Chevrolet 1977 Monte Carlo, Repair Manual

Page: 156 / 428

5-20 BRAKES
1 2 3 4 5 6
7 8 9 10 11 12 13 14
13 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. Front Housing
6. Diaphragm 14. Front Housing Seal
7.
A ir Valve Push Rod 15. Grommet
Assembly 16. Check Valve
F ig . 5 - 2 D - B e n d i x P o w e r B o o s t e r C o m p o n e n t s ( T y p i c a l)
7. T he edge o f the rear housing contains tw elve lances.
Four o f these lances (one in each quadrant) are deeper than
the other lances (fig. 5-3D ). T he m etal that form s the four
deep lances m ust be partially straightened so that the lances
w ill clear the cutouts in the front housing. If the m etal tabs
that form the deep lances crack or break during
straightening, the housing m ust be replaced.
8. Place Spanner W rench J-9504 over studs on rear
housing and attach with nuts and washers. D raw nuts down
tight to elim inate bending or dam aging o f studs (fig. 5-2A ).
9. Press down on Spanner W rench J-9504 and rotate
the rear housing clock w ise to separate the two housings. If
the rear housing cannot be readily loosened, tap the rear
housing lightly w ith plastic hammer.
10. R em ove T ool J-9504 from the rear housing.
NOTICE: Care must be exercised not to
d am age or loosen studs in th e rear
housing. Also, ta k e care th a t no pressure
is b rought to bear on plastic diaphragm
p late tension.
11. Lift the rear housing assem bly from the unit.
R ear Housing G roup
1. R em ove the air filter elem ent from location w ithin
the diaphragm plate extension.
NOTICE: To prevent chipping of 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 assem bly from the rear
h ousing and lay the rear housing aside.
3. D isassem ble diaphragm plate assem bly (fig. 5-2D ).
a. R em ove rolling diaphragm from the groove in the
diaphragm plate hub.
NOTICE: Care should be used in handling
the diaphragm of the diaphragm plate assembly.
The diaphragm should be protected from grease,
oil, foreign matter and from nicks, scratches
and gouges.
b. H old the diaphragm plate so that the push rod is in
its norm al (horizontal) installed position, depress the push
rod slightly (approxim ately 1 /1 6 inch), and rotate piston so
the air valve lock w ill fall from its location in the diaphragm
plate hub. R em ove the air valve-push rod assem bly from the
diaphragm plate. R em ove the reaction d isc 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
o f passages in the diaphragm plate. Perform Step 4 only if seal is
defective and a new seal is available. Do not reuse seal once it
has been removed from the unit.
4. Support outer surface o f rear housing on blocks o f
w ood or other suitable material (stud side up) and drive out
seal with a punch or a thin blade screwdriver. Discard seal.
Fig. 5-3D--Lances in Rear H ousing
O V E R H A U L M A N U A L