Chevrolet Light Duty Truck 1973 Service Manual page 272

5-6 BRAKES
COVER RETAINING BAIL
Fig. 7- Rear Line Failure
Front Line Failure (Fig. 8)
If there is a malfunction in the front brake line, both
pistons will move forward when the brakes are applied,
as under normal conditions. However, due to the front
line malfunction, there is nothing to resist piston travel
except the secondary piston spring. This permits the
primary piston to generate only negligible pressure until
the secondary piston bottoms in the cylinder bore. Then,
RUBBER DIAPHRAM RESERVOIR COVER
Fig. 6--Master Cylinder
sufficient hydraulic pressure will be generated to operate
the rear brakes.
It should be noted that if either the front or rear brakes
become inoperative, one brake system will remain
effective and permit the vehicle to be brought to a
controlled stop. Increased pedal travel will be evident as
well as increased pedal force since only a part of the
normally available braking surface will be used. Both of
these effects should be noticeable to the driver but, as an
u q l j q l
SECONDARY
PISTON
Jc
A fro n tA
V ^ ^ J
brakesv
Fig. 8 -Front Line Failure
:
f=£.
PRIMARY
PISTON
^vTT
H ®.
j
LIGHT DUTY TRUCK SERVICE MANUAL