Chevrolet 1977 light duty truck Service Manual page 385

The following w arning and caution notes apply to one or more steps in
the assembly procedure o f components in this portion o f the m anual as
indicated at appropriate locations by the terminology "See W a r n in g /
Caution on page l o f this section".
Warning: When servicing wheel brake parts, do not create dust by
grinding or sanding brake linings or by cleaning wheel brake parts with
a dry brush or with compressed air. (A water dampened cloth should be
used.) Many wheel brake parts contain asbestos fibers which can
become airborne if dust is created during servicing. Breathing dust
containing asbestos fibers may cause serious bodily harm."
CAUTION:
P A R T IN
V IT A L C O M P O N E N T S A N D S Y S T E M S A N D / O R C O U L D R E S U L T
IN M A JO R R E P A IR E X P E N S E . I T M U S T B E R E P L A C E D W IT H
O N E O F T H E S A M E P A R T N U M B E R OR W IT H A N E Q U IV A L E N T
P A R T I F R E P L A C E M E N T B E C O M E S N E C E S S A R Y. D O N O T U S E A
R E P L A C E M E N T P A R T O F L E S S E R Q U A L IT Y O R S U B S T IT U T E
D E S IG N . T O R Q U E V A L U E S M U S T B E
D U R IN G R E A S S E M B L Y TO A S S U R E P R O P E R R E T E N T IO N O F
T H I S P A R T .
G eneral D e s c rip tio n ..............................................................
D ia g n o s is ................................................................................. ..S-2
On-Vehicle Service................................................................... ..
Pedal T r a v e l .........................................................................
Stop Light Sw itch..............................................................
Bleeding and Flushing B r a k e s ................................... ..5-]0
Brake P ipes...........................................................................5-10
Brake Hoses..........................................................................5 - 14
Bleeding Hydro-Boost Power Steering S ystem ..... ..5 - 15
Parking Brake Pedal or H a n d l e ................................ ..5 - 15
Parking Brake A d ju s tm e n t.............................................5-15
Parking Brake (Propshaft) Internal Expanding... 5-22
Parking Brake C a b le .........................................................5-22
C om bination V alue............................................................5-22
Brake P e d a l ....................................................................... ..5-23
Brake Pedal R o d .............................................................. ..5-24
M aster C ylinder................................................................ ..5-24
All vehicles are equipped with a dual hydraulic
brake system.
The split system consists basically o f two separate
brake systems. W hen a failure is encountered on either,
the other is adequate to stop the vehicle. If one system is
not functioning, it is normal for the brake pedal lash
and pedal effort to substantially increase. This occurs
because o f the design o f the master cylinder which
incorporates an actuating piston for each system. W hen
the rear system loses fluid, its piston will bottom against
SECTION 5
BRAKES
T H I S F A S T E N E R I S A N IM P O R T A N T A T T A C H IN G
T H A T I T C O U L D A F F E C T T H E P E R F O R M A N C E O F
C O N T E N T S
_]
5
_l
5 0
_l
5 0
5-10
Specifications...................................................................... 5-47
Special T o o ls...................................................................... 5-53
GENERAL DESCRIPTION
the front piston. W hen the front system loses fluid, its
piston will bottom on the end o f the master cylinder
body. The pressure differential in one o f the systems
causes an uneven hydraulic pressure balance between the
front and rear systems. The combination valve (near the
master
illuminates the brake alarm
instrument panel. The pressure loss is felt at the brake
pedal by an ap parent lack o f brakes for most of the
U S E D A S S P E C I F I E D
Delco Disc Brake Shoe and L in i n g ..................... 5-26
Bendix Disc Brake Shoe and L in in g ................... 5 -3 1
Caliper O verh au l...........................................................5-33
Rotor Servicing.............................................................. 5-36
Brake D rum Shoe and L in in g ................................ 5-37
Standard Drum B ra k e ............................................5-37
Propeller S haft B ra k e.............................................5-40
RPO H22 R ear D rum Brakes.............................5 -4 1
Brake D r u m s .................................................................. 5-43
Wheel C y lin d e r ............................................................. 5-44
Power Brake U n i t .........................................................5-44
Vacuum Booster........................................................ 5-44
Hydro-Boost U n i t ..................................................... 5-45
Brake System D escription..........................................5-47
Brake System Application..........................................5-48
Torque Specifications................................................. 5-52
cylinder) detects the loss o f pressure and
indicator light on the