Chevrolet 10 Series 1968, Руководство по обслуживанию

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BRAKES 5-21
d. Insert a straight wire (tag wire, or any wire of
approx. .020 dia.) through the small compensating
port into the housing bore (fig. 35).
e. While moving the wire back and forth in the com­
pensating port, push the piston inward very gently
until a slight drag on the wire is felt.
f . Check clearance between the end of the piston and
the snap ring. This clearance should be .022
minimum. If the clearance is less than .022, the
primary cup should be replaced.
A ssem bly (Fig. 33)
Dual Cylinder
Brake Cylinder Side
NOTE:
Moisten all parts except snap ring with
brake fluid as assembly progresses.
1. Carefully position check valve seat at outlet end of
cylinder bore.
2. Insert check valve; then the piston return spring with
primary cup expander toward open end of cylinder.
3. Install primary cup, skirt first. Take care that skirt
is not rolled back or torn during installation.
4. Insert piston with secondary cup toward open end of
cylinder. Same care to be observed on secondary cup
as on primary.
5. Install piston stop snap ring.
Clutch Cylinder Side
Replace same as brake cylinder except for replacement
of check valve and check valve seat.
Single Cylinder
NOTE:
Moisten all parts except snap ring with
brake fluid as assembly progresses.
1. Install valve seat, valve, spring, and primary cup in
cylinder bore.
2. Install piston and secondary cup; secure with lock
ring.
Installation
Dual Cylinder (except Tilt Cab) (Fig. 1)
1. Reverse above applicable removal procedures.
2. F ill main cylinder reservoir end bleed brakes as
outlined in this section.
3. Check operation of brakes and clutch.
4. Install cover on main cylinder.
Tilt Cab (Fig. 1)
1. Align pedal push rods, position cylinder against
mounting flange and bolt in place.
2. Slide end of rubber dust boots over cylinder tubes
and connect fluid lines.
3. Tilt cab down.
4. F ill cylinder and bleed brakes and clutch systems as
noted in above installation (except tilt cab).
5. Install cover on main cylinder.
6. Adjust linkage if necessary.
Single Cylinder (Fig. 1)
1. Install boot in position and install main cylinder to
firewall with bolts, washers and nuts.
2. Connect hydraulic lines at dash, toe pan, and
cylinder.
3. Connect brake pedal return spring.
F ig . 3 5 —M ain C y lin d e r—Cross Section
4. F ill main cylinder reservoir and bleed brakes as
outlined in this section.
5. Install cover on main cylinder.
BRAKE COM PONENTS-SELF ADJUSTING
FRONT AND REAR BRAKES
Brake shoe adjustment takes place when brakes are
applied with a firm pedal effort while vehicle is backing
up. Apply the brakes moves an actuator which turns
the star wheel and lengthens the adjusting screw assem­
bly (fig. 36). This action adjusts the shoes until clearance
between the lining and drum is within proper limits.
Should low pedal heights be encountered, it is rec­
ommended that numerous forward and reverse stops be
performed with a firm pedal effort until a satisfactory
brake pedal height results.
NOTE:
Frequent usage of an automatic trans­
mission forward range to halt reverse vehicle
motion may prevent the automatic adjusters
from functioning, thereby inducing low pedal
heights.
Retracting Self Adjusters
A lanced “ knock out” area is provided in the web of
the brake drum on all models except the P20, P30 and 50
F ig . 36—S e lf Adjusting Brake
OVERRIDE
SPR IN G
PRIMARY
SH O E
PAWL
STAR W HEEL
WIRE LINK
OVERRIDE
LEVER
CHEVROLET TRUCK SERVICE MANUAL