change wheel OPEL GT-R 1973 User Guide

WHEELS AND TIRES3G- 61Cornering Tread WearThe modern independently-sprung automobile al-
lows the driver to negotiate turns at a high rate of
speed with a greater feeling of safety. This fact is
responsible for a comparatively new type of tread
wear that can easily be mistaken for toe or camber
wear.When a car is making a turn, the tires are supposed
to be rolling in a circle. When the turn is made at
high speed, however, centrifugal force acting on the
car causes the tires to be distorted sideways and to
slip or skid on the road surface. This produces a
diagonal cross type of wear, which in severe cases
will result in a fine or sharp edge on each rib of the
tire treads.
Cornering wear can be distinguished from toe or
camber wear by the rounding of the outside shoulder
of the tire and by the roughening of tread surface in
this section denoting severe abrasion. See Figure
3G-7.No alignment or tire pressure cahnge can be made
that will relieve cornering wear. Only the driver can
effect a cure and that is by slowing down on curves.
Heel and Toe Tread WearHeel and toe wear is a saw-tooth effect with one end
of each tread block worn more than the other.
The end which wears is the one that first grips the
road when the brakes are applied. High-speed driv-
ing and excessive “se of the brakes will cause this
type of irregular tire wear. This type of wear will
occur on any type of block tread design. See Figure3G-7.
Heel and toe wear is not so prevalent on the rear tires
because of the propelling action which creates a
counteracting force which wears the opposite end of
the tread block. These two stresses on the rear tires
wear the tread blocks in opposite directions and re-
sult in more even wear while on the front tires, the
braking stress is the only one which is effective. This
may be counteracted by interchanging tires.
A small amount of irregular wear, slightly
saw-toothed in appearance, at the outer segments of tires
is a normal condition and is due to the difference in
circumference between the center and the outer
edges of the tire tread. This saw-toothed appearance,
however, will be exaggerated by underinflation, im-
proper toe-in, or both.Cupped or Scalloped Type Tire Wear
Cupping or scalloping is associated with wear on acar driven mostly at highway speeds without recom-
mended tire rotation. Factors which promote cup-
ping include underinflation, incorrect toe-in setting
or camber setting, and steady highway speeds on
smooth, paved surfaces as opposed to gravel or
rough asphalt.
The following recommendations suggest action that
may be taken to help prevent cupping.
1. Rotate tires as recommended in Figure
3G-6.2. Frequently inspect front tires for irregular wear
due to underinflation, improper toe-in setting, or
camber setting. Regardless of the original cause of
cupped tread wear on either front tire, no alignment
or balance job, however perfect, can prevent future
excessive wear of the spots. Once a front tire acquires
flat or cupped spots, additional wear will continue at
a rapid rate. At the time of correction, however, the
cupped tire should be interchanged with a rear tire
on which the tread runs true. The cupped tire will,
to a certain degree, true itself on a rear wheel.
Although not normally the cause of cupping, the
following factors can contribute to the problem.
Looseness of parts in the suspension system, such as
worn steering knuckle ball joints, loose wheel bear-
ings, inoperative shock absorbers, and any excessive
looseness throughout the steering system all tend to
allow the front wheels to kick around and, if any of
the wheel alignment factors are incorrect, irregular
spotty tire tread wear of one type or another may
result.
Wobble or runout of a tire, either front or rear, due
to bent wheel or to tire being improperly mounted
will cause uneven wear.
MAINTENANCE AND ADJUSTMENTSDEMOUNTING AND MOUNTING
TUBELESS TIRESDue to “se of symmetrical rims, tires must be
mounted over the narrow rim shoulder i.e., over out-
side rim flange.
When demounting a tubeless tire “se care to avoid
damaging the rim-seal ridges on tire beads DO NOT
USE TIRE IRONS TO FORCE BEADS A WA Y
FROM WHEEL RIM FLANGES.
When tire is removed, inspect it carefully to deter-
mine whether loss of air was caused by puncture or
by improper
tit of beads against rim flanges. If im-
proper fit is indicated, check wheel as follows: Do
not reuse dented rims.

3G- 621973 OPEL SERVICE MANUAL
1. Clean rims thoroughly, using No. 3 coarse steel
wool to remove all oxidized rubber, soap solution,
etc. Remove rust with wire brush.2. Inspect butt weld and other areas of rim contactedby tire beads to make certain there is no groove or
high spot. Remove any groove or high spot by tiling
smooth.
3. Inspect valve stem and replace it if damaged.
Make certain that valve stem is properly installed to
provide an air tight joint.
4. Before mounting a tubeless tire on a wheel, mois-
ten a cloth with mounting compound or soap solu-
tion and wipe rim-seal ridges of both beads to remove
all foreign substances.
5. Moisten base of both beads with mounting com-
pound or soap solution to help beads snap into place
when tire is inflated. Start tire over rim flange at
point opposite valve stem.
6. Inflate tire until both beads are firmly seated
against rim flanges and temporarily over inflate.
Leak test wheel and tire assembly and if satisfactory,
reduce to recommended pressure.
SPECIFICATIONSWHEEL AND TIRE BALANCE
Wheel and tire balance is the equal distribution of the
weight of the wheel and tire assembly around the axis
of rotation. Wheel unbalance is the principal cause of
tramp and general car shake and roughness and con-
tributes somewhat to steering troubles.
The original balance of the tire and wheel assembly
may change as the tire wears. Severe acceleration,
severe brake applications, fast cornering and side slip
wear the tires out in spots and often upset the origi-
nal balance condition and make it desirable to rebal-
ance the tire and wheel as an assembly. Tire and
wheel assemblies should be rebalanced after punc-
tures are repaired.
Because of the speed at which cars are driven, it is
necessary to test the wheel and tire assembly for
dynamic balance. Dynamic balancing of a wheel and
tire assembly must be done on a machine designed to
indicate out-of-balance conditions while the wheel is
rotating on the car. Since procedures differ with dif-
ferent machines, the instructions of the equipment
manufacturer must be carefully followed.
General SpecificationsWheels
Opel 1900
- Manta and GT ,._......,,,._.................,...,,..............................~,,,.................... 5.J x 13
Tires
1900 - Manta __.......,,___.,...,,..,.....,,....,,...........,...,,.,,...,.........,,..................,....................... 165-13
GT . . . . . . . ..__........_..............,...,,........,,,...,,..........,....,..,,...,,........,..................,,,.....................165-13
Tire Size and Pressures (Pounds Per Square Inch
Cold)
ModelTire Size51.53.54.57
165-1357R.57L165-13
77
165-13Recommended(Standard
PressureInflation)
FrontRear24
PSI32PSI23
PSI26PSI
19PSI23
PSI
NOTE:
1.Tire inflation pressures may increase as much as 6 pounds per square inch
when hot.
2.For continuous high-speed operation (over 75 MPH), increase tire inflation
pressures 4 pounds per square inch over the recommended pressures up to a
maximum of 30 pounds per square inch cool for 4 ply rating tires. When the
4 psi pressure adjustment for sustained high speed with maximum vehicle load

4S- 91973 OPEL SERVICE MANUAL
DIAGNOSIS
DIFFERENTIAL TROUBLE DIAGNOSISConditionPossible Cause
1. Noise is the same in1. a) Road noise.
“Drive” or “Coast”.b) Tire noise.
c) Front wheel bearing noise.
d) Front or rear U-joint angle
too great.
2. Noise changes on a2. a) Road noise.
different type of road.b) Tire noise.
3. Noise lowers tone as3. Tire noise.
car speed is lowered.
4. Similar noise is pro-4. a) Engine noise.duced with car standingb) Transmission noise.
and driving.c) Driveline angle.
5. Vibration5. a) Rough rear wheel bearing.
b) Tire unbalance.
c) Worn universal joint in
propeller shaft.
d) Front or rear U-joint angle
too great.
e) Mis-indexed, propeller shaft
at companion flange.
tJ Companion flange runout too
6. A knock or click6. A brinelled rear wheel bearing
approximately every two (2)
revolutions of rear wheel.
7. Noise most pronounced on7. Differential side gear and pin
turns.
8. A continuous low pitch8. Pinion bearing.
whirring or scraping noise
starting at relatively low
speed.9. Drive noise, coast9. Ring and pinion gear.
noise or float noise.
10. Clunk on accelera-
10. a) Worn differential cross sha
tion or deceleration.in case.
11. Groan in “Forward” or11. Wrong lube in differential.
“Reverse”.
12. Clunk or knock on12. a) Excessive end play of axle
rough road operation.to differential cross shaft
b) Excessive differential gear
clearance.

POWER BRAKE BOOSTER AND MASTER CYLINDER5A- 5ConditionGrabby Brakes (Apparent
Off-and On Condition)
Possible Cause1. Broken or damaged
hydraulic brake lines.Correction1. Inspect and replace, as
“CXXSSary.2. Insufficient fluid in
master cylinder.
3. Defective master cylinder
seals.4. Cracked master cylinder
casting.2. Fill reservoirs with approved
brake fluid check for leaks.
3. Repair or replace, asnecessary.4. Replace
5. Leaks at front disc brake
calipers or rear wheel
cylinders
in pipes or connections.5. Inspect and repair, as
necessary.Brakes Fail to Release6. Air in hydraulic system.
1. Blocked passage in power
piston.
2. Air valve sticking shut.6. Bleed system.
1. Inspect and repair or replace,
as necessary.
2. Check for proper lubrication of
air valve “0” ring.
3. Broken piston return spring
3. Replace
master cylinder.
4. Tight pedal linkage.5. Repair or replace, as
necessary.
MAINTENANCE AND ADJUSTMENTS
CHECKING BRAKE BOOSTER OPERATIONThe operation of the brake booster can be checked by
simple means and without any special devices.
1. With engine off, first clear the booster of any
vacuum by depressing brake pedal several times.
2. Then depress brake pedal and start engine. If the
vacuum system is working correctly, the brake pedal,
kept under even foot pressure, moves farther down-
wards due to the additional pressure developed by
the booster. Should the brake pedal not move farther
downwards, the vacuum system is deficient. In this
case check the vacuum hose to booster, to vacuum
control valve and to engine intake manifold connec-
tions.3. If the vacuum system operates properly, the defect
is in the brake booster itself. A dirty filter impairs oreven prevents air from entering into the booster and
thereby the formation of a difference in pressure in
the vacuum cylinder.
Repairs cannot be carried out on the brake booster.
If no deficiency can be found in the vacuum system
or filter, the brake booster has to be replaced.
Under normal operating conditions the brake
booster requires no service. However, under adverse
conditions such as frequent driving on sandy or
dusty roads, the filter and sound deadener should be
replaced occasionally. To do so, the brake booster
must be removed but it isn’t necessary to detach the
master cylinder.
BRAKE BOOSTER FILTER SERVICEUnder normal operating conditions the filter need
not be exchanged for a new one.
Under adverse operating conditions
- frequent driv-

Installation1. FLYWHEEL
2. CLUTCH ASSEMBLY
3. ASSEMBLY MARKS
4. CLUTCH ALIGNING
ARBOR J-229347A-51. Slide control cable ball end through eye in clutch
housing. Connect to lever and (on GT) install return
spring.
2. Replace washers and rubber grommet, slide cable
through retainer on dash panel, and connect to
clutch pedal. To adjust, refer back to Clutch Adjust-
ment paragraph
c or d.
Figure
7A-5 Clutch Installation
SPECIFICATIONS
GENERAL SPECIFICATIONSE-l
I-‘-J- : ,“/’‘~Clutch Specifications
Type. . . . . . . . . . . . . . . . . . . .
Pedal Lash
_ 3/4” to l-1/4”-. -..-.
.........Single Plate - Dry Disc
unvenFlareuamerer.....................................................................................................6-3/4”
Driven Plate Facings
......................................................................................Woven Asbestos
Number of Facings
....................................................................................................................
2Facing Attachment
........................................................................................................Riveted
Vibration Dampening
..................................................................................4 Torsional Springs
Bolt Tightening SpecificationsCLUTCH CONTROL CABLE REMOVAL AND
INSTALLATION
(SEE FIGURE 7A.6
OR 7A-7)
If a new cable was installed or the cable adjustment
was changed during an operation, x-adjust cable
afterwards.
Removal
1. Disconnect return spring and cable with ball end
from release lever. Slide control cable out of eye in
clutch housing.
2. With a screwdriver, pry E-ring out of groove in
control cable, at tirewall, and disconnect cable from
clutch pedal.
3. Pull cable out of retainer on dash panel and
remove washers and rubber grommet.
PartLocationTorque
Lbs.Ft..’
BoltFlywheeltoCrankshaft........................................................43
/BoltClutchCovertoFlywheel....................................................36
BoltTransmissiontoClutchHousing......................................32.36;:
BoltStartertoClutchHousing..................................................40
NutSupport to Clutch Housing................................................4IBoltIntake and Exhaust Manifold to Cylindei Head............33

SubjectPage Number
Subject Page Number
o,,e, 1900 & Manta .....................1H-59
GT..................................lH-63
intake Manifold, 1.9L Engine
..........:.....6A-12
R
Radiator
JRadiator All Models .,.
Radio
66-32
Joint,
Ball
adder.; ...............................3A-7
dower...............................3A-7
K
Antenna Trimmer Adjustment GT
Antenna Trimmer Adjustment
Opel 1900
& Manta
Removal and Installation Opel 1900
& Manta
Removal and Installation GT
Trouble Diagnosis GT
.,.
Trouble Diagnosis -Opel 1900 &Manta
Reverse Clutch
Rings, Piston,
1.9L Engine
Rocker Arm Assembly.
1.9L Engine..
9C-1 06
9C-1 10
Keys and Locks ..........................OA-1
L
Low Servo Cover .........................7c-100
Lubrication
Engine Oil Change Interval ................OC-7
Oil Viscosity Chart. .....................
OC-7
Fluid Capacities........................OC-5
Lubrication System, Engine .................6A-4
9C-1 11
9c-107
9c-105
9c-109
7c-103
6A-19
6A-12
s
M
Mainshaft Assembly 4.Speed
Manual Transmission ....................
78-26
Manifold
Intake ...............................
6A-12
Exhaust ..............................
6A-12
Master
Cdlinder, Brake.....................5A-2
Model
D&ignation (Body Style)
.............. OA-2
Mountings. Engine, GT ....................
28-6
Opel 1900 & Manta
.......................28-6
0
Oil Chan& Interval ........................OC-7
Oil Filter: Engine
.........................OC-7
Oil Flow Circuits, Automatic Transmission .....7C-64
Oil
Pan. Engine ..........................6A-10
Oil Pump Engine.........................
6A-26
Oil Pump Transmission ....................
7C-103
Oil Recommendations Engine. ..............
OC-7
Oil Strainer-Transmission..................7C-99
Oil Viscosity Chart ........................
OC-7
Opel Emission Control System
(OECS)
Specifications..........................6F-64
Service Procedures......................6F-63
Trouble Diagnosis ......................
6F-62
P
Parking Brake............................5C-33
Piston, Pin Rings ..........................
6A~lS
Planetary Gear Set ........................
7C-118
Power Unit Brake ........................
5A-5
Propeller Shaft ...........................
4A-2
Pump, Oil Engine........................
6A-26 Sequence for Transmission Diagnosis
..........
7C-81
Service ProceduresClutch..................7A~5
Shift Linkage Adjustments
4.Speed Manual ........................78-19
3.Speed Automatic .....................7C~93
Shock Absorber, Rear
All Series .............................
3F-51
Spark Plug Specifications ...........................
66-68
Clean &Adjust. ........................
lC-22
Installation............................lC-22
Wires................................lC~21
Specifications
Engine ................................
6A-27
Front Wheel Alignment ....................
3C~22
Speedometer Installation
Opel1900&Manta.....................1 l-68
GT..................................11-70
Spring
Rear SuspensionAll Series ..............
:............3F-52
Front Suspension
Opel 1900
& Manta ...................3A~l6
GTO Opel ..........................
3A15
Starting Motor
Description ............................
1 E-1 0
Specifications .............:............1 B-1 7
Repairs
..................:............18-13
Removal..............................1 B-l 3
Steering Columns
Service Procedures -Opel 1900 &Manta ....
3E-36
Service Procedures
- GT ...._............3E-44
Steering Gear Adjustment. .....
:............3D-27
Steering Gear Disassembly and
Redssembly.....3D-30
Steering Gear Removal and Install&ion ........
30-28
Steering Linkage ..........................
38-19
Suspension
Front................................3A-2
Rear .................................
3F-51
,