. See Figure4B-3.
5. Press off bearing, using rear pinion bearing
remover J-22912.
Installation
CAUTION: Fasteners in the following steps b are im-
portant attaching parts in that they could at&t
tee
performance of vital components and systems, and-
/or could result in major
repair expense.They must
be replaced with one of the same part number or with
an equivalentpart ifreplacement 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 reten-
tion of these parts.1. Check radial runout of axle shaft at ball bearing

DRUM BRAKES5C- 23
Parking Brake Control System
The hand-operated parking brake lever is mounted
between the front seats on the propeller shaft tunnel.
A paw1 is riveted into the parking brake lever and is
actuated by a control rod provided with a spring
loaded push button. When the parking brake is ap-
plied, the parking brake lever is locked by the
paw1which engages the teeth on a stop plate. The parking
brake is disengaged by pressing the spring loaded
push button. See Figure
5C-41.
SPRING LOADED,-PUSH BUTTON
BRAKE LEVER
s\., \\,Figure
5C-4 1 Parking Brake Lever (Opel 1900 and
Manta)The GT arrangement of the parking brake is, with
the exception of the additional transmittal lever at
the floor panel, identical with that of the Opel mod-
els. The transmittal lever is attached to the propshaft
tunnel by means of a mounting support. See Figure
5C-42.The parking brake lever is connected with the front
parking brake pull rod. By means of an equalizer, the
front pull rod is connected to the forward portion of
a center cable. The center cable is routed rearward
through retaining guides and attaches at either end
to the lower end of a parking brake lever. See Figure
5C-43. The parking brake levers and struts actuate
the rear wheel brakes.
Service Brake Control System
-Standard Brakes
The service brake control system is a pedal operated
hydraulic system which applies the brakes at all four
wheels with equal pedal pressure. The hydraulic sys-
tem consists of a master cylinder (and attached trans-
parent fluid reservoir) connected by pipes and
1.PUSH BUTTON
2.THRUST SPRING
3.WASHER
4. PAWL CONTRO ROD
5. PARKING BRAKE LEVER
6.RIVET
7. HEX. HEAD BOLT
8.TOOTHED SEGMENT
9. PAWL WITH TWO TEETH
10.RUBBER CAP
11.THRUST ROD
12.PULL ROD
13.TRANSMITTAL LEVER
14.MOUNTING SUPPORT
15.BOLT
16. PARKING BRAKE CABLE
17. RETURN SPRING
sea2Figure 5C-42 Parking Brake Lever
(GT)flexible hoses to a wheel cylinder mounted between
the brake shoes at each rear wheel.
A mechanically-operated stop light switch is
mounted on a bracket just forward of the brake pedal
on the GT and just rearward of the brake pedal on
the Opel 1900 and Manta. With brake pedal released,
the switch plunger is fully depressed against the
switch actuating lever. See Figures
5C-45 and 5C-46.Any time the stop light switch fails, the stop lights
will stay on at all times.

6A- 21973 OPEL SERVICE MANUAL
ENGINE
CONTENTS
Subject
DESCRIPTION AND OPERATION:
EngineConstruction..........................................................
LubricationSystem............................................................
DIAGNOSIS:
Excessive Oil Consumption............................................NoisyValvesandLifters..................................................
MAINTENANCE AND ADJUSTMENTS:
Valve
LifterAdjustment..................................................
MAJOR REPAIR:
Engine Removal and Installation..................................
Engine
OilPanRemoval
andInstallation..................
Manifold, Cylinder Head, Valve Train and
Lifters................................................................................
Connecting Rod Bearings................................................
Crankshaft Bearings and Seals....................................
Piston, Rings and Connecting Rods............................
TimingChainCoverandTimingChain......................
Camshaft..............................................................................
Oil Pump Cover and Gears............................................
SPECIFICATIONS:
BoltTorque.Specifications
..............................................General Specifications......................................................
Engine Dimension and Fits............................................Page No.
6A- 2
6A- 4
6A- 6
6A- 6
6A- 7
6A- 86A-106A-126A-156A-166A-196A-236A-256A-266A-276A-286A-29
DESCRIPTION AND OPERATION
ENGINE CONSTRUCTION
Engine UsageThe 1.9 liter engine is standard equipment on all 1973
Opel
1900, Manta and GT models. This engine has
a compression ratio of
7.6:1 and operates on“regular” low lead grade fuel.
Engine ConstructionThe
cyfinderhead is made of high-grade chromium
grey cast iron. The valve guides are cast intergal with
the head. The overhead camshaft is supported in four
bearings in the cylinder head.Location of the
vzllve seats in combustion chamber
is above the center of cylinder bore. The spark plug
is positioned in the center and near the highest point
of combustion chamber. This arrangement provides
for short flame travel, uniform combustion and good
cold start prop&ties. Exhaust valves have seat in-serts of highly heat and water resisting material. The
head surface is alumetized and so are the seats of the
inlet v&es Alumetizing makes the valve heads
non- scaling and promotes long life. All engines have“rota-caps”.
The forged, five main bearing crankshaft has large-
diameter main and connecting rod bearing journals
with considerable overlap for vibration-free operat-
ion. T&metal bearing shells are used for main and
connecting rod bearings. The crankshaft end play is
controlled by the rear main bearing.

ENGINE MECHANICAL AND MOUNTS6A- 5
incorporating a gear-type pump driven by the dis-
tributor shaft. The pump body forms part of the
timing case. A passage cast in cylinder block and a
suction pipe connect the pump to the screen cover
assembly in the sump of the oil pan.
The oil pump pressure relief valve is located in the
engine oil pump cover. See Figure 6A-3. The pres-
sure relief valve serves to feed surplus oil back into
the suction passage should the required oil pressure
be exceeded. The old oil pressure relief valve which
is located above the oil filter is inoperative. A heavier
spring has been installed to keep the valve seated at
all times.
The oil filter is of the full flow type. With it in paral-
lel is a by-pass system controlled by a valve in the
timing chain cover above the oil filter which ensures
oil circulation directly to lubrication points if ele-
ment becomes clogged by dirt or oil is too thick to
pass through. Only when oil flow through element is
unrestricted the by-pass valve will close and filtered
oil is fed to the engine.
Oil flow through the engine is as follows: The oil
pump draws oil from the sump through the screenand pumps it through drilled passages in timing case
to the full flow filter. From there it passes to the
cylinder block main oil gallery with a branch in tim-
ing case to no. 1 camshaft bearing. Drilled passages
lead from the oil gallery to crankshaft main bearings
and in the crankshaft from main bearings to connect-
ing rod bearings. The camshaft front journal has a
crescent shaped groove which controls the oil supply
to cylinder head oil gallery. The cylinder head oil
gallery delivers oil under pressure to all valve lifters,
to Nos. 2, 3 and 4 camshaft bearings, and to rocker
arm seats. An additionally drilled passage connects
the valve lifter circular groove with circular groove
of rocker arm stud from where the oil is directed
upwards through a drilled passage to the rocker arm
seat. The cams are lubricated by oil under pressure.
Surplus oil collects at end of cylinder head and re-
turns through a passage to the crankcase. A cali-
brated squirt hole in connecting rod big end bearing
sprays oil against right-hand side of cylinder wall:
Additional cylinder wall and piston pin lubrication
is through oil splash from crankshaft. A jet in timing
case projects oil against oil pump drive, and the tim-
ing chain receives lubrication from above the chain
tensioner.
Figure 6A-5 Engine Lubrication System

6A. 141973 OPEL SERVICE MANUAL
wire brushes for removing carbon, avoid scratching
valve seats and valve faces. A soft wire brush such as
J-8089 is suitable for this purpose.
Figure 6A-21 Removing Valve Cap Retainers5. Clean carbon and gum deposits from valve guide
bores.6. Inspect valve faces and seats for pits, burned spots
or other evidences of poor seating. If a valve head
must be ground until the outer edge is sharp in order
to true up the face,discard the valve because the
sharp edge will run too hot.
J-22917-1 .0030” O.S.
J-22917-2 .0059”
05.J-22917-3 .Ol 18” OS.
Figure 6A-22 Reaming Valve Guide
CORRESPONDINGVALVE STEM DIA.
SIZE IN.VALVE GUIDE
PRODUCTION.3553.
.3562.3538..3543.3524.3528PRODUCTION
AND SERVICE
.3582.3592.3567.3572.3553.3559.3615.
.3622.3597.3602.3583.3588
.3671.3681.3656..3661.3642.3647
6A-2:Figure 6A-23 Valve Guides and Corresponding Valves

ENGINE MECHANICAL AND MOUNTS6A- 15New inlet valves must not be refaced or lapped with
grinding compound.The correct angle for the intake
and exhaust valve head is 44 degrees.10. Install cylinder head.
11. Adjust valve clearance. See MAINTENANCE
AND ADJUSTMENTS.
7. Inspect valve guides. Worn or pitted guides can be
reamed to accept valves with oversize stems. Over-
size valves are occasionally used in production.
Oversize valves are marked
’ 1 u “2” or “A” and are
stamped into the valve stem end and also stamped
near spark plug hole. See Figure 6A-22.
Replacing Rocker Arm Studs1. When replacing rocker arm studs become
neces-
sary, remove air cleaner, rocker arm cover and
rocker arm.
8. Reseat valve seats in cylinder head in the following
sequence:
Intake
NOTE:The rocker arm studs are screwed into the
cylinder head. A tapered part of the stem serves to
a void stud loosening.With 45 degrees cutter, remove burnt structure until
a metallic bright seat is obtained. Lightly coat valve
head with red lead, insert it into guide and turn it
under light pressure several times back and forth.
Thereby a contact pattern is obtained and the seat
width can be measured. If valve does not seat per-
fectly all around, lightly recut valve seat to the estab-
lished seat width of
,049” - .059” with 30 degrees
correction cutter.
ExhaustThe directions for reconditioning intake valve seats
apply in principle also to exhaust valve seat recondi-
tioning with the exception that the valve seat width
should be
.063-,073 in. and different cutters are em-
ployed.
NOTE:
: OTse new valve seals whenever
valves are reconditioned.9. Lube valves with engine oil and reinstall valves,
valve springs, caps and cap retainers using J-8062.
Install valve spring with closely wound coils toward
cylinder head. See Figure
6A-24.2. Attach vise grip pliers to stud being removed and
remove from cylinder head.
3. Screw in new stud. Seat tapered part of stud by
striking stud end with a rubber hammer.
4. Place two turned down rocker arm nuts on
threaded part of stud.
5. Torque stud into cylinder head to 29
lb.ft.
Valve Lifter ServiceThe valve lifters can be removed after removing
rocker arm cover and rocker arms.No oversize lifters have been released due to the
insignificant wear of the valve lifters and cylinder
head guides.
Amply oil respective parts and install in reverse se-
quence to removal.
Carry out hydraulic valve lifter adjustment as ou-
tlined in MAINTENANCE AND ADJUST-
MENTS.
VALVE
I SPRING
CLOSE
WOUND
COILS
TOWARD
HEAD6A-24
Figure 6A-24 Valve SpringCONNECTING ROD BEARINGSA connecting rod bearing consists of two halves or
shells which are alike and interchangeable in rod and
cap. When the shells are placed in rod and cap the
ends extend slightly beyond the parting surfaces so
that when rod bolts are tightened the shells will be
clamped tightly in place to insure positive seating
and to prevent turning. Theends of shells must never
be tiled flush with parting surface of rod or cap.
If a precision type connecting rod bearing becomes
noisy or is worn so that clearance on crankpin is
excessive, a new bearing of proper size must be se-
lected and installed since no provision is made for
adjustment. Under no circumstances should the con-necting rod or cap be filed to adjust the bearing
clearance.

ENGINE MECHANICAL AND MOUNTS6A- 17
seating and to prevent turning.The ends of she//s
must never be tiled flush with parting surface of
crankcase or bearing cap.Crankshaft bearings are the precision type which do
not require reaming to size. Shims are not provided
for adjustment since worn bearings are readily re-
placed with new bearings of proper size. Bearings for
service replacement are furnished in standard size
and undersizes. Under no circumstances should
crankshaft bearing caps be tiIed to adjust for wear in
old bearing.After removal of oil pan, pipe and screen assembly,
perform the following removal, inspection and in-
stallation operations on each crankshaft bearing in
turn so that the crankshaft will be well supported by
the other bearings.
If crankshaft has been removed to check straightness
the following procedure is suggested. Rest crank-
shaft on “V-blocks” at number one and number live
main bearing journals. Check indicator runout at
No. 3 main bearing journal. Total indicator reading
should not exceed
.C012”.1. Since any service condition which affects the
crankshaft bearings may also affect the connecting
rod bearings, it is advisable to inspect connecting rod
bearings
first. If crankpins are worn to the extent
that crankshaft should be replaced or reground, re-
placement of crankshaft bearings only will not be
satisfactory.
If replacement of cylinder block or crankshaft is re-
quired, always check main bearing clearance with
plastic-type gauge to obtain specified limits.
2. Remove one bearing cap, then clean and inspect
lower bearing shell and the crankshaft journal. If
journal surface is scored or ridged, the crankshaft
must be replaced or reground to insure satisfactory
operation with new bearings. Slight roughness may
be polished out with tine grit polishing cloth
thoroughly wetted with engine oil, and burrs may be
honed off with a tine stone.
3. If condition of lower bearing shell and crankshaft
journal is satisfactory, check the bearing clearance
with a plastic-type gauge.
4. When checking a crankshaft bearing with plastic-
type gauging material, turn crankshaft so that oil
hole is up to avoid dripping of oil on the gauge
material. Place paper shims in lower halves of adja-
cent bearings and tighten cap bolts to take the weight
of crankshaft
off the lower shell of beating being
checked.5. If bearing clearance exceeds
.C03”, it is advisable
to install a new bearing; however, if bearing is in
good condition and is not being checked because ofbearing noise, it is not necessary to replace the bear-
ing.6. Loosen all crankshaft bearing cap bolts
l/2 turn,
and remove cap of bearing to be replaced.
7. Remove upper bearing shell by inserting Bearing
Shell Remover and Installer J-8080 in oil hole in
crankshaft, then slowly turning crankshaft so that
the tool rotates the shell out of place by pushing
against the end without the tang. See Figure
6A-27.When turning crankshaft with rear bearing cap
removed hold oil seal to prevent it from rotating out
of position in crankcase.
8. The crankshaft journal cannot be measured with
an outside micrometer when shaft is in place; how-
ever, when upper bearing shell is removed the jour-
nal may be checked for out-of-round by using a
special crankshaft caliper and inside micrometer.
Figure 6A-27 Removing and Installing Crankshaft
Bearing Upper Shell
The caliper should not be applied to journal in line
with oil hole.
If crankshaft journal is more than
.M)12” out-of-
round, the crankshaft should be replaced since the
full mileage cannot be expected from bearings used
with an excessively out-of-round crankshaft.
9. Before installation of bearing shells make sure that
crankshaft journal and the bearing seats in crankcase
and cap are thoroughly cleaned.
10. Coat inside surface of upper bearing shell with
engine oil and place shell against crankshaft journal
so that tang on shell will engage notch in crankcase
when shell is rotated into place.
11. Rotate bearing shell into place as far as possible
by hand, then insert Installer J-8080 in crankshaft oil
hole and rotate crankshaft to push shell into place.
Bearing shell should move into place with very little