Chevrolet 1977 10 Series, Repair Manual, Page: 177 / 468

BRAKES 5-11
Fig. 5-6 B --R e m oving Rear Seal
alcohol and guide air valve rod into valve plunger. Tap end
of operating valve rod with plastic ham m er to lock ball in
grommet. Press filters and silencers into hub and install
retainer on hub.
20. Assemble silencer in dust boot, wet dust boot
opening with denatured alcohol and assemble over operating
valve rod and over flange of rear housing.
21. Install
new
check valve and grommet.
22. Apply silicone lubricant to piston end of hydraulic
push rod and insert in cavity in front plate. Twist rod to
eliminate air bubbles at reaction disc. Assemble seal over
push rod and press into recess in front housing.
Piston Rod Gauging
1. Place the power head assembly in a padded vise (front
housing up);
Do not clamp tight.
2. Remove the front housing seal to assure th at no
vacuum is in the power head while gaging.
3. Insert the master cylinder piston rod, flat end first,
into the piston rod retainer.
Fig. 5-7B--Rear Bearing and Rear Shell
Fig. 5 -8 B —In s ta llin g Rear B e a rin g and V a cu u m Seal
4. Press down on the master cylinder piston rod (with
approximately a 40-50 pound load) to be sure it is properly
seated.
5. Place Gage J-22647 over the piston rod in a position
which will allow the gage to be slipped to the left or right
without contacting the studs (fig. 5-12B).
6. The center section of the gage has two levels. The
piston rod should always contact the longer section (lower
level) o f the gage. The piston rod sh o u ld n e v e rc o n ta ct the
shorter section (higher level) of the gage. Move gage from side
to side to check piston rod height.
7. Any variation beyond these two limits must be
compensated for by obtaining the service adjustable piston
rod and adjusting the self-locking screw to meet the gaging
specifications.
8. Wipe a thin film of silicone lubricant on the I.D. of
the front housing seal and position seal in the depression in
the housing.
Fig. 5-9B~Seal Protector J-2 2 7 3 3 Installed