1973 OPEL GT-R wheel

DRUM BRAKESBC- 29
at a time to avoid getting fluid level in reservoir
dangerously low. The correct sequence for bleeding
is bleed the wheel cylinder or caliper nearest the
master cylinder first in either circuit.
Do not perform bleeding operation while any brake
drum is removed.
Bleeding Wheel Cylinder or Caliper
1. Check fluid level, in reservoir and refill, if neces-
sary. Level must be brought up to “MAX” mark on
plastic reservoir.
2. Clean all dirt from around respective bleeder
valve, and then remove cap.
3. Push bleeder hose over bleeder valve, placing
other end of hose in a glass jar. Bleeder hose should
always be used to avoid getting fluid on linings.
4. Hold pressure on brake pedal and crack open the
bleeder valve to allow air (and,or) brake fluid to flow
out of the system. Allow pedal to travel to the floor.
Close bleeder valve. Release pedal and repeat this
procedure at each wheel cylinder in the circuit until
all air is removed. Frequently check reservoir fluid
level. Allowing fluid to be emptied will draw air into
the system.
5. Remove bleeder hose and install cap.
6. When bleeding operation is completed, make sure
that fluid level is brought up to “MAX” marking on
reservoir, then install cover.
7. Discard the brake fluid deposited in glass jar dur-
ing bleeding operation.
Flushing Brake Hydraulic System
It is recommended that both brake system circuits be
thoroughly flushed whenever the master cylinder is
replaced or if there is any doubt as to the grade of
fluid in the system.
Flushing of the brake system is performed in the
same manner as the bleeding operation except that
fluid is forced through the lines and wheel cylinder
until it emerges clear in color. Approximately one
half pint of brake fluid is required to flush the hy-
draulic system thoroughly.
When flushing is completed, make certain the master
cylinder reservoir is filled to the proper level.Figure
5C-52 Rear Drum Brake Assembly
MAJOR REPAIR
REPLACE OR RELINE BRAKE SHOES
(DRUM BRAKES)Removal and Inspection
1. Jack up car in safe manner and support ade-
quately.
2. Remove wheel and drum assembly.
3. Remove upper and lower brake shoe return
springs.
4. Remove retaining pins and springs, as shown in
Figure
5C-52.5. Clean all dirt out of brake drum. Inspect drums
and replace or recondition if required.
6. Blow all dirt from brake assemblies and inspect for
any unusual condition.
7. Carefully pull lower edges of wheel cylinder boots
away from cylinders and note whether interior is wet
with brake fluid. Fluid at this point indicates leakage
past piston cup, requiring overhaul or replacement of
wheel cylinder.
8. Inspect all brake pipe and hose connections for
evidence of fluid leakage. Tighten any leaking con-
nection, then apply heavy pressure to brake pedal
and recheck connections.
9. Inspect backing plate for oil leak past rear wheel
bearing oil seals. Correct any leak by installation of
new seals.

Figure 5C-53 Rear Brake Assembly
10. Check all backing plate attaching bolts to make
sure they are tight. Using line emery cloth, clean all
rust and dirt from shoe contact surfaces on plate. See
Figure Z-53.
Relining Brake ShoesIf old brake shoes are to be relined, inspect shoes for
distortion and for looseness between the rim and
web; these are causes for discarding any shoe. If
shoes are serviceable, be governed by the following
points in installing new linings:
1. Remove old rivets by drilling them out. Punching
out rivets will cause distortion of shoe rim. Care5C- 301973 OPEL SERVICE MANUAL
must also be taken to support shoes properly while
drilling.
2. Thoroughly clean brake shoes and remove all
burrs around rivet holes.
3. Use Opel brake lining or equivalent. Install in
place and rivet in sequence shown in Figure
Z-54.Keep hands clean while handling brake lining. Do
not permit oil or grease to come in contact with
lining.
Installation and Adjustment
1. If any hydraulic conne&tions were disturbed, bleed
hydraulic system. If new parts were installed in
brake system, flushing of hydraulic system is recom-
mended.
2. Adjust rear wheel brakes.
3. Adjust parking brake.
4. Check fluid level in master cyliner and add fluid
if necessary.
5. Check brake pedal for proper feel and for proper
return.
6. Remove jacks and road test car for proper brake
action. Brakes must not be severely applied immedi-
ately after installation of new brake shoes or linings.
Severe application may perinanently injure new lin-
ings and may score brake drums. When linings are
new, they must be given moderate use for several
days until burnished.
INSPECTING AND RECONDITIONING
BRAKE DRUMSWhenever brake drums are removed, they should
bethoroughly cleaned and inspected for cracks, scores,
deep groves, and out-of-round. Any of these condi-
tions must be corrected since they can impair the
efficiency of brake operation and also can cause
premature failure of other parts.
Cracked, Scored or Grooved DrumA cracked drum is unsafe for further service and
must be replaced. Welding a cracked drum is not
recommended.
Smooth up any slight scores by polishing with tine
emery cloth. Heavy or extensive scoring will cause
excessive brake lining wear and it will be necessary
to rebore in order to true up the braking surface.
Figure 5C.54 Brake Lining Riveting
SequenceIf the brake linings are slightly worn and drum is
grooved, the drum should be rebored just enough to

DRUM BRAKES5c- 31
remove grooves, and the ridges in the lining should
be lightly removed with a lining grinder.
If brake linings are more than half worn, but do not
need replacement, the drum should be polished with
fine emery cloth but should not be rebored. At this
stage, eliminating the grooves in drum and smooth-
ing the ridges on lining would necessitate removal of
too much metal and lining, while if left alone, the
grooves and ridges match and satisfactory service
can be obtained.
If brake linings are to be replaced, a grooved drum
should be rebored for use with oversize linings. A
grooved drum, if used with new lining, will not only
wear the lining but will make it
diff%xlt, if not im-
possible, to obtain etXcient brake performance.
Out-of-Round DrumAn out-of-round drum makes accurate brake shoe
adjustment impossible and is likely to cause excessive
wear of other parts of brake mechanism due to its
eccentric action. An out-of-round drum can also
cause brake pulsation. Maximum permissible drumrunout is 004”. A drum that has more run-out than
this should be rebored. Runout can be accurately
checked by using an inside micrometer fitted with
proper extension rods.
When measuring a drum for run-out, take measure-
ments at open and closed edges of machined surface
and at right angles to each other.
Turning Brake DrumsIf a brake drum is to be turned, enough metal should
be removed to obtain a true, smooth braking surface.
Measure brake drum diameter; standard drum inner
diameter is 9.060”. Drums may be turned to an over-
size of ,030”. If maximum inner diameter after turn-
ing exceeds 9.090”, brake drum will have to be
replaced. Removal of more metal will affect dissipa-
tion of heat and may cause distortion of the drum.
1. Remove rear wheels and drums.
2. Mount brake drum on brake drum lathe and turn
drums as necessary, within limits.
3. After turning, check drum diameter. Inner diame-
ter not to exceed 9.090.
4. A newly-bored drum should always have center
contact with brake shoes. For this reason, arc grind
linings to
.OlO” under drum radius, or to ,020” under
drum diameter.
5. Clean and install drums and wheels.
BRAKE WHEEL CYLINDER OVERHAUL1. Remove wheel, drum, and brake shoes. Be careful
not to get grease or dirt on brake lining.
2. Disconnect brake pipe or hose from wheel cylinder
and cover opening with tape to prevent entrance of
dirt. Remove wheel cylinder from backing plate.
3. Remove boots, pistons, cups, and spring from cyl-
inder. Remove bleeder valve.
4. Discard rubber boots and piston cups. Thoroughly
clean all other parts with hydraulic brake fluid orDeclene. Do not use anti-freeze, alcohol, gasoline,
kerosene, or any other cleaning fluid that might con-
tain even a trace of mineral oil.
5. Inspect pistons and cylinder bore for scores, scrat-
ches, or corrosion. Light scratches may be polished
with crocus cloth. Do not use emery cloth or sandpa-
per.
Shght corro~on may be cleaned wth tine steel
wool. If scratches or corroded spots are too deep to
be polished satisfactorily, the cylinder should be re-
placed since honing is not recommended.
6. Dip internal parts in brake fluid and reassembly
wheel cylinder. When installing piston cups, use care
to avoid damaging the edges.
7. If the rear wheel backing plate is removed: Always
install new paper gaskets one on each side
- on the
backing plate. Prior to installation, lightly coat paper
gaskets with chassis lubricant. Torque backing plate
to rear axle housing bolts to 43
lb.ft. and wheel brake
cylinder to backing plate bolts to 5
lb.ft. Install wheel
cylinder on brake backing plate and connect brake
pipe or hose.
8. Install brake shoes, drum, and wheel, then flush
and bleed hydraulic system.
9. Adjust brakes, then road test car for brake per-
formance.
CAUTION:This brake backing plate to rear axle fis-
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
quahty or substitute design. Torque v&es must be
used as specified during reassembly to assure proper
retention of this part.
REPLACING BRAKE PIPESAny brake pipe assembly which is needed must be
made up from service bulk tubing and fittings. All
brake pipes must be made of tin or copper coated
wrapped steel tubing with the ends double lap flared.

5C- 321973 OPEL SERVICE MANUAL
Never use copper tubing because copper is subject to
fatigue cracking which would result in brake failure.2. Cut tubing to length. The correct length may be
determined by measuring the old pipe using a cord
and adding l/8” for each double lap flare.
To make up a brake pipe assembly, proceed as fol-
lows:3. Double lap flare tubing ends, using a suitable flar-
ing tool such as J-8051. Follow the instructions in-
cluded in the tool set. Make sure fittings are installed
1. Procure the recommended tubing and fittings of
the correct size. (Outside diameter of tubing is used
to specify size.)before starting second flare.
4. Bend pipe assembly to match old pipe.
SPECIFICATIONS
BRAKE SPECIFICATIONS
Torque Specifications
Use a reliable torque wrench to tighten the parts listed to insure proper
tightness without straining or distorting parts. These specifications are for
clean and lightly-lubricated threads only; dry or dirty threads produce in-
creased friction which prevents
accurage measurement of tightness.
PartName
TorqueNut
BoltBrakeHose to Front WheelBrake Cylinder
Brake Backing Plate to Steering Knuckle(Uccer
Bolts)Lb&.
22
22...BoltBrake Backing’Plate to Steering Knuckle and
SteeringArm(Lower
Bolts)............................................
BoltBackingPlatetoRearAxleHousing................................
NutMaster Cylinder Actuator Rod to BrakePedal
..............
BoltWheelBrake Cylinder to Brake Backing Plate
..............
General Specifications47
43
5
5OperatingMechanism,ServiceBrakes
....................................................................Hydraulic
Parking Brakes
..........................................................................................Lever and Cables
Operation of Service Brakes Independent of
ParkingBrakes
..................................................................................................................Yes
WheelBrakes,Service
......................................................................................FrontandRear
Parking.
..................................................................................................................Rear Only
BrakePedalHeightAdjustment......................................................................................None
Static Pressure in Hydraulic System When Brakes
are Released
- Drum Brakes................................................................................4 psi Min.
Static Pressure in Hydraulic System to Rear
BrakesOnly
-DiscBrakes..................................................................................
4psiMin.
Brake Master Cylinder (for Drum Brakes) Bore
............................................................13/16
Wheel Cylinder Size
- Rear - All.......................................................................................: 5/8
Approved Hydraulic Brake ,Fluid
..........................................GM or Delco Supreme No. 11
Fluid Level in Reservoir
..........................................................................Fill to “Max.” Level
BrakeDrumRebore,Max&urnAllowable Inside
Diameter........................................
9.090Max. Allowable Out-of-Round
...........................................................................................CKl4Rear Brake Drum Size. New
............................................................................................
9.060

ENGINE MECHANICAL AND MOUNTS6A- 11
a. Attach left chain to alternator support rear bolt.
b. Bolt right chain to existing threaded hole at lower
right front of engine.
2. Assemble loose ends of chain to support device J-bolts and adjust to remove engine weight from motor
mounts.
3. Remove the two motor mount bracket to motor
mount retaining nuts.
4. Remove the two front suspension to frame rail bolt
retaining nuts.
5. Remove nut and bolt at lower end of steering shaft
U-joint.
6. With a floor jack under the center of the front
suspension cross member, raise car high enough for
wheels and suspension assembly to be rolled from
under car.
7. Position jack stands under both front jack brackets
on underbody to support car in this position.
8. Remove both front cross member support to frame
attaching bolts.
9. Remove brake pipe to brake hose retaining clips
at frame rails and disconnect brake hose from brake
pipes. Use an absorbent material or suitable con-
tainer for the brake fluid that will drain out.
10. Lower the front suspension assembly and remove
from under car.
11. Drain engine oil and remove oil pan and gasket.
Installation (Opel 1900 and Manta)1. Apply a light bead of sealer to the clean sealing
surfaces of the oil pan and affix a new gasket.
2. Bolt oil pan and gasket assembly to engine block.
3. Roll front suspension and floor jack under car and
raise into position careful to pilot the cross member
to frame rail attaching bolts and steering shaft to
their respective locations.
4. Install cross member’support to frame attaching
bolts and torque to 22 lb.ft.
5. Connect brake hose to brake pipes and install
retaining clips.
6. Bleed front brake system. Maintain brake fluid1Wd.
7. Remove jack stands and lower car.8. Install suspension to frame rail bolt retaining nuts.
9. Release and remove engine supporting device.
10. Install motor mount bracket to motor mount
retaining nuts.
11. Install steering shaft U-joint lower bolt and nut.
12. Replace engine oil.
Removal (GT Series)1. Support engine in vehicle using Tool J-23375. See
Figure 6A- 15.
Figure 6A-15 Engine Holding Fixture
Install tool by removing upper engine mount nut and
installing fixture. Replace nut and tighten. The en-
gine will now be supported by the tool, between the
frame rails. The front suspension need not be
removed on GT Models.
2. Drain oil.
3. Remove oil pan bolts and remove oil.
Installation (GT Series)1. Replace oil pan and bolts.
2. Remove engine holding fixture and replace engine
mounts.
3. Replace engine oil.

6A- 18 1973 OPEL SERVICE MANUAL
pressure. If heavy pressure is required, shell was not
started squarely and will be distorted if force into place.
12. Place lower bearing shell in bearing cap, then
check clearance
with plastic-type gauge, as previ-
ously described.
13. The desired clearance with a new bearing is
.0009” to .0025”. If this clearance cannot be obtained
with a standard size bearing, insert an undersize
bearing and check again
w&h plastic-type gauge
material.
14. When the proper size bearing has been selected,
clean out all plastic gauge material, oil the lower
shell and reinstall bearing cap. Clean the bolt holes
and lube bolts, then torque cap bolts to 72 lb. ft. The
crankshaft should turn freely at flywheel rim; how-
ever, a very slight drag is permissible if an undersize
bearing is used.
15. If the thrust bearing shell is disturbed or replaced
it is necessary to line up the thrust surfaces of the
bearing shell before the cap bolts are tightened. To
do this, move the crankshaft fore and aft the limit of
its travel several times (last movement fore) with the
thrust bearing cap bolts finger tight.
16. After bearing is installed and tested, loosen all
bearing cap bolts
l/2 turn and continue with other
bearings. When bearings have been installed and
tested, tighten all bearing cap bolts to 72 lb. ft.
17. Replace rear bearing oil seals.
18. Install pipe and screen assembly and oil pan.
Installation of Rear Bearing Oil
Seals (Engine in Vehicle)
1. Remove transmission, bell housing and clutch.
Refer to appropriate section for removal procedures.
Figure 6A-28 Removing Rear Main Oil Seal
2. Remove flywheel.
3. Punch a hole into oil seal and screw in a sheet
metal screw and pull out oil seal. See Figure
6A-28.
4. To insure proper sealing, lubricate seal with a
suitable protective grease and install on taper ring
J-22928. Turn seal to ensure lip of seal is not turned
back. See Figure
6A-27.
OIL SEAL’6A-29
Figure
6A-29 Installing Oil Seal on Tool J-22928
5. Place tapered ring with oil seal on crankshaft
flange and move lip of seal
over rear of crankshaft.
Be careful not to tilt seal.
Figure 6A-30 Installing Rear Main Bearing Oil Seal
6. Drive in oil seal using Tool J-22928-2. See Figure
6A-30.
7. Install flywheel, clutch, bell housing and transmis-
.

ENGINE MECHANICAL AND MOUNTS6A- 19
sion. When replacing flywheel use new bolts and
torque to 43 lb.ft.
PISTON, RINGS AND CONNECTING RODS
Removal and Disassembly of Piston
and Rod Assemblies
1. Drain oil.
2. Remove oil pan. 3. Remove cylinder head.
4. Examine the cylinder bores above the ring travel.
If bores are worn so a ridge exists, remove the ridges
with a ridge reamer to avoid damaging rings or
cracking ring lands in pistons during removal.
5. Mark the cylinder number on all pistons, connect-
ing rods and caps. Starting at the front end of the
crankcase, the cylinders are numbered l-2-3-4,
6. Remove cap and bearing shell from number 1
connecting rod.
7. Push the piston and
rod assembly up and out of
top cylinder. Then reinstall cap and bearing shell on
rod.
0
-J-23436-4
J-23436-2+
J-6047
Figure
6A-3 1 Piston Pin Removal Tool Layout - 1 .S
Engine
8. Remove other rod and piston assemblies in the
same manner.
9. Remove compression rings and oil rings.
10. Remove piston pin in following manner:
a. Position base support J-6047 on hydraulic press.
b. Place tool J-23436-2 in base support with large
diameter bore facing upward. See Figure
6A-31.
c. Position piston and rod assembly on tool
J-
23436-2 making certain the pin is aligned on tool.
d. Position tool J-23436-4 in opposite end of piston
pin and press pin out.
Inspection of Cylinder Bores
Inspect cylinder walls for scoring, roughness, or
ridges which indicate excessive wear. Check cylinder
bores for taper and out-of-round with an accurate
cylinder gage at top, middle and bottom
ofbore, both
parallel and at right angles to the centerline of the
engine. The diameter of the cylinder bores at any
point may be measured with an inside micrometer or
by setting the cylinder gauge dial at “0” and measur-
ing across the gauge contact points with outside mi-
crometer while the gauge is at the same “0” setting.
If a cylinder bore is moderately rough or slightly
scored but is not out-of-round or tapered, it is possi-
ble to repair the bore by honing to accept a standard
service piston. If cylinder bore is very rough or deeply scored, it may be necessary to rebore the cyl-
inder to fit an oversize piston in order to insure satis-
factory results.
If a cylinder bore is tapered
.ooO5” or more, or is
out-of-round
.0005” or more, it is advisable to hone
or rebore for the smallest possible oversize piston and
rings.
Visual Inspection of Pistons, Rings, and Pins
Clean carbon from piston surfaces and under side of
piston heads. Clean carbon from ring grooves with a
suitable tool and remove any gum or varnish from
piston skirts with suitable solvent.
Carefully examine pistons for rough or scored bear-
ing surfaces, cracks in skirt, head cracked or broken
ring lands, and chipping or uneven wear which
would cause rings to seat improperly or have exces-
sive clearance in ring grooves. Damaged or faulty
pistons should be replaced.
Fitting Pistons to Cylinders
The pistons are cam ground, which means that the

6A- 24 1973 OPEL SERVICE: MANUAL
on front side of timing chain to permit reinstallation
in original position.
Timing Chain Cover and Timing
Chain installation
Reinstall timing chain cover by reversing removal
procedures, pay particular attention to the following
points.
1. Clean all parts, check for wear and replace as
required. The Parts Department supplies either the two sprockets complete with chain or the chain
alone. It is not permissible to replace sprockets alone.
The chain tensioner is, with the, exception of the
tensioner body, only available as a complete unit.
2. Turn crankshaft so that key for sprocket is on top
and vertical. Assemble chain’, with camshaft
sprocket, then put chain on crankshaft sprocket al-
ready installed. Be sure paint dot
on chain is in front
so that chain moves in same direction as prior to
disassembly.
3. Make sure camshaft sprocket mark is in alignment
with mark on support and chain in parallel with
damper block.
4. To install new timing case oil seal, drive out oil
seal from the rear using a drift. Coat circumference
of oil seal sparingly with suitable sealer and press seal
in, using tool J-22924. Take care not to damage tim-
ing case. See Figure
6A-40. 5. Inspect chain tensioner for proper operation and
reusability.
6. Install timing case rubber gaskets to cylinder
block. Stick on with grease as necessary. Gaskets will
somewhat overlap with oil pan gasket.
7. Position timing cover onto guide pin in upper left
corner of cylinder block and insert centering bolt
through timing chain cover into lower right corner
of cylinder block. See Figure
6A-40A. No sealing is
required.
SA-40.4
Figure 6A-40A Installing Timing Chain Cover
INSTALLER
Figure 6A-40 Installing Timing Cover Oil Seal onProtector
It is not necessary to use crankshaft bolt to install
seal when cover is off engine. 8. Install cylinder head
After sprocket has been attached to camshaft, re-
check alignment
LO see that chain has not slipped. At
this time both No.
1 and No. 4 pistons will be at TDC
position. No. 4 piston will be in tiring position and
No. 1 piston up on exhaust stroke. To time engine to
fire on No. 1 cylinder, rotate crankshaft 360 degrees.
This will position the timing mark 180 degrees from
original alignment of camshaft sprocket and support
bracket, and will completely close No. 1 intake and
exhaust valves. Also, the timing mark on the fly-
wheel
(ball) and cylinder block (pointer) will coin-
cide. See Figure
6A-41.
Replacing Timing Cover Oil Seal
(Engine Installed)
1. Remove fan belts.
2. Remove crankshaft pulley bolt and remove pulley. 3. Insert screwdriver behind seal and rest screw-
driver on crankshaft pin. Pry out oil seal.