Master Cylinder; Valve; Disc Brakes Front; Drum Brakes Rear - Chevrolet CHEVY VAN G10 SERIES Service Manual

BRAKES 5-2
Fig. 1 —M aster C y lin d e r—T y p ic a l
travel and th en, when failed cham ber is b o tto m ed , the pedal
will harden.
If a vehicle displays these sym ptom s, it is a good indication
th at one o f the system s contains air or has failed, and it is
necessary to bleed or repair the brakes.
MASTER C Y LIN D E R
The m aster cylinder has tw o entirely separate reservoirs and
o utlets in a com m on body casting. The front reservoir and
o u tlet is connected to the front wheel brakes, and the rear
reservoir and outlet is connected to the rear wheel brakes. Two
pistons w ithin the m aster cylinder receive m echanical pressure
from the brake pedal push rod and transm it it through the
brake lines as hydraulic pressure to the wheel cylinders. The
filler cap is accessible from inside the engine com partm ent.
M O U N T IN G B R A C KET
BRAKE A N D C LU T C H
P ED A L BRA C KET
L O C K N U T
PU SH R O D
G A S K E T
Fig. 2 —Master Cylinder Mounting
V A LV E
All m odels have a com bination valve located below the
m aster cylinder. The front and rear hydraulic lines are routed
through this com bination " m etering" and " brake failure warn­
ing sw itch" to their appropriate wheel cylinders or caliper.
The m etering p o rtio n o f the com bination valve tends to
" hold o ff" front hydraulic pressure until the rear brake system
overcomes their pull back springs; th en pressure is allowed to
flow w ith the result being a good distribution o f braking
effort.
The brake failure warning sw itch portion o f the com bina­
tion valve " senses" a loss o f hydraulic pressure, if a failure
should occur, and illum inates a red light in the dash to warn
the operator of the failure.
DISC BRAKES FRO NT—(Fig. 4)
All m odels have disc brakes on the fro n t. The one piece
caliper m ounts on the steering knuckle/steering arm , which is
also a one piece casting, and astride the brake disc. The caliper
is the single piston design which is said to be a sliding caliper
sliding piston. No front brake adjustm ent is necessary once the
system is in operation and the pedal has been stroked to
" seat" the shoes to the caliper.
DRUM BRAKES REAR—(Fig. 5)
The rear brakes are duo servo w hich are self adjusting.
Brake adjustm ent takes place when the brakes are applied w ith
a firm pedal effort while the vehicle is backing up. Applying
the brakes moves the actu ato r w hich turns the star wheel and
lengthens the adjuster screw assembly. This action moves the
shoes outw ard until clearance betw een the lining and drum is
w ithin proper limits.
BRAKE PED A L
B U M P ER
STO P L A M P S W IT C H
STRIKER
C LEVIS
C H E V Y V A N SH O P M A N U A L