1973 OPEL GT-R brake pads replacement

5B- 19i973 OPEL SERVICE MANUAL
Figure
56-24 Removing Dowel Pins
Figure 56-25 Removing Friction Pads
4. Check rubber seals for wear. If rubber seals are
hardened, brittle or cracked, they must be replaced
as follows:
(a) Remove brake caliper from steering knuckle and
brake disc. Leave hose attached to brake caliper.
(b) Remove seal clamp rings with screwdriver and
remove seal rings from calipers. See Figure
5B-26.(c) Install new rubber seals and clamp rings. Make
sure rubber seal is properly seated. Make sure clamp
ring is correctly positioned on rubber seal,Figure 56-26 Removing or Installing Rubber Seal
Clamp Ring
(d) Attach brake caliper to steering knuckle and
torque bolts to 72
Ib.ft. Prior to installation of
caliper, make sure contacting surfaces of both caliper
and steering knuckle are perfectly clean and free of
any burrs.
CAUTION: This disc brake caliper attachments fas-
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
quality or substitute design. Torque values must be
used as specified during reassembly to assure proper
retention of this part.5. Before installing new friction pads, press both pis-
tons of each caliper to bottom of their bores, using
Return Clamp J-22430.
While pressing piston into
bores, open caliper bleeder valve to prevent excess
brake fluid from overflowing master cylinder con-tainer As soon as pistons are bottomed, tighten
bleeder valve.
6. Check brake disc for lateral runout.
7. Install new friction pads into brake caliper. Fric-
tion pads must be free enough to be easily moved in
their caliper recesses. See
Figure X3-25.If new friction pads are not free, it will be necessary
to remove pads and clean recesses and recess corners
with a wooden spatula and then with denatured al-
cohol and a brush. After cleaning, blow out recesses
with compressed air. Remove any high spots on
edges of friction pads contacting caliper recesses with

DISC BRAKES58.17a tine cut file.Do not use any solvent except dena-
tured alcohol. Do not use a
metaIJic scraper too/.8. With a punch, drive one dowel pin from inboard
side through caliper and friction pads to stop. Install
new cross-shaped retaining spring under installed
dowel pin, then install second dowel pin. Loose tit-
ting dowel pins must be replaced.
9. Before operating vehicle, depress brake pedal sev-
eral times to adjust friction pads to brake discs.
Check brake fluid level and add fluid as necessary to
bring level up to “MAX” on reservoir.
Car owners must be informed that a break-in period
exists for new friction pads, and that they must avoid
unnecessary, forceful braking during the first 125
miles after installation of new friction pads.
Checking Brake Disc for Lateral Runout1. Remove front wheel assembly.
2. Remove front wheel bearing hub cap and spindle
nut cotter pin. Tighten spindle nut until all free play
is removed from wheel bearings.
3. To check disc runout, use Dial Indicator Set
J-
8001. Attach dial support C-clamp to an upper ball
joint attaching bolt as shown in Figure
5B-27. Posi-
tion dial indicator button against brake disc
l/2 inch
from outer circumference.
Figure 58-27 Checking Brake Disc Lateral
Runout4. Rotate disc, reading maximum dial indicator
movement. Maximum permissible runout is
,004
inch.5. If runout exceeds
0% inch, remove disc and hubassembly and true disc in a suitable disc turning
lathe, following manufacturer’s instructions. The
depth of cut on each side of disc should be just deep
enough to get a true flat surface.
6. After truing disc on both sides, check thickness
with a micrometer. A disc with a thickness of less
than ,394 inch is liable to warp after hard braking
and, therefore, must be discarded.
7. Reinstall brake disc and hub assembly, removing
all play from wheel bearings. Repeat runout check.
If runout still exceeds
,001 inch, replace brake disc.
8. Adjust front wheel bearings.
9. Reinstall front wheel assembly.
MAJOR REPAIR
REMOVING AND INSTALLING BRAKE CALIPER1. Remove left or right front wheel and remove fric-
tion pads from brake caliper.
2. Loosen brake line to brake caliper union nut sev-
eral turns. Unscrew brake caliper plus brake hose
bracket from steering knuckle. Remove it from brake
disc and swing it sideways. Then unscrew brake pipe
from brake hose and remove brake caliper and brake
pipe (bent pipe). To prevent brake fluid loss, close
brake hose with a plug.
3. Prior to installation,check contacting surfaces of
the brake caliper and steering knuckle to make sure
they are free of any burrs and dirt.
4. Install brake caliper on steering knuckle and
torque attaching bolts to 72
lb.ft. See Figure 5B-28.CAUTION: This disc brake
cah@er attachments fas-
tener is an important attaching part in that it could
affect the performance of vital components and sys-
tems, a,ld/or could result in major repair expense. It
must be replaced with one of the same part numberor with an equivafent part, if repfacement becomes
necessary. Do not use a replacement part of Jesser
quaJity ‘or substitute design. Torque vafues must be
used as specitied during reassembly to assure proper
retention of this part.
5. Attach brake pipe to brake hose.
6. Install friction pads and replace wheel.
REMOVING AND INSTALLING
BRAKE DISC
1. Jack-up and support front of car and remove front

DISC BRAKES5B- 19
CAUTION:
Fasteners in Steps 7 and 9 are important
attachingparts in that they cooId affect theperfom-
ante of vital components and systems, and/or couJd
resuJt in major repair expense. They must be re-
placed with one of the same part number or with an
equivaJent part if repJacement becomes necessary.
Do not use a replacement part
or Jesser quaJity or
substitute design. Torque
vaJues must be used as
specified during
reassembJy to assure proper reten-
tion of these parts.7. Install brake disc on wheel hub and torque attach-
ing bolts to 36
Ib.ft. If old brake disc is reused, pay
attention to locator marks on brake disc and wheel
hub.8. Prior to installing brake disc and hub assembly to
steering knuckle, check lubrication of both roller
bearings and quantity of grease in cavity of wheel
hub. If necessary, repack front wheel bearings.
9. Adjust front wheel bearing clearance and tighten
brake caliper to steering knuckle, attaching bolts to
a torque of 72
lb.ft. Prior to installing brake caliper
to steering knuckle, ensure that all contacting sur-
faces are free of dirt and burrs. Also make sure that
the friction pads are not damaged when sliding the
brake caliper onto brake disc.
10. Install wheel assembly, remove supports and
lower front of car.
REMOVING AND INSTALLING
BRAKE DISC SHIELD
Removal
1. Remove brake disc.
2. Remove disc shield from steering knuckle by
removing one Phillips head screw on the outside and
on the inside, the lower steering arm and disc shield
to steering knuckle bolt. Remove paper gaskets from
steering knuckle. See Figure
5B-32.Installation
1. Prior to placing new paper gasket between brake
disc shield and steering knuckle, lightly coat both
surfaces of paper gasket with chassis lubricant.
2. Install disc and tighten disc shield and steering
arm to steering knuckle bolt to a torque of 47
lb.ft.CAUTION:
This steen;Og arm and steering knuckJe to
backing plate
fisteneris an important attachingpart
in that it
couJd at&t the performance of viral com-
ponents and systems, and/or
couJd resuJt in major
repair expense. It must be replaced with one of theFigure 58-32 Brake Disc Shield Attached
to SteeringKnuckle
same part number or with an equivalent part, if re-
pJacement becomes necessary. Do not use a rep/ace-
merit part of Jesser quaJity or substitute design.
Torque values must be used as specitied during reas-
sembly to assure proper retention of this part.3. Replace one Phillips head screw on outside of disc.
See Figure
5B-32.DISASSEMBLY AND ASSEMBLY
OF BRAKE CALIPER
1. Remove brake pipe from brake caliper. If both
calipers have to be repaired, it is advisable to mark
them with “L” or “R” on removal to avoid errors
when installing parts, such as pistons, etc. The brake
caliper halves must not be disassembled during re-
pair work. All work, such as pressing out pistons,
replacing seals in brake caliper, is carried out with
the two caliper halves bolted together.
2. Pry clamp rings from rubber seals, using a screw-
driver (Figure
5B-26) and remove rubber seals.
3. Remove piston first from caliper rim half (Figure
5B-33), and then out of the caliper mounting half
(Figure
5B-34) of the brake caliper, using mounting
clamp J-22429. To be able to force the piston out of
the caliper rim half, block the piston in the caliper
mounting half with mounting clamp J-22429 as
shown in Figure
5B-33. To force the piston out of the
caliper mounting half, place the mounting clamp on
caliper rim half, as shown in Figure
5B-34, and
tighten wing nut so that the rubber plate seals off the
caliper rim half bore. Then connect compressed air
hose to brake line connection in the caliper mounting