Buick LeSabre 1965 Service Manual page 540

9 - 1 8 RELINE
BRAKES
-SHOE RETURN SPRINGS
ACTUATOR
LINK
PIVOT
ACTUATOR
OVERRIDE
SPRING
HOLD D O W N
SPRINGS
& CLIPS
ACTUATOR
RETURN SPRING
ACTUATOR
the requirements existent in the
various Buick models.
a. Removal and Inspection
Figure 9-13-Rear Wheel
Brake Assembly
materials are used for their lub-
ricating qualities to guard them
against drum scoring while others
are used to control the friction
producing property of the lining,
called "coefficient of friction."
Good linings also have imbedded
particles of material used to con-
trol friction and wear. When
linings are ground, some of the
surface particles may be pulled
out, giving a pitted appearance.
These pits do not affect lining
efficiency.
The heat generated by friction
will produce different effects in
different compounds of bonding
material. Some compounds in-
crease friction with increased
temperature, which might cause
grabbing or locking. Other com-
pounds lose friction with in-
creased temperature, which might
cause materially lowered braking
power. Brake lining compounds
must be carefully selected to pro-
duce the braking friction required
at the temperatures normally at-
tained in each vehicle application.
Since the many factors which
govern the selection of brake lin-
ing vary widely in different vehi-
cle designs, it is impossible to
compound one lining which will
work satisfactorily on all cars.
GM engineered brake lining has
been selected after exhaustive
tests on all types of lining and
with complete consideration of all
NOTE: When paragr
ences in parentheses
aph
0
refer-
have an
asterisk (*) the operation referred
to is additional work not covered
by the s t a n d a r d replacement
operation.
1. Jack up car in a safe manner,
remove wheel and brake drum
(rear) or drum and hub assembly
(front). NOTE: Safety stops lo-
cated on the backing plates will
prevent pistons from leaving the
wheel cylinders; however, brake
pedal must not be operated while
a brake drum is removed since
damage to wheel cylinder rubber
boots will result.
NOTE: It may be necessary to
back off the brake shoe adjust-
ment before the brake drums can
be removed. To back off shoe
adjustment, rotate shoe adjusting
screw upward. See Figure 9-11.
2. Unhook the primary and sec-
ondary shoe return springs using
large pliers.
3. Remove shoe hold down
springs.
4. Lift up on actuator, unhook
actuating link from anchor pin,
then remove.
5. Spread shoes to clear wheel
cylinder connecting links, remove
parking brake strut and spring
(rear only), disconnect cable from
parking brake lever, remove
shoes from the backing plate.
6. Separate the brake shoes by
removing adjusting screw and
lock s p r i n g . Remove parking
brake lever from secondary brake
shoe (rear only). See Figure 9-13.
7. Clean all dirt out of brake
drum, using care to avoid getting
dirt into front wheel bearings.
Inspect drums and replace or re-
condition if required (*par. 9-12).
If front drum and hub is removed,
inspect wheel bearings and oil
s e a l and replace faulty parts
(•Group 7).
8. Blow all dirt from brake as-
semblies and inspect for any un-
usual condition.
9. Carefully pull lower edges of
wheel cylinder boots away from
cylinders and note whether in-
terior is wet with brake fluid.
Fluid at this point indicates leak-
age past piston cup, requiring
overhaul of wheel cylinder (*par.
9-13).
10. If working at rear wheels, in-
spect backing plate for oil leak
past wheel bearing oil seals. Cor-
rect any leak by installation of
new seals (*par. 6-6).
11. Check all backing plate at-
taching bolts to make sure they
are tight. Clean all rust and dirt
from shoe contact surfaces on
plate, using fine emery cloth.
b. Relining Brake Shoes
If old brake shoes are to be re-
lined, inspect shoes for distor-
tion 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 linings by drilling
out rivets. Punching rivets out
will distort shoe rim. Thoroughly
clean surface of shoe rim and file
off any burrs or high spots.
2. Use Buick brake lining or
equivalent. Rivets are included
in lining package which are of
correct size. The rivets must fit
the holes and the solid body of
rivet should extend through the
shoe rim, but no farther.
3. Keep hands clean while han-
dling brake lining. Do not permit