Chevrolet 1977 10 Series, Repair Manual, Page: 187 / 468

BRAKES 5-21
1 2 3
4
5 6
7 8 9 10 11 12 13 14
15 16
1.
Rear Housing Mounting 8. A ir Valve Lock
Brackets 9.
Diaphragm Plate
2. Push Rod Boot
10. Reaction Disc
3. Foam and Felt A ir
11. Piston Rod
Filter-Silencers 12.
Diaphragm Return
4.
Rear Housing
Spring
5. Rear Housing Seal
13. F ront Housing
6.
Diaphragm
14. F ront Housing Seal
7. A ir Valve Push Rod
15. Grommet
Assembly
16. Check Valve
Fig. 5 -2 D --B e n d ix P ow er B o o s te r C o m p o n e n ts (T y p ic a l)
rear housing cannot be readily loosened, tap the rear housing
lightly with plastic hammer.
10. Remove Tool J-9504 from the rear housing.
CAUTION: Care m ust be exercised not to damage
or loosen studs in the rear housing. Also, take care
that no pressure is brought to bear on plastic
Fig. 5-3D--Lances in Rear Housing
diaphragm plate tension.
11. Lift the rear housing assembly from the unit.
Rear Housing Group
1. Remove the air filter element from location within the
diaphragm plate extension.
CAUTION: To prevent chipping o f the plastic
diaphragm plate, exercise extreme caution when
removing the air filter retainer. Use a small
screwdriver or other suitable tool, and pry at several
peripheral locations until the retainer is freed.
2. Separate the diaphragm plate assembly from the rear
housing and lay the rear housing aside.
3. Disassemble diaphragm plate assembly (fig. 5-2D).
a. Remove rolling diaphragm from the groove in the
diaphragm plate hub.
CAUTION: Care should be used in handling the
diaphragm o f the diaphragm plate assembly. The
diaphragm should be protected from grease, oil,
foreign m atter and from nicks, scratches and
gouges.
b. Hold the diaphragm plate so that the push rod is in
its norm al (horizontal) installed position, depress the push
rod slightly (approxim ately 1/16 inch), and rotate piston so
the air valve lock will fall from its location in the diaphragm
plate hub. Remove the air valve-push rod assembly from the
diaphragm plate. Remove the reaction disc from its location
in the diaphragm plate bore (insert the piston rod or other
suitable tool through diaphragm plate extension and push
disc from its seat). Exercise care so as not to chip surface of
passages in the diaphragm plate.
NOTE:
Perform Step 4 only if seal is defective and a new
seal is available. D o not reuse seal once it has been
removed from the unit.
4. Support outer surface of rear housing on blocks of
wood or other suitable m aterial (stud side up) and drive out
seal with a punch or a thin blade screwdriver. Discard seal.
Front Housing Group
1. Remove check valve from grom m et and then remove
grommet from front housing; discard valve and grommet.
2. Remove front housing and holding fixture from vise;
then remove holding fixture from front housing.
Cleaning
Use clean brake fluid to thoroughly clean all reusable
brake parts. Im m erse in the cleaning fluid and brush metal
parts with hair brush to remove foreign matter. Blow out all
passages, orifices and valve holes. A ir dry and place cleaned
parts on clean paper or lint free clean cloth. If slight rust is
found inside either the front or rear half housing assemblies,
polish clean with crocus cloth or fine emery paper, washing
clean afterwards. D irt is the m ajor cause of trouble and wear
in service. Be sure to keep parts clean until re-assembly. Re­
wash at re-assembly if there is any occasion to doubt
cleanliness-such as parts dropped or left exposed for eight
hours or longer.
CAUTION: I f there is any suspicion o f
contamination or any evidence o f corrosion,
completely flush the vehicle hydraulic brake
system. Failure to clean the hydraulic brake system
can result in early repetition o f trouble. Use o f
gasoline, kerosene, anti-freeze, alcohol or any other
cleaner, with even a trace o f mineral oil, will
damage rubber parts.