Chevrolet 1980 Light Duty Truck Repair Manual page 158

5-22 BRAKES
Final Assembly
1. A ttach base o f H olding Fixture J-22805 to front
housing w ith nuts and washers and draw down tight to
elim inate bending or damage to studs. Clamp base in bench
vise w ith power section up (fig. 5-1 A).
NOTICE: Be sure to align tool so that the check
valve in the front housing is not damaged.
2. Place Spanner W rench J-9504 over studs on rear
housing and attach with nuts and washers. Draw nuts down
tight to elim inate bending or damaging o f studs.
3. Place diaphragm plate return spring in front housing
and position rear housing assembly on front housing (small
end o f spring downward). Position rear housing so that
when housings are locked, scribe marks on front and rear
housings w ill be in alignment.
4. Press down on Spanner W rench J-9504 and rotate
the rear housing counterclockw ise to assemble the two
housings.
NOTICE: Bend lances in on the rear housing.
If the tangs crack or break during this opera­
tion it will be necessary to replace that half of the
housing.
5. R em ove T ool J-9504 from the rear shell.
6. Install air silencers over push rod end and then
install push rod boot. Install boot retainer.
Clevis Type Push Rod
7.
rod clevis.
8. Install m ounting bracket to the rear shell, if so
equipped.
NOTICE: See "Notice" on Page 1 of this
section.
9. R em ove power cylinder from vise and remove
H olding Fixture J-22805.
10. A pply silicone lubricant sparingly to the piston rod,
keeping lubricant away from rounded end o f rod. G uide
piston rod into center bore o f the diaphragm plate until it
is fully seated against reaction disc.
11. Install front housing seal. Press seal into front
housing until seal is bottom ed in recess o f housing.
BENDIX H YDR A U LIC BRAKE BOOSTER (HYDRO-BOOST)
C A U T IO N : The accum ulato r
compressed gas. A lw a y s use proper tools
and fo llo w recom m ended procedures or
personal inju ry m ay result. Do not apply
h e a t to accum ulator. Do not a tte m p t to
repair an inoperative
O V E R H A U L M A N U A L
- Install locknut and push
UNIT REPAIR
contains
accum u lator.
Gaging
1. Place the power head assem bly in a padded vise
(front housing up). D o n o t cla m p tig h t .
2. R em ove the front housing seal to assure that no
vacuum is in the power head w hile gaging.
3. Insert the master cylinder piston rod, flat end first,
into the piston rod retainer.
4. Press down on the m aster cylinder piston rod (with
approxim ately a 40-50 pound load) to be sure it is properly
seated.
5. Place G age 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. 5-5D ).
6. The center section o f the gage has two levels. The
piston rod should always contact the longer section (lower
level) o f the gage. The piston rod should n ev er contact the
shorter section (higher level) o f the gage. M ove gage from
side to side to check piston rod height.
7. A ny variation beyond these tw o limits must be
com pensated for by obtaining the service adjustable piston
rod and adjusting the self-locking screw to meet the gaging
specifications.
8. W ipe a thin film o f silicone lubricant on the I.D . o f
the front housing seal and position seal in the depression in
the housing.
a lw a y s replace w ith a n ew accum u lator.
Dispose of an inop erative accu m u la to r by
drilling a 1 /1 6 " d ia m e te r hole th ro u g h the
end of th e accu m u lato r can opposite the
"O" ring.