Table of Contents
Advertisement
BRAKES
5-5 1
Fig.
5-85
Gaging Piston Rod
5. Remove seal from front housing, and if defective,
vacuum check valve.
Disassembly of Power Piston Assembly
CAUTION: Care must be used in handling the
diaphragm of power piston assembly. Guard
diaphragm against grease, oil foreign matter and
nicks or cuts.
1. Remove power piston assembly from rear housing.
2. Remove silencer from neck of power piston tube.
3. Remove lock ring from power piston by prying one
end out from under large divided locking lug and then
proceed to. pull ring from under other two locking lugs on
power piston. See Fig. 5-89.
4. Remove reaction retainer, piston, reaction plate, three
(3) reaction levers and air valve spring. Also remove reaction
bumper and air valve spring retainer from air valve. See Fig.
5-90.
5. Place power piston Wrench J 21524 with square shank
in vise. Hold support plate and power piston with tube of
power piston up. See Fig. 5-91.
6. Pull diaphragm edges away from support plate so
hands can grip steel support plate. Position assembly on
power piston Wrench J 21524 so three lugs on tool fit into
three notches in power piston. See Fig. 5-92.
7.
Press down
on
support
plate
and
rotate
counterclockwise until support plate separates from power
piston. See Fig. 5-93.
8. Remove diaphragm from support plate and lay both
parts aside.
9. Position 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 center, clamped in a vise. Do not clamp tube in vise.
10. Use No. 22 Truare Pliers or J 4880 to remove snap
ring on air valve. See Fig. 5-94.
11. Set up Power Ram and Hydraulic Pump with J 9746
Press Plat
.
Insert power piston, tube down, in press plate and
remove air valve assembly using a 3/8" drive extension as a
remover. See Fig. 5-95.
12. Removal of air valve push rod assembly disassembles
the following parts from power piston: floating control valve
assembly, floating valve retainer, push rod limiter washer and
air filter.
13. Remove floating control valve assembly from push
rod as it must be replaced by a new floating control valve
assembly at rebuild.
14. The master cylinder push rod can now be pushed
from center of reaction retainer. Remove
"0"
ring from
groove in master cylinder piston rod.
CLEANING AND INSPECTION OF
DELCO MORAINE POWER
BRAKE UNIT
Cleaning of Parts
1. Use Declene or denatured alcohol to clean thoroughly
all metal brake parts. Immerse in cleaning fluid and brush
with hair brush to remove foreign matter. Blow out all
passages, orifice and valve holes. Air dry and place cleaned
parts on clean paper or lint free clean cloth.
2. If slight rust is around inside either front or rear
housing assemblies, polish clean with crocus cloth or fine
emery paper, washing clean afterwards with specified
cleaning fluid.
CAUTION: If there is any suspicion of
contamination or any evidence of corrosion,
complete& flush hydraulic brake system. Failure
to clean hydraulic brake system can result in early
repetiton of trouble. Use o f gasoline, kerosene,
anti-freeze alcohol or any other cleaner with even
a trace of mineral oil will damage rubber parts.
Dirt is the major cause of trouble and wear in service.
Be sure to keep parts clean. Rewash at reassembly if there
is any occasion to doubt cleanliness--such as parts dropped
or left exposed for eight hours or longer.
Inspection and Replacement of Parts
1. Inspect all rubber parts. Wipe free of fluid and
carefully inspect each rubber part for cuts, nicks or other
damage. These parts are the key to control of fluid or air flow
and should account for the majority of troubles traceable to
leakage. Re-use rubber parts only if a fairly new unit is
dissassembled for some particular trouble and only then if
there is no doubt that the parts are in equal-to-new condition.
Badly damaged items or those which would take extensive
work or time to repair should be replaced. In case of doubt,
install new parts for safety and for ultimate lower cost.
2. Inspect in accordance with Inspection Table: (The
table is organized by power brake unit groups.)
Advertisement
Table of Contents
