1973 OPEL GT-R light

The 1973 Opel Chassis Service MayI has been completely revised with respect to layout, format and information content
in a” attempt
to provide you “The Technician” with a tiore logical and usable publication. An example of the new grouping
layout 6 exhibited on the preceding
page. Each wow is rubdivided as follows:
Grouo 1
_. _
Subiect IIContents.
0
General InformationIGeneral InformationLifting
Maintenance and Lubrication
1ElectricalBattery
Starting System
lgriition System
Charging System
Washers and Wipers
Lighting Systems
Signal SystemI
Instrument Panel
Gauges
Wiring Diagrams
2
Body and Bumpers:General Body InformationI
Frame & Body Mountings
Windows
& Window Moldings
DONS
Rear Compartment LidRoof &Sun Roof
Seat?., Interior Trim & Headlining
Bumpers.
3Suspension and Steering
Front Suspension
Steering Linkages1Front End Alignment
Steering Gear
Steering Column
Rear Suspension
Wheels and Tires
4
Propelley Shaft & Rear AxlePropeller Shaft & Central Joint
Differential
5Brakes ~Power Booster and Master Cylinder
Front Disc BrakeI
Rear Drum Brake
6EngineEngine Mechanical and Mounts
Cooling System
Fuel System
Exhaust Systems
Carburetor and Throttle Linkage
Emission Control Systems
Tune-up
7TransmissionClutch
Manual Transmission
Automatic Transmission
BChassis Sheet MetalHood, Fenders and Grille
9
Accessol;iesHeaterAirConditioning
Radio

CC-10 1973 OPEL SERVICE MANUAL
wiper blades. Check amount and direction of fluid
sprayed by washers during use.,
E. Defrosters - Check performance by moving con-
trols to “DEF” and noting
am$nmt of air directed
against the windshield.
I
F. Wheel Alignment and
Balabce - In addition to
abnormal tire wear, the need fbr wheel alignment
service may be indicated by a pull to the right or
!eftwhen driving on a straight and level road. The need
for wheel balancing is usually
iddicated by a vibra-
tion of the steering wheel or
se;+ tihile driving at
normal highway speeds.I
IG. Brakes
- Be alert to illumiriation of the brake
warning light or changes in braking action,
SUCK as
repeated pulling to one side, unusual sounds when
braking or increased brake pedal travel. Any of thesecould indicate the need for
brakk system inspection
and/or service.
H. Parking Brake and Transmission “PARK”
Mechanism
- Check parking brake holding ability by
parking on a fairly steep hill and restraining the vehi-
cle with the parking brake only.
eon cars with auto-
matic transmissions, check the holding ability of the
“PARK” mechanism by releasing all brakes after
the transmission selector lever hak been placed in the“P” position.
I. Glass
- Check for broken, scrritched, dirty or da-
maged glass on vehicle that
coulld obscure vision’or
become an injury hazard.
J. Lights and Buzzers
- Check all instrument panel
illuminating and warning lights,’ seat belt reminder
light and buzzer, ignition key
b&er, interior lights,
license plate lights, side marker! lights, headlamps,
parking lamps, tail lamps, brake lights, turn signals,
backup lamps, and hazard warding flashers. Have
someone observe operation of
&ach exterior light
while you activate the controls: The operation of
instrument panel warning lights is covered in the
“Starting and Operating“ section of your
Own&%
Manual.K. Transmission Shift Indicator
‘- Check to be sure
automatic transmission shift
indiCator accurately i”-
dicates the shift position selected.
I
CAUTION: Before making thk check below,I
be sure to have a clear dist&e ahead and:
behind the car, set the parking brake and
firmly apply the foot brake.
Do not depress
accelerator pedal. Be prepared to
turn off ’
ignition switch
immediat+y if engine
should start.L. Starter Safety Switch (Automatic Transmissibn
Cars)
- Check starter safety switch by placing the
transmission in each of the driving gears while
at-tempting to start the engine. The starter should oper-ate only in the Park (“P”) or Neutral (“N”)
positions.
M. Horn
- Blow the horn occasionally to be sure thatit works. (Ignition switch must be in the “ON” posi-
tion.)
N. Seat Back Latches
- Check to see that seat back
latches are holding by pulling forward on the top of
each folding seat back.
0. Rearview Mirrors and Sun Visors
- Check that
friction joints are properly adjusted so mirrors and
sun visors stay in the selected position.
P. Door Latches
- Check for positive closing, latch-
ing and locking.
Q. Hood Latches - Check to make sure hood closesfirmly by pressing on the hood at the latching point
after each closing. Check also for broken, damaged
or missing parts which might prevent secure latch-
ing.R. Fluid Leaks
- Check for fuel, water, oil or other
fluid leaks by observing the ground beneath the vehi-cle after it has been parked for a while. If gasoline
fumes or fluid are noticed at any time, the cause
should be determined and corrected without delay
because of the possibility of fire.
S. Exhaust System
- Be alert to any change in the
sound of the exhaust system or a smell of fumes
which may indicate a leak.
Head Restraints
- Check that no head restraint
components are missing, damaged or loose. (Does
not apply to GT Models).
Disc BrakesCheck brake pads and condition of rotors while
wheels are removed during tire rotation. (Note belowregarding more frequent checks also applies to disc
brakes.)
Parking and Drum BrakesCheck drum
brake linings and other internal brake
components at each wheel (drums, wheel cylinders,
etc.). Parking brake adjustment also should be
checked whenever drum brake linings are checked.
NOTE: More frequent checks should be
made if driving conditions a.nd habits result
in frequent brake application. When brakes
require relining, it is recommended thatyou use those genuine General Motors
parts specified for your car,and Delco fluid
as required.

LUBRICATION AND MAINTENANCE OC-11
Throttle Linkage
Check for damaged or missing parts, interference or
binding. Any deficiencies should be corrected with-
out delay.
Headlights
Check for proper aim. Correct as necessary. More
frequent checks should be made if oncoming motor-
ists signal when you are already using your low
beams, or if illumination of the area ‘ahead seems
inadequate.
Underbody
In geographic areas using a heavy concentration of
road salt or other corrosive materials for snow re-
moval or road dust control, flush and inspect the
complete under side of the car at least once each
year, preferably after a winter’s exposure. Particular
attention should be given to cleaning out underbody
members where dirt and other foreign materials may
have collected.
EMISSION CONTROL MAINTENANCE
Thermostatically Controlled Air Cleaner
Inspect installation to make certain that all hoses and
ducts are connected and correctly installed. Also,
check valve for proper operation.
Carburetor Choke
Check choke mechanism for free operation. A bind-
ing condition may have developed from petroleum
gum formation on the choke shaft or from overtight-
ening of air cleaner clamp. Also check electric choke
terminal connections and fuse.
Timing, Dwell and Distributor
Adjust timing and dwell accurately as outlined under
Tune-Up in Group 6 at the first 4 months or 6,ooOmiles of operation, then at 12 month or
12,OQO mile
intervals. Adjustments must be made with test equip-
ment known to be accurate.
Replace distributor points every 12 months or 12,000
miles and carefully clean and inspect the complete
distributor cap to prevent misfiring and deteriora-
tion.
Carburetor and Idle
SpeedTorque carburetor attaching bolts and/or nuts to 12
ft.lbs. to compensate for compression of gasket atiirst 4 months or 6,000 miles of vehicle operation.Adjust idle speed to specifications with known accu-
rate equipment.
Proper functioning of the carburetor is particularly
essential to control of emissions. Correct mixtures
for emission compliance and idle quality have been
preset by Opel. Plastic idle mixture limiters have
been installed on the idle mixture screw, idle air
screw, and throttle stop screw to preclude unauthor-
ized adjustment. The plastic caps on the idle mixture
screw and the idle adjustment screw must be
removed to perform an idle speed adjustment. The
plastic cap on the throttle stop screw is not to be
removed unless some major carburetor repair or re-
placement which affects the throttle stop screw ad-
justment has been necessary.
Carburetor Fuel Inlet Filter
Replace filter at 12 month or
12,OCO mile intervals
or more often if clogged.
Spark Plugs
Replace at
6,ooO mile intervals when operating with
leaded fuels or at 12,000 mile intervals when using
unleaded fuels. Use of leaded fuels results in lead
deposits on spark plugs and can cause misfiring at
mileages less than
12,OilO miles. Where misfiring oc-
curs prior to
6,ooO miles, spark plugs in good condi-
tion can often be cleaned, tested and reinstalled in an
engine with acceptable results.
Spark Plug Wires
Inspect spark plug wires for evidence of checking or
cracking of exterior insulation and tight fit in the
distributor cap and at the spark plugs. Exterior of
wires should be cleaned, any evidence of corrosion
on ends removed and wire replace if deteriorated.
Positive Crankcase Ventilation System
The PCV metered orifice should be cleaned at 12,000
mile intervals under normal use, and at 6,000 mile
intervals when the vehicle is used under the follow-
ing conditions: driving in dusty conditions, extensive
idling, trailer pulling and short trip operation at
freezing temperatures (engine not thoroughly
warmed-up).
Evaporation Control System
Check all fuel and vapor lines and hoses for proper
connections and correct routing as well as condition.
Remove canister and check for cracks or damage.
Replace damaged or deteriorated parts as necessary.
Replace filter in open end of canister at 24month/24,000 mile intervals.

ELECTRICALGROUP 1
Section
IAIBICIDIE
IFIGIH
II
IJTitle
Battery and Cables. . . . . .
StartingSystem. . . . . . . . . . . .
Ignition System, .
ChargingSystemWashers and Wipers
.,
LightingSystems
SignalSystems
instrument Panel.........
Gauges...........................Wiring Circuit Diagram:
Page No.
lA- 2lB-10lC-18
1 D-28
1 E-37
1 F-45
1 G-54
1 H-57
1 l-65
1 J-72

1A. 4 1973 OPEL SERVICE MANUAL
gravity corrected to 80 degrees F.’ shows more than
a thirty point
(.030) drop from the initial tilling with
electrolyte, or if one or more cells’gas violently after
addition of electrolyte, the batteiy should be fulty
charged before use.
3. For best performance in cold weather (32 degrees
F. or less), or if the battery and the electrolyte are not
at 60 degrees F., or above at time of activation, warm
the battery by boost charging.
TROUBLE DIAGNOSIS
BATTERY AND CABLES. TRDUBLE DIAGNOSIS
Quick Check of Battery and Cables
Whenever electrical trouble developes, it is desirable
to make a quick check of the battery and cables to
make certain that this source of current is in good
condition, securely connected, and is functioning
properly. This check will also give a good check on
the cranking system.
1. Turn on the lights. They should’burn steadily and
with normal brilliance.
2. With lights burnings, operate the cranking motor.
Either have the headlights shining on a wall so their
brilliance can be noted, or have someone watching
the headlights.
3. When cranking motor solenoid switch is
closeh,one of the following conditions will occur; (1) Lights
will stay bright or will dim slightly if temperature is
cold, and engine will be cranked at normal speed; (P
Lights will
gb out; (3) Lights will dim considerably;
(4) Lights will stay bright but no cranking action will
take place. The first named condition indicates that
nothing is wrong with the battery, cables, and crank-
ing system. The other conditions indicate trouble
aSfollows:
4. If fightsgo
out as cranking motor solenoid switch
is closed, it indicates a poor connection in the circuit
between battery and cranking motor. Check battery
cables and clean and tighten loose or corroded termi-
nals.
5. If
lights dim considerably as cranking motor
solenoid switch is closed, it indicates that the battery
is run down, or there is a condition in cranking
mb-tor or engine which causes an excessive current drain
on the battery. A low battery will be indicated by ,a
clattering noise in cranking motor solenoid because
the battery cannot sustain the voltage required to
hold solenoid plunger “in” after switch contacts
close and the “pull in” winding is shorted out.
Test battery with a 421 Battery Test. If battery is
found to be in good condition check cranking motor.
6.Iflights stay bright but no cranking action occurswhen cranking motor solenoid switch is closed, it
indicates an open circuit in cranking motor, switch,
or control circuit.
Testing Resistance of Cables and Terminal
Connections
Battery cables and terminal connections may be
tested with equipment comprising of a voltmeter (5
volts maximum), ammeter of 300 or more amperes
capacity, and carbonpile rheostat having a minimum
capacity of 300 amperes connected in series with the
ammeter.
I. Adjust rheostat to provide maximum resistance
(“OFF” position).
2. Connect ammeter positive lead to post on starting
motor. Connect ammeter negative lead to one side of
rheostat and connect other side of rheostat to ground
on engine, preferably at point where battery ground
strap is attached. In the instrument shown in FigurelA-1, the ammeter and rheostat are connected in
series inside the case.
3. Connect voltmeter negative lead to post on start-
ing motor. Use prod with voltmeter lead, if neces-
sary, to insure direct contact with the terminal stud.
Do not connect to the ammeter lead clip.Attach a
prod to voltmeter position lead and apply the prod
to center of battery positive post (Figure lA-1.)
Make sure that clips of voltmeter leads have clean
metal contact with prods.
Figure l A-l Battery Cable Test Connections
4. Adjust rheostat until ammeter reads 200 amperes,
immediately read voltmeter, then turn rheostat to
starting (“OFF”) position to avoid excessive drain on
battery. Voltage drop across battery positive cable

BATTERY AND CABLES - ALL MODELSlA- 5
and terminal connections should not exceed 2/10
volt.
5. Connedt voltmeter positive lead to ground on en-
gine.
At&h prod to voltmeter negative lead and
apply prod to center of battery negative post. Volt-
age drop across the battery ground cable and termi-
nal conne$tions should not exceed 2/10 volt at
200amps.
6. A reading in excess of 2/10 volt when testing
either battery cable indicates excessive resistance in
cable or cpnnections. Clean and tighten cable or con-
nections. Clean and tighten cable terminals
(sub-para. c, below) and recheck for voltage drop. If volt-
age drop Still exceeds 2/10 volt, replace cable with a
genuine Buick-Opel cable to insure ample capacity.
Undercharge Failure of BatteryThe most frequent trouble experienced with storage
batteries is failure to maintain a state of charge suffi-
cient to crank the engine and also furnish current to
the ignitibn system, lights and accessories. Failure to
maintain a proper state of charge may be due to one
or more of the following conditions:
1.
Opertiting Conditions. When determining cause
of premature failure of a battery, consideration must
be given /to the conditions under which the car is
operated.,
In very low temperatures the capacity of a storage
battery
ii considerably reduced and the energy re-
quired f& cranking the. engine is considerably in-
creased. :
Frequent starting, particularly in cold weather,
ac-compani the batteqy for cranking than the generator can re-
place in the limited running time. This condition is
aggravated by night driving when lights are turned
on, or by operation of an air conditioner in heavy
traffic.
When thk car is operated under these conditions,adjusting,the voltage regulator to the high limit may
allow enough increase to keep the battery at a safe
state of charge. If the high limit setting does not
maintain a safe state of charge, an occasional booster
charge should be given to the battery.
2. Low charging Rate. In case of premature battery
failure, tbe charging rate of alternator should always
be checked and adjusted if below specifications.
3.
Zntemd Condition The internal condition of the
battery niay be such that it cannot hold a chargesatisfactoiily. Check electrolyte level and test the
battery using the 421 Battery Test.
Overcharge Failure of BatteryA common cause of battery failure is overcharging,
that is, continued input of excessive charging current
after the battery has reached a fully charged condi-
tion.
One evidence that battery is being overcharged is the
need for frequent addition of water to the battery in
order to maintain the electrolyte level above the tops
of the battery separators, since overcharging causes
rapid water loss. When this becomes evident, the
charging rate of alternator should be immediately
checked, as well as the voltage regulator, and ad-
justed to avoid internal damage to battery.
ADJUSTMENTS AND MINOR SERVICEPERIODIC BATTERY INSPECTION AND SERVICE
The battery requires very little attention, but peri-
odic inspection is essential to secure the maximum
efficiency and life. The following services are essen-
tial to maintain the battery at maximum efficiency.
WARNING: Never expose battery to open flame or
electric spark
- battery action generates hydrogen gas
which is flammable and explosive. Do not allow bat-
tery fluid to contact skin, eyes, fabrics or painted
surfaces
- fluidis a sulfuric acid solution which could
cause serious personal injury or property damage.
Wear eye protection when working with battery.
Maintain Electrolyte LevelAdd distilled water as required to maintain the elec-
trolyte level at the split ring at bottom of tiller well.
See Figure IA-2.
Figure lA-2
Battery Filler Well

BATTERY AND CABLES - ALL MODELSlA- 7
421 Test
F$ocedure1. Visual Inspection
- The first step in testing the
Energizer br 12-V& Battery should be a visual in-
spection
which very often will save time, labor and
expense in determining the condition.
(a) Check for broken or cracked case or cover.
(b) Check ,for loose terminal posts.
fiozeck Ifor defective or mutilated sealing com-(d) Check for other visible signs of physical damage.
Obvious d?mage as a result of conditions described
above indicates the need for Energizer or batteryreplaceme$t.
2. The “421” Test is a programmed test procedure
consisting bf a series of timed discharge and charge
events, reqtdring approximately 2 to 3 minutes, that
will determine the condition of the Energizer or bat-
tery with a high degree of accuracy when used inconjunctioti with this entire test procedure. “421”
Testers
a$ produced by a number of different manu-
facturers
r+nd their directions for tester operation
should be carefully followed. General comments on
overall “42 1” Tester operation follow:
(a) Energi@rs or batteries should
nor be charged
prior to
making this test. Defects within the unit can
be hidden by the charging and erroneous test results
will be obtpined.
(b) Erratic, or extremely low, initial meter readings
may indicate poor connections at the tester termi-
nals.Obt{in clean and tight connections beforeper-
forming the 421
Test.(c) All meter readings should be made immediately
after the meter indicator light comes on even if the
meter needle is still moving.
(d) If additional discharges are required after the
initial discbarge, set meter indicator following thefast discharge cycle.
(e) Batteries designated as “bad” by the tester should
be replaced.
(f) Batteries designated as “good” with no owner’s
complaint or indication of poor performance, should
be left in s+vice. Posts, cable clamps, and top should
be cleaned, water should be added and recharging
should be
,performed, if required. For dependable
and reliable battery service, the battery should be in
at least a
75 per cent state-of-charge.
(g) Batteries designated as “good” that are suspected
of being questionable because of owner complaint, orage of the battery, should be further tested by the
Hydrometer Test.
HYDROMETER TEST OF BATTERY
The 421 Battery Test as described in the previous
paragraph is the fastest and most accurate means of
determining the serviceability of a one-piece cover
battery. However, ifa 421 Battery Tester is not avail-
able, a hydrometer test may be used on a battery that
has failed to give proper service.
Hydrometer Test1. Fully charge battery.
2. Measure specific gravity of each cell as described
in sub-paragraph below.
Decide battery serviceability as follows:
(a) If all cells read between 1.230 and 1.310, the
battery is okay. All it needed was a full charge.
(b) After fully charging battery, if any cell reads less
than 1.230, the battery is defective and should be
replaced.
Use of HydrometerThe Hydrometer measures the percentage of sulphu-
ric acid in the battery electrolyte in terms of specific
gravity. As a battery drops from a charged to a dis-
charged condition, the acid leaves the solution and
enters the plates, causing a decrease in specific
gravity of electrolyte. With a hydrometer, an indica-
tion of the concentration of the electrolyte is ob-
tained.
The specific gravity of the electrolyte varies not only
with the percentage of acid in the liquid, it also varies
with temperature. As temperature increases, the
electrolyte expands so that the specific gravity is re-
duced. As temperature drops, the electrolyte con-
tracts so that the specific gravity increases. Unless
these variations in specific gravity are taken into
account, the specific gravity obtained by the hy-
drometer may not give a true indication of the con-
centration of acid in the electrolyte.
Correction can be made for temperature by adding
,004, usually referred to as 4 “points of gravity”, to
the hydrometer reading for every 10 degrees F. that
the electrolyte is above 80 degrees F. or subtracting004 for every 10 degrees F. that electrolyte is below
80 degrees F. Figure IA-4 shows the exact correctionfigure to use for any temperature above or below 80
degrees F., the three steps used in obtaining the cor-
rected or true specific gravity, and two examples
showing how it is figured.

1A. 81873 OPEL SERVICE MANUALELECTROLYTESPECIFIC GRAVITY
TEMPERATURE
(F)CORRECTION
-+0&&n _
THERMOMETER 30”
EXAMPLE A:
--,012---,016---,026
- -.02h
- -.028
- -.032~
-.036
YEXAMPLE 6:TEMPERATURE = 120”
i.TEMPERATURE = -0” F.HYDROMETER = ,,230HYDRdiETER
= 1.230
READINGREADING
‘,9R2Ro~CF;‘“” = +.0,6go!RFfCilON = .,032
TRUE SPECIFIC = ,.246
GRAVITY;RU”v;,‘;CIFIC = 1.198
3xA‘l
Figure
l A-4 Specific Gravity Temperature CorrectionScale
When using a hydrometer, obsqve the following
pain Is:1. Hydrometer must be clean, inside and out, to in-
sure an accurate reading.
2. Hydrometer readings must never be taken im-
mediately after water has been added. The water
must be thoroughly mixed with the electrolyte by
charging for at least 30 minutes before hydrometer
values are reliable.
3. If hydrometer has built-in thermometer, draw liq
aid into it several times to insure correct temperature
before taking a reading.
4. Hold hydrometer vertically and draw in just
enough liquid from battery cell so that float is
freefloating, and with bulb fully released. Hold bydrom-eter at eye level so that float is vertical and free
!ofouter tube, then take reading at surface of liquid.
Disregard the curvation where the liquid rises
against float stem due to surface tension.5. Avoid dropping liquid on car or clothing as it is
extremely corrosive. Any liquid that drops should be
washed off immediately with soda solution.
FUSIBLE LINKSAll 1973 Opel Models have fusible links located be-
tween the starting motor post and the generator
regulator. These links are the weakest point in the
electrical supply system for the complete car, and, as
such, will act like a fuse for every wiring harness in
the
ca.r. Every electrical accessory is still protected
by a fuse or circuit breaker, of course, but fusible
links protect the wiring harnesses before the fuses.
A fusible link consists of soldering a smaller gauge
wire to a heavier gauge wire end to end. In the event
of a circuit overload where the heavier gauge
becomes short circuited, the fusible link or smaller
gauge wire will burn out first, thus, protecting its
circuit from major damage. These fusible links are
located in the engine compartment in such a manner
that if overheated, the possibility of a fire is veryr¬e.
The attachment of the fusible links and the circuits
they protect are as follows: See Figure
l A-5.
D+61TERMIN\AL ;;!$6,,FL #3
B+ TERMINAL
I3QlA5
SOLENOID ON STARTER
Figure
t A-5 Fusible LinksFusible link (1) is connected to the starter solenoid
at the battery cable terminal, on one end and to the
red and white stripped main feed wire at the other
end.
Fusible link (2) is connected between the red wirean&s
terminal of the voltage regulateand protectsagainst a situation where the battery will not accept
a charge and the generator is charging to handle
various electrical loads. Fusible link (3) is connected
between the light blue with white stripes wire and D