Final Assembly - Chevrolet 1980 Light Duty Truck Repair Manual

INSTALLER
J-2 1 601
POWER
PISTON
F ig . 5 -1 1 C ~ ln s t a llin g F lo a t in g C o n t r o l V a lv e A s s e m b ly
17. This assembly can now be turned over and placed,
SUPPORT
PL A T E
PO W ER
PISTON
SUPPORT PL A T E
REM O VER AND
IN STA LLER J-21524
Fig. 5-1 2 C— I nsta 1 1 i n g S up po rt Plate on Power Piston
tube down, in a tool, fabricated from a piece of wood, 2"
x 4" x 8" long with a 1-3/8" hole in the center, clam ped
in a vise.
18. W ith Snap R ing Pliers J-4880, assem ble snap ring
into groove in air valve.
19. Place air valve spring retainer on snap ring.
A ssem ble reaction bumper into groove in end o f air valve.
20. Position air valve return spring, large end down,
on spring retainer.
21. The three reaction levers are now placed into
position with ears on wide end in slots in power piston. The
narrow ends w ill rest on top o f air valve return spring.
22. Position reaction plate (with numbered side up) on
top o f reaction levers. Press down on plate until large ends
o f reaction levers pop up so plate rests flat on levers. Be sure
reaction plate is centered.
23. M aster cylinder piston rod and reaction retainer
assembly is now assembled to the power piston.
24. W ith round end o f piston rod up, and with reaction
retainer held toward top o f piston rod, place small end o f
piston rod in hole in center o f reaction plate. Line up ears
on reaction retainer w ith notches in power piston and push
reaction retainer down until ears seat in notches.
25. M aintain pressure on reaction retainer and position
large lock ring dow n over master cylinder push rod.
26. There is a lug on the power piston which has a
raised divider in the center. One end o f lock ring goes under
lug and on one side o f divider.
27. A s you work your way around pow er piston (either
way), the lock ring goes over ear o f reaction retainer, under
a lug on power piston, and so forth, until other end o f lock
ring is seated under lug w ith raised divider.
Be sure both ends o f lock ring are securely under large
lug.
Rear Housing G roup Assem bly
1. Place a new power piston bearing in center o f rear
housing so flange on center hole o f housing fits into groove
o f power piston bearing. The large flange on power piston
bearing w ill be on stud side o f housing.
2. Coat inside o f power piston bearing w ith D elco
Power Brake Lube (or equivalent).

Final Assembly

1. Place air silencer over holes on tube o f power piston.
W ipe tube o f power piston with D elco Power Brake Lube
(or equivalent).
2. A ssem ble power piston to rear housing.
3. W ipe tube o f reaction retainer with D elco Power
Brake Lube (or equivalent) and lay assembly aside.
4. Place front housing in a vise. Place power piston
return spring over the insert in the front housing. Lubricate
the I.D . o f the support plate seal with power brake lube or
equivalent.
5. Lightly lubricate beaded edge o f the diaphragm with
Pow er Brake Lube (or equivalent). H old rear housing and
power piston assembly over front housing with master
cylinder push rod down. Position rear housing so that when
rotated into locked position, scribe marks on the housings
w ill be in line.
6. U sing H older J-22805-01 and W rench J-9504-01
lock housings together. Stake housing interlocks at 2 new
BRAKES 5-17
O V E R H A U L M A N U A L