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BRAKES
5-57
8. Insert square channel tube in end of tool J 22805-01
and using a crescent wrench, turn front housing clockwise
until fully locked.
Final Assembly of Power Brake Unit All Except
X Car
1. Place air silencer over holes on tube of power piston.
Wipe tube of power piston with Power Brake Lube.
2. Assemble power piston to rear housing.
3. Wipe tube of reaction retainer with Power Brake Lube
and lay assembly aside.
4. Place front housing in a vise. Position power piston
return spring over inset in front housing. Lubricate the I.D.
of support plate seal with Power Brake Lube.
SUPPORT PLATE
5. Lightly lubricate beaded edge of diaphragm with
REMOVER AND
Power Brake Lube. Hold rear housing and power piston
NSTAUFR J-215%
assembly over front housing with master cylinder push rod
down. Position rear housing so that when rotated into locked
position, scribe marks on housings will be in line.
Fig. 5-97 Installing Power Piston into Support Plate
6. Using Holder J 22805-01 and Wrench J 9504-01 lock
24. With round end of piston rod up, and with reaction
retainer held toward top of piston rod, place small end of
piston rod in hole in center of reaction plate. Line up ears
on reaction retainer with notches in power piston and push
reaction retainer down until ears seat in notches.
25. Maintain pressure on reaction retainer and position
large lock ring down over master cylinder push rod.
26. There is a lug on the power piston which has a raised
divider in the center. One end of lock ring goes under lug and
on one side of divider.
27. As you work your way around power piston (either
way), the lock ring goes over ear of reaction retainer, under
a lug on power piston, and so forth, until other end of lock
ring is seated under lug with raised divider.
Be sure both ends of lock ring are securely under large
lug.
Assembly of Rear Housing Group
1. Place a new power piston bearing in center of rear
housing so flange on center hole of housing fits into groove
of power piston bearing. The large flange on power piston
bearing will be on stud side of housing.
2. Coat inside of power piston bearing with Power Brake
Lube.
Final Assembly of Power Brake Unit
-
X Car
1. Wipe power piston hub with power brake lube.
2. Push hub of power piston through rear housii~g seal.
3. Wipe O.D. of reaction retainer with power brake lube.
4. Place new front housing seal in center of front housing
so that flat surface of cup lies against bottom of depression
in housing.
5. Install new vacuum check valve grommet.
6. Attach Tool J 22805-01 to front housing. Lubricate
I.D. of support plate seal with power brake lube.
housings together. Do not break studs loose in rear housing
or put pressure on power piston tube when locking housings.
7. Push felt silencer over push rod to seat against end
of power piston tube. Snap ring retainer is now placed on push
rod so it can hold silencer against power piston tube. Plastic
boot is now pushed to seat against rear housing. Raised tabs
on side of boot will locate in holes in center of brackets. The
jam nut and clevis can now be reassembled to push rod.
GAGING OF DELCO MORAINE POWER
BRAKE UNIT
The following gaging operation is necessary only when
a major structural part such as front or rear housing, power
piston assembly, master cylinder piston or master cylinder
assembly is replaced with new part. The gauge measures how
far the master cylinder push rod projects from front housing.
This dimension must be correct to insure proper clearance
in master cylinder between primary cup and compensating
port.
Make check as follows:
1. Place gage over piston rod in a position which will
allow gage to be slipped to left or right without contacting
studs.
The center section of gage has two levels. The piston rod
end should always touch the longer section gage which
extends into front housing. The piston rod end should never
touch the shorter section of gage. See Fig. 5-98.
2. Any variation beyond these two limits must be
compensated for by obtaining the service adjustable piston
rod, and adjusting the screw in end to match height of gage.
7. Hold power piston return spring in position between
front housing and power piston, then start front housing into
final position with hands, making sure that scribe marks align
on front and rear shells.
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