Chevrolet 1963 Corvette, Руководство по ремонту и настройке, Страница: 288 / 346

268 BRAKES
to the pedal. This will apply hydraulic pres-
sure to the switch which will recenter it.
5. Repeat Step 4 for the front bleed screw.
6. Turn the ignition OFF and lower the
vehicle.
NOTE: If the warning lamp does not light
during Step 4, the switch is defective and
must be replaced.
Combination Valve
1978-82
The combination valve is mounted on the
frame and is connected to the hydraulic lines
from the master cylinder. The proportioning
section of the combination valve proportions
outlet pressure to the rear brakes after a pre-
determined rear input pressure has been
reached. This is done to prevent rear wheel
lock-up. The valve is designed to have a by-
pass feature which assures foil system pres-
sure to the rear brakes if the front brake sys-
tem fails and full system pressure to the front
brakes if the rear brake system fails.
The warning switch is designed to con-
stantly compare front and rear brake pres-
sure from the master cylinder and turn on the
light on the dash in case of front or rear sys-
tem failure. The warning light switch portion
of the combination valve is not serviceable. If
the switch is found defective the combination
valve must be replaced.
REMOVAL AND INSTALLATION
1. Disconnect the hydraulic lines at the
combination valve. Plug the lines to prevent
loss of fluid and to protect the system from
dirt.
2. Disconnect the valve switch wire ter
minal and remove the combination valve.
3. To install reverse the above and bleed
the brake system.
TESTING
1. Raise the vehicle on a hoist.
2. Attach a bleeder hose to a rear brake
bleed screw and immerse the other end of
the hose in a container partially filled with
clean brake fluid. Make sure the master cyl
inder reservoirs are filled.
3. Turn the ignition switch to "On" and
open the bleeder screw while a helper ap
plies moderate pressure to the brake pedal.
The warning lamp should light. Before the
helper releases the brake pedal close the
bleeder screw. Press down on the brake pedal
and the light should go out.
4. Attach the bleeder hose to the front
brake bleeder and repeat Step 3. Turn the
ignition switch off.
5. If the warning lamp does not light dur
ing Steps 3 and 4 but does light when a
jumper is connected to ground, the warning
light switch portion of the combination valve
is defective and the combination valve must
be replaced.
Brake Bleeding
The hydraulic brake system must be bled any
time one of the lines is disconnected or air
enters the system. This may be done man-
ually or by the pressure method. Correct
bleeding sequence is: left rear wheel cylin-
der, right rear, right front, left front.
The manufacturer recommends that the
entire hydraulic system be thoroughly flushed
with clean brake fluid whenever new parts
are installed in the hydraulic system. Flush-
ing is also recommended if there is any doubt
as to the grade of fluid in the system. If fluid
has been used which contains the slightest
trace of mineral oil, all rubber parts that have
been subjected to the contaminated fluid
should be replaced. When bleeding the rear
brake system, the front of the car should be
raised higher than the rear. This will position
the bleeder valve near the 12 o'clock position
and prevent air from being trapped in the
caliper.
Combination valve mounted below master cylinder