Chevrolet 70 1969 Series, Руководство по ремонту

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BRAKES 5A -9
when overhauling master cylinders. Refer to ap­
plicable Parts Book for part number of repair kit.
In addition to replacement of parts contained in
repair kit, master cylinder should be inspected
and repaired, if necessary, as follows:
1. Examine cylinder bores. If scored or rust­
ed, recondition by honing. Be sure to use proper
size hone. (Refer to "Specifications" for nominal
diameter of cylinder bores.) Do not hone more than
necessary to remove scores and smooth up cylin­
der. Remove burrs caused by honing from around
by-pass and intake ports.
2. Check piston fit in cylinder bore. Clearance
between piston and cylinder wall should be within
0 .0 0 1 " to 0.005" when checked with feeler gauge.
Assembly (Fig. 7)
1. Before assembling, coat inside of cylinder
bores and dip all internal parts in hydraulic brake
fluid.
2. Install components in brake cylinder bore
of double barrel cylinders as follows:
a. Install check valve seat in cylinder bore,
then position check valve on seat.
b. Install return spring (shortest of the two)
in bore with large diameter end of spring over
check valve.
WHEEL
All models covered by this manual have type
" F " front brakes and type "FR- 3" rear brakes.
Except for size of cylinder bore and diameter of
internal parts all front wheel cylinders are the
same and all rear wheel cylinders are the same.
See figure 8 for cross-section illustration of both.
Since wheel cylinders can be disassembled and
repaired without removing them from the vehicle
the procedures are covered in this manual along
with "Replacement" procedures.
WHEEL CYLINDER REPLACEMENT
T Y P E " F "
Removal
1. Jack up axle and remove brake shoes as
directed under "Brake Shoe Removal."
2. Disconnect axle brake tube from inlet con­
nector at upper cylinder. Remove inlet connector
attaching connecting tube fitting to upper cylinder,
and remove bolt attaching connecting tube fitting
to lower cylinder. Remove connecting tube and
fittings assembly.
3. Remove one large and two small bolts at­
taching each cylinder to backing plate, then remove
cylinders from backing plate.
c. Install primary cup in cylinder bore with
lip of cup toward outlet end. Make sure end of re­
turn spring seats inside the cup.
d. Insert piston and secondary cup assembly
into cylinder bore, with open end of piston toward
open end of cylinder.
e. Press piston into cylinder bore, compress­
ing spring, and install snap ring in groove in bore.
Make sure snap ring is fully seated in groove.
N O T E : The procedure is the same for single
barrel cylinders except they do not have a check
valve.
3. Install components in clutch cylinder bore
as follows:
a. Install return spring (longest of the two)
in cylinder bore, large diameter end first.
b. Install primary cup in cylinder bore with
lip of cup toward outlet end. Make sure end of
spring seats ihside the cup.
c. Insert piston and secondary cup into cylin­
der bore, with open end of piston toward open end
of cylinder.
d. Press piston into cylinder bore, compress­
ing spring, and install snap ring in groove in bore.
Make sure snap ring is fully seated in groove.
4. Install cover on cylinder reservoir.
CYLINDERS
Installation
N O T E : The two wheel cylinders mounted on
each brake are identical; however, cylinders on
right- and left-hand brakes have opposite cylinder
castings. Clean mating surfaces of cylinders and
backing plate to insure proper alignment.
1. Place each cylinder on backing plate and
attach with one large and two small bolts and lock
washers.
2. Position wheel cylinder connecting tube
and fittings assembly and attach fitting to lower
opening in upper cylinder with inlet connector,
using new copper gasket on both sides of fitting.
Attach fitting to lower opening in lower cylinder
with special bolt, using new copper gasket on both
sides of fitting. Tighten inlet connector and special
bolt firmly.
3. Install bleeder valve in upper opening in
each cylinder.
4. Install brake shoes as directed under "Brake
Shoe Installation." Bleed brake system as directed
under "Bleeding Brakes."
T Y P E "FR- 3"
Removal
1. Jack up axle and remove brake shoes as
directed under "Brake Shoe Removal."
CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L